Meeting Abstract
The fruit fly, Drosophila, has an extensive repertoire of behaviors generated by a brain with only 100,000 neurons, which suggests remarkably low computational complexity. One essential behavior is foraging, which is complicated by the fact that food is variable in quality and patchy in distribution. One strategy that flies use to adapt to patchy and variable food environments is to execute a local search once they initially find food. During this local search, flies exhibit path integration; that is, they keep an internal memory of the location of the initial food patch. Path integration is arguably one of the most sophisticated tasks performed during locomotion and is thought to depend on the function of the Central Complex (CX), a set of unpaired nuclei in the core of the insect brain.
Our lab recently showed that local search can be induced by an optogenetic stimulus in lieu of actual food. Using this paradigm, we can make flies perform local search in a constrained arena, such as a narrow circular channel. Using this fictive food within this simplified, one dimensional arena, we studied whether flies remember more than one food location. When we presented one or two fictive food sites, we found that fly’s search behavior is biased toward food locations it previously encountered. We propose that when multiple foods are present, flies use the specific spacing of the food sites to update their search range to include all the food sites they have experienced. As the fly cannot see and must rely on an internal representation of distance, these experiments help provide compelling evidence of how spatial distributions may be encoded in the insect brain and future studies will be critical in determining whether the CX is involved in these functions.
