An example larval collection strategy based on rescue of a loss-of-function mutant phenotype.

A) Schematic of behavioral bias for the escape versus reorientation decision of various larvae. At low stimulus intensities, WT larvae perform predominantly reorientations (pink). As stimulus intensity increases, WT larvae shift their preference towards escapes (light blue). CaSR mutant larvae, by contrast, are highly reorientation-biased across all stimulus intensities, although they do occasionally perform escapes. B) Example of a loss-of-function rescue strategy for collecting groups of larvae with divergent phenotypes. When responding to a strong acoustic stimulus, CaSR homozygous mutant larvae (red squares) are reorientation-biased relative to sibling controls (blue circles). Overexpressing CaSR in a variegated fashion in neurons in CaSR mutants (empty red squares) sometimes, but not always, rescues the mutant phenotype. We collected larvae in rescued (above light blue line) and non-rescued (below pink line) groups. Some data from Panel B also appears in Shoenhard, Jain, and Granato [19].