7-spot ladybirds are a regular sight everywhere around the Country Park, including the patch of nettles outside the VC. A close look at one revealed that it was unmoving and appeared to be sitting on a nest. The apparent nest is the cocoon of a parasitoid wasp Dinocampus coccinellae. The adult wasp is found in all continents except Antarctica and has been reported to parasitise 13 of the UK species of ladybird, but the majority are from the subfamily Coccinellinae, of which the species most frequently seen around the Country Park is the 7-spot ladybird. The adult wasp lays an egg within the body of the ladybird, that egg subsequently goes through three larval stages (instars) before emerging as a yellow maggot from the ladybird’s abdomen. It then spins a silken cocoon between the legs of the host, and pupates. The ladybird does not survive.
There is a new nationwide research project seeking to record the prevalence of Dinocampus coccinellae around the UK in order to determine whether it is increasing as a result of disruption to the natural balance between the 7-spot and the parasitoid wasp since the arrival of the Harlequin.
Information about this research project may be found here: https://ladybirdchallenge.co.uk/ and records of sightings are welcomed.