Sex is matter of life, then death for male marsupials

A new study suggests that some species of marsupials mate with such vigour and intensity that it quite literally kills them.

The scientists say that males die in large numbers after mating with as many partners as possible in sex sessions lasting up to 14 hours at a time.

A key factor in this costly coitus is the promiscuous behaviour of females who all breed at the same time of year.

The study is published in the journal PNAS.

Suicidal reproduction or semelparity is well known in many species of plants and fish but is rare in mammals.

This new study looks at the mating behaviour of 52 different species of small, insect eating marsupials in Australia, South America and Papua New Guinea.

They found that in some of these animals, such as the antechinus, the phascogale and the dasykaluta, male attempts to father offspring cost them their lives.

Lust for life?

This "dying-off" trait is more likely to be found in species living in regions where food was plentiful in one period of the year.

This makes the females of the species more likely to shorten their mating seasons so they only give birth when there is plenty to eat.

In these marsupials, the females have also synchronised their reproductive cycles.

Continued