Faculty Sponsor

Erin Baumgartner


Chemoreception of the cues that allow a caterpillar to locate and select a specific host plant reflects evolutionary constraints. In a stable environment, the evolution of innate preferences for specific host plants can increase feeding efficiency through stimulus filtering in a noisy environment. However, food choice plasticity, including the learning of new food cues, can allow survival when a population is faced with a changing environment. We used the caterpillars of cabbage whites, Pieris rapae, to test the hypothesis that preference for innate food cues would be stronger than for learned food cues. P. rapae caterpillars have sensitivity to a sugar compound, gluconasturtiin, found in their host plants, family Brassicaceae, which allows for search specificity to members of this family. We offered caterpillars, both in pairs and individually, choices between artificial food on which they had previously been reared (a learned cue) and kale, Brassica oleraceae, (an innate cue). Caterpillars grouped in pairs did not demonstrate a significant preference for either choice, although the first caterpillar in each pair to select a food item chose the innate cue of kale. Caterpillars tested individually showed a significant preference for the innate cue of kale, which persisted with experience. These individual results support our hypothesis that cabbage whites primarily use innate cues when choosing a food source. The presence of other caterpillars, however, may affect that choice, as observed in the initial group trials.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.