According to a new study published in the Journal of Medical Entomology, researchers analyzed the oldest bedbug ancestors found to date, fragments ranging from 5,000 to 11,000 years of age.
The remains were found in a cave in southern Oregon, where the oldest evidence of human activity in North America was recorded, near Paisley, Oregon.
Bats, bedbugs, and humans living together
Apparently, the bedbugs discovered in the cave did not latch themselves onto people but instead were bat parasites. The discovery consists of the remains of 14 cimicids, found in the Paisley Five Mile Point Cave, dating from the late Pleistocene and early Holocene. Nine of the specimens were correctly identified with the more modern species of bedbugs, while the remaining five could not be identified.
What’s interesting is that through the discovery, a new gap was found in the evolution of the cimicids. The other significant bedbug remains are just over 50 years old, providing background for only 16 recognized species of the Cimex genus.
The Paisley Caves are over 13,000 years old, a compound consisting of eight caves where thousands of insect remains have been recovered, alongside remains of other animal species, such as camels and horses, these being the first remains discovered in the compound back in 1940. Those early discoveries were made by Luther Cressman, who also found evidence of human occupation in the area. The issue was that, at the time, there was no radiocarbon dating, so his observations were temporarily dismissed until artifact collectors looted the place.
The site was reinvestigated in 2002, trying to preserve what Cressman had found concerning human remains on the site. Over the years, more cimicids were recovered and documented for future study.
Researchers appear to be confident that the bedbugs necessarily had to be bat parasites, although the cave’s skeletal remains of bats are yet to be identified. It also appears that humans and bats coexisted in Cave 2 for over 11,000 years, although human may have resided in the cave in a sporadic manner.
“Recent molecular research on Cimex lectularius supports this notion, and it suggested there are both human- and bat-associated lineages within the same species. As there are many instances where non-lectularius cimicids have fed on humans when the opportunity presented itself, it is probable that similar occurrences befell the human occupants of Paisley Caves,” reads the study.
The research team wondered why the cimicid could not establish themselves outside the caves, maybe because host populations were too small, or perhaps because humans did not settle in a single location, only temporarily residing in caves.
Also, identifying the bedbugs allows having an idea of the climate in the area. For instance, Cimex antennatus prefers warmer climates such as in Nevada and California. Cimex antennatus, being one of the most climate-tolerant bedbugs found in the caves, serves as evidence to suggest that the Paisley Caves had a similar weather 5,100 years ago to what it sees today.