Trissolcus brochymenae is an egg parasitoid that attacks eggs of the Brown Marmorated Stink Bug. Like many Hymenopteran parasitoids, it faces its host when laying eggs. Hymenoptera have an abdominal constriction, a thin flexible area to allow the abdomen to bend under the head. An egg can be laid while the wasp is facing its host.
Trissolcus brochymenae is observed to touch potential host eggs with its antenna before laying eggs. The wasps have contact chemoreceptors on the antennae that can detect chemicals on the host egg. The wasp uses these chemical cues to decide whether or not the egg is a suitable host.
Alessia Iacovone, Alice Sarah French, Frédérique Tellier, Antonino Cusumano, Gilles Clément, Cyril Gaertner, Eric Conti, Gianandrea Salerno, Frédéric Marion-Poll. 2016. The role of contact chemoreception in the host location process of an egg parasitoid. Journal of Insect Physiology Vol. 91–92 Pages 63-75.