Where Have All the Butterflies Gone?

I have seen very few butterflies so far this year. This black swallowtail on Thalia Island is only the ninth I’ve photographed so far. As of this time last year, my records indicate I had images of twenty-one. Although, the black eyed susans came back in profusion this year, I have seen no butterflies on them (although a goldfinch is trying to harvest the seeds), nor on the few flowers that have bloomed on the butterfly bushes. There also does not seem to be as many flower flies around. The winter creeper is in bloom, but there have been very flies, which usually swarm the flowers, as well as assorted hairstreaks. I wonder if it was the relatively severe past winter or the pesticides developed to replace DDT that are killing off the insects. On the plus side, there has been many fewer mosquitos around this summer,