Editor’s Note: This article was reprinted with permission from Techletter, a biweekly training letter for professional pest control technicians from Pinto & Associates.
It’s bad enough that male bed bugs mate with females through the process of “traumatic insemination.” They simply poke a hole in the female’s abdomen, anywhere, with their copulatory organ and inject their sperm into her body cavity.
It’s not like it doesn’t affect the female, she essentially has an open wound that is subject to infection until it heals. It’s hard to understand how or why this method of mating evolved. Apparently, bed bugs have a special gene (pro-resilin) that allows the exoskeleton to be flexible enough to receive puncture wounds without killing the bugs.
Now Dr. Gail Ridge of the Connecticut Agricultural Experiment Station, has discovered something similar occurring among bed bug nymphs.
TRAUMATIC FEEDING. Ridge observed very young bed bug nymphs engaged in a cannibalistic traumatic feeding, stealing food from their relatives. Young nymphs were using their mouthparts to pierce older and recently fed nymphs in the abdomen to suck the stored blood.
The young nymphs get a secondhand blood meal, leftovers sort of, but this occasional behavior allows the youngest and most vulnerable bed bug nymphs to remain in a protected hiding place while older nymphs must go through the risky process of finding and feeding on a human host in the real world.
GOOD GRANDPARENTS. There’s another way that bed bugs seem to collectively protect their young. Most insects live just to reproduce, dying soon after they have done so, or after their reproductive usefulness is over. But, older bed bugs that are no longer reproductive seem to hang around, playing a role of caretaker “grandparents” for the young nymphs.
Ridge says when bed bugs aggregate and “stack” themselves together for protection, the older and larger bed bugs are often on the outer layers of the stack, perhaps to shelter those beneath that are still approaching reproductive age.
Young nymphs like to hide under the bodies of older bed bugs and that helps protect them from insecticide applications as well. Young nymphs also use older bed bugs for transportation. They will hitch a ride on top which gets them to a new location without touching treated surfaces, thereby spreading the infestation.
Ridge points out that because young bed bug nymphs seem to have various protections from insecticides, controls such as vacuuming should be part of your program.
The authors are well-known industry consultants and co-owners of Pinto & Associates.