Bats may have introduced bed bugs to humans when we shared caves together, a new paper suggests.
Enitled "Host Association Drives Genetic Divergence in the Bed Bug, Cimex lectularius" and authored by Warren Booth et al., the paper describes recent genetic research which shows that there are two distinct strains of bed bug Cimex lectularius in Europe. It concludes that the divergence in DNA may have been driven by host specification.
The split in bed bug populations would have happened when bed bugs feeding on bats found a new host: humans. One lineage probably co-evolved with humans, and the other with bats, suggesting a surprising, previously unknown origin for these troublesome pests of human residences.
As the paper states: "In conjunction with the expansion of modern humans from Africa into Eurasia, it has been speculated that bed bugs extended their host range from bats to humans in their shared cave domiciles throughout Eurasia."
The absence of interbreeding between the two populations of bed bugs is signified by a lack of gene flow in the nuclear and mitochondrial data, and laboratory testing has shown that offsrping from the two populations when interbred are less fertile that offsrping from their seperate 'purebred' populations. These points add credence to the conclusion that the two populations are indeed distinct.
Published in the journal Molecular Ecology, the study suggests that bats and humans probably shared cave dwellings at some point in our shared history, and that the two strains of C. lectularius had a common ancestor. The bed bug, a member if the Cimicidae true bugs that evolved to be highly specialised blood-feeders, made a good model for studying host-specific parasite genetic differentiation because of its limited mobility arising from flightlessness.
By Jon Fern
Picture credit: Brown long-eared bat Plecotus auritus via The Guardian
