There have been irruptions–rapid increases in the numbers–of several butterfly species this season.
Will irruptions of the natural predators of those butterflies cause a decrease in the numbers? This is one of those natural predators. This is a tachnid fly–I don’t know the species. The larva of these flies become internal parasites of other insects, most commonly caterpillars. So will there be a rapid increase in the numbers of these natural enemies of butterflies, and the will there be a decrease in butterfly numbers later this year? Possibly. That’s often how nature works.
But I kind of hope it doesn’t happen that way.