Inbreeding in nature promotes promiscuity

Promiscuity in nature is considered to be a good thing, according to a new study. Through recent investigations, scientists have discovered that females who are promiscuous are simply solving the problem of inbreeding.

Researchers, who reported their findings in the journal Science, now believe they have found the reason why many females have several different mates, when in essence they only need one male to breed.

By mating with several different males, females who come from inbred groups are opening themselves up to a larger gene pool. This strategy enables them to screen the sperm they collect, then filter the one that is genetically less compatible.

Scientists from the University of East Anglia used flour beetles in an experiment to study these breeding patterns.

In regular populations they found the rate of breeding was identical, irrespective of the number of mates the females took. However, when they carried out the same test among inbred groups they noticed that the survival rateof the offspring was halved when the females only mated with one individual.

The university team then deliberately produced a group ofinbred beetles, by breeding them with their close relatives, and watched the effects.

They noticed that they too began to mate more regularly and with several different suitors in order to combat the ill effects of inbreeding.

‘Exactly how females filter the most compatible sperm is not yet understood,’ said Professor Matthew Gage. ‘They might simply mate more frequently, and allow the ‘best sperm to win’, or they might choose to mate most with less related males, thereby concentrating their sperm stores from those males.’

Either way females were able to easily adapt their natural behaviour to boost their chances of healthy offspring.