www.ukbutterflies.co.uk

Hi New to this site, so appologies if this has come up before. I'm currently frowning plants, radishes in particular which gained a population of what I think are small whites. One of which went into chrysalis a few weeks ago, I wasn't that bothered about the plants so I've just let them live on it. Anyway today I've come down to find small flies burrowing into the chrysalis, which is extremely upsetting as I was hoping to catch the butterfly hatching. Any info of what these flies are and if there is anything I can to to stop them apparently eating or laying eggs in the chrysalis would be great. Many thanks

Hi Ryan,
It is actually very likely that the small flies you are seeing are parasitic wasps and they are probably hatching from the butterfly chrysalis rather than trying to get into it... These small parasitic wasps inject their eggs into the body of growing caterpillars and gradually take them over from inside. The caterpillars continue to eat as normal and eventually turn into a chrysalis, but instead of an adult butterfly developing inside, a clutch of wasps is destined to emerge through the surface. Nature is cruel sometimes, but the body of the caterpillar makes a perfect food source for the wasp larvae, which can grow unmolested by things which might actually parasitise them.

Trev

Here is an interesting video on the same subject :

https://www.bing.com/videos/search?q=yo ... &FORM=VIRE

Chris

Many thanks for the replies! Yes they do indeed look like tiny wasps. I didn't even know these type of wasps existed. Very sad, would you think it's likely the other caterpillars are also infected?

Chris, also that's probably one of the most disturbing nature videos I've seen. Very interesting though.

Here's another link Ryan:

https://www.youtube.com/watch?v=fchB-w67vTg

Chris