Have you ever had someone stand on the edge of your property for over an hour with a camera directed right at your house? Oh dear! That sounds really spooky, doesn’t it? ….. even if the photographer was wearing tennis shoes and has lots of white hair? … and I did stay on the shoulder of the narrow country lane. But , I have to admit, I didn’t bother to think about the house.
Well, I succeeded in bugging the people in the house when all I intended to do was bug the bugs. Eventually the husband came out and let his big black dog loose. With lots of woofing, the dog raced up to me, hair raised all along his backbone. I took a deep breath and concentrated on the wagging tail. Fortunately the homeowner was even friendlier than the wagging tail when he realized all I am is a crazy lady with a big camera and a fool idea to try and photograph his box elder bugs.
That house had a huge, old incense cedar tree next to the road. The deep furrows of the bark are a winter housing complex for several hundred box elder bugs …. Western box elder bugs, Boisea rubrolineata. For those of you who are familiar with eastern box elder bugs, these are very similar but have more red veins. Box elder bugs overwinter as adults. In the fall they find protected crevices to crawl into, sometimes taking advantage of opportunities in our houses. The five hundred plus box elder bugs I was looking at and trying to photograph had picked this beautiful old cedar. An unusually warm winter day brought them out into the sun to check out their world. Is it spring?
The bugs were obviously fairly cool. I didn’t see any fly and mostly they just clustered together. Once in a while one slipped back into a crevice, or another two or three came out. Then something else caught my eye, a tiny white spot on the back of one … an egg, I think. It’s only about the size of a grain of sand. Tiny. It didn’t seem like the right place for a box elder egg so I was immediately suspicious it might be something more interesting. Perhaps the egg of a parasite. My curiosity was piqued.
Such a tiny egg, but I did my best photographing it and posted my photo on www.BugGuide.net. Bug Guide is a wonderful resource. One can register and then submit photos and ask for help identifying the insects. I got a response almost immediately. The egg was probably laid by a tachinid fly. Tachinid flies are all parasitic in their larval stage. Just how they do it varies from one species of Tachnid to another. Some insert the egg, some lay the egg on the surface of the host. Often the host is a caterpillar, but in this instance the host is an adult box elder bug. The egg will soon hatch, drill into the box elder bug’s body and eventually kill its host. Eventually the tachinid larva will pupate and emerge as an adult.
Today the sun was even warmer and I spent another hour in front of the cedar tree. The home owner gave me a friendly ‘Hello” and a FedEx truck stopped in the middle of the road to see what I was up to. I christened my new close focus filter which I can screw onto my zoom lens and got an even bigger photos of the box elder bugs. One of them shows a tiny hole, probably made by one of the tachinid fly larva drilling into its back. The box elder bug was still alive, but didn’t seem very energetic. I was hoping one of those tachinid flies would come along but no such luck.
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Just in case you are tired of big, black bugs, I'll toss in this little chestnut-backed chickadee that I took yesterday. Such sweet little birds!