sperm competition
One night of passion and you're filled with a lifetime full of sperm with no need to ever mate again. As sex lives go, it doesn't sound very appealing, but it's what many ants, bees, wasps and termites experience. The queens of these social insects mate in a single "nuptial flight" that lasts for a few hours or days. They store the sperm from their suitors and use it to slowly fertilise their eggs over the rest of their lives. Males have this one and only shot at joining the Mile High Club and they compete fiercely for their chance to inseminate the queen. But even for the victors, the war…
You've got to feel sorry for the female seed beetle. Whenever she mates with a male, she has to contend with his spiked, nightmarish penis (remember this picture?). And despite the damage that it inflicts, one liaison just isn't enough; female seed beetles typically mate with many males before they lay their eggs. Surely, she must benefit in some way?
The most likely idea is that she somehow ensures that her eggs are fertilised by sperm from males with the "best" genes - those that either make for particularly fit and healthy young, or that are a compatible match for the female's own genes.…
If you've ever complained about having bad sex, you really have no idea. Human women may have to complain about poor stamina or incompetent technique but the female seed beetle (or bean weevil; Callosobruchus maculatus) has to contend with her partner's nightmarish penis - an organ covered in hard, sharp spikes. Just see if you can look at the picture on the right without wincing.
It's no surprise then that females sustain heavy injuries during sex. But why have male beetles evolved such hellish genitals? What benefits do they gain by physically harming their partners?
It's possible that…