Kirsti Abbott is currently travelling around Australia running the School of Ants program. Because ants are EVERYWHERE, we figured that all Australian citizens had a duty to know about ants and help us collect information on their diversity, distribution and diet. We’re particularly excited to be working with lots of indigenous Australians who we’re anticipating will have some fabulous knowledge and stories about ants in Central Australia, Far North Queensland and the Northern Territory and Western Australian outback. We are visiting schools with the aim to share knowledge about ants; their role in our ecosystems, culture and society. We will also collect data for our project and do some great science, peer down microscopes, make ant t-shirts and become ants for some challenging games based around the social structure and altruism of ants. The trip will go something like this: western NSW, Fraser Island coast, Longreach, Cairns & Cape York, down through Mt Isa to Alice Springs, north to Darwin, west around WA, then across the bottom through Port Augusta and schools in regional VIC. We have enlisted the skills of lab manager Sarah Hill, newly started PhD student Steve Tremont, parataxonomist Liz Broese and a host of volunteers to help sort, identify, and manage the collections once they arrive back in the Insect Ecology Lab. To keep up to date with Kirsti’s travels visit: http://schoolofants.net.au/ . In collaboration with Australian Ant Art ( https://www.facebook.com/australianantart), Sarah is also investigating the feasibility of developing 3D models using photogrammetry of aluminium cast ant nest to determine if we can model the architecture of the ant nests.
Jean Drayton has been a postdoc in the lab for just on a year now. Her project is titled: Ecosystem Services in a changing climate; dung beetles and climate change. There are two main aims of this project: 1) to investigate the effect that dung beetles have on greenhouse gas emissions from cattle farming and 2) to examine the effect that climate change will have on the dung burial service that dung beetles provide. To investigate the first aim, we are currently comparing the greenhouse gases that are emitted from manure that is either colonised by dung beetles or that contains no beetles. To do this, we are using a closed, non-steady state chamber system to measure fluxes of CO2, CH4 and N2O from cattle dung pats. We have also measured NH3 fluxes to test the commonplace claim that dung beetles reduce nitrogen volatilization. The preliminary results suggest that dung beetles drastically reduce CH4 emissions but actually increase NH3 loss (and this may be related to whether the beetles are feeding on the surface or burying manure for brood production). Furthermore, beetles initially increase CO2 emissions but, over time, the trend is reversed with control pats (i.e. no beetles) releasing more CO2.
To investigate the second aim of this project, dung beetles will be exposed to temperature regimes that are expected under climate change and dung burial rates will be measured. Custom built climate controlled chambers will soon be built for these experiments. Not only will we assess dung burial by individual species under climate change scenarios, we will also look at the rate of burial by assemblages of beetles that vary in species richness to test if increasing species diversity makes beetle assemblages more robust to the effects of climate change.
Jean recently won the 2015 Science and Innovation Awards for Young People in Agriculture, Fisheries and Forestry are coordinated by the Australian Bureau of Agricultural and Resource Economics and Sciences, on behalf of the Department of Agriculture. The recipients of the 2015 Science and Innovation Awards for Young People in Agriculture were announced at the ABARES Outlook 2015 conference dinner. The Science Awards recognise big ideas from young rural innovators that contribute to the success of Australia’s agriculture sector. Jean was awarded the Dairy Australia award.
Matthew Binns is about to submit his PhD thesis assessing the response of grassland Thysanoptera to climate. Thysanoptera were collected from Themeda triandra grasslands across a climatic gradient in NSW and Victoria, Australia across four seasons. A multivariate generalised linear model was used to determine how different species are associated with different environmental variables. It was found that mostly microclimate data obtained at tussock level was best at explaining the variation of thysanoptera abundances. Microclimate data at certain periods, such as during thysanoptera growth periods and near sampling, was important to consider in addition to annual means. There were enough differences in the direction and extent of responses of Thysanoptera to predictor variables to make it beneficial to look more closely at how some of the individual species respond rather than making broad generalisations.
A model based implementation of the ‘fourth corner problem’ was used to determine the interaction between environmental variables (matrix ‘R’) and morphological measurements (matrix ‘Q’) in determining abundance (matrix ‘L’). We demonstrate that morphological traits are associated with both climate and habitat structure, which has significant implications regarding the prediction of functional diversity in a changing climate.
We also simulate a warmer, drier climate by performing a transplant experiment across three different sites using both diploid and tetraploid Themeda triandra plants. A multivariate generalised linear model was used to determine how Thysanoptera community composition varies across different sites and on plants from different sources. We found that two species of thrips preferentially colonised foreign Themeda triandra when transplanted in the field. The indication that plants of foreign genotype could be particularly attractive to generalist herbivores may imply an increase in herbivory pressure on the plants when insect shift their range to accommodate changing climatic conditions.
PhD student Isobel Roberts is working on the antennal sensilla responsible for chemoreception in Iridomyrmex sp. and Polyrhachis sp. Ant communication is known to be heavily reliant on chemical cues. However, there is still more to understand of the structures associated with chemical detection. Chemoreceptors, commonly found on the antennae, are responsible for the detection of chemical cues. Isobel is using a combination of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to examine the internal structures of ant antennal sensilla to more accurately determine sensilla function. Using this classification I also hope to determine the variety of chemoreceptors found upon ant antennae and the density of those chemoreceptors. These measures of chemoreceptor variety and density can be linked to foraging, nest size and general activity seen within a species and as such, differences between species are expected.
Behnaz Ghaedi, has just finished the final experiments of her PhD project assessing the thermal tolerances of aphids (Myzus persicae). She has investigated the effect of repeated high temperature on many physiological characters such as thermal tolerance, respiration, and osmolytes such as polyols and sugars. Behnaz has been assessing the overall costs and benefits of repeated high temperatures in aphids by subjecting individuals to either a single sustained heating (at 38°C) or multiple heating with 24h recovery: to examine the physiological consequences of repeated high temperature with recovery. Using chemically defined diets, she has been revealing the central role of sucrose concentration, amino acid concentration and composition, and sucrose: amino acid ratio in shaping aphid performance, and examining the effect of these vital compounds on physiological character at high temperature. Behnaz used three artificial diets which are different in amino acid and sucrose concentration at for our experimental diets and to investigate their impacts on critical temperatures tolerance. Finally Behnaz has been investigating the costs and benefits of different time of recovery between high temperature conditions by measurement important compounds and their thermal tolerance. Behnaz will be presenting some findings of her PhD at the sixth International Symposium on the Environmental Physiology of Ectotherms and Plants (ISEPEP6) in Aarhus, Denmark, 3-7 August 2015.
Zac Hemmings is doing his PhD on the thermal games dung beetles play: assessing how temperature and competition influence a critical ecosystem service provider. His research looks at the effects of temperature on dung beetle physiology and ecology and how the microclimate and food quality preferences of a species are affected when exposed to different competitive regimes. He is also undertaking a systematic review of the available dung beetle literature to look at the historical trends and bias’ in dung beetle research and identify aspects of their physiology and ecology where research is lacking so that we may better formulate questions in the future.
To investigate the effect temperature has on dung beetle physiology he is conducting a laboratory experiment and a survey. In the laboratory experiment dung beetles are cultivated in custom climate controlled chambers. The internal temperature of these chambers can be mapped to the ambient external temperature +/- the desired offset in degrees Celsius. These chambers allow us to expose the beetles to small changes in temperature over long periods of time while still subjecting them to the natural range of temperatures they are exposed to in the field. The survey involves volunteers trapping beetles along an altitudinal gradient from 0 metres asl to 1400 metres asl. The use of volunteers to bait traps and collect samples has allowed for a much larger to be surveyed than otherwise possible.
Sue Jaggar has started her PhD investigating the interactions between two parasitoid wasps (Encarsia formosa and Eretmocerus warrae) and a predatory Hemiptera (Nesidiocoris tenuis) as natural enemies of greenhouse whitefly (Trialeurodes vaporariorum). Greenhouse grown tomatoes are an important industry in the New England area. The use of biological control can minimise or eliminate the need for chemical control of these pests. Sue will undertake laboratory experiments to examine the feeding and oviposition preferences, the extent of multiparasitism, the level of competition and the outcome of interactions between these natural enemies. Greenhouse tests will then be conducted to determine the most effective combination for control of T. vaporariorum.
Steve Tremont is researching patterns of ant diversity and distribution in the New England Region of New South Wales for his PhD. Steve has already uncovered more than 250 species from across the region. Many are undescribed and some are previously unknown. His research project has four main objectives. The first and foremost is to determine just what species do occur on the New England Tableland and how they are distributed throughout the region. To achieve this, extensive sampling will be conducted in a wide variety of habitats, primarily targeting the least disturbed niches, often in remote locations. The assumption being that the greatest diversity still exists in the least disturbed habitats.
Results from this widespread sampling will provide data for addressing the project’s second objective of examining changes in the assemblages of ants across environmental gradients. The two obvious gradients are altitudinal (range from 280 metres to 1560 metres) and latitudinal (28° 50′ south to 31° 30′ south).
The third objective will be ambitious in itself in conducting a taxonomic revision of the ants that occur in the New England Region and producing a dichotomous key (and ideally a photographic guide) to assist with identifications. Already more than 250 species are known to occur here and many more species are known from previous sampling from earlier research projects throughout the region.
The final objective will link in with Kirsti’s School of Ants program looking at diversity and distribution of ants at a national scale and comparing that with diversity and distribution at a regional scale.
Bianca Boss-Bishop started her Master of Science this year and is co-supervised by Melodie McGeoch (Monash University). Bianca’s study aims to investigate beetle diversity on Acacia host plant species, along an environmental gradient (represented by decreasing rainfall), and determine the importance of climate on beetle morphology and assemblage structure. The arthropods in this study were collected over six seasons, along a 950km transect from sub-tropical north-eastern NSW to arid, central south-western NSW. Lab work is progressing well, with ordinal sorting completed and in the next few weeks Coleoptera will be sorted into higher taxa. Images will be taken of each voucher specimen and ImageJ will be used to measure key morphological features (e.g. total body length, head, thorax, legs). This data will be used to assess community and morphology differences along the gradient.
Sandie Manns is halfway through her honours in the lab assessing seed dispersal by burier and roller dung beetles. Sandie has been collecting dung beetles in the last phases of warm weather on the tablelands so the experiments can be carried out in a climate controlled mesocosm over winter.]]>
Well done Jean!]]>