Drosophila is a genus of insect which are commonly known as fruit flies. They're very well-studied, with Drosophila melanogaster in particular being a model organism for scientists and widely-used in research. This is how we know all about what they get up to.
Fruit flies reproduce quickly, which is why if you leave an apple core in the bin too long you'll probably find your kitchen swarming with the little gits (tip: add a small amount of washing up liquid to a cup of vinegar, this traps them before they become a problem).
But we're not here for exchanging tips on how to keep Drosophila out of you're kitchen! We're here to talk about how they do the nasty.
Before fruit flies have sex, they perform courtship rituals. First, the male sings a song by vibrating its wings. They might also strike a series of poses. And then, it's the foreplay. The male taps the female's genitalia with its legs, and licks the area.
If, at any point in this process, the female isn't feeling it, it will kick the male away, move away, or extend its ovipositor to shove the male away. If it works out, fruit fly sex lasts up to 20 minutes.
You might have learned the word "spermatheca" from our thread on bees (linked), and it's our pleasure to tell you that female fruit flies have two spermathecae, shaped like mushrooms, as well as a third organ, also used for storing sperm. https://masto.ai/@vagina_museum/109556992096895824
Now, when we think of sperm, we're typically told at school that sperm is tiny and eggs are huge. This, we are delighted to inform you, is absolutely not the case for Drosophila. Fruit fly sperm is absolutely enormous.
In Drosophila bifurca, a single sperm cell is almost six centimetres long, which is 20 times the length of its body. That's equivalent to a human nutting a sperm that's the length of three double decker buses and a Land Rover lined up.
Other fruit flies don't form quite such dramatically large gametes, for example Drosophila melanogaster produces sperm that's only 1.8mm long, and therefore only about 35 times bigger than a human sperm cell (and only about 80% of the body length of the fly).
How do such gargantuan sperm fit inside something as dinky as a fruit fly? Essentially, it's balled up like yarn inside the male, and the female's sperm storage organs are like a labyrinth in there.
In the 20 minutes fruit flies are copulating, they're sort of unravelling and then weaving a ball of string, except they're doing it with their genitals. You probably couldn't do that.
Female fruit flies' capacity for storing sperm is a problem for scientists because the insects are used for genetic research. For their experiments to work, they want to control who the Drosophila's babydaddy is, and ensure it's only got its own genetic material in there.
This means fruit fly researchers have developed a method for spotting if a fruit fly is a virgin at a glance. Virgin fruit flies have a little visible dark spot, which is called meconium, and is basically poop. Once they're old enough to have mated, they don't have the spot.
Please note that as a general rule, you can't tell if someone is a virgin or not by whether or not their poop is visible. This only really applies to fruit fly research.
Despite our familiarity with fruit flies, scientists have managed to get things spectacularly wrong about them, and because of their use as model organisms, this has had huge implications which have followed us around for years. The biggest cock-up is Bateman's principles.
Bateman's principles, based on a 1948 fruit fly experiment, is that females are choosy about their mates because eggs are costly to produce, while males are promiscuous and sow their wild oats everywhere.
Bateman's principles have been formative, and repeated widely, applied to other animals as well as fruit flies.
However, Bateman's fruit fly experiment showing that females are choosy and males are promiscuous has failed to be replicated and was absolutely riddled with methodological flaws. Drosophila females do mate with multiple partners and have babies with different fathers.
Bateman screwed up in a number of ways. First of all, he never actually watched the flies having sex. And because he did the experiment in 1948, he didn't have access to techniques for checking the parents of the offspring - he simply checked which mutant dad they looked like.
In Bateman's experiments, on which the choosy female, promiscuous male paradigm is built, he didn't account for variables like female Drosophila reaching sexual maturity a little later, and also that the females usually leave it a few days between mating.
Even such a widely-studied creature as the fruit fly continues to wield surprises. And honestly, we can''t wait to find out the next wild discovery about how these little bugs get it on.
@vagina_museum We did breeding experiments on fruit flies (D. melanogaster) when I was in junior high school. We were supposed to euthanize them with ether (as opposed to, say, a flyswatter or a rolled-up newspaper) at the end of the experiment.
Ether not only failed to kill my fruit flies, but the little degenerates came crawling back for more. I may have single-handedly bred a new strain of drug-crazed ether-addicted (and ether-proof) fruit flies.
@vagina_museum
for fun, here's some pictures of Drosophila novamexicana 'slinky-shaped' sperm (right) dissected from a mated female, and her dissected reproductive tract (left) including her 2 spermathecae and her massive labyrinthine seminal receptacle (the other storage organ)
[Both pics by Brooke Peckenpaugh, IU]
@vagina_museum Background: years ago while playing final fantasy xi online and chatting with some japanese players one of them idly asked the room "what means cum?" and before anyone could respond they added: "corned beef?" to which I emphatically said: 'yes, when I get off there is an explosion of corned beef... I should see a doctor about that.'
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