in Austral Entomology
entitled “Effects of microclimate and species identity on body temperature and thermal tolerance of ants (Hymenoptera: Formicidae).
Well done Zac!
Matt and Behnaz have both submitted their PhD’s for examination in the last few weeks – its a huge achievement for them both!
Sandie submitted her Honours thesis today – its a huge achievement.
Ecosystem services provided by dung beetles in a temperate region of Australia
Kirsti profiled in an article about School of Ants in WildLife Australia magazine. Check it out here
I have completed two of the three proposed experiments for my honours project so far. I have completed the secondary seed dispersal experiment, looking at how tunneller dung beetle species, Onthophagous binodis, and dweller dung beetle species, Aphodius fimetarius, contribute to the ecosystem service of secondary seed dispersal in Australia by using beads as surrogates for seeds, and observing and recording if they take the bead seed mimics underground when creating brood balls, or if they move the beads around in general through their manipulation of the cattle dung, and the depths at which they take these broods. I have counted all the beads in the brood balls and am currently putting the data together in spreadsheets for analysis. I have also completed the roller experiments proposed using the arena. I used species Sisyphus spinipes and Sisyphus rubrus for these experiments and conducted a number of pilot studies looking at how far roller species take their brood balls, if they have preferential burial sites, and if they would take seeds within the dung (bead mimics) in their broods. The data from this experiment is ready for further analysis. At present and I am conducting the third proposed experiment for my honours project, which involves looking at the difference in gas emissions in frozen cattle dung vs. unfrozen cattle dung. For this experiment I am using the Gasmet machine in the zoology glasshouse for a period of time yet to be fully determined. Furthermore, I am in the process of organising the data collected from my experiments so I can analysis it statistically and make a series of graphs, and am also in the process of reading papers and writing my thesis.
I am now seven months into my MSc., investigating beetle diversity on Acacia host-plants along an environmental gradient. Since the last issue of Myrmecia I have been busy in the lab sorting through the Coleoptera specimens, which were collected over six seasons. Coleoptera from seasons 1-3 will be sorted into morphospecies by the end of October. Voucher specimens are being identified to family level, photographed and databased using Biota (biodiversity database manager). Photographs are being catalogued separately using Adobe Lightroom (see Figure 2). Preliminary results for the first two seasons (spring & summer) are showing that temperate sites host the highest beetle diversity, while the chrysomelids (leaf beetles) are currently the most diverse beetle taxa across the gradient.
I started my 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. I will commence confirmation of identification of the parasitoid and whitefly species in the greenhouse and then 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.
My temperature controlled chambers have been completed and are ready for the effects of temperature on dung beetle experiment. They work very well and I have high hopes for them. Currently I’m just waiting for beetle season to commence before beginning the experiment. In meantime I have been sorting through samples from my altitudinal gradient survey. As expected there are few beetles active in the winter months but there have been one or two surprise finds. It’s almost time to do another run to collect samples from my wonderful volunteers and drop off some more supplies. The endnote dung beetle library has been updated again and now has close to 1900 papers.
Acacia falcata plants exude a sugary substance from the leaf-like phyllodes that attracts various insects, particularly ants. Two ant species, an Iridomyrmex sp. and a Polyrhachis sp. both commonly harvest this sugary secretion from A. falcata. To locate this resource, ant’s antennal sensilla come in contact with volatiles that come off the secretion when it is exposed to air. The specific structures responsible for the detection of these volatiles are porous sensilla trichoidea/chaetica which appears on both Iridomyrmex sp. and Polyrhachis s.p antennae (see Figures). These structures can be found on all sides of each antennal flagellomere and increase in shape and number closer to the end of the antenna. By using Scanning and Transmission electron microscopy (SEM and TEM), I am able to determine the function of several antennal sensilla found on the Iridomyrmex sp. and Polyrhachis sp.
I have just finished the final experiments of my PhD project assessing the thermal tolerances of aphids (Myzus persicae). I have investigated the effect of repeated high temperature on many physiological characters such as thermal tolerance, respiration, and osmolytes such as polyols and sugars. Also, with using chemically defined diets, I have 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. Finally I have been investigating the costs and benefits of different time of recovery between high temperature conditions by measurement important compounds and their thermal tolerance. I had presentation for some findings of my PhD at the sixth International Symposium on the Environmental Physiology of Ectotherms and Plants (ISEPEP6) in Aarhus, Denmark, 3-7 August 2015.