Subject: Beetle invasion.
Location: Chantilly, Virginia, USA
May 9, 2014 7:09 am
Today I came to work in Chantilly, Virginia and our building is inundated with these beetles. At first glance I thought that they are Japanese Beetles, but something about the shape of the body tells me I’m wrong. I’ve searched several of the insect identification guides but I cannot find any photos that match this beetle.
I’d like to find out what this beetle is, in hopes of understanding why there were none yesterday and there are hundreds of them today.
Your beetles are Caterpillar Hunters in the genus Calosoma. The beetle in one image seems considerably darker than the beetle in the other image, so we are wondering if they are all metallic green with red or gold borders. We believe the discrepancy in coloration is due to camera exposure and lighting. We also believe your beetles are most likely Fiery Searchers, Calosoma scrutator, and you may compare your images to the images on BugGuide. Perhaps populations are peaking this year because there is a significantly larger proportion of prey, namely caterpillars and other insects.
Thank you for the quick response. I did some searching later and you confirmed my suspicion about Calosoma Scrutator. Truly a beautiful beetle.