Professor Ken Cheng

Studies in Animal Behaviour

portrait

Ken Cheng
Professor
Department of Biological Sciences
Macquarie University
Sydney NSW 2109 Australia
phone: 612 9850-8613
FAX: 612 9850-9231
 
email: ken.cheng@mq.edu.au

Skype: kcycheng

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Research

My research crosses mechanistic, functional and evolutionary questions in the study of animal behaviour. A central theme of my research concerns how animals process information. Dealing with information is crucial for many important behaviours in an animal's life, including choosing a mate, avoiding predators, and finding food. The range of species I have studied include humans, rats, pigeons, chickadees, Clark's nutcrackers, desert ants, and honeybees. A large part of my research has concentrated on how animals deal with space and time. I have collaborations with a number of researchers around the world.

Macquarie University funds postgraduate students from anywhere in the world with scholarships. I am currently looking for students to study the behaviour of ants in Australia. We are studying one species of desert ant, the highly thermophilic the red honey ant Melophorus bagoti, that lives in cluttered semi-arid habitats. We are also launching into the study of bull ants found on campus here. The latest venture is to provide reconstructed reality for ants, replicas of their natural scenes so that we can better control and manipulate the cues. I welcome enquiries from those interested.

Research links

For prospective Masters and PhD students

 


Current research

 

ants

I have been collaborating with Ruediger Wehner of the Brain Research Instiitute, University of Zurich on research on desert ants. Wehner has established and run a field research station in Tunisia for over 30 years. The subject of his research has been various species of the desert ant, genus Cataglyphis. Much about the navigational behaviour of these ants is known as a result of the very fruitful work of Wehner and his collaborators. But of course much more remains to be researched.

More recently, starting this century, we have collaborated on studying an Australian desert ant located in Central Australia. Known as the red honey ant (pictured here), Melophorus bagoti shares many characteristics with Cataglyphis. It is long-legged, active in the heat of the day, and moves fast. But their ecology differs from that of Cataglyphis's. The deserts of Central Australia are richer in plant life, making the visual world of M. bagoti cluttered with landmarks in the form of grass tussocks, bushes, and trees. We are interested in comparing the navigational behaviours of Melophorus with those of Cataglyphis. We have two reviews on the work (Cheng et al., 2009, Behavioural Processes; Cheng et al., 2014, Behavioural Processes).

We have also done some research on a species of Melophorus ants (yet to be named) living on the salt pans of South Australia. This environment is barren and devoid of landmarks. We only found the animal in December 2011. One paper has been published (Schultheiss et al., 2012, Australian Journal of Zoology).

In the latest venture, I am collaborating with a team (Jochen Zeil, Ajay Narendra, Andy Barron, and including Ruediger Wehner) to delve into the neurobiology of navigation in ants. Australian bull ants, genus Myrmecia, will feature. We are only just getting started.

Cataglyphis in Tunisia

Melophorus in Central Australia

Saltpan Melophorus ants in South Australia



Recently, we have tested the role of ultraviolet (UV) wavelengths on how it affects the ants' navigation using the terrestrial panorama. We trained ants to come to a feeder, both in an artificial arena as shown in the photo, and in the natural scenery (imagine this set up without the circular arena). Our key manipulation was blocking the scene that the ants saw at the feeder with a transparent plastic that cut out most wavelengths under 400 nm. This would greatly reduce the stimulation for the ants' UV receptor, although not completely, a knock-down but not a knock-out manipulation. The surrounding plastic was uniformly tall.

We hypothesised that the biggest difference in UV-green contrast would define where the skyline is for ants. The sky contains lots of UV light, while earthly objects reflect a lot of green. This idea is due to Ralf Moeller. The UV-blocking clear plastic would make the biggest UV-green contrast at the top of the clear plastic, making the skyline uninformative. We tested ants that had gone home with food, were captured again and brought back to the start of the journey for a test. Indeed, these zero-vector ants oriented worse with the clear plastic, giving some support to the hypothesis.



In this figure, ants were tested with their natural scene. The tested ants had travelled to the feeder that they had visited many times, took food, returned home, and were captured just before they entered their nest. These ants are called zero-vector ants because they have run off the vector calculated from path integration. They were returned to the feeder for a test, and the graph represents their heading: where they crossed a circle at 30 cm distance from the release point. On the x-axis, 0 is the nest direction, while 180 and -180 both represent the opposite direction (nest-to-feeder). The graph is thus cylindrical. Ants attempting to head home with the UV-blocking plastic around them (UV block, grey dots) were more scattered in their distribution of headings. The curve fits are splines without theoretical import, meant to help readers to visualise the data.

The story is more complex, with more conditions effected. A paper has appeared: Schultheiss, P., Wystrach, A., Schwarz, S., Tack, A., Delor, J., Nooten, S. S., Bibost, A.-L., Freas, C. A., & Cheng, K. (2016). Crucial role of ultraviolet light for desert ants in determining direction from the terrestrial panorama.  Animal Behaviour, 115, 19-28.


Some old stories

 

memory in honeybees

My experiments on honeybees have investigated how the foragers find a rewarding place. Past work focussed on the theme of the mechanisms by which honeybees find a place. Current research focuses on the topic of how the worker retrieves the correct memory of a place and whether and how multiple memories are integrated. Catherine Prabhu recently completed a thesis on how honeybees deal with conflicting evidence.

research on free flying honeybees

gallery of bee pictures

 


geometry and navigation

This is a topic that I started to study in my graduate school years. It has quite taken off. I haven't done any more empirical work on it, but have contributed theoretically. The unkind might say that I have milked other people's work. The kinder might say that theoretically contributions can be important.

Geometry is the layout of surfaces in the environment. What any animal learns about geometric cues is a matter of some debate. The link has more information.

geometry and navigation

 


Clark's nutcrackers

The Clark's nutcracker has a prolific spatial memory. The bird lives in the Rocky Mountains of North America, and stores a lot of food, mostly pine seeds. It relies on its stored caches for sustenance over winter. It can remember thousands of caches for months. Alan Kamil and Russell Balda have done many studies on this bird. We now know that they use landmarks to remember and retrieve their caches. I collaborated with Debbie Kelly, now at the University of Manitoba, and Alan Kamil in figuring out the cues used by these birds to remember cache locations in the lab.

 


crab spiders and bees

I collaborated with Astrid Heiling and Marie Herberstein of the Department of Biological Sciences, Macquarie University, on the study of signal interactions between crab spiders, flowers, and bees, which are potential prey for spiders. Crab spiders may lure bees deceptively with their body coloration, to the detriment of the bees.

crab spiders and bees


Spatial generalisation in bees

In spatial generalisation, a worker is trained to find food in a container at one location. After sufficient training, she is presented a container at various locations, including the training location. The question at stake is: how should the animal 'bet' on whether the container at each location has food or not. See the link for some answers.

 

Self control in bees

In experiments on self control, the forager is presented with two choices of rewards. One is immediately available but is small. The other reward is larger, but the forager has to wait some time for it. Waiting for a larger reward is technically called self control, lack of which is often a nemesis in human behaviour. Bees show a good deal of self control.


learning and face perception in humans

I have an ongoing collaboration with Marcia Spetch of the Department of Psychology, University of Alberta. Students and colleagues have been collaborators, including Colin Clifford of the School of Psychology, University of Sydney. We investigated a number of topics in spatial and temporal cognition in pigeons and humans. A story on spatial cognition is linked below.

We found both peak shift and range effects in human face identification.

 

Spatial cognition in humans

Marcia Spetch and I have published a substantial story on spatial cognition in university students, investigating spatial generalisation and peak shift. Students were presented marked locations on a computer screen, and had to bet whether it was the rewarding 'hot' spot. Our latest work, published in 2010 online, tries to provide functional explanations for all range effects in human learning.

 

Perception of bilateral symmetry

Two colleagues at our University, Chris Evans and Peter Wenderoth, both now deceased, collaborated with me in studying the perception of bilateral symmetry in complex stimuli in humans. Bilateral symmetry means mirror symmetry. It is often an attractive property in mate selection. We studied in human subjects the perception of symmetry in complex, naturalistic objects.

 

Virtual ecology of bee-flower interactions

Chris Evans and I have been exploring this topic 'on the back burner' for a number of years. The idea is to present virtual flowers, generated on computer to real bees. Each flower contains the same reward, but the bees get to choose which flower to land on and get their sugar water from. The virtual aspect makes it possible to manipulate key parameters in evolution, such as costs in producing flowers. It also speeds up the 'evolutionary' process, making generations go by in days. We think that this makes a great project for an interested graduate student.


Publications and curriculum vitae

selected publications and abstracts

curriculum vitae and publication list (some of which can be downloaded)


Students

Cody Freas: studying navigation in ants

Tim Pearson: studying auditory communication in flying foxes



Teaching

I teach BIOL122 Biological Basis of Behaviour. A brief description:

The Greatest Show on the Planet. BIOL122 is a suitable introductory science course for all students. It offers an integrative approach to the amazing world of behaviour. Basic mechanisms are covered, together with function and evolution. Lecture topics include micro- and macro-evolution, evolutionary origins of behaviour, basic neuroscience, perception, learning, brain and behaviour, and topics in animal behaviour. Lectures culminate with some reflections on the lives of humans in our modern world and the role of culture in human evolution.

For prospective Masters and PhD students