Bed Bug Evolution: from Oldest Found to Increased Pesticide Resistance

Bed bug evolution is a constant, ongoing process that plays an incredible role in making them much more difficult to treat. By examining populations of bed bugs we can witness these changes with an eye towards finding new ways to treat against them, as well as understanding how they evolve to survive current treatment methods. This week there have been two new studies that show the process of bed bug evolution throughout history.

First,the oldest specimens of bed bugs ancestors have been found recently by researchers in the Paisley Five Mile Point Caves complex in Oregon. The three species – Cimex antennatus, Cimex latipennis, and Cimex pilosellus – differ from modern bed bugs in several ways. As with all bed bug ancestors that we are aware of thus far they fed on bats instead of humans. Modern day “bat bugs” are still a common relative of the bed bug, so this divergence of species is an interesting glimpse into the history of bed bugs and their co-existence with humans. The newly discovered specimens are between 5,000-10,000 years old. Previous to this discovery the oldest Cimex species that has been discovered was a 3,500 year old Egyptian fossil. After that point we have lots of historical evidence for bed bugs, including mentions of them in the historical records and more recent samples such as those found in colonial Jamestown.

In the last century we have a huge amount of samples, including ones from isolated populations that allow us to study insecticide/pesticide resistance. That brings us to the second study to come out this week, published in the Journal of Economic Entomology, that found an increased resistance in bed bugs to bifenthrin and chlorfenapyr – common ingredients previously thought to still work well against bed bugs. As we’ve discussed in a number of our previous posts, bed bugs are very adept at developing pesticide resistance. With each new generation of bed bugs the amount of resistance to pesticides grows as the bugs that are hardest to kill survive to reproduce.

The good news is that despite new evidence of bed bug evolution there is still no sign of any resistance to heat treatments or mechanical methods of death. So remember, if you’re fighting bed bugs always use a multifaceted approach such as our 8-Step guide. Isolate the bed bugs, apply diatomaceous earth, and heat treat whenever possible.