Research

Evolution and phylogeography of an ant – lycaenid butterfly mutualism


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The Australian lycaenid butterfly Jalmenus evagoras (Common Imperial Blue) is engaged in a mutualistic relationship with ants of the genus Iridomyrmex. The ants protect the caterpillars and the pupae from parasites and predators, while the caterpillars provide the ants with nutritional secretions from specialized glands. This mutualism is obligate for the caterpillars, while the ants do not rely on the caterpillars’ secretions for survival.

The close dependency of J. evagoras on its attendant ants in combination with its widespread yet locally patchy distribution offers the possibility to study in detail the evolutionary dynamics of this mutualistic association. Next-generation sequencing of individuals sampled across the geographic range as well as across attendant ant species allows us to investigate the species’ phylogeography and the possibility for ongoing speciation associated with host ant switches.

Primary investigators: Sebastian Pohl

Funding source: ARC Discovery Grant to MAE

 

Anti-predatorial effects of propolis from the nests of stingless bees


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Stingless bees of the Meliponini use a combination of resin-derived compounds and self-produced wax to construct their nests. This material, propolis, provides the structural support of the nest, as well hydrophobic and anti-bacterial properties. These characters have been previously attributed to the genetically produced compounds present in the resin, and the functional importance of the environmentally-produced resins is less understood. Given the threat of predators in these tree dwelling species we suggest there should be defensive chemicals in the nest material to deter intruders. We are using nest material collected from the Australian native stingless bee, Tetragonula carbonaria and a common species of stingless bees in China, Trigona ventralis to investigate predator deterrent effects of the propolis.

Primary investigators: Yujie Wang

Funding source: National Natural Science Foundation of China

The Symbiosis Between Arthropod Predators


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Interactions between animals vary depending on local selection pressures, trophic status, and evolutionary history. Interactions among arthropod predators these are usually considered to be competition, predation, or parasitism. However, interspecific interactions among spider symbiotic systems show a malleability ranging widely in outcome from araneophagy to mutualism. Do pliable patterns of interspecific interaction between Araneae predators change given different spatiotemporal scales? Herein the evolution of spider symbiotic systems is addressed from a multidisciplinary perspective through field experiments quantifying the nature of interactions and via mathematical models identifying geographic and seasonal variables of outcome parameters while exploring evolutionary patterns of symbiotic association between arthropod predators via phylogenetic analysis.

Primary investigators: Po Peng

The use of chemicals cues in the mating and foraging strategies of Argiope spiders


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Pheromones are chemical cues used to communicate between individuals of the same species. Like all signals, pheromones are shaped by a combination of environmental and genetic factors. The most significant environmental factor shaping pheromone expression is diet. This project will investigate the role of diet in shaping the expression of web-based pheromones in orb-weaving spiders from the genus Argiope by using a combination of behavioural assays and chemical analyse to understand how diet drives the expression of these cues and the consequences this has for their mating and foraging strategies.

Primary investigators: Jessica Henneken

Funding source: Loftus Hills Memorial Award

The role of communication in the evolution of sociality


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The evolution from solitary to social behaviour requires individuals to communicate efficiently within and among groups. This transition has occurred multiple times in bee lineages, and there are numerous examples of reversion, leaving us with bee species representing multiple behavioural types – eusocial, semi-social, solitary and secondarily solitary, socially polymorphic and parasitic. This diversity of behaviour allows us to investigate the role of communication in these transitions, through phylogenetic comparisons of antenna. In addition, we are examining the maintenance of social societies using nest-mate recognition experiments and investigating the chemical ecology of a number of behaviourally diverse species.

Primary investigators: Bernadette Wittwer

Funding source: Holsworth Wildlife Research Endowment

Evolution of cooperative behaviour in Australian lycaenid butterflies and ants


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Communication is critical to the maintenance of the often extraordinary levels of cooperation that may occur between individuals of the same and different species. Ants are frequent partners in interspecific cooperative relationships, including with the larvae of butterflies of the family Lycaenidae (Lepidoptera). This project examines communication mechanisms in the Australian butterfly Jalmenus evagoras and its attendant ants by investigating a variety of chemical signals and their role in initiating and maintaining this mutualistic association. The combination of chemical analysis of secretions, volatiles and cuticular hydrocarbons with behavioural experiments will improve our understanding of communication and cooperation in ant-butterfly associations. 

Primary investigators: Dany Zemeitat

Funding source: ARC Discovery Grant to MAE, Holsworth Wildlife Research Endowment

Evolution of colour patterns in Australian chrysomeline leaf beetles


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The risk of predation is pervasive, and numerous anti-predator strategies have evolved in response to this selection pressure. The same animal can be cryptic in one habitat but conspicuous in another, depending on its background. Chrysomeline leaf beetles have a variety of colour patterns that, to varying degrees, fit or contrast with their environments. Chrysomelines also possess glands that produce defensive chemicals, and these toxic defence mechanisms, together with their diurnal lifestyle, encourage the view that the colour patterns of chrysomelines are aposematic. However, attributing an aposematic role to colour patterns commonly associated with toxicity may not reflect the evolutionary significance of the colour patterns. Through comparative and experimental studies, we suggest that the diversity of colours and patterns of chrysomeline beetles do not serve a single purpose of aposematic colouration, despite the presence of chemical defences in these taxa.

Primary investigators: Eunice Tan

Funding source: Holsworth Wildlife Research Endowment

The evolutionary significance of parthenogenesis and sexual reproduction in Macleay's spectre, Extatosoma tiaratum


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The evolution of sexual reproduction has been a great debate in evolutionary biology for the previous decades. In theory, sexual reproduction is associated with various costs, yet it is the usual form of reproduction among most organisms. Many theoretical models have provided evidence of benefits that can outweigh these costs and give sex a net advantage, but experimental tests of the theory are scarce and often reveal contradictory findings. The Australian spiny leaf insect or Macleay’s Spectre Extatosoma tiaratum is a promising system in which to compare costs and benefits of sex and parthenogenesis, as females mate with males when possible, but also have the ability to reproduce parthenogenetically. The evolution of facultative parthenogenesis in turns is not well understood, but it has been associated with male limitation. This project utilises a range of approaches, from behavioural ecology to molecular biology, to investigate the evolution of facultative parthenogenesis in this system.

Primary investigators:  Yasaman Alavi

Funding source: Holsworth Wildlife Research Endowment

Deconstruct the soup: sources and functions of uneven distributed cuticular hydrocarbons in Australian meat ants


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Social insects use cuticular hydrocarbons (CHCs) to convey different social signals, including colony or nest identity. The exact source and identity of CHCs that act as nest-specific identification signals remain largely unknown. Perhaps this is because studies that identify CHC signals typically use organic solvents to extract a single sample from the entire animal. We take a novel approach by first identifying CHC profiles from different body parts of ants (Iridomyrmex purpureus), then use behavioural bioassays to reveal the location and function of specific social signals. We will then determine how ants maintain and distribute this uneven layer of CHC.

Primary investigators:  Qike Wang

Funding source: Holsworth Wildlife Research Endowment

The impact of artificial light at night on melatonin, oxidative stress and pigmentation in Australian black field crickets


 

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Most animals have evolved with almost true darkness each night.  The penetration of light into the night-time environment from artificial lighting has the potential to disrupt nocturnal species in particular.  This project will investigate how melatonin production, oxidative tissue damage from free radicals, and body pigmentation are affected by variation in the intensity of artificial light at night (ALAN) using the Australian black field cricket Teleogryllus commodus as a model species.  Changes in these traits have the potential to decrease the ability of crickets to fight tissue damage from free radicals and to alter their visibility to predators.  This research will deepen our understanding of the way in which various intensities of ALAN may induce such changes, and thereby inform strategies to minimise the impact of ALAN on urban animal populations.

Primary investigators:  Christopher Freelance

Funding source: Holsworth Wildlife Research Endowment

 

Thermoregulatory strategies in the heat: worker behaviour in response to shade and exposure in meat ants Iridomyrmex purpureus


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This project aims to understand the reasons for the success of the meat ant Iridomyrmex purpureus across Australia and the significance of the workers’ responses to their immediate environments that aids this success. This project aims to know if workers can respond to a change made to the pebbles that adorn their nests, possibly regulating nest temperature and how workers engaged in different activities respond to shade which would give them temporary respite from their energy-intensive work. The reserach will help deepen our understanding of social living and whether these advantages can act as a buffer in the future which will see a change in the climate and successively, the landscape.

Primary investigators:  Megha Majoe

Funding source: Holsworth Wildlife Research Endowment