Peacock Butterfly ( Aglais io )

Yes I know I blipped a Peacock a few days ago!  My excuse is simply that I am seeing so few butterflies this year that I just can't resist taking shots when I see them.  Couple that with the fact I like this shot more than my previous one.

I am wondering why they aren't more numerous this year.  They are a species that hibernates and the winter wasn't very cold.  The food for the caterpillars is nettles and heaven knows there are plenty of those in the area.  What is more worrying is that insects in general seem to be in short supply.  Humans and the natural  environment rely so heavily on insects for food etc.