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Female Spiders That Want Some Lovin’ Have Their Own Birth Control | Wolf Spiders

Female Spiders That Want Some Lovin’ Have Their Own Birth Control

I guess it’s not only human females that want to have sex without also having babies. Female wolf spiders also have their own form of birth control, a natural strategy they have developed to kill off unwanted sperm after they’ve mated with a male spider. But why would spiders even need birth control when the whole purpose of mating is to make more baby spiders? Well, it turns out that not all female wolf spiders are monogamous, and want to have a little fun with more than one male spider. So, they’ve found a natural method of killing off unwanted sperm so they can have multiple mating partners.

Now, wolf spider sex in general has already proven to be rather odd in the insect world according to researchers. Researchers have already confirmed that wolf spider sex can get pretty kinky, involving prolonged threesomes (bet you thought that was only a human thing), coitus averaging 100 minutes, twin sexual organs, and lots of vibrating legs. Yeah, these spiders are making me blush bright red just writing this.

Researchers have now confirmed that the females have a way to reduce the amount of sperm they take inside them after (and even during) these marathon mating sessions. Now, I can understand their need for this, as after mating, these females can end up having to carry up to 200 of the resulting spiderlings on their backs until they are capable of going about on their own. Can you imagine if they didn’t use some kind of birth control?! Now that sounds like a nightmare I certainly wouldn’t want to deal with.

So, how does this birth control work? Well, when the male and female spiders are going at it, the male uses his pedipalps to inject sperm into the female’s twin sex organs, which can last upwards of half an hour. The female isn’t automatically inseminated, however. She can actually store that sperm for around a month before choosing to fertilize a batch of 200 eggs. This means that the females can mate with more than one male during that month, and those batches of eggs often include offspring from more than one father.

The females are somehow able to reduce the amount of sperm they actually take in and store from each male down to a measly 17% of what was originally inserted. Researchers aren’t completely sure how they do this, but guess that they kill it off inside them, have some way of ejecting it from their bodies, or absorb and then digest the extra sperm as a mean of nutrition. These females aren’t about to let any males cramp their free-loving ways.

Do you think this spider birth control phenomenon is true only for these female wolf spiders, or are there other spiders out there with their own form of birth control?