Researchers discover male bats have ‘timeshare’ arrangement

Researchers discover male bats have ‘timeshare’ arrangement

For the male lesser short-tailed bat, attracting a female is a challenge, but pungent aftershave and an excellent singing voice will increase the chance of success - as long as the flatmates don’t come home early.

Research into the New Zealand’s lesser short-tailed bat (Mystacina tuberculata) gives remarkable new insights into the bats’ mating behaviour. The bats are one of only two land mammals endemic to New Zealand and are a threatened species.

Carried out over a three-year period at Pureora Forest in the central North Island, a population of more than 700 Mystacina tuberculata were studied using microchip technology along with infrared cameras.

The research, by doctoral student Cory Toth from the University of Auckland’s School of Biological Sciences, confirms the species as one of only two bats in the world to use lek breeding, a mating system whereby males aggregate close to groups of females and produce sexual displays in order to attract a mate.

“In more than forty years of research, Mystacina tuberculata are only the second bat species anywhere in the world discovered to use lek-breeding, it’s a relatively rare behaviour in mammals,” Mr Toth says.

A single male lesser short-tailed bat takes up residence in a tree cavity at night and sings to attract females travelling to and from nearby communal roosts. Males not only sing but cover themselves in their own urine to add to their attractions.

The big surprise of the research is that solo-occupied tree cavities within the male singing roosts are used on a ‘timeshare’ basis, with multiple males sharing a single cavity – on a strictly one-at-a-time basis.

“The roost-sharing by males was a complete surprise,” Mr Toth says. “Up to five males take turns occupying a single roost but if another male arrives while one is already in residence, a fight will ensue.”

Lek-breeding in mammal or bird species is thought to occur when males cannot monopolise females and so resort to producing sexual displays near groups of females, even though this potentially increases competition.

Mystacina tuberculata is only the second bat species in the world where lek breeding has been confirmed – lek breeding in bats was first discovered in 1977 in a large fruit bat species in equatorial Africa.

As well as being important seed dispersers and pollinators in New Zealand old-growth forests, the short-tailed bats’ threatened status gives new research an added importance, Mr Toth says.

“While we have confirmed lek-breeding in the lesser short-tailed bat, we need to carry out more work to investigate the roost-sharing by males and other breeding behaviour such as which males receive matings and why,” Mr Toth says.

The research is published today in Behavioural Ecology.

ENDS

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