Even microbes like to know how busy it is somewhere. But knowing how many of your species are around is harder than it seems when you don’t have eyes. Luckily, most microbes have found an elegant solution to this problem.
Even microbes like to know how busy it is somewhere. But knowing how many of your species are around is harder than it seems when you don’t have eyes. Luckily, most microbes have found an elegant solution to this problem.
Excrete and take up
Most species of microbes use a smart trick to know with how many they are: quorum sensing. Every individual of the species constantly excretes a little amount of a certain substance and at the same time takes up a little bit. Based on the concentration of the substance, the microbe then knows how many others are present. Compare it to a room full of people where everybody places and searches for Easter eggs. The more people there are in the room, the more Easter eggs you will encounter.
Better together
But why do microbes want to know how busy it is? That depends a little bit on the species. It can tell them something about the amount of food present, but it can also make cooperation possible. Together they can optimize the uptake of food or form a protective biofilm. But it can also play a role in bioluminescence. The bioluminescent bacterium Aliivibrio fischeri for example, will only light up if there are enough of its peers around. Flashing light all alone is just not worth it. Or worse: you might get spotted and eaten.