Researchers have discovered that bed bugs have been around for a lot longer than previously assumed – 115 million years ago, to be exact – long before the arrival of humans.
Scientists frequently look at the evolutionary pathways of parasites, as it can help improve our understanding of the relationship between parasites and hosts, with the potential for realising alternative control methods.
For bed bugs, it is generally believed that bed bugs emerged with the appearance of bats on the evolutionary timeline and that the emergence of the human bed bugs, Cimex lectularius (the common bed bug) and C. hemipterus (the tropical bed bug), occurred through a divergence event at the time the first humanoid species appeared. However, a recent study suggests a different story.
A multinational team of researchers collected bed bugs from around the word and using molecular dating tools and a single bed bug fossil, the team put together an evolutionary timeline for bed bugs.
Their first major finding indicated that ancestral bed bugs appeared around 115 million years ago, some 50 million years or so before the emergence of bats. The researchers are not sure what these ancient bed bugs would have fed on. Although it was the age of dinosaurs, they are not sure dinosaurs were the hosts. Certainly for modern bed bug species, we associate them with ‘nesting’ animals or those with a regular sleeping location, as although they feed off their hosts, they do not live on their hosts. It is believed that dinosaurs generally did not have a ‘home’ and therefore would not have been suitable hosts for bed bugs.
Their second major finding was that the tropical bed bug and common bed bug separated from the ancient bat bed bug lineages some 47 million years ago – a long time before the arrival of humanoid species. The implication being that the common pest bed bugs did not co-speciate with ancient humans, as other hypotheses have suggested. The authors of this latest research hypothesised that these species simply adapted to the presence of humans as an alternative food source. With ancient humans and bats likely to inhabit similar caves, it certainly makes sense.
The researchers hope that by understanding how bed bugs evolved to use different hosts it could help in developing new methods of control.
Further reading: Roth, S. et al. (2019). Bedbugs Evolved before Their Bat Hosts and Did Not Co-speciate with Ancient Humans. Current Biology. 10.1016/j.cub.2019.04.048.