The Red-backed Spider Strikes

Some of you may have read our earlier post on our overwintering visitor: the Red-backed Spider. This subadult female has been hanging out in our house for a couple of months. Most of the time she has been hidden away; I suspect she has been using a cool dark place down behind a bookshelf.

Except in the last 10 days she has suddenly been showing up: dropping down on a six foot length of silk from the ceiling, not far from where I was sitting. I've seen her on the wall, not far from the bookshelf. She has appeared in the corner, above the clock. With all these appearances, she, like the clamoring spring birds filling up our yard, is announcing that she thinks spring is coming.

At the same time, Glen has been getting his mason bees ready for the spring. He has been a mason beekeeper for 15 years, and nothing says spring to him more than getting ready for their emergence. So he has been bringing in some of last year's bee boxes, cleaning them out, inspecting for insect pests, and preparing new housing. In the process, a few cocoons have been accidentally left inside our warm house. The warmer temperatures combined with sun pouring in the windows has awoken these sleeping mason bees. They have been chewing their way out of their tiny, leathery cocoons and are making their way to the sunny window. Often we come home at the end of the day to find a few in the window, which we then put outside the following morning. So far the system works.

However. In last few days, we are coming home to dried up bee carcasses scattered on the inside of the window sill. We were surprised at this, but were speculating that maybe the bees just did not have enough stored resources to make it through the day. But today, we happened upon the crime scene, literally catching the culprit bloody-fanged: the Red-Backed Spider has been stalking and feeding on these newly emerged bees. In this picture you can see that she was successful: here we have a detailed picture of her fangs deep in the head of this (mercifully dead) bee, sucking away the life fluids.

As I started to write this, the feeding process had been going on for over 90 minutes. I just went back to check; she has moved on to the abdomen and continues to drink deep. It appears to me that her red abdomen is swelling, getting bigger with each passing minute. I went back to check at the two hour mark, and there was only the desicated bee, its corpse leaning against the glass.

This is the end for this bee. For the Red-backed Spider, this is a much-needed source of nutrition that will jump-start her (excuse the pun) into the new season, and her life to come.

Janet