ⓘ Gaster, insect anatomy. The gaster is the bulbous posterior portion of the metasoma found in hymenopterans of the suborder Apocrita. This begins with abdominal ..

                                     

ⓘ Gaster (insect anatomy)

The gaster is the bulbous posterior portion of the metasoma found in hymenopterans of the suborder Apocrita. This begins with abdominal segment III on most ants, but some make a constricted postpetiole out of segment III, in which case the gaster begins with abdominal segment IV.