The office has received numerous questions regarding the abundance of butterflies (most of what I’ve seen are Painted Lady butterflies) in the area. An extension entomologist told me the following: “It is hard to pinpoint reasons these insects survive and flourish better in one year over another. Painted Lady butterflies overwinter in southern areas of the country and migrate north in the spring. They have a broad food host range which includes thistle plants. If any of these food sources are abundant, the weather is favorable and natural enemy populations are minimal, the butterflies can grow and develop quite successfully. This results in the high population that we are seeing now.” Hopefully this answers questions you might have. Butterfly information can be found at http://lancaster.unl.edu/pest/butterflies.shtml.