1. Detection
Sensitive antenna lead the ichneumonid wasp to a caterpillar hidden in the stem of grass.
2. Localization
The position of the larvae needs to be accurately determined.
3. Prepare tools
The ovipositor, a thin and long stinger, is protected by a sleeve and gets engaged.
4. Zielen
The ovipositor is brought into optimal position.
5. Control
Maximal antenna surface contact allows for control of the invisible target.
6. Sting
The ovipositior stings into the larva in the stem and a tiny egg is implanted. The ichneumonid larvae will use the caterpillar as a source of food during growth.
7. Ei-Ablage
This ichneumonid is not able to sting trough human skin. However, there are other species with shorter and solid stinger who can. Anyway, humans are very rarely stung for defense only and not for ovipositing.
Platygastridae
This is a very tiny ichneumonid wasp with interest for a, in comparison, very large caterpillar. The ovipositor of this group is so long in comparison to their body length, that they carry it in a kind of long quiver on their back that even reaches their head. Anyway, the caterpillar on the image is probably to large for this tiny wasp.
Details
Ichneumonid coccoon
When a caterpiller gets stung, its body turns into the coccoon for the ichneumonid larvae. Only the head shows, that this was a caterpillar once.
Ichneumonid coccoon
Typically, these ichneumonid cocoons are fixed on the substrate at the neck region of the former caterpillar.
Ichneumonid coccoon
Not all cocoons of ichneumonids are "empty" caterpillars. Sometimes, the larve produce a separate structure, like the family of campopleginae.
Details