Larval Behavior of Drosophila Central Complex Mutants: Interactions Between No Bridge, Foraging, and Chaser

Abstract

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 defect1 (cbd1), central complex deranged1 (ccd1), central brain deranged1 (ceb1) and central complex1 (cex1) larvae all had general defects in locomotion (on a non-nutritive agar surface). Both ellipsoid body open2 (ebo2) and no bridge1 (nob1) had larval foraging behavior defects (on a nutritive yeast surface). Only cex1 larvae required significantly longer time in a roll over assay of muscle tone. Genetic analysis suggested that nob1 interacts additively with two other genes influencing larval foraging behavior, foraging (for) and Chaser (Csr). for 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).

GABAergic modulation of motor‐driven behaviors in juvenile Drosophila and evidence for a nonbehavioral role for GABA transport

“…The CC is a substructure of the brain that regulates locomotor activity in adults and larvae; reduced larval crawling was observed in Drosophila third-instar mutants with CC defects (Varnam et al, 1996;Martin et al, 1999aMartin et al, , 1999b. Differentiation and elaborization of the larval CC into the mature, adult structure begins in the early pupal stage of development (Renn et al, 1999), a stage in which we observed increased GABA transport activity.…”

“…As a consequence of this acute disruption in locomotion, descending inputs from the CC may have been required to reinitiate CPG activity. However, Drosophila larval mutants with defects in the CC show normal rollover activity, indicating that basic motor functions are normal in the absence of descending inputs from the CC (Varnam et al, 1996). It is also plausible that basic motor functions driven by the peripheral nervous system in DABA-treated larvae were more severely compromised and therefore refractory to recovery by PIC cotreatment.…”

Drosophila neuropeptide F and its receptor, NPFR1, define a signaling pathway that acutely modulates alcohol sensitivity

“…Extensive arborizations were observed at several regions in the posterior side of the central brain, whereas no NPF immunoactivity was detected in the optical lobes. One of the sites that exhibited intense NPF immunostaining was the fan-shaped body of the central complex, previously implicated in coordinating motor activities (17,18). The NPF neuronal projections also innervate contralaterally the subesophageal ganglion, which might be important for regulating feeding and walking (19).…”

The foraging gene of Drosophila melanogaster: Spatial‐expression analysis and sucrose responsiveness

“…It is thought to be an integration center of the brain for processes such as locomotor behavior and learning (Heisenberg, 1994;Strauss, 2002). The EB was previously implicated in foraging behavior using structure-function analysis (Varnam et al, 1996). Images of this FOR-IR region taken at higher magnification show that the cell bodies are situated at the anterior region of the brain (Fig.…”