Meeting Abstract

98.6  Monday, Jan. 6 14:45  Plant nutrients, mouthparts and temperature: the intricacies of insect nutrition CLARK, X*; SIMPSON, SJ; CLISSOLD, FJ; University of Sydney, NSW, Australia; University of Sydney, NSW, Australia; University of Sydney, NSW, Australia ximonie.clark@sydney.edu.au

Plant tissues, temperature and mouthparts all affect the amount and ratio of nutrients an insect can obtain from its host plant. When investigating herbivorous insect nutrition it is therefore important to not only examine the nutritional composition of the plant but also the insect’s ability to acquire these nutrients. Chewing insects need to break open plant cell walls to gain access to nutrients. Insect mandible size is important as many insects do not chew their food but simply bite off sections. The particle size produced by each bite is an indication of the amount of cells broken open and therefore nutrients released. We have shown that smaller locusts are able to extract more nutrients from a given meal of grass than larger locusts; an outcome that supports the assumption that relatively more plant cells are crushed and ruptured because of their smaller bite size. Additionally, temperature has been shown to affect the amount and ratio of nutrients obtained by a larger locust, Locusta migratoria, leading to impacts on final body size. A smaller locust species, Chortoicetes terminifera, however showed no effect, again indicating smaller insects are more efficient at extracting nutrients, thereby conferring relative independence from temperature effects on nutritional outcomes. We will present our latest results and reveal the implications that behaviour and morphology have for locust nutrition in thermally variable environments.