Mont. - There. That black dot on this page looks just like one on Bob Nowierski's graphs. Except where the dot is positioned on his graph tells him what kind of a home his bugs like. A little to the right, drier habitats with sandier soils. A bit up and left, heavier clay soils with a richer plant community and more leafy spurge.
Leafy spurge is the key.
The insects that Nowierski works on are flea beetles that feed on leafy spurge, a noxious weed that is damaging Western rangelands. Until Nowierski's work, there was little scientific evidence of what habitat the beetles need to thrive. Consequently, many flea beetle releases failed when they were released in the wrong habitats. Though that's not something everyone would do for a beetle, these are insects that think a mouthful of leafy spurge tastes better than a hot-fudge sundae with whipped cream. He had to keep the beetles alive for later identification by genetic analysis, because the differences between beetles can be too subtle for anyone to trust field identification, even with a trained eye.