A tiny parthenogenetic wasp which is an endoparasitoid of adult ladybird beetles. The adult wasp is rarely seen but investigation of non-moving ladybirds will sometimes reveal a cocoon of this wasp beneath.
Wherever its host ladybird species are to be found. 7 Spot, 11 Spot and Cream-streaked Ladybirds seem to be the preferred hosts.
When to see it
Spring and summer when the host ladybirds are about in numbers.
The adult wasp locates and stalks its prey before inserting a single egg by thrusting its ovipositor through any weak point in the cuticle. The hatching larva then uses its mandibles to kill the eggs or emerging larvae of any other wasps which may have attacked the same ladybird. It will soon moult into its second instar with mouthparts more suitable for feeding on the host. This feeding concentrates on the fat reserves and the food that would be used to develop the gonads, leaving the vital organs intact. When ready to pupate, the larva causes the ladybird to become immobile, before breaking out of the host’s abdomen through the membrane between the fifth and sixth or sixth and seventh abdominal plates. It then spins a cocoon between the host’s legs. The ladybird is still alive at this point, but in a paralysed state with its warning colours serving to protect the pupa from predation. Once pupation is complete the adult wasp emerges and flies off to seek a new host, leaving the ladybird to succumb to starvation or fungal infection…. Naturespot