Earlier this season we saw huge numbers–irruptions–of butterflies. Will we see similar irruptions of their predators?
A group of tachinid flies can be seen on this wild parsnip umbel. Tachinid flies lay eggs on or near other insects, often caterpillars, and the young develop as parasitoids of those insects.
So is this a higher than normal number of tachnids? I have to say that I never really paid attention before this year. Will the flies wipe out the butterflies? Or will the butterflies continue to show up in record numbers? Already butterfly numbers have gone down, but that is perfectly normal for this time of year.
And if butterfly numbers decrease will it be because of the flies, or because of another predator, or because of weather, or because of something else?
We probably won’t know.