Some aphid species build nests that are attached to plants and remain sealed for months — so how do the insects avoid drowning in their own waste? It seems that they flush waste products using the fluid-transport systems of their host plants.


Takema Fukatsu of the National Institute of Advanced Industrial Science and Technology in Tsukuba, Japan, and his colleagues compared the nodule-like nests, or galls (pictured), of six species of aphid from the Hormaphidinae subfamily. By injecting various fluids, including some containing dye, into the closed galls, the team found that several species build sealed nests with spongy, absorbent walls that drain into the host plant's vascular system. By contrast, other species make open galls that have waxy, non-absorbent walls.

The authors suggest that aphid species evolved different strategies to balance colony hygiene with defence against predators and parasites.

Nature Commun. 3, 1187 (2012)