Petiolus
The term petiolus ( small stalk , stalk or abdomen stalk ) refers to a specific segment of the abdomen ( abdomen ) of some insects:
- in the whitefly it is the first segment
- in the waist wasps ("Apocrita", so the hymenoptera with wasp waist) the second segment. In these insects the first is firmly fused with the thorax to form the mesosoma .
In waist wasps with a petiolus narrowing forward like a stalk (for example in some digger wasps ), the rear, widened part is referred to as postpetiolus .
In contrast, in some ants the third abdominal segment is also referred to as the postpetiolus, if this is part of the abdominal stalk (e.g. in the knot ants ). Petiolus, Postpetiolus and Gaster then together form the metasoma .
The "stalk link" as a movable connection between the breast section and the abdomen is characteristic of all ants. It allows them greater freedom of movement of the abdomen, on the one hand downwards, which allows defense secretions to be sprayed forward, and on the other hand upwards, which is particularly preferred when releasing fragrances.
Individual evidence
- ↑ Abdominal stalk. In: Stefan von Kéler : Entomological dictionary. Akademie-Verlag, Berlin 1963, p. 283.
- ^ Postpetiolus. In: Stefan von Kéler: Entomological dictionary. Akademie-Verlag, Berlin 1963, p. 507.