Bedbugs had been troubling creatures longer than thought earlier. Until now, it was believed that the oldest "cimicids" were 3,500 years old and unearthed from Egypt almost two decades ago.

However, a new study says that ancestors of today's bedbugs have lived nearly 11,000 years ago at the Paisley Caves of Oregon, where evidence of some of the oldest human activity also exists.

The study said the Paisley Cave site had fossils of a total of 14 bedbugs in the age of 5,100 and 11,000 years. The scientists used carbon dating in analyzing the age of fossils.

The research was led by two archaeologists — Dennis L. Jenkins, from the Museum of Natural and Cultural History at the University of Oregon, and Martin Adams, a zooarchaeologist.

The findings have been published in the journal of Medical Entomology.

At the late Pleistocene Epoch, the cave was home to humans as well as bats, noted the researchers.

Among the 14 fossils found out, three species have been identified as part of the Cimex genus of insects. The common bedbug belongs to the genus Cimex lectularius.

Not Similar To Hotel Room Bed Bugs

"In total, I recovered the remains of 14 individual cimicids, but they were not the bedbug we all know and love from hotel rooms," said coauthor Adams.

According to the researchers, the cimicids in Oregon were basically bat parasites and least troublesome to ancient humans barring some rare occasions.

Unlike other cimicids, the species under the study rarely bugged humans, though they would have done so over a suitable opportunity. That means they were not very keen on bugging humans for a diet.

Coexistence Of Bats And Humans

According to Adams, the discovery gave an insight on the history of bedbugs and the co-sharing of habitat among humans and bats thousands of years ago.

Now the question remains — why the cimicids were not asserting outside the caves, or was it a case that the host population was too small.

"Or were there other constraints involved?" asks Adams and says the next phase of research will examine this question.

So far, it is clear that the species detected in the Paisley Caves were Cimex latipennis, Cimex pilosellus, and Cimex antennatus, which were parasites of bats. It raised the mystery why they were tolerant of humans, as two-bed bug species — Cimex lectularius and Cimex hemipterus — have been known to feed on humans.

Indications Of Ancient Climate Factors

The researchers claimed that the newly found ancient Cimex species also hold clues to the climate trends of that past era.

"The presence of warm-tolerant cimicids in the caves, such as Cimex antennatus, may suggest that climatic conditions at Paisley Caves 5,100 years ago were similar to what Cimex antennatus enjoys today in its current range," noted Adams.