Parastic wasps

[WPG]

After the bumper crop of cabbage whites this year, there's around a dozen of the caterpillars now settled to cocoon themselves around my window frames. But I've noticed at least 80% must've been infected by parasitic wasps and have now been eaten from the inside out (ugh!).
I've noticed this happening before, but never in such numbers. I'm not sure if the parasitic wasps are gardeners friends, or whether they attack other butterfly species? Should I leave the wasp larvae alone, or dispose of them?

[Martin H]

I would leave them.

There have been so many white butterflies around this year the wasps must have had a great time earlier in the season and increased in numbers as a result. They'll knock back the white butterfly numbers for the next year or two before the population recovers again.

The wasps are picky, apparently, they won't attack all species of caterpillar indiscriminately.

Nice pics by the way!

[WPG]

Thanks for that Martin, I'll just leave them in peace (even better, now I've got an excuse not to wash the window frames for a few months!)