Ah, the bedbugs! Some of them they crush but others know that by crushing them they stink (an excellent defensive strategy, you kill me and in the meantime I’ll plague your house), they don’t make an impression like a spider and yet they give us nuisancenot to mention those in the beds that suck our blood.
Yet for tens of millions of years they have been practicing a biological technique of incredible precision. A new study published in Current Biology from Yu Matsuura’s groupKyoto University confirmed previous studies that some species of bedbugs Asian they don’t just host the bacteria, they cultivate them in a form of “symbiotic agriculture”, maintaining in the body, in special intestinal pockets, bacteria essential for their larvae from both a nutritional and antimicrobial point of view. In fact the Asian marmorated stink bug (Halyomorpha halys) protects its offspring thanks to an obligate symbiotic bacterium, Candidatus Pantoea carbekiiwhich lives inside its intestine and provides essential nutrients for the growth of the larvae. When she lays her eggs, the female covers the shell of this bacterium and at the moment of hatching the nymphs ingest it and become carriers of it. It is a form of microbial inheritance that has probably been passed down for at least 30 or 40 million years, a pact of survival between species that perpetuates without ever breaking. In short, bedbugs don’t grow anything, but they breed within themselves what keeps them alive. They are not farmers, they are incubators of microbes (in reality we are, we fear pathogenic microbes but without the billions of microbes we carry inside us we would not be alive).
Their bacteriumin fact, is not a parasite, it is a ally. It lives in a special organ of their intestine, in perfect metabolic balance. Without him, the insect does not develop, and without the insect the bacterium does not exist. The most common mistake (for those who know a little about bacteria) is to confuse this bacterium with Beauveria bassianaa pathogenic fungus that we humans use as a natural pesticide to eliminate them: another biological paradox, given that evolution, indifferently, creates and destroys with the same elegance.
Speaking of pesticidesit makes you think about related antstrue farmers of evolution. They have been cultivating mushrooms for 50–60 million years, and the most advanced, the leaf cutters (Atta and Acromyrmex), which appeared between 8 and 12 million years ago, have brought the systems to a level of industrial complexity: they cut fresh leaves and knead them and regulate temperature and humidity to nourish a specific mushroom, Leucoagaricus gongylophoruswhich represents their only source of food. To defend the crop from mold and parasites, some castes breed such bacteria Pseudonocardia that produce natural antibiotics: a real microbiology laboratory, organized in an anthill.
In essence, bedbugs practice intestinal symbiosis, that is, an internal alliance between host and microbe, while attine ants practice external symbiosis, a form of mutualistic agriculture in which society itself becomes a biological machine to grow another species. The principle is the same: a blind and pragmatic refinement that evolution maintains only because it works. But don’t go out and say: oh, Nature does wonderful things! Nature is not an intentional agent, and evolution never invents anything, it does not plan, it is the result of random genetic mutations and, by natural selection, those that are successful move forward. In short, we boast of having invented agriculture ten thousand years ago and antibiotics in the last century, bedbugs and ants arrived many tens of millions of years ago, when we were not even a biological hypothesis.