Gaster (insect anatomy)

In the worker ant the metasoma is divided into the narrow petiole and bulbous gaster. The abdomen technically includes the metasoma and the propodeum which is fused to the thorax.

The gaster is the bulbous posterior portion of the metasoma found in hymenopterans of the suborder Apocrita (bees, wasps and ants). 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.[1][2]

Certain ants in the genus Cataglyphis, including Cataglyphis bicolor and Cataglyphis fortis, have a cubiform petiole that allows them to decrease their inertia (and therefore increase their speed) by raising their gaster into an upright position.[3]

  1. ^ Cite error: The named reference antinfo was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference desertants was invoked but never defined (see the help page).
  3. ^ McMeeking, Robert M .; Arzt, Eduard; Wehner, Rüdiger (July 2011). "Cataglyphis desert ants improve their mobility by raising the gaster". Journal of Theoretical Biology. 297: 17–25. doi:10.1016/j.jtbi.2011.12.003. PMID 22178639.