Supervisors: Saul Cunningham
Background
Many previous studies have found that, when examining many different species within a group of animals, body size is correlated with a wide range of ecological variables. For example, body size relates to life history, diet, abundance, and range size. Most studies, however, have focused on vertebrate animals like birds and mammals. Most of the organisms in the world are insects, which are smaller and more abundant than vertebrates. There is relatively less data on patterns of body size in insect communities and in particular little is known about how patterns of body size might differ between different kinds of insect community.
It is thought that changes in body size patterns in communities might be a useful indicator of the changing function of that community. For example, a community that is prone to pest outbreaks might have a different body size pattern to one that has more stable population dynamics. Similarly, the body size pattern of a community might be affected in predictable ways by the loss of species due to habitat decline. The use of body size patterns as an indicator of change is limited, however, because we have not yet done enough work to understand the general patterns.
Experiment
The Australian National Insect Collection (ANIC) holds a rich collection of insects collected in forests in southwest Western Australia from a recent forest survey. The survey focussed on beetles and moths, and compared the fauna of Eucalyptus plantations to native Eucalyptus forests. The specimens have already been sorted, identified and counted. This resource can be used to ask whether body size relations in the relatively simple plantation community are different to the body size relations in the more diverse forest community. In addition the analysis can be expanded by further sorting of material collected in the Western Australian survey, or by collecting more insects in the local Canberra area, contrasting simple and complex environments.
Questions to be asked in this study include:
Sample references
Kruger, O. and McGavin. C. 2000. Macroecology of local insect communities. - Acta Oecologica 21: 21-28.
Siemann, E. and Tilman, D. H. J. 1996. Insect species diversity, abundance and body size relationships. - Nature 380: 704-706.