We humans have to live with parasites of all kinds always, and more generally with what in English are called “pest”: a term that includes all those insects and arachnids that feed on our blood, but also for example the cockroaches, and even rats.
However, what was the first ever to notice how comfortable it was to associate with our species? According to a study published on Biology Lettersthe primacy has been going to bed bedbugs, which have been our companions for 50,000 years now, and which have literally exploded in terms of numbers in the last 20,000.
Men or bats? We have already talked a little more than a month ago of bed bedbugs, insects that have gone from being a big health problem to disappear or almost from cities, and who are knowing one unwelcome rebirth in the last 15 years. They feed on our blood, they are highly infesting and are even becoming resistant to certain insecticides.
Originally, however, they were not human parasites: They began their career in bats, until, about 50,000 years ago, they made the jump of species. We know thanks to a genetic analysis of the species, which as the study explains is relatively low and therefore easy to reconstruct. We do not know exactly where the first jump occurred, but we know that since then the bedbugs of the beds that parasite have had a completely different destiny from those of bats.
The jump of species and life in the city. The latter, in fact, about 20,000 years ago they met a decline coincided with the latest maximum glacial, which has given them a decisive blow: since then, the bins’s bedtters are in decline, and they never resumed. The bedbugs that were already “skipped” to humanson the other hand, have passed the period of crisis and since then they have multipliedspreading all over the world.
The real boom, says the study, however happened about 12,000 years ago, when the first cities were born – or what could be defined at the time: we are not talking about metropolis, but of stable housing agglomerations and with a fairly dense population to allow the bedbugs of the beds to thrive. Since then they have not left us anymore, and given the latest news about their pesticide resistance it is difficult to think that they will do it shortly.
