The temperature today was an incredibly balmy 8 degrees Celsius. This was a one-off, however, because a cold front is supposed to roll in tonight and tomorrow is forecasted to be -10 oC (I shouldn’t complain; today in the Canadian prairies it was -50. Before windchill). Still, the warm weather was nice. I wasn’t the only one to think so. This afternoon I found a wasp crawling, somewhat sluggishly, along the windowsill in the den.
In my very first post I talked about the appearance of ladybugs mid-winter. Wasps are very similar visitors. They crawl in to cracks in the walls of the house in the fall when looking for hibernation spots to spend the winter. Normally they would only come out when the warmer spring weather finally arrives, but warm spells can cause a few to come out prematurely. Those that chose to hibernate in your house will quite often go the “wrong” way, toward the warmer temperatures inside, and end up crawling along your floor or windowsill.
Wasps are like honeybees, in that most species spend the majority of their year living in colonies. There’s a queen who “rules” the colony, although her primary job is simply laying eggs. There are sterile worker wasps, who spend their time collecting food for the young grubs and the queen (and themselves), repairing and defending the nest. And there are fertile male wasps, whose only job is to mate with new queens.
In the spring, a new queen, who mated with a male before going into hibernation in the fall and stored the sperm inside her, will pick a site for the nest and start a new colony. Depending on the species, she may start it alone, or with a few of her sisters who overwintered with her. She lays fertilized eggs, which develop into sterile female workers. She’ll care for the first couple of broods herself, but once there are enough workers to tend to the eggs and larvae properly, she concentrates on just laying more eggs. Once the sperm runs out, in mid- to late summer, the unfertilized eggs grow into fertile males and new fertile queens, who go out and mate, and start the cycle again. The wasps that turn up in your house in the middle of winter are all young mated females who have gone into hibernation till the spring. All the other groups – the original queen, the sterile workers and the males – died once the weather turned cold (if not before).
These mated females are stingless. The initial reaction upon seeing a wasp, particularly if you have kids or pets, is to worry about someone getting stung. However, the stinger in wasps and bees is a modified ovipositor (the body part used to lay eggs). Males don’t have an ovipositor to begin with, and mated females need theirs to lay their eggs come spring. Only the sterile worker females have the ability to sting. I suppose she could give you a good chomp with those powerful jaws (look at the size of them in that first photo!), but it’s unlikely to feel like more than a pinch. Paper wasps use their jaws to strip bits of wood from logs or dead trees, which they then mix with saliva to create the “paper” used in building their grey papery nests. If you spend a lot of time on your deck in the summer, you might catch one collecting wood from the deck or siding.
Wasps are generally predatory, preying on other insects, although they can sometimes be seen feeding on the nectar of flowers. The particular composition of their diet depends on the species. They’re useful to have around your yard because they’ll take care of many other undesirable bugs in your garden or around your home. As long as you don’t actively disturb their nest, or pester an individual (intentionally or not), they’re generally fairly docile, willing to let you do your thing while they do theirs. If it’s a mild day when you come across a wasp in your house, let her crawl onto a piece of paper and then transport her outside, where she can find herself a new hibernation spot, and she’ll take care of your garden for you come spring.