just science day 2 theyre only after

Just Science day 2: They're only after one thing

Before we begin, I notice that the aggregator at Just Science has

given yesterday's post the date of 31 December 1969. Can anyone help

with why this has happened, and how to stop it happening again?

Anyway, on with the madness. With Valentine's day just a week away,

this paper in the new issue of Ethology is a must-read. In it,

self-proclaimed `media friendly expert', Karim Vahed, of the

many male animals (especially insects and spiders) bring to their

intended mates.

The orthodox view of this is that everyone wins -- the female gains a

meal that increases her fertility, the male gets a mating. Vahed,

however, has a rather more cynical take on things:

sensory traps: by exploiting the female's gustatory responses, the

male may be able to entice females to accept superfluous matings

and/or transfer greater volumes of ejaculate than are in the

female's reproductive interests.

Gift composition is more likely to be tailored to increasing the

handling time than to suit the female's nutritional needs ...

resistance of the female to accepting an extra large ejaculate.

There is some evidence for this notion. Experiments in the fly

Rhamphomyia sulcata suggest that females are almost as enthusiastic

indiscrimate behaviour leaves the door open to an invasion of cheating

males.