Honours projects for 2011 are described below arranged alphabetically by primary supervisor. Visit the FORMS page to download an expression of interest document for you to complete and submit to the Zoology office.

2011 Honours Projects

Quantifying the ecological benefits of environmental flow regimes to a floodplain of the lower Murray-Darling

An exciting collaborative, multi-disciplinary ecological study is about to commence. The goal of this study is to investigate the effects of floodplain inundation on a selection of key groups of organisms. The floodplain under investigation is on the lower Murray River at Mulcra Island, northern Victoria. Significant environmental works worth $6.2 M (including the construction of regulators and levee banks) are currently being undertaken at Mulcra Island as part of The Living Murray Program (a Federal Government initiative). Annual floodplain inundation will be possible once the works are completed in late 2010. Quantification of the benefits of these environmental flow regimes for floral & faunal communities inhabiting the floodplains has not been a high priority in the past. Generous funding from industry partners has created an extraordinary opportunity to attempt to fill this knowledge gap. The effects of floodplain inundation will be investigated by comparing sites of known flooding history, as well as monitoring faunal populations before and after controlled flooding events.

Spatial patterns of Murray cod reproduction along a weir-pool gradient.
Co-supervised by Clayton Sharpe, Murray Darling Freshwater Research Centre (MDFRC).

Weirs and the hydrological changes that impose to the natural flow of lowland rivers are known to cause a multitude of effects upon fish. Some species benefit from the pool environment created by weirs, whilst others are thought to be negatively impacted as they have adapted to flowing environments and hydrological variability. One such species considered to be negatively impacted by the effects of weirs is the Murray cod. This projects to examine how weirs negatively impact upon the ecology of Murray cod reproduction by examining spatial patterns of Murray cod reproduction along two reaches of the Murray River that run from free-flowing zones into weir-pools. The project would involve blocks of field work on the Murray River, and students would be training in boat handling and electro-fishing. This project would qualify for the student to apply for a MDFRC scholarship.

Habitat use by young-of-year (age 0+) and juvenile ( 1-4+) Murray cod.
Co-supervised by Clayton Sharpe, Murray Darling Freshwater Research Centre (MDFRC).

Murray cod love snags. This is indeed the case for adult and sub-adult Murray cod, who establish home ranges of 5m that consist of highly complex individual structural woody habitats (‘snag complexes) and utilise snags as spawning and nesting sites. However, very little is known regarding the habitat preferences or requirements of age 0+ or 1+ Murray cod. As little fish grow up to become big fish, knowledge of habitat requirements at age 0+ is crucial for the management of rivers and for habitat rehabilitation efforts aimed at providing for rehabilitation of Murray cod populations. This project aims to examine the habitat use and preference of 0+ Murray cod in the Darling River. The study will be conducted in a location where both adult and 0+ Murray cod are abundant, and will establish habitat use from a range of available habitats thus determining habitat preference. The project would involve blocks of field work on the Murray River, and students would be training in boat handling and electro-fishing. This project would qualify for the student to apply for a MDFRC scholarship.

Reintroduction of Murray Crayfish (Euastacus armatus) to Mullaroo Creek and the Lower Murray River.
Co-supervised by Bernard McCarthy, Murray Darling Freshwater Research Centre (MDFRC).

The Murray Crayfish was once abundant throughout the Lower Murray and supported commercial and recreational fisheries in South Australia until the 1950-60s. Recent research along the 700km Mallee reach of the River Murray revealed the absence of Murray Crayfish downstream of Mildura to the South Australian border. Causes for the decline are not known, although changes in habitat, river regulation and pollution have been implicated. This project will include a trial restocking of Murray Crayfish to determine their survivability. Twenty adult, free-ranging Murray Crayfish (14 egg-bearing females, 6 males) will be introduced at two sites and individuals will be monitored by radiotelemetry. The project will also involve an investigation of Murray Crayfish density along a free-flowing river to weir-pool gradient. The project would involve blocks of field work on the Murray River, and students would be training in boat handling. This project would qualify for the student to apply for a MDFRC scholarship.

The research of my group proceeds along two distinct, but complementary, lines. The first is basic research in the field of behavioural ecology-studying the evolution and adaptive value of social behaviour, particularly among birds. It involves testing current hypotheses using empirical data collected in the field. The second is applied research in the field of conservation biology-studying ecology in conservation-related contexts, with a particular focus on the response of fauna to fire.

2011 Honours Projects

How does landscape mosaic burning in Box Ironbark woodlands affect the composition and behavior of bird communities?
There is currently great public pressure to increase the extent of prescribed burning conducted in native forests, with the aim of reducing the risk of catastrophic wildfires on days of extreme fire danger. Little is known of the role or impact of fire on the wildlife of Box-Ironbark woodlands. This Honours project is part of a much larger collaborative project being conducted by La Trobe (Assoc Prof Mike Clarke) and Deakin Universities (Prof Andrew Bennett and Dr Greg Holland), in which 8 landscape blocks are going to be subjected to prescribed burning in the Autumn of 2011 by the Department of Sustainability and Environment. The aim of the project will be to compare the composition and behavior of bird communities in burnt and unburnt landscapes before and after prescribed burning.

Dr Travis Dutka and A/Prof Mike Clarke
Food Discrimination Behaviour of Coastal Pelicans (Pelecanus conspicillatus): when opportunity knocks, should you always open the door?
What makes an opportunistic feeder reject a nutrient rich meal? Obviously there must be some adverse affect that outweighs any possible benefit to the organism as a whole.
Firstly, the observation that has fascinated me over the years is that Pelecanus conspicillatus will not eat elasmobranch flesh high in nutritional value, but will continue to devour as much teleost fish scraps of poorer nutritional value as they can. It is quite startling to watch. Whilst this is my own observation, I have observed this phenomenon for more than 20 years, at several different coastal locations and with different generations of pelicans and am absolutely confident it can be empirically validated. The reasoning I think is that being a seabird they have nasal salt glands and therefore fresh drinking water is often limiting so they cannot afford to waste water on excreting urea if it is unnecessary. Elasmobranches actively reabsorb urea into their blood for osmoregulatory purposes as opposed to teleost that don’t. What I would like to know is to they possess the physiological ability to detect urea via olfactory sensitive means or have they behaviourally ‘learnt’ by trial and error that eating them gives them digestive/dehydration issues. Whilst pelicans are known to eat carrion of all descriptions, fish crabs, birds, turtles etc. sharks are not frequently part of their diet so I think it is a learnt behavior and not due to a physical structural ability to detect nitrogenous waste products.

I have done some preliminary research and this observation has not been described before in the literature that I am aware of. Additionally, I have been thinking about physiological reasons why they would not eat elasmobranches and have come up with a physiological constraint that prevents them from taking advantage of this nutrient rich food source. It seems water balance/conservation is the most important barrier for the pelican to hurdle if it consumes elasmobranch fishes

Primarily, my research focuses on how skeletal muscle fibres normally function and how their function might be altered under diseased/aberrant or fatigued states. Of particular interest is trying to understand the exact nature of how muscles fibres produce and respond to action potentials, which are the normal physiological stimuli. My studies predominantly utilise single mechanically-skinned muscle fibres that have their surface membrane (sarcolemma) removed, yet still function more or less the same as they do in situ. The technique is extremely useful because it allows direct access to the inside of the cell and therefore it can be precisely and rapidly altered as desired to test a particular treatment.

2011 Honours Projects

Dr Travis Dutka and A/Prof Mike Clarke
Food Discrimination Behaviour of Coastal Pelicans (Pelecanus conspicillatus): when opportunity knocks, should you always open the door?

What makes an opportunistic feeder reject a nutrient rich meal? Obviously there must be some adverse affect that outweighs any possible benefit to the organism as a whole.

Firstly, the observation that has fascinated me over the years is that Pelecanus conspicillatus will not eat elasmobranch flesh high in nutritional value, but will continue to devour as much teleost fish scraps of poorer nutritional value as they can. It is quite startling to watch. Whilst this is my own observation, I have observed this phenomenon for more than 20 years, at several different coastal locations and with different generations of pelicans and am absolutely confident it can be empirically validated. The reasoning I think is that being a seabird they have nasal salt glands and therefore fresh drinking water is often limiting so they cannot afford to waste water on excreting urea if it is unnecessary. Elasmobranches actively reabsorb urea into their blood for osmoregulatory purposes as opposed to teleost that don’t. What I would like to know is to they possess the physiological ability to detect urea via olfactory sensitive means or have they behaviourally ‘learnt’ by trial and error that eating them gives them digestive/dehydration issues. Whilst pelicans are known to eat carrion of all descriptions, fish crabs, birds, turtles etc. sharks are not frequently part of their diet so I think it is a learnt behavior and not due to a physical structural ability to detect nitrogenous waste products.

I have done some preliminary research and this observation has not been described before in the literature that I am aware of. Additionally, I have been thinking about physiological reasons why they would not eat elasmobranches and have come up with a physiological constraint that prevents them from taking advantage of this nutrient rich food source. It seems water balance/conservation is the most important barrier for the pelican to hurdle if it consumes elasmobranch fishes

My research group investigates a range of topics in terrestrial insect ecology, including competition, ant-plant interactions, morphometrics and restoration ecology. Insects are the focus group because they make up the bulk of biodiversity and perform many important functional roles in ecosystems. Much of our research is focused on how humankind influences insect communities and how to conserve species diversity and the ecological functions performed by insects. The fundamental science questions covered by research in this lab focus on the role of biotic processes, such as competition, in structuring insect communities. We address these questions with a combination of mensurative and experimental studies, taking into account the range of scales at which processes may operate. Focal organisms include ants, saproxylic beetles, parasitoids and spiders.

2011 Honours Projects

Nest relocation behaviour and navigation in beauty ants, Calomyrmex sp.
Co-supervised by Ajay Narendra (The ANU)

Nesting behaviour varies considerably between ant species, with some ants often relocating to new nesting sites. Little is known about why ants relocate to new nests, but factors such as disturbance, environmental stress or the availability of food resources may be important. It is also unclear how ants choose a new nest site or navigate toward this new nesting location. This project addresses the following questions in Calomyrmex sp. in semi-arid mallee: a) What drives nest relocation? and b) How do ants navigate to novel nest sites? Initial observations suggest that these ants commonly carry their nestmates between nests and present an ideal target species with which to address these questions.(mid-year start)

Seed selection and dispersal by ants: Is it based on elaiosome size or chemistry?
Co-supervised by Pete Green

Ants are important dispersers of seeds and many seeds are adapted specifically for ant dispersal. Such seeds usually bear an elaiosome: a fat-rich food body attached to the seed. Elaiosome mass and seed mass are known to scale allometrically, but it is unclear whether this is a result of selection by ants or some other factor. This study will experimentally test the role of seed:elaiosome mass and seed chemistry in determining ant choice and therefore dispersal success of plants with elaiosome-bearing seeds.

How do reintroductions of critical weight range mammals affect vegetation?
Co-supervised by Pete Green

More than twenty critical weight range (CWR) mammal species have become extinct since European colonisation of Australia and more are threatened. Many of these species are active diggers, so the loss of this trophic level may have had significant impacts on the success of species that respond to soil disturbance. Scotia Sanctuary, in western NSW provides an opportunity to test effect of this digging in an environment with substantial populations of threatened omnivores. An exclusion experiment will be used to test the effect of digging by CWR mammals on germination success. This study will provide important insights into the broader effects of the functional extinction of this important trophic group.

My main research interest is the ecology of disturbance. Disturbances such as fire and herbivory are known to be shapers of ecosystem composition and function, but disturbances may also interact with each other in unexpected ways. In addition vegetation and fauna may not only be influenced by but also influence disturbance regimes. Unravelling these complex relationships is an intriguing area in which to work and crucial to the conservation management of many Australian ecosystems. I am currently working on the Habitat Refuges Project led by A/Prof. Mike Clarke (La Trobe Uni) and Prof Andrew Bennett (Deakin Uni). This project is examining the effects of the 2009 Kilmore-Murrindindi fires on biodiversity.

2011 Honours Projects

Do lyrebirds create fire breaks? Effects of superb lyrebird (Menura novaehollandiae) foraging on fire potential.

Lyrebirds are best known for their mimicry of calls by other bird species and other sounds. Lyrebirds are also ecologically important due to their foraging for invertebrates in the litter layer of forests. They do this by using their large feet to rake through the litter. Lyrebird foraging has been shown to be significant disturbance within forests, with up to 200 tha-1 of soil and litter being displaced annually. This disturbance accelerates litter decomposition and hence nutrient cycling. The bare ground created by lyrebird scratching may also provide sites for the establishment of plant seedlings.

Transferring the effects of lyrebird foraging into a fire ecology context, areas in which lyrebirds are present are characterised by a paucity of fine fuel at ground level. This can occur over wide areas, particularly along the margins of wet gullies. These gullies are likely to be important fire refuges for fauna and fire sensitive plants. Due to their topography and micro-climatology, gullies are less likely to burn than the surrounding landscape. However field observations suggest the possibility that the fuel reduction caused by lyrebirds also contributes to reducing the likelihood of gully vegetation burning. This idea will be tested using a combination of natural and manipulative experiments in the foothill forests north of Melbourne.

Habitat Refuges Project- vegetation studies

Within the Habitat Refuges Project we plan to examine several aspects of how fire and fire regimes influence vegetation. Vegetation patterns created by fire in turn have implications for fauna. Some of the issues we wish to investigate are:

Visible versus invisible fire mosaics- What are the effects on vegetation patterns of fire regime compared to those of a major fire event?
The landscape legacy of fire consists of ‘visible’ and ‘invisible’ mosaics. The visible mosaic is the pattern produced by the most recent fire(s) within a landscape and is a product of variation in burn severity within and between burnt patches. The invisible mosaic refers to the patterns arising from the cumulative effects of past fires (the fire regime). Vegetation and (potentially) faunal patterns are determined by the interplay of these two mosaics. We will investigate the relative contribution of the visible and invisible mosaics to vegetation patterns in the wake of a major fire event. In particular we will focus on the issue of whether a large intense fire homogenises vegetation across the landscape, or does the ‘signal’ of fire history persist?

Tree persistence and recruitment in relation to fire history- How does variation in fire history influence demography of trees?
Fire is an important factor in the life cycle of trees, causing mortality for some individuals while also facilitating establishment of new plants. We will examine the effects of fire history on tree demography. In particular we will focus on large old trees, which are important faunal habitat. Questions we will seek to answer include: Are large old trees more likely to occur in areas subject to a particular fire regime? How does fire history influence the presence of cohorts of ‘future’ large old trees?

Influence of fire history on vegetation regenerative capacity- how does variation in fire history affect soil seed banks?
For plant species to persist in a post-fire landscape they must regenerate either vegetatively or from seed. We will examine the effects of fire history on the regenerative capacity contained within soil seed banks. In particular we will focus on the potential, in the wake of a major fire event, for species to regenerate after a subsequent fire.

I am a member of the Muscle Cell Research Group within the Department of Zoology. Within this group, I head the Muscle Biochemistry Laboratory. Our group is internationally renowned for work on muscle physiology and biochemistry using mechanically-skinned single muscle fibres. The focus of my future research is to understand numerous calcium-dependent processes in skeletal muscle, in particular how these may be affected in certain disease states, using both animal and human models. For much of my work I use an innovative development of the technique of Western blotting to analyse proteins in small segments of individual skeletal muscle fibres. This approach allows proteins to be examined in particular fibre types and advantageous because of their differential expression between different fibre types of skeletal muscle. As a result, an aspect of my research addresses questions which are currently confounded in the literature owing to the difficulty of interpreting biochemical data from samples of mixed fibre types. I collaborate with other members of the Muscle Cell Research Group to examine physiological responses of skeletal muscle fibres during controlled interventions and then examine the same fibres used for physiological assays for biochemical changes. In addition, I collaborate with other members of the Zoology department to examine the metabolic and contractile profile of skeletal muscle in various species (eg. reptiles – Dr Richard Peters, marsupials – Dr Kylie Robert).

Overall, my research objectives are to further investigate the importance of many key proteins including calpains, calsequestrin and caveolin-3 and to identify mechanisms of their regulation in skeletal muscle function. The proteins of interest are each involved in certain disease states, through an aberration either in their expression and/or regulation. The Muscle Cell Research Group is supported by two Research Assistants (one of whom is dedicated to my Biochemistry laboratory) and one Technical Assistant. My major research funding is through National Health and Medical Research Council of Australia (NHMRC).

I would anticipate that I would be able to offer a maximum of TWO Honours projects in 2011.

2011 Honours Projects

Dr Robyn Murphy and Prof Graham Lamb
Calpains are Ca2+-dependent proteases and exclusive to skeletal muscle is the 94 kDa isoform, calpain-3 (or p94). If calpain-3 is absent or it is present as a non-functional protein, then an individual will develop limb-girdle muscular dystrophy type 2A (LGMD2A). The following two projects involve examining aspects related to the regulation of calpain-3 in rodent skeletal muscle. The outcomes will help provide insight into factors relevant to understanding LGMD2A.

The Ca2+-dependency of calpain-3 activation in fast- and slow-twitch rat skeletal muscle
Mechanisms regulating the proteolytic activity of calpain-3 are currently poorly understood. At rest, intracellular [Ca2+] is about 50 nM and it has been shown in rat fast-twitch muscle fibres that calpain-3 is activated if this is raised to ~200 nM for a prolonged period of time (1 hour). It is also known that calcium handling properties are different between fast-twitch and slow-twitch muscle. In this project, the Ca2+-dependence for the activation of calpain-3 in the two types of muscle fibre types will be examined. This will require preparing solutions with precisely controlled [Ca2+] and applying these to individual skeletal muscle fibres where the surface membrane (or sarcolemma) has been removed by mechanical dissection. This approach allows the effective intracellular environment to be precisely controlled.

Biochemical analysis of Ca2+-handling proteins in fast and slow-twitch skeletal muscle from calpain-3 deficient mice.
Calpain-3 is activated under very tightly controlled intracellular Ca2+-concentrations. It is therefore possible that when calpain-3 is absent or aberrant, such as in the calpain-3 deficient mice, that proteins involved in Ca2+-regulation are differentially expressed. Whilst it is known that calcium handling properties are different between fast-twitch and slow-twitch muscle, it is not known if the absence of calpain-3 affects the expression of these proteins. Proteins to be examined in this project include calsequestrin (CSQ1 and CSQ2), SR Ca2+-ATPase – SERCA, ryanodine receptor – RyR1 and dihydropyridine receptor – DHPR. A possible extension of this work would be to examine physiological properties of SR Ca2+ release in mechanically-skinned fibres from calpain-3 knock-out mice.

Dr Robyn Murphy and Dr Travis Dutka
Effects of taurine on chloride conductance and force responses in mechanically-skinned single fibres
Taurine plays an important role in many cells, including muscle, and within the body taurine has various physiological functions. In both skeletal and cardiac muscle taurine can alter the regulation of a number of ion channels and it can alter the Ca2+-handling properties of the cells. Taurine has been used as a therapeutic agent in various disease states, including myotonias and dystrophies, muscle injury and disuse, and aging. Additionally, taurine is an active ingredient and present in high concentrations in many soft/stimulating drinks (eg. V). The precise effect(s) and therapeutic advantages of taurine are yet to be fully tested.

Muscle requires a high Chloride conductance in order to maintain normal membrane polarization, in particular the t-tubular system potential. A reduced Chloride conductance can have major consequences to the excitability of muscle. It has been suggested that taurine can modulate Chloride conductance by altering the function of the Chloride channel (ClC1). Therefore, this project will examine the effect of exogenously added taurine at various concentrations on the maintenance of t-system polarization and the ability of a muscle fibre to produce force in fibres where the surface membrane (or sarcolemma) has been removed by mechanical dissection (mechanically-skinned single fibres). To determine pathway(s) involved, blockers such as 9-AC (a specific blocker of the chloride channel) and phorbol esters (which would block the protein kinase C mediated modulation of the chloride channels) will be used. Biochemical analyses will allow an understanding of what modifications occur.

Dr Robyn Murphy and Dr Kylie Robert
The effect of high fat feeding on properties of skeletal muscle in the fat-tailed dunnart
The Fat-tailed Dunnart (Sminthopsis crassicaudata, shown right) is a good model species for other endangered Dasyurid species, including the Dibbler (Parantechinus apicalis), the Tiger quoll (Dasyurus maculatus) and the Tasmanian devil (Sarcophilus harrisii). In this project fat-tailed dunnarts will be used for laboratory based experiments investigating how perturbations of diet affect biochemical properties of skeletal muscle. In other species, for example rodents and humans, skeletal muscle is known to make adaptive metabolic changes in response to dietary intervention. Very little, however is understood about how such dietary manipulations influence the metabolic profile of marsupials. This project will combine the expertise of Drs Murphy and Robert to explore the effect of a high-fat diet on properties of skeletal muscle in the marsupial rodent, the fat-tailed dunnart.

Dr Robyn Murphy and Dr Richard Peters
A comparison of the metabolic and contractile profile of skeletal muscles involved in behavioural signaling in the Jacky lizard (Amphibolurus muricatus)
It is well established that differences in fibre type, such as the relative abundance of highly aerobic, fatigue resistant slow-twitch fibres and the glycolytic and readily fatiguable fast-twitch fibres, affect the ability of given muscles to perform specific tasks. Much research has been undertaken in typical laboratory animals, such as rodents, however there is less known about skeletal muscle from more obscure animals. In this study, well-established biochemical techniques such as fibre typing (eg. histochemistry) and measuring oxidative capacity (eg. citrate synthase) will be undertaken to characterize skeletal muscle obtained from two different regions (eg. tail, limbs) from the Jacky lizard. The outcomes will be related to known functions of those particular muscles during territorial signalling.

Research in the Peters Lab considers the behavioural ecology of motion signaling and integrates knowledge and techniques from a range of scientific disciplines. Work also investigates more broadly the visual ecology of animals. I welcome discussion about the projects listed below, but also open to suggestions about other projects within a Visual Ecology theme.

 

 

Effect of predators on signalling behaviour of Jacky lizards
The Sensory-Drive model of signal evolution predicts that the threat posed by eavesdropping predators will influence the evolution of signal design and lead to moment-to-moment variation in signalling behaviour. When predator pressure is high, signals are predicted to be more cryptic; more elaborate and conspicuous signals should evolve if predators are rare. The role of predators in determining movement-based signalling strategies has not been investigated. This project will first assess the response of Jacky lizards (Amphibolurus muricatus) to model predators. In this study you will identify stimuli that vary in apparent threat to lizards. One of the stimuli that evoke recognition in the lizards without leading to escape responses will be used in a subsequent experiment. Male lizards will be presented with a rival male with or without concurrent presentation of the predator model. The objective is to compare signalling behaviour in the presence/absence of simulated predators. (Mid-year start)

Motion sensitivity in Jacky lizards
Collaboration with Shaun New (The ANU)

Behaviour and vision are inextricably linked and identifying how one constrains the other is a fascinating area of study. Our particular interest within visual ecology concerns motion vision, focussing particularly on Jacky lizards (Amphibolurus muricatus), which rely on movement for all aspects of their lives including communicating with conspecifics. However, our knowledge of how sensory capabilities direct and/or constrain signal evolution is rather limited. For example, do sensory systems simply constrain signals to fall within some broad range of possible designs, or do they exert strong directional selection towards some optimal set of signal features? This project will use behavioural experiments with captive lizards to assess basic motion sensitivity in Jacky lizards. Additional experiments will also consider predictions from computer modeling that predicts the effectiveness of eye-catching movements will depend on the environmental noise conditions (i.e., plant motion) and habitat geometry. (Mid-year start)

Recognition of heterospecific alarm calls by Zebra finches
Collaboration with A/Prof Rob Magrath (The ANU)

Many animals use alarm signals to warn others about impending danger and can include information about the type of predator and the level of threat. Benefiting from the alarm signals of others needn’t be limited to your own species and there are many examples where animals eavesdrop on other species to glean information about the presence of predators. Research on acoustic communication has provided considerable insight into the nature of eavesdropping networks yet the mechanism by which species are able to interpret the alarm calls of other species has been largely unexplored. This project will consider the possibility that Zebra finches (Taeniopygia guttata) learn to recognise the alarm calls of heterospecifics. Associating learning paradigms will be used to consider the mechanisms involved in recognising the information value of heterospecific alarm calls.

My research is principally focused on fundamental physiology of skeletal muscle of vertebrates and examining metabolic factors that contribute to skeletal muscle fatigue. My research interests also extend to work on cardiac muscle examining developmental changes in contractile behavior of the heart under normal and diseased conditions.

2011 Honours Projects

The research of my group is broadly focused around ecological and evolutionary physiology of reproduction. With particular interests in viviparity (pregnancy), maternal effects on offspring phenotypes, sex allocation and the physiological and endocrinological basis for variation in life history. The research uses a multidisciplined approach to question orientated rather than species orientated research, hence a wide range of model organisms are used, including reptiles, birds and marsupials.

 

2011 Honours Projects

How does maternal stress shape offspring phenotypes in viviparous lizards?

Although most reptiles reproduce by egg-laying (oviparity), more than 100 separate lineages of reptile have evolved live birth (viviparity). The conditions experienced by embryos during gestation can modify offspring size, shape, physiology, behaviour and performance. This project will examine the role of physiological stress during pregnancy in shaping offspring characteristics in a viviparous lizard. (mid-year start)

Are there changes in milk composition in Tammar wallabies birthing sons vs. daughters?

Recent research in my lab, using a cross-fostering experiment to test the adaptive advantage of raising one sex offspring over the other found female Tammar wallabies that birthed a son had higher investment ability (likelihood of weaning an offspring) regardless of the sex fostered. This finding has led to the possibility of milk composition differences between mothers birthing sons (with higher investment ability) and mothers birthing daughters. This project will measure milk compositional changes throughout lactation in wallabies birthing sons and those birthing daughters.

Effects of environmental stressors on offspring phenotypes in viviparous aphids
Co-supervised by Dr Martin Steinbauer and Dr Peter Trebicki (Vic DPI)

Some aphids have unusual reproductive adaptations, including parthenogenesis, viviparous and telescoping generations. In telescoping generations, the parthenogenetic, viviparous female has a daughter within her, who is already parthenogenetically producing her own daughter. Thus a female's diet and condition can affect offspring characteristics, including body size and birth rate of more than two generations (daughters and granddaughters). (mid-year start)

Suggestions for other projects in the field of reproduction will also be considered

My research spans a variety of topics in entomology, including insect biology, taxonomy, behaviour and population dynamics and chemical ecology as it relates to herbivory. Insects are fascinating animals whose sheer abundance and diversity dwarfs that of vertebrates and, as a consequence, they have been fundamental influences on the evolution of other animals and plants. My research seeks to know a species and their interactions with their environment so that our knowledge of Australia’’s diversity is not “skin-deep”, i.e. known only by name – if that! This emphasis also has applied significance because fluctuations of insect populations have always been a matter of concern to humans. My approach is experimental and relies on a combination of laboratory and field studies. My current focal insects are psyllids, moths and gum-tree bugs and their interactions with eucalypts and acacias.

 

2011 Honours Projects

Can anyone join? Specificity of procession formation among hairy caterpillars

Head-to-tail, single-file processions of hairy Processionary caterpillars (Ochrogaster lunifer) are maintained by simple contact cues not species-specific info-chemicals. This simple mechanism could facilitate the joining of subspecies (suspected within O. lunifer) and even other species of hairy caterpillar with the processions of O. lunifer. This project will investigate this possibility and its role in the composition of groups of co-nesting caterpillars. It will also provide opportunities to investigate the role of the caterpillars’ silken trails in moving to and from nests.

Shelter from whom? Role of nest type in protection of caterpillars from fly parasitoids
Collaboration with: Dr Anthony Rice (AQIS)

Groups of Processionary caterpillars (Ochrogaster lunifer) live together in either of two types of nest. Ground-nesting caterpillars live beneath comparatively simple “nets” of leaf litter loosely woven together by silk threads; canopy-nesting caterpillars live in elaborate silken nests supported by the host plant which become filled with their frass (which they burrow into during the day). Caterpillars exhibiting both nesting behaviours are attacked by a suite of fly parasitoids. This project will investigate whether nest type has any influence on the rate of mortality of caterpillars and the causes of variation in mortality. It will also provide opportunities to document the behaviours and mortality caused by three predatory insects, namely a dermestid beetle and a true bug that attack caterpillars and an egg-eating pyralid moth.

 

See also: Effects of environmental stressors on offspring phenotypes in viviparous aphids which I will co-supervise with Dr Kylie Robert and described under her name.