Major research themes of the Animal Behaviour Group
at La Trobe University

Animal communication: motion signals		Animal communication: acoustic signals
Animal communication: vibration signals		Other projects

View brief summaries of current projects under these themes in the adjacent slides.

• Current projects on motion signals of lizards

   

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  	Evolutionary simulations
  	Virtual environment reconstructions (3D animations)
  	Comparative study of agamid lizard signalling
  	Anolis of Ecuador
  	Factors affecting signal structure
  	Geographic variation in jacky lizards

• Motion signals → Evolutionary simulations

   

  Combining tools from evolutionary robotics and behavioural ecology to address movement-based signal evolution. The approach uses live animals as selective agents to optimise the fine structure of a motion signal in an artificial evolution environment. A tight feedback loop between the responses of real animals and evolving signals will be implemented in an evolutionary simulation controlled by a standard genetic algorithm.

  
  

  Signals are defined by binary strings that encodes movement information that is translated into a signal using animation software. Animations are presented to live lizards and relative effectiveness calculated before signals are selected and crossed to give the next generation and the cycle starts again

  By manipulating the environmental conditions in which this evolution takes place, we can systematically explore what makes a signal effective from the perspective of a receiver under close to natural conditions.

   

  Participants: Richard Peters (La Trobe Uni) & Jan Hemmi (The ANU).

• Motion signals → Virtual environment reconstructions

   

  We will use a virtual lens to take a fresh look at these signals in the environmental context in which they are performed to understand how signalling conditions affect signal efficacy. Systematic manipulation of the scene allows us to consider circumstances influencing signal effectiveness.

  
  

  A scene in nature ... recreated in the virtual world ... can help understand signalling behaviour

  The approach involves:
  •  reconstructing microhabitats (complete with plants and lizards)
  •  simulate environmental conditions
  •  analyse the scene to identify the relative effectiveness of the signal.

  
  

  Participants: Richard Peters (La Trobe Uni) & Tom Chandler (Monash Uni)

• Motion signals → Dragon wars!

   

  Our work has generated predictions about the relationship between signal design features and habitat structure. The Australian agamid lizards represent an exciting opportunity to test these predictions, while at the same time, documenting the diversity in their signals in unprecedented detail. Many Australian agamid lizards are known to utilise movement-based displays but detailed knowledge is lacking.

   

  
  
  
  
  

  Participants: Jose Ramos & Richard Peters (La Trobe Uni)

   

• Motion signals → Anolis lizards in Ecuador

   

  This study will focus on several Anolis species of Ecuador to evaluate the replacement or co-utilization of motion and colour during signaling and the influence of habitat on the structure of displays within and between species.

   

  Anolis biporcatus | Caimito, Ecuador (Photo: A. Narvaez) Anolis fusoauratus | Yasuni, Ecuador (Photo: A. Narvaez) Anolis trachyderma | Yasuni, Ecuador (Photo: A. Narvaez) Anolis transversalis | Yasuni, Ecuador (Photo: A. Narvaez)

   

  Participants: Andrea Narvaez, Richard Peters (La Trobe Uni) & Omar Torres-Carvajal (Pontificia Universidad Católica del Ecuador)

   

• Motion signals → Factors affecting signal structure

   

  Focus: Role of predators

  

  
  Whether predators influence movement-based signalling strategies is unclear. Models of signal evolution predict that the threat posed by eavesdropping predators will influence the evolution of signal structure and moment-to-moment variation in signalling behaviour. We are exploring this possibility in Jacky lizards using the kookaburra as our model predator.

  
  

  Participants: Richard Peters & Katy Weller (La Trobe Uni)

   

  Focus: Energetic costs

   

  Movement is coordinated by the musculature and the smaller muscles, such as those in the tail, require less energy to function than larger muscle groups, such as the limbs. For this reason the tail seems ideally suited to sustained signaling and matches their behaviour. We are examining the biochemical and contractile properties of these muscles to verify whether this is the case. We are measuring Citrate synthase (CS) activity, which is a marker of oxidative capacity and mitochondrial abundance and an indicator of the oxygen requirements of the muscle.

   

  Participants: Richard Peters, Peta Taylor & Robyn Murphy (La Trobe Uni)

  
  

• Motion signals → Population differences in jacky lizards

   

  Jacky lizards are found in different habitats across New South Wales and Victoria, with their range believed to extend to Queensland and South Australia. Marco Baquero is examing population differences in behaviour, including signalling.
  Video of Jacky lizard courtesy of Marco Barquero

  
  

  Participants: Marco Barquero, Martin Whiting (Macquarie Uni) & Richard Peters (La Trobe Uni)

Alarm calling by zebra finches

Vocal communication between conspecifics is vital for survival in many vertebrate species. Many animals produce what is generally known as an alarm call, a sound produced in the presence of a threat and mainly used to warn conspecifics of the danger. Alarm calling does not only benefit conspecifics, it can also benefit sympatric heterospecifics if they are able to associate the call with danger. Eavesdropping on the alarm call of a heterospecific is useful if both species are vulnerable to the same predators. The response may be due to the acoustic properties of the heterospecific call,, or due to learning and recognising that the call signals alarm. Very little is known about how zebra finch (Taeniopygia guttata) respond to predators, in particular whether and how they use alarm signals. Anecdotal evidence strongly suggests alarm calling is utilized, but the details of their structure and function are not clear. We will be conducting a series of studies on wild and captive birds to identtify if and how zebra finches respond to predatory threat.

Participants: Nicole Butler, Richard Peters, Christine Giuliano (La Trobe Uni), Rob Magrath (The ANU), Simon Griffith (Macquarie Uni) & Andrea Griffin (Newcastle Uni)

Vibratory signalling by psyllids

Psyllids are small cicada-like insects that are pests of forestry because populations cause extensive leaf loss and sometimes tree death. Mating strategies are crucial to their success and Australian psyllids are believed to use vibratory signals for attracting mates, although the mechanisms are largely unknown. We are characterizing the vibratory signals of several psyllids and the transmission properties of host plants to investigate the mechanisms of mate attraction.

Below: Duet and image of Anoeconeossa bundoorensis

Participants: Martin Steinbauer, Richard Peters, Umar Lubanga, Rachel Wood (La Trobe Uni) & Gary Taylor (Adelaide Uni)

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  Avoiding predators

  Click to show the lizard

  
  

  
  Many animals exhibit brilliant colour patterns - jacky lizards are not one of these species. However, they do exhibit interesting body patterns (see above middle) which may serve an important functional role in camouflage (see above-right: Rollover to highlight the lizard; click for an enlargement).

   

  We will investigate the functional significance of body patterns and markings of jacky lizards by photographing them in the wild and use modern quantitative techniques to characterise them in the context of their natural surroundings. We will also run choice tests in large captive facilities in our Zoology Reserve to see whether lizards choose basking sites wisely under the threat of predation.
  

   

  Participants: Richard Peters, Jonathan Salisbury (La Trobe Uni)

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• Motion sensitivity

  
  

  Animal sensory systems might limit signal structure to be within a range of possible designs, or exert strong directional selection towards a set of features. Recent empirical evidence strongly suggests that signalling strategies, particularly for eliciting attention, are partly determined by the context-specific demands placed on the motion vision mechanisms of receivers. Behavioural studies will complement morphological on Jacky lizard retinas by our collaborators to assess motion sensitivity and acuity.

  
  

  Participants: Richard Peters (La Trobe Uni), Shaun New & Jan Hemmi (The ANU)