Researchers have found that a species of parasitic wasp Dinocampus coccinellae, protects itself from potential predators by turning its host into a “zombie bodyguard”.
The adult female wasp injects its egg into the unfortunate ladybird, and the hatched wasp larvae then eats through the host ladybird’s internal tissues, causing partial paralysis.
The host ladybird twitches and lunges out with its feet, scaring off possible predators. The exact cause of the ladybird’s twitching and grasping movements is in still in doubt, but venom from the hatched larvae is considered the most likely cause.
Scientists at the University of Montreal have discovered that the survival rate of wasp cocoons in living ladybirds is considerably higher than that of those covered on dead ladybirds.
The negative side to this for the wasps is that wasps being “protected” by ladybirds produce fewer eggs, although their lifespan remains the same.
The survival rate of ladybird “zombies” after the wasp leaves them is estimated at 25%.
Reference: Maure, Brodeur, Ponlet, Doyon, Firlej, Elguero & Thomas. 2011. The cost of a bodyguard. Biology Letters http://dx.doi.org/10.1098/rsbl.2011.0415