Larval behavior of Drosophila central complex mutants: Interactions between no bridge, foraging, and chaser

The central complex (CC) is a prominent component of the adult insect brain. In Drosophila melanogaster, mutations which alter CC structure also impair adult locomotion. This has led to the suggestion that the CC functions as a higher organizer of adult locomotor patterns (Strauss and Heisenberg, 1993). In the present study, we describe altered larval behavior resulting from mutations in six CC structural genes. Differences from the control strain were found for larvae from each CC mutant strain in at least one of three assays. central body defect(1) (cbd(1)), central complex deranged(1) (ccd(1)), central brain deranged(1) (ceb(1)) and central complex(1) (cex(1)) larvae all had general defects in locomotion (on a non-nutritive agar surface). Both ellipsoid body open(2) (ebo(2)) and no bridge(1) (nob(1)) had larval foraging behavior defects (on a nutritive yeast surface). Only cex(1) larvae required significantly longer time in a roil over assay of muscle tone. Genetic analysis suggested that nob(1) interacts additively with two other genes influencing larval foraging behavior, foraging (for) and Chaser (Car). Sor also had an influence on adult foraging, whereas here we found that Csr did not. We did not include adult foraging behavior tests of the CC mutants due to general locomotion defects in these flies (Strauss and Heisenberg, 1993).