The Echo
What's Singing Got to Do with It?

The Echo

What's Singing Got to Do with It?

Published on August 27, 2015

Tucked away in a tiny tree hollow is a creature that loves to sing. Conventional wisdom might suggest it’s a bird. But don’t be fooled—it’s actually the male lesser short-tailed bat, Mystacina tuberculata.

Lesser short-tailed bats are one of only two land mammals endemic to New Zealand. In the central North Island, a population of 700 lesser short-tailed bats were studied for three years with the hope of shedding more light on the species’ mating technique. With funding from BCI, Cory Toth led an Auckland University research team to confirm that the lesser short-tailed bat practices lek breeding— a very rare and unique form of mating.

New Zealand Bat

“Lek breeding is a system where females receive no resources from the males,” Toth said. “They're just selecting males based on the quality of their displays and so it's basically a distilled version of sexual selection.”

Part of that sexual display involves the males warming up their vocal cords for the ladies.

“The males sing much like a bird,” said Toth. “They go into their singing roost and vocalize for hours…upwards of about 400 songs per minute.”

Interestingly, there exists a relationship between body size and song— the frequency characteristics of the songs male bats produce actually scale with their forearm length, meaning females should be able to tell the size of the male merely by his pitch. To Toth’s surprise, the male bats also divvied up the “singing duties,” with multiple males sharing a single cavity on a one-at-a-time basis.

Lek-breeding is thought to occur when males cannot monopolize females and turn to self-advertisement instead, even though this potentially increases competition. The lesser short-tailed bat is only the second bat species in the world to practice lek breeding – the first was discovered nearly four decades ago in a large fruit bat species found in equatorial Africa.

Bat roost

Lek breeding is rare in bats and…rare overall,” said Toth. “It doesn’t happen very often in many species of animal, so it's interesting just to begin with.”

Lek breeding is also thought to be tied to high mobility. Indeed, this mating system is most commonly found in bird species. For Toth, however, this poses a serious question: why are the lesser short-tailed bats only one of two bat species confirmed to be exhibiting this behavior?

“Bats aren't limited by mobility,” Toth said. “In fact, we would think that there should be lots of bats with lek breeding.”

While Toth and his team have confirmed lek breeding in the lesser short-tailed bat, there are still many unanswered questions. Moving forward, Toth hopes his research will serve its purpose by increasing public awareness of the short-tailed bat and inspiring others to learn more.





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