Gaster (insect anatomy)

The gaster (from Ancient Greek γαστήρ 'belly, paunch') 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]

The gaster in ants contains what is sometimes called the "social stomach," which is named for the fact that food can be carried within it and then shared with other members of the colony.^[3] It also contains the ant's heart as well as the rest of their digestive system.^[4]

In the ant subfamily Formicinae, the gaster houses an acidiphore which they can use to spray formic acid.^[5]

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.^[6]

The ant species Cephalotes atratus is capable of gliding by changing the angle of their gaster as they fall.^[7]

^ Cite error: The named reference antinfo was invoked but never defined (see the help page).
^ Cite error: The named reference desertants was invoked but never defined (see the help page).
^ Bouisset, Guillaume; Merienne, Hugo; Fourcassié, Vincent (2024). "Walking kinematics of ants carrying food in the mandibles versus gaster". Journal of Experimental Biology. 227 (24). Bibcode:2024JExpB.227B9350B. doi:10.1242/jeb.249350. PMID 39555852.
^ Holbrook, Tate (22 September 2009). "Ant Anatomy | Ask A Biologist - Arizona State University".
^ Klotz, John H., ed. (2008). Urban ants of North America and Europe: identification, biology, and management. Cornell paperbacks. Ithaca: Comstock Pub. Associates. ISBN 978-0-8014-7473-6. OCLC 226304732.
^ 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.
^ Munk, Jonathan (2011). "The Descent of Ant". UC Berkeley.

[antinfo-1] Cite error: The named reference antinfo was invoked but never defined (see the help page).

[desertants-2] Cite error: The named reference desertants was invoked but never defined (see the help page).

[3] Bouisset, Guillaume; Merienne, Hugo; Fourcassié, Vincent (2024). "Walking kinematics of ants carrying food in the mandibles versus gaster". Journal of Experimental Biology. 227 (24). Bibcode:2024JExpB.227B9350B. doi:10.1242/jeb.249350. PMID 39555852.

[4] Holbrook, Tate (22 September 2009). "Ant Anatomy | Ask A Biologist - Arizona State University".

[5] Klotz, John H., ed. (2008). Urban ants of North America and Europe: identification, biology, and management. Cornell paperbacks. Ithaca: Comstock Pub. Associates. ISBN 978-0-8014-7473-6. OCLC 226304732.

[6] 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.

[7] Munk, Jonathan (2011). "The Descent of Ant". UC Berkeley.

[1]

[2]

[3]

[4]

[5]

[6]

[7]