Homozygous embryos show no overt defects in the salivary gland. Homozygous larvae show no overt cuticle defects. The lethal phase of Aats-trp homozygotes is either during the larval stage or the larval-pupal transition, depending on the mutant allele used. Females carrying homozygous germline clones do not produce any eggs, indicating that Aats-trp is required during oogenesis.