Subject: What’s this bug?
Location: Northern California foothills
November 29, 2015 5:18 pm
I live in the California Gold Country, halfway between Sacramento and Reno, NV. The elevation here is about 2500 ft. We have been in a prolonged drought, but have recently had a little bit of rain. I have lived in my house for 3 years and never seen these bugs before. About a month ago when the night time temperatures got cooler these bugs appeared on the sunny side of my house. The seem to enjoy sunning themselves but also seem undeterred by temperatures at or slightly below freezing. They particularly gather on window screens and windows. They fly or they run quickly when approached. The are about 1/2 to 1 inch in length and they have some red on their underside. They are very active during the day and I don’t see them after dark. They don’t seem to be doing any damage but there are a growing number of them and I am a bit concerned about them getting into my house and causing a problem. I have seen a few on my neighbor’s house but they seem to prefer my yellow house that gets a lot of sun. Oddly, my cat and dog who typically will play or catch bugs leave these guys alone. Any idea about what they are and should I be concerned? Thanks so much for your assistance.
This is a Western Boxelder Bug, Boisea rubrolineata, and it is considered a benign creature though they are prone to forming large aggregations that can become a nuisance if they are plentiful or if they enter the home. The behavior you describe is very common for the species. When weather cools down, they will enter homes to hibernate, but they will not cause you or your home any damage.
Thanks so much! Glad to know I can let them be without worrying that they are eating my home. Have a wonderful day!