This article from Science is absolutely fascinating: female Megymenum gracilicorne cultivate fungi on their back legs; they inoculate their eggs with this fungi; and that in turn offers protection from wasps that would otherwise parasitize the eggs. From the article:
The scientists put five sexually mature female wasps, which they had raised in the laboratory, into a small chamber. The chamber held about 20 stinkbug eggs, half of which had the fungi and half of which had the fungi brushed off. The wasps approached the eggs, tapping them with their antenna. They didn’t like the eggs covered in fungi; they would carefully circle around and groom themselves after making contact. Averaged across many trials, the wasps parasitized 62% of the clean eggs but only 10% of the fungi-covered eggs.
The videos in the article are amazing – you can clearly see the patch on the back legs that holds the fungus, and how the stinkbug applies it to the eggs. Now I want to go back through my own stinkbug observations (quite taxonomically distant from this species, I’m sure) to see if there’s anything similar!
The paper is published at https://www.science.org/doi/10.1126/science.adp6699; it’s paywalled, but you can get a preprint at https://www.biorxiv.org/content/10.1101/2024.03.25.586038v1.