Wasps use parasitic mites as baby bodyguards
Parents will go a long way to protect their children, and one type of wasp goes as far as offering a home to a parasitic mite that helps fight off intruders at its nest.
After breeding, potter wasps (Allodynerus delphinalis) build a nest and lay eggs inside cavities that contain food and are sealed with mud and saliva. But the insect's offspring are threatened by parasitic wasps that try to invade the nest and lay their eggs inside the cavities. This kills the baby potter wasp in the process.
Ensliniella parasitica, is a parasitic mite known to feed on the potter wasp's haemolymph, a vital circulatory fluid that is rich in nutrients. Inside a nest, some mites move to the cavities, feeding on the food stores and the baby wasp without damaging the developing offspring. But the mite was thought to offer nothing to the potter wasps in return.
Now, Kimiko Okabe and Shun'ichi Makino from the Forestry and Forest Products Research Institute in Tsukuba, Japan, have found that the mites actually serve as tiny bodyguards, attacking parasitic wasps that venture into a host's nest.
It was a surprising discovery since the mites normally show no aggressive behaviour. "None of astigmatid mites, which include this species, were previously known to attack other species, particularly ones larger than themselves," Okabe says.