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Bedbugs chose humans on several occasions in their evolutionary past

Bedbugs chose humans on several occasions in their evolutionary past

18 May 2019 12:00

Bedbugs rank high among the list of most unwanted human bedfellows but have been parasitic companions with other animals for more than 100 million years. Work by an international team of scientists, including Assoc. Prof. Nikolay Simov from the National Museum of Natural History in Sofia compared the DNA of dozens of bedbug species in order to understand the evolutionary relationships within the group as well as their relationship with us. The team spent 15 years collecting samples from wild sites (and museums) around the world, dodging bats and buffaloes in African caves and climbing cliffs to collect from bird nests in South East Asia. 'The first big surprise we found was that bedbugs are much older than bats, which everyone assumed to be their first host', said Dr Steffen Roth from the University Museum Bergen in Norway, who led the study. He added 'it was also unexpected to see that evolutionary older bedbugs were already specialised on a single host type, even though we don't know what the host was at the time when T. rex walked the earth.'

The team also found that the two major bedbug pests of humans, the common and the tropical bedbug, are much older than humans. 'This was a real surprise because it contradicts the common notion that the split in ancient humans caused the split of the bedbug into two new species', added Prof. Mike Siva-Jothy from the University of Sheffield in the UK.

The study also reveals that a new species of bedbug conquers humans about every half a million years: moreover, when this happened the bedbugs were using the new hosts (us) without giving up their old ones. 'A rare case in bedbugs’ says Professor Klaus Reinhardt, a bedbug researcher from Dresden University in Germany, who co-led the study and added: 'These species are the ones we can reasonably expect to be the next ones drinking our blood, and it may not even take half a million years, given that many more humans, livestock and pets that live on earth now provide lots more opportunities.'

Most bedbug species use bats as their host. However bats are not the bedbugs’ first hosts and were even colonised several times.

'On the other hand, it is amazing to see (we clearly see) that many (far most) bedbug species and populations living with the bats and swallows surrounding us are safe for humans (do not tend to leap to humans).'

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