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Professor Graham Pyke


I was an undergraduate at Sydney University where I majored in mathematics and mathematical statistics, but minored in biology. I commenced a PhD in Mathematical Statistics before leaving in 1970 to pursue a PhD in the USA..

While in the USA, I completed my PhD in Mathematical Biology in 1974 and then took a position as an Assistant Professor in Biology at the University of Utah. After three years in that position, I returned to Australia as a Queen Elizabeth II Fellow, based at the University of Sydney. I have remained based in Australia ever since.

In 1980, after finishing my three-year term as a QEII Fellow, I took up a research position at the Australian Museum where I have continued to work up until the present. While based at the Museum, I progressed as a research scientist, ending up as a Principal Research Scientist. I officially retired from this position in 2007, but have continued there as a Senior Fellow, maintaining my research program.

In 2012 I took up a position at UTS as a Distinguished Professor in the School of the Environment. My roles in this position will include continuing my research program, lecturing in various courses (e.g., ecology, animal behaviour, environmental management), giving public lectures, mentoring researchers at various stages in their careers in terms of how to be successful (especially regarding citations), supervising student research projects (Honours, Masters, PhD), and helping to promote UTS as an institution.

Together with Professor Paul Ehrlich I am a founder of Sustainability Central which seeks to provides a place to share ideas and develop future champions in Sustainability. The focus of SC is to achieve cross-disciplinary sustainability across the four pillars: Health; Economic; Environmental; and Social.

Citation Success seminar: Professor Graham Pyke explains the importance of being cited, and shares his ‘secrets’ to achieving citation success.


My most significant professional achievements have been in terms of my scientific publications. I have so far published over 100 scientific articles, which have covered a wide range of topics and have included a broad range of organisms. A number of my publications have been highly cited. Since 2004 I have been recognised as a Highly Cited Author in the Ecology/ Environment category, putting me in the top 0.5% of researchers in this area in terms of citations.

In addition, I have been and continue to be involved in many professional societies and advisory groups.

Associate of the Faculty, School of Life Sciences
B Sc (Hons 1st Class), Ph D
+61 2 9514 9203

Research Interests

SResearch Background

My principal research goal has been, and continues to be: understand ecological, behavioural and evolutionary processes, and thereby inform environmental appreciation and stewardship. In terms of ecological research, I have sought to determine the factors that control the distribution and abundance of various kinds of animal, including honeyeaters (group of Australian nectar-feeding birds) and frogs, and how these factors operate. When particular species are considered at significant risk of extinction, this research can lead to recommended plans of management and/or recovery for these species. I have also sought to determine the impacts of environmental pollution on frogs, and hence the extent to which they are the excellent environmental bio-indicators they are often touted to be, and to determine the impacts of the introduced honeybee on Australia’s native flora and fauna, hence making recommendations regarding its management and/or control. My research has included the effects of fire and climate change on ecological systems.

My behavioural research has focused on attempts to use evolution-based theories to explain certain kinds of animal behaviour, especially foraging behaviour, but also including social behaviour (e.g., flocking or schooling) and anti-social behaviour (e.g., territoriality or dominance). Such understanding of behaviour is important because these behaviours contribute to the wellbeing of individuals, and hence their reproductive contributions to subsequent generations, which in turn affects population dynamics for individual species, interactions between species, and the structure of multi-species communities.

I have used evolution-based theory to explain animal traits such as body size and speed of movement, and to explain how plants and their animal pollinators have co-evolved. The size of an animal (including its dimensions and mass) and its speed (or velocity) are, from both biology and physics perspectives, two fundamental attributes. As the vast majority of flowering plants are animal pollinated, including most of the crop plants that support humanity, further understanding of pollination systems should be of great benefit.

As I have been involved in the above research, two additional areas have caught my attention: the scientific process, in terms both of pursuing excellence and defending it, and the scientists who practise it; and promoting sustainability of humanity, because we, our kids, grandkids and so on depend on it. Of course, given the level of attacks over the years against “sustainability science”, these two areas overlap significantly.

For an additional perspective on my evolving research interests, my list of publications may be helpful. These can be found under the Publications tab.

Current Research Interests & Potential Projects

    I am interested in supervising student projects (Honours, Masters, PhD) re any of these research interests. I would especially like to encourage students who wish to combine different disciplines, including biology, mathematics, chemistry, economics and engineering.

Within these areas, there is scope for collaborative projects at various levels, so long as they accord with my principal goal and the pursuit of excellence. With discussion, collaborative projects could be developed for undergrad, honours, postgrad, postdoc, or any kind of colleague. I have always, sometimes explicitly but always implicitly, attempted to pursue scientific excellence. I expect to maintain this commitment in future, and hope that those I collaborate with will be similarly inclined.

Below I shall discuss each of the above five areas in some detail.

  1. Optimal Foraging Theory (OFT) & Plant-Pollinator Co-evolution (PPC)

OFT attempts to understand foraging behaviour by organisms on the basis that observed foraging behaviour maximises some currency of biological fitness associated with foraging. PPC attempts to understand observed relationships, such as the so-called ‘pollination syndromes’, between plants and their pollinators. I propose to combine them because PPC is not possible without understanding how pollinators respond to variation floral traits as they forage for floral resources, and such understanding should come from OFT applied to the pollinators. Of course, there will also need to be a corresponding Optimal Plant Theory.

Working in this area ideally requires confidence and skills in terms of mathematics, statistics and computer simulation on the one hand, and biological observation, through both lab and field work, on the other. Developing theory requires the former; determining biological patterns and testing the theory requires the latter.

Some current potential projects within this area are as follows:

  1. Determining optimal rules for movement by foraging organisms, and comparing their predictions with observed patterns of movement;
  2. Developing and testing models of optimal morphology and speed of movement for foraging organisms;
  3. Quantitative empirical evaluation of plant-pollinator syndromes, such as the correlation between nectar production rate per flower and pollinator body-size;
  4. Development and testing of models that incorporate both OFT and OPT

  1. Frog Ecology

The general aim here is to develop an understanding of what factors affect population dynamics of frogs and how these factors operate, within the contexts of climate change, conservation, and environmental management. Since 1998 I have been carrying out a program of research on two frog species, the endangered Green and Golden Bell Frog and the widespread and common Striped Marsh Frog, with a view to facilitating conservation of the former species, understanding differences between the two species, understanding the ways in which climatic variables affect them, and hence understanding and predicting possible effects of climate change. I have also been involved in projects attempting to evaluate the extent to which frogs may be considered bio-indicators of environmental quality and change, including climate change.

Some current potential projects within this area are as follows:

  1. Frogs as bio-indicators of environmental quality around Sydney;
  2. Effects of climate change on urban frogs;
  3. Mining Museum frog collections for information concerning possible effects of environmental stressors;

    C:  Bird Ecology

My interest in bird ecology arises from a lifetime love of birds and previous studies, spanning over a decade but now 25 or more years ago, that I carried out in relation to the population biology of honeyeaters (major group of Australian nectar-feeding birds).

Some current potential projects within this area are as follows:

  1. Evaluating effects on birds of long-term factors, including habitat alteration, fire history and climate change, through repeating bird surveys that I carried out in about the early 1980s and relating any apparent changes to these factors;
  2. Comparing birds, frogs and other organisms as environmental bio-indicators;
  3. Understanding the ecology and evolution of honeyeaters through a bio-geographical investigation of their foraging behaviour, morphological traits, patterns of species co-existence, etc
  4. Mining existing data, collected over about 20 years, in relation to the Eungella Honeyeater, to assess its ecology and behaviour;

  1. Sustainability for Humanity

Like you, and many other kindred spirits, I have a great concern for humanity’s sustainability and would like to make a positive contribution in this regard. So I have teamed up with a number of people including Prof Paul Ehrlich (world-renowned environmental scientist, based at Stanford University), with a view to promoting future sustainability through the encouraging and facilitating the following:

  • Development of future Leaders in the area of Sustainability through appropriate training and mentoring
  • Improving the quality of significant decisions affecting Sustainability through appropriate training to those charged with such decisions
  • Development of messages (mostly written, but possibly in other formats) aimed at activating the masses (assumed intelligent, but largely uniformed and/or misinformed) to actively promote sustainability
  • Development of ways to get these messages delivered to and taken on board by the targeted masses (e.g., through websites, social media etc)

Some current potential projects within this area are as follows:

  1. Reviews of sustainability issues resulting in messages suitable to delivery to the targeted masses;
  2. Studies/ reviews of various message-delivery systems, and their effectiveness;
  3. Studies/ reviews of what drives public opinion and political action in relation to sustainability issues;

  1. Cross-disciplinary Studies

It is obvious, I think, that much of what I describe above would be best, or necessarily, carried out as cross-disciplinary endeavours. Optimal Foraging Theory and related issues would benefit through an obvious combination of biology and mathematics, and a possible combination of physics and biology given the possibility that organisms and inert particles might move in accordance with similar rules. Understanding frogs as bio-indicators warrants a joint biology and chemistry approach. Human health and environmental health are inter-related and so these two areas should come together. Sustainability for humanity has four pillars: environment, economics, social, health, and achieving sustainability rests fundamentally on communication. Hence these four areas, plus communication, must be combined in considering sustainability.

I am therefore interested in encouraging any such cross-disciplinary study program. Potential examples that spring to mind are as follows:

  1. What do foraging organisms and Bayesian statisticians have in common, and how well do they cope with needing to estimate conditions? (biology/ mathematical statistics)
  2. What is the contribution of particle physics to the understanding of organismal movement and resulting patterns of distribution and spread? (biology/ physics)
  3. To what extent does fractal analysis help us to understand behaviour and distribution of organisms? (biology/ physics/ mathematics)
  4. How are environmental and human health connected, and how will understanding this connection help us to progress sustainability? (environment/ human health)
  5. How can communication work with the four pillars of sustainability to achieve progress? (communication/ everything else)
Can supervise: Yes

My teaching at UTS will consist of course lectures, workshops re citation success and research supervision.


Pyke, G.H. 1986, The relationships between abundances of honeyeaters and their food resources in open forest areas near Sydney..
Honeyeater density (or honeyeater energy requirement) was positively correlated, both seasonally and spatially, with the rate of production of nectar energy per unit area, but these correlations were weak. -from Author

Journal articles

Pyke, G.H. & Szabo, J.K. 2017, 'Conservation and the four Rs, which are rescue, rehabilitation, release, and research.', Conserv Biol.
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Vertebrate animals can be injured or threatened with injury through human activities, thus warranting their 'rescue'. Details of wildlife Rescue, Rehabilitation, Release, and associated Research (our 4 R's) are often recorded in large databases, resulting in a wealth of information. This information has huge research potential and can contribute to our understanding of animal biology, anthropogenic impacts on wildlife, and species conservation. However, such databases have been little used, few studies have evaluated factors influencing success of rehabilitation and/or release, recommended actions to conserve threatened species have rarely arisen, and direct benefits for species conservation are yet to be demonstrated. We therefore recommend additional research based on rescue, rehabilitation and release of animals, broader in scope than previously carried out, which would also maintain support from the general human community. This article is protected by copyright. All rights reserved.
Pyke, G.H. 2016, 'Floral Nectar: Pollinator Attraction or Manipulation?', TRENDS IN ECOLOGY & EVOLUTION, vol. 31, no. 5, pp. 339-341.
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Pyke, G.H., Thomson, J.D., Inouye, D.W. & Miller, T.J. 2016, 'Effects of climate change on phenologies and distributions of bumble bees and the plants they visit', ECOSPHERE, vol. 7, no. 3.
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Pyke, G.H. 2016, 'Plant-pollinator co-evolution: It's time to reconnect with Optimal Foraging Theory and Evolutionarily Stable Strategies', Prespectives in Plant Ecology Evolution and Systematics, vol. 19, pp. 70-76.
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Pollination syndromes (correlations between floral and pollinator traits), have long interested ecologists, but remain inadequately explained. For example, plant species pollinated by relatively large animals cannot have evolved correspondingly high rates of nectar-energy production simply because such animals need relatively more energy; evolution does not work that way. The inverse correlation between pollinator body-size and nectar concentration is similarly difficult to explain. To remedy this, I propose that Optimal Foraging Theory (OFT) and the Evolutionarily Stable Strategy approach (ESS) be combined and applied to pollination syndromes. Both hypothesise that, through evolution, average biological fitness of individuals has been maximised. OFT predicts foraging consequences for pollinators varying in body size, and other attributes, allowing the ESS approach to be applied to co-adapted plant–pollinator traits. This should lead to predicted relationships between plants and their pollinators. The steps involved in this process are conceptually straightforward, but empirically difficult, which may explain why the approach has been very little pursued in the past. However such difficulties can be overcome, thus pointing to the future. We surely need to understand pollination systems, in order to conserve and manage them. It is therefore time to reconnect OFT and plant–pollinator co-evolution, within the general ESS approach, and hence increasing our understanding of pollination syndromes and other plant–pollinator relationships
Pyke, G.H. 2015, 'Understanding movements of organisms: it's time to abandon the Levy foraging hypothesis', Methods in Ecology and Evolution, vol. 6, no. 1, pp. 1-16.
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Pyke, G.H. 2015, 'On the Confusion of Quality with Impact: A Note on Pyke's M-Index Reply', BIOSCIENCE, vol. 65, no. 2, pp. 117-118.
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White, A.W. & Pyke, G.H. 2015, 'Vegetation mounds as over-winter habitat for Green and Golden Bell frogs Litoria aurea', Australian Zoologist, vol. 37, no. 4, pp. 510-516.
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Long-term refugia or "over-winter" habitats are often overlooked in habitat restoration for the endangered Green and Golden Bell frog Litoria aurea. Studies identifying the occupation of this habitat or materials suitable to re-create it are lacking. Vegetation mounds were trialled and monitored for 26 months to determine if they could provide shelter conditions for Green and Golden Bell frogs. Covered and uncovered mounds were monitored at two sites (Arncliffe and Woonona) and both types of mounds were utilised by Bell frogs. Most frogs using the mounds for shelter remained active while inside the mounds, a few became torpid while in the mounds. The use of the mounds was influenced by ambient weather conditions. Vegetation mounds have a management advantage over other types of over-winter habitat in that they are portable, cheap and easy to maintain and easy to monitor. In addition, they provide a thermal and humidity gradient and allow frogs to move within the mound to select the preferred microhabitat conditions. As mounds temperatures are above ambient temperatures during winter, they may also assist in reducing the susceptibility of over-wintering frogs to chytrid infection. More detailed studies are needed to determine the optimal size, composition and best management use of the mounds.
Pyke, G.H. 2014, 'Achieving Research Excellence and Citation Success: What's the Point and How Do You Do It?', BIOSCIENCE, vol. 64, no. 2, pp. 90-91.
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Pyke, G.H. 2014, 'Evaluating the Quality of Taxonomic Publications: A Simple Alternative to Citations and Effort', BIOSCIENCE, vol. 64, no. 11, pp. 961-962.
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Pyke, G.H. & Ehrlich, P.R. 2014, 'Conservation and the holy grail: The story of the night parrot', Pacific Conservation Biology, vol. 20, no. 2, pp. 221-226.
The Night Parrot Pezoporus occidentalis, known from just two specimens and with no confirmed sightings for just over 100 years, and having declined from being one of the most widespread of Australian birds, has surely been amongst the most enigmatic birds of the world and deservedly the 'holy grail' for many birders. Amazingly, a population of this species has recently been re-discovered by John Young and the 'quest' is over, but swift action is now required lest the 'grail' slip from our grasp. Steps must be taken to protect and manage the newly-located population, and to better understand the biology of the species and the reasons for its widespread decline. Much of this decline occurred before the end of the 19th century and must therefore have resulted from broad factors associated with earlier landscape changes, such as cat predation and altered fire regimes. Searches for additional Night Parrot populations also seem warranted. Progress toward these goals would benefit from acceptance of the reasonable accumulation of 'unconfirmed' observations of the species and further utilizing the large numbers of 'amateur' birders who would doubtless be keen to be involved. We suggest that the Night Parrot should now be viewed as an 'icon' for conservation, possibly even an indicator' for how successful we are in terms of conservation in general. With his discovery of the Night Parrot, John Young has thus made a significant contribution to conservation, opening a new realm of necessities and possibilities.
Pyke, G.H. 2013, 'Struggling scientists: please cite our papers!', Current Science, vol. 105, no. 8, pp. 1061-1066.
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We scientists, whether struggling or not, need colleagues to cite our papers, and increasingly so; we also need to carry out worthwhile research. I present a strategy that simultaneously enhances citations and research quality, but is simple and straight
Pyke, G.H., Ahyong, S.T., Fuessel, A. & Callaghan, S. 2013, 'Marine crabs eating freshwater frogs: Why are such observations so rare?', Herpetology Notes, vol. 6, no. 1, pp. 195-199.
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We present the first records of predation by a marine crab (Leptograpsus variegatus) on a freshwater frog (Litoria aurea), and consider why such observations are so rare. We have studied two frog species on an island where breeding occurs in ponds near the ocean, and often observed marine crabs at these ponds. Given the broad diet and speed of these crabs, they would be expected to prey on various life-stages of these frogs. However, despite spending much time, both during the day and at night, surveying tadpoles and frogs, we have observed crabs attempting to prey on tadpoles on only a few occasions and on an adult frog just once. Possible reasons for the rarity of these observations include the crabs finding the tadpoles and frogs distasteful and hence avoiding them, and the rapidity with which crabs can capture and consume prey or move out-of-sight immediately after prey capture.
Walshe, D.P., Garner, P., Adeel, A.A., Pyke, G.H. & Burkot, T. 2013, 'Larvivorous fish for preventing malaria transmission', The Cochrane Database of Systematic Reviews, vol. 12, no. 1, pp. 1-65.
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Adult anopheline mosquitoes transmit Plasmodium parasites that cause malaria. Some fish species eat mosquito larvae and pupae. In disease control policy documents, the World Health Organization includes biological control of malaria vectors by stocking ponds, rivers, and water collections near where people live with larvivorous fish to reduce Plasmodium parasite transmission. The Global Fund finances larvivorous fish programmes in some countries, and, with increasing efforts in eradication of malaria, policy makers may return to this option. We therefore assessed the evidence base for larvivorous fish programmes in malaria control.
Pyke, G.H., Inouye, D.W. & Thomson, J.D. 2012, 'Local geographic distributions of bumble bees near Crested Butte, Colorado: Competition and community structure revisited', Environmental Entomology, vol. 41, no. 6, pp. 1332-1349.
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Surveys in 1974 of bumble bee species distributions along elevational gradients (Pyke 1982) were revisited to reevaluate the original conclusion that coexistence of bumble bee species can be ascribed to niche differentiation, primarily on the basis of pr
Pyke, G.H., Inouye, D.W. & Thomson, J.D. 2011, 'Activity And Abundance Of Bumble Bees Near Crested Butte, Colorado: Diel, Seasonal, And Elevation Effects', Ecological Entomology, vol. 36, no. 4, pp. 511-521.
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1. We revisited bumble bee survey data collected by Pyke in 1974 (Pyke, Ecology, 63, 555-573, 1982) to evaluate seasonal changes in abundances of bumble bees and their floral resources, diel patterns of bumble bee activity, and elevation effects on plant
Pyke, G.H. 2011, 'World War II and the rise of the plague minnow Gambusia holbrooki (Girard, 1859) in Australia', Australian Zoologist, vol. 35, no. 4, pp. 1024-1032.
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The Plague Minnow Gambusia holbrooki (Girard, 1859) was first introduced into Australian waters in 1925. Early introductions were carried out in Sydney, Melbourne, Brisbane, and later Perth, by government agencies in an attempt to reduce the incidence of mosquitoes in the capital cities. G. holbrooki flourished, but no reports were made of any apparent ecological problems arising from its introduction. World War Il and the advent of the war in the Pacific resulted in heavy Allied troop movements between mainland Australia, New Guinea and the Pacific Islands. Malaria began to take a heavy toll, so the US Army instigated a means of mosquito control through the captive-breeding and introduction of the Western Gambusia G. affinis (Baird and Girard, 1853) throughout the south-west Pacific region. The Australian Army initiated a similar campaign using the already-available G. holbrooki to establish gambusia in creeks and wetlands near military bases and hospitals in eastern Australia.The Australian Army Malaria Unit was deployed to develop gambusia breeding ponds and to disperse the fish to suitable sites. Other methods of mosquito control were also employed. By the end of WW Il G. holbrooki was widely established throughout many parts of eastern Australia, but the program of captive breeding and release remained in place for several more years as many malaria-affected personnel were now resident in Australia. In the early 1960s the first reports of adverse environmental impacts of gambusia on native fish populations appeared, and these were quickly followed by reports of impacts on other organisms, such as frogs.
Pyke, G.H. & Ehrlich, P. 2010, 'Biological Collections And Ecological/Environmental Research: A Review, Some Observations And A Look To The Future', Biological Reviews, vol. 85, no. 2, pp. 247-266.
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The work remaining in systematics has been expanding as the estimated total number of species of organisms on Earth has risen over recent decades, as have estimated numbers of undescribed species. Despite this increasing task, support for taxonomic and s
Pyke, G.H., White, A.W., Shoulder, J. & Ching, P. 2010, 'Using museum frog collections to assign sex and age categories to frogs in field studies: A case study with the striped marsh frog, limnodynastes peronii', Herpetological Review, vol. 41, no. 3, pp. 281-285.
Burkot, T., Abdel-Hameed Adeel, A.A., Pyke, G.H., Beach, R., Wirtz, R.A. & Garner, P. 2009, 'Larvivorous fish for malaria prevention', Cochrane Database of Systematic Reviews, no. 4.
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Pyke, G.H. 2008, 'Plague Minnow or Mosquito Fish? A Review of the Biology and Impacts of Introduced Gambusia Species', ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS, vol. 39, pp. 171-191.
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White, A.W. & Pyke, G.H. 2008, 'Frogs on the hop: Translocations of Green and Golden Bell Frogs Litoria aurea in Greater Sydney', Australian Zoologist, vol. 34, no. 3, pp. 249-260.
Translocations involving the endangered Green and Golden Bell Frog Litoria aurea have been under way in the Greater Sydney area since 1993. Case studies for four of these translocations are presented; the translocation sites being at Botany, Marrickville, Long Reef and Arncliffe. Bell frogs have persisted at only one of these sites since their introduction (Arncliffe). The success or failure of each translocation has provided insights into the habitat requirements and management of bell frogs. In unsuccessful translocations, the reasons for the inability to establish a permanent population became more apparent with monitoring; at Botany, young bell frogs failed to survive the winter because of inadequate or inappropriate over-winter habitat being available; at Long Reef, foraging and breeding habitat were inadequate; at Marrickville, urban predators and disease eliminated frogs. Other factors also appear to have a significant effect on the likely outcome of the translocation. These include: the proximity of a source population, the presence or absence of predatory fish, pond water temperature and the timing of the release of tadpoles at translocation sites. Despite the difficulties and uncertainties associated with habitat creation and the establishment of translocated frogs, translocations remain as a last resort strategy for the conservation of frog populations that may otherwise be lost.
Pyke, G.H. & Muir, G.W. 2008, 'Rice-growing and conservation of the Southern Bell Frog Litoria raniformis New South Wales, Australia', Australian Zoologist, vol. 34, no. 3, pp. 453-458.
The Southern Bell Frog Litoria raniformis has declined dramatically in distribution and abundance in New South Wales, where it is presently considered 'endangered'. However, cultivation of rice through irrigation has created suitable habitat for this species, thus enabling it to colonise some, but not all, rice-growing areas. One such area, the Coleambally Irrigation Area, presently contains a large proportion of the remaining known locations of the species in New South Wales. Within this area this frog is widespread and locally abundant, and it uses flooded rice fields for breeding, though there are other kinds of water bodies that may also be used for breeding. The seasonal flooding regime for the rice mirrors the breeding requirements for this frog species. However, through reduction in flooding of natural habitat areas, diversion of water to rice and other irrigation-based agriculture has probably also contributed to the decline of this frog species and reversal of this through 'environmental flows' along rivers could be to its benefit. Its conservation in New South Wales is therefore likely to depend on the nature and extent of rice-growing in this state.
Pyke, G.H. & Rowley, J.J.L. 2008, 'Interactions between tadpoles of Green and Golden Bell Frog Litoria aurea and Striped Marsh Frog Limnodynastes peronii', Australian Zoologist, vol. 34, no. 4, pp. 570-576.
Experiments with tadpoles have been used to distinguish between intra- and inter-specific interactions and between interactions that arise through direct physical contact or indirectly through water-born movement of chemicals or micro-organisms. In the case of two Australian frog species, the Green and Golden Bell Frog Litoria aurea and the Striped Marsh Frog Limnodynastes peronii, it has been suspected that there are negative chemical interactions between the tadpoles of these two species, and that management of the former species, which is considered 'threatened' with extinction, may have to consider such interactions. We therefore sought to evaluate the nature of any interactions between tadpoles of these two species using three experimental treatments in which each tadpole species occurred on its own (i.e., "separate"), in the same water as the other species but separated by a mesh partition (i.e.,"adjacent"), and intermingling together in the same water (i.e.,"mixed"). We minimized any effects of coprophagy through the use of a mesh that was below the tadpoles and through which the faeces settled and became unavailable. We found that (a) L aurea tadpoles grew faster but developed more slowly than Lim. peronii tadpoles; (b) for both frog species, tadpoles grew more slowly in the "adjacent" treatment than in the "mixed" or "separate" treatments, but there was no significant difference between these latter two treatments; and (c) treatment had no apparent effect on tadpole survival or development for either species. These results indicate that there were no differences between the effects of intra- and inter-specific interactions on either growth or development when tadpoles were allowed to intermingle. It is difficult to explain why our "adjacent" treatment was significantly outside the range exhibited by the other two treatments in terms of tadpole growth and there was no clear evidence of any indirect chemically-based interactions between tadpoles of the two...
White, A.W. & Pyke, G.H. 2008, 'Green and Golden Bell Frogs in New South Wales: Current status and future prospects', Australian Zoologist, vol. 34, no. 3, pp. 319-333.
Surveys carried out between 1990 and 1995 of almost all known historic locations within New South Wales (including the ACT) for the Green and Golden Bell Frog Litoria aurea revealed that the species had suffered a dramatic decline in distribution and abundance in this region, with over 80% of all historic populations having gone extinct, and many of the extant populations being reduced to low numbers. The present study involved surveys of the Green and Golden Bell Frog locations that were known in 1995, surveys of new locations or potential areas for new locations of this species, and review of management plans and other documented information concerning particular populations. Over the last 12 years extinctions have continued with the loss of almost 50% of those sub-populations and 23% of populations known in 1995. Obviously the species cannot sustain this rate of loss for much longer and continue to exist within New South Wales. Protection for remaining extant populations is very limited and most are under continuing threat. Management plans have been prepared in relation to a number of sub-populations/populations, but these plans have not focused on populations under current threat, and associated management actions designed to benefit this frog have occurred in only a few cases. Hence, decline of this species within NSW is likely to continue. Habitat change, mostly through destruction and disturbance, has been the major factor in population loss with the likelihood of extinction increasing with increases in the extent of habitat loss as measured by the number of habitat variables that have declined. Invasion by exotic predatory fish Gambusia holbrooki, previously linked with declines in this frog species, shows no apparent association with extinction of populations over the last 12 years and poses no apparent current threat to any population, apparently because any impact of this species has been ameliorated through the presence of submerged/floating aquatic ...
Pyke, G.H., Rowley, J., Shoulder, J. & White, A.W. 2008, 'Attempted introduction of the endangered Green and Golden Bell Frog to Long Reef Golf Course: A step towards recovery', Australian Zoologist, vol. 34, no. 3, pp. 361-372.
The Green and Golden Bell Frog Litoria aurea is threatened with extinction, but generally occurs in disturbed sites and has successfully colonized some sites that are essentially artificial. It should therefore be possible to promote recovery of the species by increasing the availability of suitable habitat through habitat modification or creation and, where necessary, translocating individuals into these habitat areas. Apparently suitable habitat for this species had been created at Long Reef Golf Course in the northern Sydney suburb of Collaroy. We translocated approximately 9,000 captive-bred tadpoles from Taronga Zoo into these habitat areas over 7 years. This program has not led to the establishment of a self-sustaining population of the Green and Golden Bell Frog at Long Reef Golf Course and must therefore be considered unsuccessful. It has had partial success as some released tadpoles metamorphosed into frogs, some of these developed into adults, and a few males were recorded calling. However, breeding by these introduced animals has not been recorded, and, in the absence of continuing tadpole releases, the number of bell frogs has declined to zero. It has, however, provided a number of guidelines for future similar programs. Success with this program has been limited by fish, time of tadpole release and water temperature, and hence we recommend that future translocations of Green and Golden Bell Frog tadpoles should be carried out during spring or summer and should target ponds that are warm and fish-free. Program success was also limited by the numbers of tadpoles available for release. The lack of tadpoles for spring/summer release since the 2003/2004 breeding season has prevented evaluation of new, relatively warm ponds. Any captive-breeding program for this frog species must therefore be successful, in its own right, if it is to provide tadpoles for release. Disease is unlikely to have influenced the outcomes of this program, but should always be cons...
Pyke, G.H. 2008, 'Mining a museum frog collection for environmental bio-indicators using specimens of the Striped Marsh Frog Limnodynastes peronii', Pacific Conservation Biology, vol. 14, no. 3, pp. 200-205.
Museum specimens of the Striped Marsh Frog, (Limnodynastes peronii; Myobatrachidae), were examined to evaluate its potential role in providing bio-indicators of environmental quality and change. I hypothesized that chemical pollution of their breeding habitat would have peaked during the 1960s or 1970s, and that the levels of physical abnormality and morphological asymmetry for this frog species would tend to increase with increasing pollution. Consistent with this, I found that both the proportion of frogs with physical abnormalities and the average difference in length between the left and right lower legs peaked for specimens collected during the 1960s or 1970s and were lower for specimens collected during earlier and later decades. I also found that the overall proportion of specimens of this species with physical abnormalities was high relative to presumed background levels, which is consistent with relatively elevated levels of pollution in the degraded habitats where this species generally occurs. In this and similar ways, biological collections may be mined to provide environmental bio-indicators.
Rowley, J., Rayner, T. & Pyke, G.H. 2005, 'New Records And Invasive Potential Of The Poeciliid Fish Phalloceros Caudimaculatus', New Zealand Journal Of Marine And Freshwater Research, vol. 39, no. 5, pp. 1013-1022.
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Many species from the family Poeciliidae have been transported around the world by the aquarium trade, often establishing populations in areas far Outside their natural range. The one-spot livebearer, Phalloceros caudimaculatus is one such poeciliid spec
Pyke, G.H. 2005, 'A Review Of The Biology Of Gambusia Affinis And G-Holbrooki', Reviews in Fish Biology and Fisheries, vol. 15, no. 4, pp. 339-365.
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Eastern and Western Gambusia (i.e., Gambusia holbrooki and G. affinis, respectively) are considered together here because these two fish species are very closely related, similar in appearance, similar in biology and often confused. Widely divergent atti
Pyke, G.H. 2005, 'The use of PIT tags in capture-recapture studies of frogs: A field evaluation', Herpetological Review, vol. 36, no. 3, pp. 281-285.
Pyke, G.H., White, A.W., Bishop, P.J. & Waldman, B. 2002, 'Habitat-use by the Green and Golden Bell Frog Litoria aurea in Australia and New Zealand', Australian Zoologist, vol. 32, no. 1, pp. 12-31.
Patterns of habitat-use are used widely as management guides in the conservation of wildlife. However, even for relatively well-studied species, such the Green and Golden Bell Frog Litoria aurea, our knowledge of specific habitat requirements is lacking. This study sought to compare the patterns of breeding habitat shown by L aurea in New South Wales (NSW), Victoria and New Zealand (where it is a feral species), with those described in an earlier study of Pyke and White (1996), to review the conservation status of this species in Victoria, and to relate its observed patterns of distribution and habitat-use to the distribution of the introduced Plague Minnow (Gambusia holbrooki in Australia; G. affinis in New Zealand). We found that L aurea used similar breeding habitats in NSW, Victoria and New Zealand. Across these areas its breeding is almost completely restricted to water bodies that are still, relatively unshaded, and low in salinity (i.e., <7.3 ppt). All of its known breeding sites are highly disturbed, mostly through human activities but also through flooding and other natural processes. It generally breeds in small (i.e., <1000 sq m), shallow (i.e., <1 m) ponds that are either ephemeral or fluctuate significantly in water level, are free of Gambusia and other predatory fish, and have emergent aquatic vegetation. Its breeding habitat also usually has potential shelter provided by nearby rocks or thick, low vegetation. Yet L aurea is adaptable to different habitats and we found it breeding in a wide range of conditions including ponds lacking emergent vegetation and those already colonised by Gambusia. Breeding ponds ranged in terms of substrate, nearby terrestrial vegetation, water source, and water properties including turbidity, dissolved oxygen, oxidation reduction potential, pH and temperature. Gambusia may have had a negative impact on the distribution of L aurea in New Zealand and could threaten populations in Victoria. We failed to find Laurea at sit...
Pyke, G.H. 2002, 'A review of the biology of the Southern Bell Frog Litoria raniformis (Anura: Hylidae)', Australian Zoologist, vol. 32, no. 1, pp. 32-48.
The Southern Bell Frog Litoria raniformis, like the closely-related Green and Golden Bell Frog Litoria aurea, is considered to be threatened with extinction and subject to the future development of strategies aimed at its recovery. A necessary component of this recovery process will be a detailed and comprehensive review of available biological information concerning this species. This paper aims to provide such a review. Litoria raniformis is, at least in comparison with L aurea, poorly studied and many aspects of its biology warrant further investigation. Research conducted to date, however, reveals few, if any, differences in biology between the two species. They are similar in size, appearance, call, breeding biology, habitat and general behaviour. Recovery strategies for the two species are therefore likely to be similar. Both are apparently threatened by habitat loss and modification, and by predation by the introduced Plague Minnow or Gambusia Gambusia holbrooki, and so may benefit from increased legal protection and control of Gambusia impact. Both are able to live in sites that are largely or completely human-made, and so may benefit from programs to either enhance or develop suitable habitat. Disturbance, either natural or human-induced, is apparently important to both frog species.
Pyke, G.H. & White, A.W. 2001, 'A review of the biology of the Green and Golden Bell Frog Litoria aurea', Australian Zoologist, vol. 31, no. 4, pp. 563-598.
The Green and Golden Bell Frog Litoria aurea is an unusual endangered frog species. It has a high public profile as many populations occur in areas affected by human activities. As a result, there has been considerable recent scientific and popular interest in the species. Despite the interest and large volume of documented information there has been no general review of the biology of the species. Litoria aurea is not typical of other endangered species. It has many attributes of a "weedy" or "colonizing" species. Like other such species, it is characterised by occurrence in disturbed or newly created sites, high fecundity and high dispersal ability. However, unlike many "colonizing" species that are very common, L. aurea is considered to be endangered. Though the decline of L. aurea is continuing as a result of ongoing threats, it should be possible to promote some recovery of the species through such strategies as increased legislative protection, conservation agreements, habitat manipulation, and control of the impacts of the introduced Plague Minnow Gambusia holbrooki. As in many similar situations, further research will be essential to provide the necessary information-base for the threats to be arrested and the opportunities to be pursued. In this paper we review all available published information with regard to the biology of L. aurea, and include some previously unpublished field observations. We consider the implications of this review in terms of recovery and/or management of the species and the extent of further research on L. aurea that could benefit the recovery process.
Pyke, G.H. & White, A.W. 2000, 'Factors influencing predation on eggs and tadpoles of the endangered green and golden bell frog Litoria aurea by the introduced plague minnow Gambusia holbrooki', Australian Zoologist, vol. 31, no. 3, pp. 496-505.
The Green and Golden Bell Frog Litoria aurea has declined dramatically in New South Wales. One hypothesis suggests that this decline is largely due to predation by the Plague Minnow Gambusia holbrooki, which was introduced into Australia as part of efforts to control mosquitoes. Other frog species, such as Striped Marsh Frog Limnodynastes peronii and Peron's Tree Frog Litoria peronii have not apparently suffered from this predation to the same degree. Laboratory experiments were undertaken in order to evaluate the extent to which predation on eggs, fry and tadpoles of L. aurea by Gambusia is influenced by the presence of rocks (as potential shelter), the presence of other frog species (as alternative food) and a number of variables that reflect the ratio of the number of prey available to the amount of food that would be required to satiate the fish. These experiments showed that the proportion of available L. aurea eggs or tadpoles eaten increased with both decreases in the number of prey available and increases in the satiation requirements of the fish. Less expected, however, were the results that the extent of predation on L. aurea did not depend on whether rocks were present, nor on whether other frog species were present. Similarly, predation on both the Lim. peronii and the L. peronii was not influenced by whether these species were presented to the fish on their own or in the presence of one or other of the other two frog species. Gambusia was observed to employ different predatory strategies when attacking tadpoles of different sizes. Tadpoles were most often attacked from the rear, usually by a school of fish. Larger tadpoles were rarely eaten after being killed. Smaller tadpoles and fry were eaten mid-ventral region first, often only the viscera and yolk sac being consumed. L. aurea eggs were torn open and sometimes the yolk was consumed. Preliminary experiments on the extent of predation on L. aurea eggs, fry and tadpoles by Empire Gudgeon Hypseleotri...
Pyke, G.H. 2000, 'A strategy for reviewing the biology of animals', Australian Zoologist, vol. 31, no. 3, pp. 482-491.
With the advent of computer-based technology and the increasing need to focus on the biology of plant and animal species, it is both necessary and timely to adopt strategies for reviewing available information concerning individual species. To be most useful, biological reviews should be able to cope with taxonomic uncertainty and change, should be comprehensive with regard to topics, sufficiently detailed, repeatable and easy to keep up-to-date, should include anecdotal observations, and should indicate the nature and extent of support for each statement concerning a species. I present here a computer-based strategy which I have adopted for carrying out such reviews and illustrate it with the example of the diet of the Green and Golden Bell Frog Litoria aurea.
Pyke, G.H. & White, A.W. 1999, 'Dynamics of co-occurring frog species in three ponds utilized by the endangered Green and Golden Bell Frog Litoria aurea', Australian Zoologist, vol. 31, no. 1, pp. 230-239.
Populations of five frog species were monitored at three ponds utilized by the endangered Green and Golden Bell Frog Litoria aurea over a three year period 1993-1996. Litoria aurea bred at the two semi-permanent ponds with fluctuating water levels but did not breed at the permanent pond with a relatively constant water level, though it was abundant there. Other frog species generally bred at all ponds where they were found. At the semi-permanent ponds the numbers of the various frog species fluctuated, but there were no apparent long-term trends. On the other hand, at the permanent pond there were changes through time in both plant and frog species. As the pond aged, the relative abundance of various species of emergent aquatic plants changed, the area of open water steadily decreased, and the depth decreased. Over the same period, the relative abundance of several frog species changed with the most abundant species being first L. aurea and then Limnodynastes peronii, and finally Crinia signifera increased to become co-dominant with Lim. peronii. The temporal changes in the numbers of each species were attributed to the changes in the condition of the ponds.
Pyke, G.H. 1999, 'The introduced Honeybee Apis mellifera and the precautionary principle: Reducing the conflict', Australian Zoologist, vol. 31, no. 1, pp. 181-186.
For more than 20 years there has been conflict arising from different points of view concerning the role of the introduced honeybee. There is a strong prima facie argument, and some supporting evidence, that introduced honeybees are likely to adversely affect the environment. Some land management agencies have consequently adopted a policy of removal of hive honeybees from areas devoted primarily to conservation. On the other hand, some argue that the scientific evidence on the issue remains poor, point out the economic benefits that arise from the honeybee industry and suggest that removal of apiaries from such areas is unjustified. It is suggested in this paper that adoption of the Precautionary Principle could significantly reduce this conflict. Instead of the focus being on obtaining definitive "proof" concerning possible impacts of honeybees, it could shift to finding ways to reduce the density of feral honeybees, and hence their impacts on both the natural environment and honeybees in hives. The focus could also shift to finding sites where reduction in honeybee density is feasible and the likely conservation gains arising from such a reduction are relatively high. In this way both the honeybee industry and the natural environment could benefit.
Pyke, G.H., Christy, M. & Major, R. 1996, 'Territoriality In Honeyeaters: Reviewing The Concept And Evaluating Available Information', Australian Journal Of Zoology, vol. 44, no. 3, pp. 297-317.
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We define territorial behaviour as aggressive behaviour that occurs repeatedly in about the same location with associated submissive behaviour on the part of the individuals or groups to which the aggression is directed. Of a worldwide total of about 170
Pyke, G.H. & White, A.W. 1996, 'Habitat requirements for the Green and Golden Bell Frog Litoria aurea (Anura: Hylidae)', Australian Zoologist, vol. 30, no. 2, pp. 224-232.
We examined the habitat features of sites where the Green and Golden Bell Frog is known to have been present, differentiating between those sites where breeding is known to have occurred and those where breeding has not been recorded. We found that, for a site to support a breeding population of the species, it should contain water bodies which are still, shallow, ephemeral, unpolluted, unshaded and free of Gambusia and other predatory fish. It should have a grassy area nearby and other nearby vegetation should be no higher than woodland. The substrate of the ponds should be sand or rock, aquatic plants should be present and there should be a range of possible diurnal shelter sites, including vegetation and rocks.
White, A.W. & Pyke, G.H. 1996, 'Distribution and conservation status of the Green and Golden Bell Frog Litoria aurea in New South Wales', Australian Zoologist, vol. 30, no. 2, pp. 177-189.
The Green and Golden Bell Frog Litoria aurea has undergone a dramatic population decline in New South Wales. During this time the species' status in this state has changed from being common in the 1960s to endangered in 1992. To assess the present population numbers and environmental pressures, 31 sites within the Greater Sydney region and 61 sites from regional areas of New South Wales were surveyed. The sites consisted of previously known but no longer used localities prior to 1990, as well as more recently discovered localities. Since 1990, only 38 localities have been recorded for Green and Golden Bell Frogs, 19 of these are in the Greater Sydney region. Since the 1960s Green and Golden Bell Frogs have disappeared completely from all highland areas above 250 m a.s.l. Coastal populations have been reduced in number and are more isolated from other extant populations. Many of the extant sites are new sites (post 1990) for this species and occur in highly disturbed environments. The ecological niche of this species is discussed in the light of new observations on these frogs. The introduction of Mosquito Fish Gambusia holbrooki may be one of the factors limiting the recovery of Green and Golden Bell Frog populations in New South Wales.
Pyke, G.H., Saillard, R. & Smith, J. 1995, 'Abundance Of Eastern Bristlebirds In Relation To Habitat And Fire History', Emu, vol. 95, no. 2, pp. 106-110.
Eastern Bristlebirds were counted in Jervis Bay Territory along transects that were located in area that had been burnt recently (i.e. 0-7 years ago) and in areas that had last burnt longer ago (i.e. 13-14 years ago). Most of the reserve had not burnt fo
Pyke, G.H. 1995, 'Justice Stein's 1993 judgment in the New South Wales land and environment court: What does it mean for conservation of endangered fauna and fauna impact statements?', Australian Zoologist, vol. 30, no. 1, pp. 79-90.
The law affecting the protection and conservation of "endangered" fauna in New South Wales (i.e., animal species listed on Schedule 12 of the New South Wales National Parks and Wildlife Act 1974) is continuing to evolve. In this paper I discuss the implications in this area that arise from a 1993 judgment by Justice Stein in relation to an appeal in the Land and Environment Court.
Pyke, G.H. 1995, 'Fauna Impact Statements: a review of processes and standards', Australian Zoologist, vol. 30, no. 1, pp. 93-110.
Fauna Impact Statements (FISs) are now required in association with all actions in New South Wales which are considered likely to "take or kill' "endangered' fauna. In this paper it is argued that "take or kill' is equivalent to having a significiant impact on either individuals or the habitat of a species of endangered fauna. In addition the author reviews the context in which these FISs are required and considers the adequacy of FISs that have so far been produced as well as potential improvements in the FIS process. -Author
Major, R., Pyke, G.H., Christy, M., Gowing, G. & Hill, R. 1994, 'Can Nest Predation Explain The Timing Of The Breeding-Season And The Pattern Of Nest Dispersion Of New-Holland Honeyeaters', OIKOS, vol. 69, no. 3, pp. 364-372.
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We tested the following two predictions of the hypotheses that predation rate may select for nest spacing and winter breeding in New Holland honeyeaters: (a) the level of nest predation should be lower during the breeding season than outside it, and (b)
Pyke, G.H. & Oconnor, P. 1993, 'Use Of Heathland And Adjoining Forest By Honeyeaters - Results Of A Radiotracking Study', Australian Journal Of Ecology, vol. 18, no. 3, pp. 269-274.
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New Holland (Phylidonyris novaehollandiae) and White-cheeked (Phylidonyris nigra) Honeyeaters that are resident in heathland during February and March, when there is negligible nectar production in that habitat, are expected to forage for nectar at that
Pyke, G.H., Oconnor, P. & Recher, H. 1993, 'Relationship Between Nectar Production And Yearly And Spatial Variation In Density And Nesting Of Resident Honeyeaters In Heathland Near Sydney', Australian Journal Of Ecology, vol. 18, no. 2, pp. 221-229.
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The maximum density of resident honeyeaters in heathland near Sydney was very similar from one area and year to another, despite large variation in production of nectar-energy. The most likely explanation for this is that density is determined by the spa
Pyke, G.H. & Cartar, R. 1992, 'The Flight Directionality Of Bumblebees - Do They Remember Where They Came From', Oikos, vol. 65, no. 2, pp. 321-327.
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Pollinators usually maintain directionality while moving through a flower patch, presumably to increase foraging success by minimizing revisitation of previously-emptied flowers. Two alternative directionality-generating mechanisms have been proposed: fo
Sugden, E. & Pyke, G.H. 1991, 'Effects Of Honey-Bees On Colonies Of Exoneura-Asimillima, An Australian Native Bee', Australian Journal Of Ecology, vol. 16, no. 2, pp. 171-181.
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Honey bee hives were placed, during two consecutive summers, in an experimental site which contained natural and artificially placed colonies of Exoneura asimillima, a semi-social, native bee. Two classes of colonies were studied: founders, and establish
Pyke, G.H. 1991, 'What Does It Cost A Plant To Produce Floral Nectar', Nature, vol. 350, no. 6313, pp. 58-59.
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TO understand the adaptive nature of floral nectar production it is necessary to determine for individual plants the associated costs and benefits in terms of growth and/or reproduction 1-3. Nectar production may use up to 37% of a plant's available ener
Armstrong, D. & Pyke, G.H. 1991, 'Seasonal Patterns Of Reproduction In Heathland Honeyeaters Are Not Responses To Changing Nectar Availability', The Auk, vol. 108, no. 1, pp. 99-107.
We monitored nesting attempts of New Holland (Phylidonyris novaehollandiae) and White-cheeked (P. nigra) honeyeaters on two sites throughout 1987 and 1988. Two aspects of the birds' reproduction were correlated with changes in availability of nectar. Fir
Pyke, G.H. & Oconnor, P. 1990, 'The Accuracy Of A Radiotracking System For Monitoring Honeyeater Movements', Australian Wildlife Research, vol. 17, no. 5, pp. 501-509.
Pyke, G.H. 1989, 'Effects Of Flower Removal On Abundance And Behavior Of Honeyeaters In Heathland Near Sydney', Australian Journal Of Ecology, vol. 14, no. 4, pp. 415-421.
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Pyke, G.H., Recher, H. & Oconnor, P. 1989, 'Patterns Of Residency And Movement Among Honeyeaters In Heathland Near Sydney', Emu, vol. 89, pp. 30-39.
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New Holland Phylidonyris novaehollandiae and white-cheeked honeyeaters P. nigra accounted for most birds captured or observed. A resident bird is defined as one observed nesting and/or is repeatedly sighted in about the same area over at least 2 days. Species that satisfy the latter criterion also exhibit high recapture rates whereas other species have relatively low recapture rates. Most individual New Holland and white-cheeked honeyeaters are either transients that are captured just once and are never mapped as resident; or occasional residents that are captured more than once, visit the study area throughout their lives but satisfy the definition of resident only some of the time. Emigration of resident birds is negligible and departures of residents must be due to mortality. This mortality of residents, which averages c54% p.a., is associated with low availability of nectar, the principal source of energy to these birds. Individuals often change partners but not unless their partner vanishes, presumed dead
Pyke, G.H. & Oconnor, P. 1989, 'Corroboree Behavior Of New-Holland And White-Cheeked Honeyeaters', Emu, vol. 89, pp. 55-57.
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Pyke, G.H., Day, L. & Wale, K. 1988, 'Pollination Ecology Of Christmas Bells (Blandfordia-Nobilis Sm) - Effects Of Adding Artificial Nectar On Pollen Removal And Seed-Set', Australian Journal Of Ecology, vol. 13, no. 3, pp. 279-284.
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Studies the effects of adding artificial nectar to Blandfordia nobilis plants on pollen removal and seed-set. Manner in which natural selection affects nectar production; Positive effect of enhanced nectar production on plant reproduction; Rate of nectar production for plants flowering in December..
Zimmerman, M. & Pyke, G.H. 1988, 'Pollination Ecology Of Christmas Bells (Blandfordia-Nobilis) - Patterns Of Standing Crop Of Nectar', Australian Journal Of Ecology, vol. 13, no. 3, pp. 301-309.
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Describes the standing crop of nectar patterns found in a population of Christmas Bells. Influence of the quantity and quality of floral nectar on pollen transportation by nectar-gathering animals; Impact of viscosity on intake rates by pollinators; Positive relationship between the amount of reward offered to pollinators by flowers on a single plant..
Zimmerman, M. & Pyke, G.H. 1988, 'Experimental Manipulations Of Polemonium-Foliosissimum - Effects On Subsequent Nectar Production, Seed Production And Growth', Journal of Ecology, vol. 76, no. 3, pp. 777-789.
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In Polemonium foliosissimum the amount of available carbon was decreased by defoliating 50% of each plant, while available carbon was enhanced by daily watering and by removing either 50% or 100% of the flower buds. Rates of nectar production per flower were constant across all treatments except for a significant increased in watered individuals. There were no consistent changes in average seed set per flower or per plant across treatment groups. Defoliated and control individuals did not differ significantly from one another with respect to average seed weight, but end-of-season underground biomass was significantly less for defoliated plants. In the year following treatment, no differences were observed in nectar production per flower, seed production per flower or seed production per plant, although a significant difference in rate of growth was observed. Defoliated plants grew least during the 2 yr period, followed by control individuals. Debudded plants increased in size by the greatest margin. Trade-offs between resources allocated to nectar, flowers, seeds and vegetative growth can apparently to expressed in terms of biomass
Inouye, D.W. & Pyke, G.H. 1988, 'Pollination Biology In The Snowy Mountains Of Australia - Comparisons With Montane Colorado, Usa', Australian Journal Of Ecology, vol. 13, no. 2, pp. 191-210.
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Studies various aspects of the pollination biology of the alpine flora of Kosciusko National Parks in New South Wales. Examination of the flowering phenology; Analysis of corolla tube lengths and flower color; Assessment of ultraviolet reflectance patterns and visitation rates to the flowers and proboscis lengths of the flower-visiting insects..
Zimmerman, M. & Pyke, G.H. 1988, 'Reproduction In Polemonium - Assessing The Factors Limiting Seed Set', The American Naturalist, vol. 131, no. 5, pp. 723-738.
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Although hand-pollinated Polemonium foliosissimum flowers set significantly more seeds than did either set of control blossoms, results suggest that individual reproduction (ie the total number of seeds produced by a plant) was limited by resources other than pollen. Pollen availability may also have limited seed production, but to a lesser extent
Pyke, G.H. 1988, 'Yearly Variation In Seasonal Patterns Of Honeyeater Abundance, Flower Density And Nectar Production In Heathland Near Sydney', Australian Journal Of Ecology, vol. 13, no. 1, pp. 1-10.
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Examines the relationships between honeyeater density, energy productivity and insect abundance in heathland and woodland habitats in Sydney, New South Wales. Negative relation between seasonal fluctuations in honeyeater density and nectar-energy productivity; Variation between circles in honeyeater density; Indication that the birds are transient..
Zimmerman, M. & Pyke, G.H. 1988, 'Pollination Ecology Of Christmas Bells (Blandfordia-Nobilis) - Effects Of Pollen Quantity And Source On Seed Set', Australian Journal Of Ecology, vol. 13, no. 1, pp. 93-99.
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Assesses the effect of a number of experimental hand-pollination regimens on the numbers of seeds set by Blandfordia nobilis flowers in Australia. Determination of the nature of pollen flow within plant populations; Number of plants pollinated by animal vectors; Percentage of flowers per plant setting seed..
Pyke, G.H. & Recher, H. 1988, 'Seasonal Patterns Of Capture Rate And Resource Abundance For Honeyeaters And Silvereyes In Heathland Near Sydney', Emu, vol. 88, pp. 33-42.
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Oconnor, P., Pyke, G.H. & Spencer, H. 1987, 'Radio-Tracking Honeyeater Movements', Emu, vol. 87, no. 4, pp. 249-252.
PYKE, G.H. 1987, 'FORAGING THEORY - STEPHENS,DW, KREBS,JR', SCIENCE, vol. 238, no. 4828, pp. 831-833.
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Zimmerman, M. & Pyke, G.H. 1986, 'Reproduction In Polemonium - Patterns And Implications Of Floral Nectar Production And Standing Crops', American Journal Of Botany, vol. 73, no. 10, pp. 1405-1415.
Pyke, G.H. & Recher, H. 1986, 'Relationship Between Nectar Production And Seasonal Patterns Of Density And Nesting Of Resident Honeyeaters In Heathland Near Sydney', Australian Journal Of Ecology, vol. 11, no. 2, pp. 195-200.
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Some individual honeyeaters were repeatedly seen near the same location over at least a 2 day period and were considered resident. Such residents (mostly New Holland Phylidonyris novaehollandiae and white-cheeked honeyeaters P. nigra) were present on the heathland study areas from about February until about October. Production of nectar energy is negligible prior to April and low after October. Density of residents is probably determined by their ability to obtain energy in nearby habitats while establishing nesting sites in the heathland in February and March. Nesting tended to occur between April and July when there was sufficient production of nectar-energy
Booth, D.J., Pyke, G.H. & Lanzing, W. 1985, 'Prey Detection By The Blue-Eye, Pseudomugil-Signifer Kner (Atherinidae) - Analysis Of Field Behavior By Controlled Laboratory Experiments', Australian Journal of Marine and Freshwater Research, vol. 36, no. 5, pp. 691-699.
Observations in a brackish creek in E Australia indicate that blue-eye includes various kinds of insects in its diet in the proportions encountered, provided that they are below a maximum size dictated by the mouth-gape of the fish. Encounter rates are affected by prey body size and water turbidity, but not by hunger level of the fish. Fish fed on insects at 0.04-0.08 mg s-1
Pyke, G.H. & Recher, H. 1985, 'Estimated Forest Bird Densities By Variable Distance Point Counts', Australian Wildlife Research, vol. 12, no. 2, pp. 307-319.
During variable distance point counts a stationary observer records the species and distance for all birds detected during a fixed time interval. Such counts, repeated throughout the area of interest, can be used to estimate bird density so long as the following assumptions are made: 1) the distribution of birds is unaffected by the observer, 2) observers are certain of detecting near birds; 3) there is no error in measurement or estimation of distances; and 4) birds are stationary. Data indicated that at least 2 of these assumptions are not satisfied: estimates of distance based on sound are inaccurate and observers do not always detect near birds. No effect of observer presence on bird distribution was detected nor did there appear to be any significant movement of birds during counts. Bird counts should be based only on sight detections. When bird movement is significant, instantaneous counts be used.-
Pyke, G.H. 1985, 'Seasonal Patterns Of Abundance Of Insectivorous Birds And Flying Insects', Emu, vol. 85, no. MAR, pp. 34-39.
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Insectivorous birds made up only 8% of all birds in heathland near Sydney, NSW, and only 18% in open forest; other birds were almost all honeyeaters. The abundance of variegated wrens Malurus lamberti the most commonly recorded insectivore, showed no consistent seasonal pattern in the heathland. Otherwise the abundances of insectivorous birds were lowest during June-August and peaked during September-November or December-February. Average biomass of flying insects exhibited peaks during September- December and March-April and troughs at other times, especially during May-August. Except for September-November, when insectivore density and biomass of flying insects were both at their highest levels, the correspondence between the two was poor. -Author variegated wren Malurus lamberti heathland Sydney New South Wales
Pyke, G.H. 1985, 'Seasonal patterns of abundance of insectivorous birds and flying insects', Emu, vol. 85, no. 1, pp. 34-39.
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PYKE, G.H. 1985. Seasonal patterns of abundance of insectivorous birds and flying insects. Emu 85: 34-39. Insectivorous birds made up only 8% of all birds in heathland near Sydney and only 18% in open forest; other birds were almost all honeyeaters. The abundance of Variegated Wrens, the most commonly recorded insectivore, showed no consistent seasonal pattern in the heathland. Otherwise the abundances of insectivorous birds were lowest during June to August and peaked during September to November or December to February. Average biomass of flying insects exhibited peaks during September to December and March to April and troughs at other times, especially during May to August. Except for the period September to November, when insectivore density and biomass of flying insects were both at their highest levels, the correspondence between the two was poor. &copy; 1985, CSIRO. All rights reserved.
Booth, D.J., Pyke, G.H. & Lanzing, W.J.R. 1985, 'Prey detection by the blue-eye, pseudomugil signifer kner (Atherinidae):Analysis of field behaviour by controlled laboratory experiments', Marine and Freshwater Research, vol. 36, no. 5, pp. 669-691.
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Observations in a brackish creek in eastern Australia indicate that the blue-eye, P. signifer, includes various kinds of insects in its diet in the proportions encountered, provided that they are below a maximum sizedictated by the mouth-gape of the fish. Encounter rates are affected by prey body size and water turbidity, but not by hunger level of the fish. Fish fed on insects at rates varying between O'04 and 0'08 mg s-1. &copy; 1985 CSIRO. All rights reserved.
Pyke, G.H. 1984, 'Optimal Foraging Theory - A Critical-Review', Annual Review Of Ecology And Systematics, vol. 15, pp. 523-575.
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Pyke, G.H. 1983, 'Relationship Between Time Since The Last Fire And Flowering In Telopea-Speciosissima R Br And Lambertia-Formosa Sm', Australian Journal Of Botany, vol. 31, no. 3, pp. 293-296.
For Telopea speciosissima the percentage (or density) of plants in flower, average number of flowers per inflorescence and average number of fruits per inflorescence all appear to peak 2 yr after a summer fire and decline thereafter. Average height of the inflorescences above the ground, however, increases with time since the last fire. For Lambertia formosa the density of inflorescences appears to reach a peak 2 or 3 yr after a summer fire
Pyke, G.H. 1983, 'Seasonal Pattern Of Abundance Of Honeyeaters And Their Resources In Heathland Areas Near Sydney', Australian Journal Of Ecology, vol. 8, no. 3, pp. 217-233.
Seasonal fluctuations in honeyeater density showed no apparent relationship with seasonal fluctuations in nectar-energy productivity or in biomass of flying insects. Variation between circles in honeyeater density was also unrelated to spatial variation in energy productivity and insect biomass. The relatively low incidence of nectar-feeding and high incidence of flying exhibited by birds observed during troughs in nectar-energy production suggest that many of these birds are transient and that their density may consequently be unrelated to local conditions
Pyke, G.H. 1983, 'Analysis Of An Instantaneous Census Method For Heathland Birds', Australian Wildlife Research, vol. 10, no. 3, pp. 521-526.
Pyke, G.H. 1982, 'Fruit-Set In Lambertia-Formosa Sm (Proteaceae)', Australian Journal Of Botany, vol. 30, no. 1, pp. 39-45.
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Pyke, G.H. 1982, 'Foraging In Bumblebees - Rule Of Departure From An Inflorescence', Canadian Journal of Zoology, vol. 60, no. 3, pp. 417-428.
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Pyke, G.H. 1982, 'Local Geographic Distributions Of Bumblebees Near Crested Butte, Colorado - Competition And Community Structure', Ecology, vol. 63, no. 2, pp. 555-573.
Seven of 12 species of bumblebees accounted for 97% of all bumblebees observed. These 7 species form 4 groups in terms of both their proboscis lengths and the corolla lengths of the plants they preferentially visit. Long-, medium-, and short-tongued groups were most often observed foraging at flowers with long, medium, and short corollas, respectively. Proboscis lengths tended to be very similar within each group but quite dissimilar between groups. The 4th group consisted of a single short-tongued species which has well- developed mandibles which enable it to rob nectar from many plants with long corollas. It also feeds legitimately on short-corolla flowers. When the data on bumblebees and plant distributions are combined with data on flower preferences, a pattern consistent with a competition hypothesis emerges. Within each proboscis-length group, bumblebee species tend to replace one another altitudinally in a manner consistent with the hypothesis
Pulliam, H., Pyke, G.H. & Caraco, T. 1982, 'The Scanning Behavior Of Juncos - A Game-Theoretical Approach', Journal Of Theoretical Biology, vol. 95, no. 1, pp. 89-103.
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Pyke, G.H. 1981, 'Optimal Travel Speeds Of Animals', American Naturalist, vol. 118, no. 4, pp. 475-487.
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Pyke, G.H. 1981, 'Why Hummingbirds Hover And Honeyeaters Perch', Animal Behaviour, vol. 29, no. AUG, pp. 861-867.
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Evidence is presented in support of the suggestion that a hovering bird is able to move between flowers more quickly than one that is perching. This advantage to hovering may be offset, however, by the higher energetic costs of hovering as compared with perching. This trade-off is evaluated in two field situations, one for perching honeyeaters and the other for hovering hummingbirds. In each case it is estimated that the birds employ the foraging mode (hovering versus perching) that results in the greatest net rate of energy gain.
Pyke, G.H. 1981, 'Honeyeater Foraging - A Test Of Optimal Foraging Theory', Animal Behaviour, vol. 29, no. AUG, pp. 878-888.
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Honeyeaters (Meliphagidae) were observed foraging for nectar from Lambertia formosa inflorescences, each of which has seven flowers. The frequency distribution of numbers of flowers probed per visit to an inflorescence was found to be bimodal, with one peak at two and the other at seven. It is hypothesized that this frequency distribution results from a rule of departure from inflorescences that maximizes the net rate of energy gain. Patterns of nectar distribution were determined for a large sample of inflorescences. In addition the extent to which the honeyeaters re-probe flowers during a visit to an inflorescence was estimated. From these data and from field measurements of the times required by the honeyeaters to perform the various foraging behaviours, computer simulations of honeyeater foraging were constructed. These simulations led in turn to optimal frequency distributions of numbers of flowers probed per inflorescence that were bimodal but had peaks at 1 and 7 instead of 2 and 7. Although the observed and predicted behaviour were consequently similar, the difference between them was nevertheless significant. This difference could have been due to the birds' transient occupancy of the study area.
Pyke, G.H. 1981, 'Optimal Foraging In Hummingbirds - Rule Of Movement Between Inflorescences', Animal Behaviour, vol. 29, no. AUG, pp. 889-896.
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The movements of hummingbirds between inflorescences of scarlet gilia (Ipomopsis aggregata) were studied. These movements exhibited the following patterns: (1) Although the hummingbirds appeared to avoid moving to the previous inflorescence, no significant correlation was found between the directions of successive inter-inflorescence movements. (2) The frequency distribution of inter-inflorescence flight distances was found to be leptokurtic. (3) The hummingbirds were more likely to move to an inflorescence the larger and/or closer it was. (4) The hummingbirds moved to inflorescences of greatest apparent size (i.e. ratio of number of flowers available to distance from present inflorescence) more often than they moved to the largest inflorescence, the closest infloresence, or the inflorescence estimated to yield the greatest rate of energy gain. (5) The frequency distribution of moves to the inflorescence having the ith greatest apparent size is well fitted by a geometric distribution. This is consistent with the hummingbrids choosing the inflorescence of greatest apparent size (excluding the previous inflorescence) from within some scanning sector. These movement patterns are consistent with the expectations of optimal foraging theory only if the hummingbirds cannot or do not determine the directions of possible inflorescences relative to the direction of arrival at the present inflorescence and if they cannot assess independently the sizes and distances of possible inflorescences.
Pyke, G.H. 1981, 'Effects Of Inflorescence Height And Number Of Flowers Per Inflorescence On Fruit-Set In Waratahs (Telopea-Speciosissima)', Australian Journal Of Botany, vol. 29, no. 4, pp. 419-424.
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Pyke, G.H. 1981, 'Hummingbird Foraging On Artificial Inflorescences', Behaviour Analysis Letters, vol. 1, no. 1, pp. 11-15.
Pyke, G.H. & Waser, N. 1981, 'The Production Of Dilute Nectars By Hummingbird And Honeyeater Flowers', Biotropica, vol. 13, no. 4, pp. 260-270.
A survey of data from tropical and temperate regions confirms that nectars of hummingbird and honeyeater flowers are dilute, especially relative to nectars of bee flowers. These data are used, along with theoretical considerations, to examine three recently proposed hypotheses to explain low concentration of hummingbird nectars. None of the quantitative or qualitative predictions of these hypotheses appears to be upheld
Pyke, G.H. 1981, 'Optimal Nectar Production In A Hummingbird Pollinated Plant', Theoretical Population Biology Theoretical Population Biology Theoretical Population Biology Theoretical Population Biology, vol. 20, no. 3, pp. 326-343.
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It is hypothesized that the average rate of nectar production per flower for a population of plants is such than an individual plant which possesses this rate has maximum fitness (i.e., is optimal). This basic hypothesis is used to develop predictions concerning nectar production in scarlet gilia (Ipomopsis aggregata), a hummingbird pollinated plant. The optimal standing crop of nectar per flower is not significantly different from the observed.
Pyke, G.H. 1980, 'Optimal Foraging In Bumblebees - Calculation Of Net Rate Of Energy-Intake And Optimal Patch Choice', Theoretical Population Biology Theoretical Population Biology Theoretical Population Biology Theoretical Population Biology, vol. 17, no. 2, pp. 232-246.
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To test many predictions of "optimal foraging theory" it is necessary to calculate the rate of net energy intake of a foraging animal. Equations are derived for the calculation of the rate of net energy intake of a foraging bumblebee. The assumptions that form the basis of these energy equations are discussed. As examples, the rates of net energy intake are calculated for Bombus flavifrons workers foraging on neighboring patches of Aconitum columbianum and Delphinium barbeyi. If the bumblebees forage optimally, their net rates of energy intake in the two patches should be equal. The observed rates are consistent with this hypothesis. The application of an optimality approach to pollination biology is briefly discussed
Pyke, G.H. 1980, 'The Foraging Behavior Of Australian Honeyeaters - A Review And Some Comparisons With Hummingbirds', Australian Journal Of Ecology, vol. 5, no. 4, pp. 343-369.
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Pyke, G.H. 1979, 'Economics Of Territory Size And Time Budget In The Golden-Winged Sunbird', American Naturalist, vol. 114, no. 1, pp. 131-145.
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Pyke, G.H. 1979, 'Optimal Foraging In Bumblebees - Rule Of Movement Between Flowers Within Inflorescences', Animal Behaviour, vol. 27, no. NOV, pp. 1167-1181.
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It is hypothesized that nectar-collecting bumblebees will be found to forage in ways that maximize their net rate of energy intake. Attention is focused, in this paper, on the manner in which these bumblebees move from one flower to another within inflorescences. Observations were made on workers of Bombus appositus, which were collecting nectar from Aconitum columbianum (monkshood). The rule of movement of the bumblebees was determined and compared, in terms of net rate of energy intake, with several possible alternative rules. Two of these alternatives gave equally high net rates of energy intake. The observed rule was very similar in nature to one of these and indistinguishable from both in terms of net rate of energy intake
Debenedictis, P., Gill, F., Hainsworth, F., Pyke, G.H. & Wolf, L. 1978, 'Optimal Meal Size In Hummingbirds', The American Naturalist, vol. 112, no. 984, pp. 301-316.
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Pyke, G.H. 1978, 'Optimal Foraging In Hummingbirds - Testing The Marginal Value Theorem', American Zoologist, vol. 18, no. 4, pp. 739-752.
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To a hummingbird, clusters of flowers on inflorescences represent patches and provide an ideal situation to test prediction of optimal patch-use. The basic question is what decision rule should a hummingbird use to decide whether or not to leave an inflorescence? The hypothesis is that hummingbirds will adopt the decision rule that maximizes their net rate of energy gain while foraging. This hypothesis leads to an analogue of Charnov's marginal value theorem which determines an optimal decision rule. The optimal decision ruleis then used to predict aspects of the hummingbirds' foraging, and these predictions are compared with field data. The optimal decision rule is a function of how much information is used by the hummingbirds. Data indicate that a decision to leave an inflorescence is a function of the number of flowers visited, the number of flowers available on the inflorescence, and the amount of nectar obtained at the last flower. The optimal decision rule was calculated assuming no additional information is used. &copy; 1978 American Society of Zoologists.
Pyke, G.H. 1978, 'Are Animals Efficient Harvesters', Animal Behaviour, vol. 26, no. FEB, pp. 241-250.
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As animals move from one place to another there are patterns to their movements. It is hypothesized that these patterns are such that the net rate of food gain is maximized, and to test this hypothesis a model of a `harvesting animal is formulated. A harvesting animal is one whose movements are determined solely by previous movement and not by responses to sensory stimuli. Available data suggest that this harvesting model is inappropriate and that models which incorporate responses to sensory stimuli are likely to provide a better predictive understanding of animal movement patterns.
Pyke, G.H. 1978, 'Optimal Foraging In Bumblebees And Coevolution With Their Plants', Oecologia, vol. 36, no. 3, pp. 281-293.
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The aims of this paper were to consider the coevolution between bumblebee movement patterns within plants and various properties of the plants such as the spatial distribution of their flowers, and to determine the extent to which the bumblebees and the plants can be considered to be maximally adaptive or optimal. Attention was restricted to plants which have flowers arranged on vertical inflorescences and to the bumblebees which visit these plants. It was found that the bumblebees tend to commence foraging at the bottom of each infloresence, that they tend to move from one flower to the closest vertically higher flower, that they miss flowers as they move upwards and that they tend to leave each inflorescence before reaching the top. It was also found for the four common plant species considered that nectar abundance per flower decreases with flower height on an inflorescence, that the flowers with receptive stigmas are restricted to the bottoms of the inflorescences while the flowers shedding pollen occur above them, and that the flowers are arranged approximately in spirals on the inflorescences. The pattern of movements of the bumblebees and the various properties of the plants appear to represent coevolved adaptations. Furthermore the bumblebees' movement patterns appear to be optimal in the sense that they result in the maximum net rate of energy gain to the bumblebees. Further studies are necessary, however, to determine whether or not the plants can be considered to be optimal. An exception to the above scheme is provided by a plant which is quite uncommon in the study area. This plant also has flowers on vertical inflorescences and appears to be pollinated by bumblebees. However, while the pattern of movements of the bumblebees on this plant species are extremely similar to those on the four common species, this plant species exhibits quite different properties from the other four. Two possible explanations for this exception are presented.
Pyke, G.H. 1978, 'Optimal Body Size In Bumblebees', Oecologia, vol. 34, no. 3, pp. 255-266.
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Pyke, G.H. 1978, 'Optimal Foraging - Movement Patterns Of Bumblebees Between Inflorescences', Theoretical Population Biology Theoretical Population Biology Theoretical Population Biology Theoretical Population Biology, vol. 13, no. 1, pp. 72-98.
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Nectar-collecting bumblebees are hypothesized to employ rules of movement which result in the maximum net rate of energy gain (i.e., are optimal). The optimal movement rules are derived from a mathematical model and are used to generate predicted patterns of movement. The predicted patterns are compared with field observations. These observations support the hypothesis. An important component of the mathematical model is the memory of the foraging animal. The field data have implications concerning the memory capabilities of the bumblebees.
Pyke, G.H., Pulliam, H. & Charnov, E. 1977, 'Optimal Foraging - Selective Review Of Theory And Tests', QUARTERLY REVIEW OF BIOLOGY, vol. 52, no. 2, pp. 137-154.
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  • Animal behaviour, especially in terms of foraging behaviour and the development and testing of theoretical approaches (Collaborators: Prof Ron Pulliam, University of Georgia, USA)
  • Pollination biology, especially in terms of understanding observed correlations between various plant traits and traits of their pollinators (Collaborators: Prof David Inouye, University of Maryland, USA; Prof James Thomson, University of Toronto, Canada)
  • Climate change, especially using long-term survey data and revisiting old survey data in relation to relevant long-term weather data (Collaborators: Prof David Inouye, University of Maryland, USA; Prof James Thomson, University of Toronto, Canada)
  • Ecology of birds, especially the biogeography of honeyeaters (Collaborator: Prof Paul Ehrlich, Stanford University, USA) and effects on bird communities of fire history and climate change.
  • Ecology of frogs, especially re the Green and Golden Bell Frog & Striped Marsh Frog and effects of climate change on frog communities.
  • Chemical ecology, especially re role of frogs as bio-indicators of environmental quality and nature & function of frog secretions (Collaborator: Prof Philip Doble, UTS).