Between 1991 and 2002, Rossiter and his colleagues caught bats in nets and collected samples of skin from their wings. The scientists were able to analyze 19 different genes in a group of 452 bats, which included mothers, offspring, and potential fathers.
The researchers positively identified the mothers of 371 individual bats and the fathers of 232. The researchers also determined breeding pairs.
Further study showed that specific males and females paired together on multiple occasions more times than would have occurred at random. This finding suggests that mothers and their female offspring are selecting one male and returning to him for subsequent mating.
More Questions Than Answers
According to Rossiter, less-studied bats in other parts of the world might exhibit some of the same mating habits of the greater horseshoe bats.
Gary McCracken, professor of ecology and evolutionary biology at the University of Tennessee in Knoxville, agrees.
"It's safe to assume other bat species are doing this. The genetic data [for greater horseshoe bats] are great. But this research is just the tip of the iceberg."
Much remains unknown about how and why female bats choose certain males. Both McCracken and Rossiter suspect it involves smell, because the males mark their cave areas with an oily substance from their cheeks.
Fenton, the University of Western Ontario bat expert, says the study is important because of the length of time it covers and the large amount of genetic data collected.
He argues, however, that the data don't actually reveal much about mating behaviors.
"We don't know if the female is mating with several males in the same cave or not," Fenton said.
Rossiter uses a camera in the mansion to watch the females, but he has yet to install a similar device in a cave to observe the actual mating.
But the zoologist says he believes in bat fidelity because his team observed many individual females returning to the same mating site from year to year.
In addition, he says, the seminal fluid of the male coagulates to form a plug in the female that stays in place until pregnancy and likely prevents further mating.
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