Yum, A Meaty Snack

Just don’t even ask me about tomorrow. Just don’t. Mechanics 3 & 1 begin at 1315, and those are the third and fourth challenges of the day. I’d best be going to bed, I think.

I didn’t sleep well over the weekend and have been trying to exhaust myself today. I walked for 1.5 hours with Megan this morning while listening to This Week in Science in which I learnt about spider mating habits. I knew that in some species of spider it’s common for the female to eat the male after coitus, but what I didn’t know was that in one species each gender has two sets of genitalia. Here’s how it works:

Mr Spider approaches Ms Spider and impolitely initiates coitus. In order to prevent other spiders from taking ‘his woman’, he breaks off his penis and leaves it in situ. Ms Spider, now satisfied, becomes hungry, so eats Mr Spider. Sometimes, however, Mr Spider is a particularly strong specimen. If he survives the first attack then, being male, he thinks to himself:

“So she tried to eat me the first time, so what? She’s just playing hard to get. Wait till she gets a load of this.”

And proceeds to insert his second penis into the female’s remaining unblocked orifice, once again detaching himself from said member. Ms Spider, by now annoyed, bites off Mr Spider’s head. At some point she will dump both loads of sperm into the vicinity of her egg. This benefits the selfish genes because it increases their chance of mixing with “strong and healthy” genes. The usual “first come, first served” strategy adopted in most species has the disadvantage that the “first come” may be a poor specimen. Mixing the sperm of two different mates (not true in my example, but most don’t survive the first attack) is a way around this limitation. The same technique used to be applied in human IVF treatments, in which samples were taken from multiple family members. That doesn’t happen any more – can’t think why.

Gotta love evolution.

Anyway, I must away myself. Speak to you tomorrow afternoon…