Intake of Plant Resin Through the Genitalia of Two Asian Assassin Bugs (Reduviidae: Harpactorinae: Harpactorini)

Many insects use tactics to protect their eggs from predation, infection, and water loss, among other risks. Some assassin bugs only in the New World tribe Apiomerini are known to use plant substances, such as resin, instead of secretions to protect their eggs. Here, we report a novel storage mechanism and the utilization of plant resin for egg protection in Asian assassin bugs, Velinus nodipes and Agriosphodrus dohrni (tribe: Harpactorini). Adult females of both species were observed to take in plant resin through their genitalia. We reported on the handling of resin by these species and confirmed that A. dohrni adult females stored resin in their subrectal glands and that the substance covering their egg masses was derived from plant resin. This is the first report on the storage of plant resin inside the bodies of assassin bugs and on resin-protected eggs in Harpactorini. Such internal resin storage was not accompanied by external morphological features, as observed in some Apiomerini assassin bugs, thereby suggesting that this tactic has been overlooked and may have evolved in broader tribes of assassin bugs than previously thought.