Associations Between Australian Pseudoscorpions and Ants

The distribution of three species of pseudoscorpions, found under the bark of blue gum Eucalyptus globulus, is closely correlated with the presence of three species of ants. Marachernes bellus is never found on trees without Anonychomyrma sp. near foetens, and Protochelifer victorianus and Paraustrochernes victorianus are more commonly found on trees with Technomyrmex jocosus and/or Tapinoma minutum. The distribution of another pseudoscorpion, Conicochernes sp., is not influenced by the presence of these ants. Observations of the behavior of these pseudoscorpions indicate that at least some species may be specialist predators of ants

Dual pathways in social evolution: Population genetic structure of group-living and solitary species of kleptoparasitic spiders (Argyrodinae: Theridiidae)

Group-living behavior is taxonomically widespread but rare in spiders. The conventional view is that the main pathways to group-living in spiders are either sub-social, where extended maternal care leads to prolonged sibling association; or communal living, where individuals aggregate to exploit a common resource. Female egg-sac guarding behavior occurs throughout kleptoparasitic spiders in the subfamily Argyrodinae (Theridiidae), while individuals in group-living species cohabit in the resource rich webs of their host spiders. These attributes fit both sub-social and communal routes to group-living, which offers new insights to study the early stages of social evolution. We investigated whether members of kleptoparasitic groups in natural populations comprise related individuals by comparing the population structure of two group-living species, Argyrodes miniaceus and A. cf. fissifrons, and two solitary species, A. fasciatus and Neospintharus trigonum. We found that: (1) genetic-spatial autocorrelation in group-living species was highest among spiders sharing the same host web and declined steeply with increasing distance, but no significant autocorrelation at any scale for solitary species; (2) there was high relatedness among group members in two cases of group-living species, which indicated relatedness was not an adhesive agent in most of the groups, but no high relatedness in solitary species; and (3) the host web boundary was not the sole predictor of genetic structures in group-living species. These results suggest that population genetic structure in the group-living species is caused by limited dispersal of group members that is favored by ecological conditions, including the nature and size of resources. In contrast, the absence of genetic structuring in populations of solitary species indicates a high level of dispersal with individual interactions unlikely to have fitness benefits.2006353KMU-Q107006MOST107-2621- B-037-001-MY

The evolution of body size, antennal size and host use in parasitoid wasps (hymenoptera: chalcidoidea): a phylogenetic comparative analysis

Chalcidoid wasps represent one of the most speciose superfamilies of animals known, with ca. 23,000 species described of which many are parasitoids. They are extremely diverse in body size, morphology and, among the parasitoids, insect hosts. Parasitic chalcidoids utilise a range of behavioural adaptations to facilitate exploitation of their diverse insect hosts, but how host use might influence the evolution of body size and morphology is not known in this group. We used a phylogenetic comparative analysis of 126 chalcidoid species to examine whether body size and antennal size showed evolutionary correlations with aspects of host use, including host breadth (specificity), host identity (orders of insects parasitized) and number of plant associates. Both morphological features and identity of exploited host orders show strong phylogenetic signal, but host breadth does not. Larger body size in these wasps was weakly associated with few plant genera, and with more specialised host use, and chalcidoid wasps that parasitize coleopteran hosts tend to be larger. Intriguingly, chalcidoid wasps that parasitize hemipteran hosts are both smaller in size in the case of those parasitizing the suborder Sternorrhyncha and have relatively larger antennae, particularly in those that parasitize other hemipteran suborders. These results suggest there are adaptations in chalcidoid wasps that are specifically associated with host detection and exploitation

APRES: electronically managed student feedback via peer review

Students maximise learning when they receive timely and detailed feedback on their performance from teachers as well as peers. Yet in many subjects taught at university level, feedback consists only of grades and written commentary from teachers, on a final version of submitted work. This form of feedback provides little incentive or opportunity for improvement and places considerable demands on staff in subjects with high enrolments. In 2004 we addressed these problems in our subject Experimental Animal Behaviour, by involving other students (peers) in the feedback process, and designing a web-based software platform APRES to manage the administratively complex task of exchanging submitted work and reviews between students in an anonymous context. We evaluated the success of our innovation by means of written student evaluations, changes in Quality of Teaching survey scores, and changes in the quality of submitted work. All three areas indicate that the project was highly successful. We believe that there is considerable promise for widespread application of this form of feedback and the software platform that enabled us to implement it

Artificial Light at Night as a Driver of Evolution Across Urban–Rural Landscapes

Light is fundamental to biological systems, affecting the daily rhythms of bacteria, plants, and animals. Artificial light at night ( ALAN ), a ubiquitous feature of urbanization, interferes with these rhythms and has the potential to exert strong selection pressures on organisms living in urban environments. ALAN also fragments landscapes, altering the movement of animals into and out of artificially lit habitats. Although research has documented phenotypic and genetic differentiation between urban and rural organisms, ALAN has rarely been considered as a driver of evolution. We argue that the fundamental importance of light to biological systems, and the capacity for ALAN to influence multiple processes contributing to evolution, makes this an important driver of evolutionary change, one with the potential to explain broad patterns of population differentiation across urban–rural landscapes. Integrating ALAN ’ s evolutionary potential into urban ecology is a targeted and powerful approach to understanding the capacity for life to adapt to an increasingly urbanized world

Investment in sensory structures, testis size, and wing coloration in males of a diurnal moth species: trade-offs or correlated growth?

For dioecious animals, reproductive success typically involves an exchange between the sexes of signals that provide information about mate location and quality. Typically, the elaborate, secondary sexual ornaments of males signal their quality, while females may signal their location and receptivity. In theory, the receptor structures that receive the latter signals may also become elaborate or enlarged in a way that ultimately functions to enhance mating success through improved mate location. The large, elaborate antennae of many male moths are one such sensory structure, and eye size may also be important in diurnal moths. Investment in these traits may be costly, resulting in trade-offs among different traits associated with mate location. For polyandrous species, such trade-offs may also include traits associated with paternity success, such as larger testes. Conversely, we would not expect this to be the case for monandrous species, where sperm competition is unlikely. We investigated these ideas by evaluating the relationship between investment in sensory structures (antennae, eye), testis, and a putative warning signal (orange hindwing patch) in field-caught males of the monandrous diurnal painted apple moth Teia anartoides (Lepidoptera: Lymantriidae) in southeastern Australia. As predicted for a monandrous species, we found no evidence that male moths with larger sensory structures had reduced investment in testis size. However, contrary to expectation, investment in sensory structures was correlated: males with relatively larger antennae also had relatively larger eyes. Intriguingly, also, the size of male orange hindwing patches was positively correlated with testis size

Task-Specific Recognition Signals Are Located on the Legs in a Social Insect

Task allocation ensures a high level of organization within social insect colonies. Workers reveal their task assignment through cuticular hydrocarbon (CHC) signals. The source and chemical composition of these signals are largely unknown. We ask whether task recognition signals are located on particular body parts of workers of Australian meat ants (Iridomyrmex purpureus). We analyzed the CHC profile on the antennae, legs, and abdomens of workers engaged in different tasks. Discriminant analysis showed that the leg profile is the best indicator of task identification. Behavioral assays confirmed this finding: workers typically reacted differently to non-nestmates engaged in different tasks, but not if the CHCs on the legs of their opponents were removed by a solvent. Lasso and Elastic-Net Regularized Generalized Linear Model (GLMNET) revealed which CHC components show the highest correlation in task and nestmate recognition, suggesting that social insects can simultaneously convey different CHC signals on different body parts, thereby allowing efficient signaling and signal perception.a University of Melbourne Postgraduate Scholarship and a Holsworth Wildlife Research Endowment (to QW)

The role of life-history and ecology in the evolution of color patterns in Australian chrysomeline beetles

The variation in animal coloration patterns has evolved in response to different visual strategies for reducing the risk of predation. However, the perception of animal coloration by enemies is affected by a variety of factors, including morphology and habitat. We use the diversity of Australian chrysomeline leaf beetles to explore relationships of visual ecology to beetle morphology and color patterns. There is impressive color pattern variation within the Chrysomelinae, which is likely to reflect anti-predatory strategies. Our phylogenetic comparative analyses reveal strong selection for beetles to be less distinct from their host plants, suggesting that the beetle color patterns have a camouflage effect, rather than the widely assumed aposematic function. Beetles in dark habitats were significantly larger than beetles in bright habitats, potentially to avoid detection by predators because it is harder for large animals to be cryptic in bright habitats. Polyphagous species have greater brightness contrast against their host plants than monophagous species, highlighting the conflict between a generalist foraging strategy and the detection costs of potential predators. Host plant taxa-Eucalyptus and Acacia-interacted differently with beetle shape to predict blue pattern differences between beetle and host plant, possibly an outcome of different predator complexes on these host plants. The variety of anti-predator strategies in chrysomelines may explain their successful radiation into a variety of habitats and, ultimately, their speciation