In a recent post, I mentioned the theory of sexual selection, which involves males competing against one another for females and said females being choosy in deciding who to mate with. But this isn’t the entirety of the story. What if I told you that males can also be choosy?
Indeed, there have been a number of studies that have demonstrated male preference for certain females. In seahorses, for example, the males are the ones who provide all the care for the offspring in their brood pouch.
Do you think they take eggs from just any female? Pshaw! Remember, caring for offspring is a HUGE investment of time and energy. In short, the answer is no. Especially when you consider the oh-so-busy lives of the male seahorse (cue David Attenborough voice here).
So what kind of traits does a male seahorse look for in a partner? Experiments have shown that males base their preferences on body size – and they like their ladies large! What can larger ladies provide? It’s often the case that larger females tend to produce more eggs (or sometimes bigger eggs), so he may reap the benefits of having more offspring, bigger offspring, or both!
Another interesting male preference that was recently discovered in black widow spiders is a preference for – you guessed it – virgins!
Why might this be the case?
Males may be ensuring their paternity by mating only with females who have never mated before (and so avoid any sperm competition whatsoever). Or perhaps females in this species tend to have most of their eggs fertilized by the first male to mate, so you really win the lottery by being that male. Or maybe these males just really took Madonna literally.
If you were a black widow male, how would you tell the mating status of a potential partner? Through pheromones the females emit for advertisement. “Come here you, I’ve never mated.” “No, pick me, I’m a virgin AND I’m well-fed.” “Oh my, a talking spider.”