The fact that the free markets on King’s Day are not allowed this year is a pity for the enthusiasts. And for the proponents of recycling. Free markets offer the possibility of reuse. The vase that would otherwise have been thrown away finds a new owner in someone who does not see the ugliness, and that book would otherwise have ended up in the waste paper. What is waste for one person is a treasure for another.
For us, manure is waste. We turn up our noses and think it’s filth. But for a dung fly, Scathophaga stercoraria, the scent of fresh cow dung is the alluring aroma of wealth and passion. It’s the smell of a flea market, literally. Even before a flan has fallen, there are male shit flies around it: fluffy, orange-yellow hairy animals, which stand out with their golden sparkle as soon as sunlight hits it. They are waiting for a woman, a somewhat less exuberantly colored or hairy fly, to come for that seductive scent. Often before she even has landed, she is already jumped on by several horny men who want to mate with her. She may be drowning in the still wet shit under all their enthusiasm. But if she’s lucky, those male dung flies will have delivered their seed packets to a still living female.
Here’s a shocking fact: Many female insects are smarter than humans. They have a so-called spermatheca, an organ in which they store semen. This is useful, because then you can fertilize your eggs at a time that suits you. Whoever keeps what has what. Dung fly women are even smarter, because they have not one, but three spermathecae. Some examples go a step further and even have four. That way they have a choice. A female dung fly chooses to store the sperm of large males – because that’s what she likes – in one or two specific spermathecae on the right side of her abdomen. Treasuries, as it were. Seed of less attractive types is rather randomly distributed among the three or four storage organs and, moreover, she keeps less of them.
That semen is actually diluted. If a dung fly woman then starts laying eggs on that scented manure, she will preferably fertilize it with seed that she has stored in a treasure house. So she chooses the better men. She ignores bad seed.
Still, she stocked that sperm and stored it on that free market that we think of as shit. She could hardly do otherwise with all those pushy male salesmen. The gentlemen offered them wares for free, but the shit fly woman had to risk her life to get it. It is logical that in such a situation you only grab what you can grab. You keep the best in the treasury. You store the rest in a junk shed, just in case you need it again.
A version of this article also appeared in NRC on the morning of April 23, 2021