Post by L Roebuck on Jan 18, 2006 14:27:14 GMT -5
When it comes to male bats, size matters
By Sarah Moses
NEWHOUSE NEWS SERVICE
Sunday, January 15, 2006
SYRACUSE, N.Y. — It turns out size does matter.
At least, according to a recent study, when it comes to bats, their brains and their testes.
Syracuse University biology professor Scott Pitnick found that male bats can develop either big brains or big testes.
"The larger the testes, the smaller the brains," said Pitnick.
He also found that in species with promiscuous females, male bats have relatively smaller brains — but larger testes — than in species with females that are faithful to their mates, according to the study published in the current issue of Proceedings of The Royal Society: Biological Science. Pitnick said the study does not relate to humans.
Evolutionarily speaking, big testes win when female mates are promiscuous because larger testes allow male bats to fertilize more females, he said.
"If female bats mate with more than one male, a sperm competition begins," Pitnick said. "Males want to make sure their genes make it to the next generation. And evolution is all about tradeoffs."
The study has received news coverage in Europe.
"A lot of the newspapers have used the research as a punch line, but for me, any way to get science to the public is an accomplishment," he said.
Pitnick looked at 334 species of bats, about one-third of the known number of bat species. He said he found an "outrageously" large contrast in testes sizes.
In species with faithful females, males had testes starting at 0.11 percent of their body weight. But in species where the females had a large number of mates, Pitnick found testes that were as big as 8.5 percent of the males' body weight.
Pitnick's research found that in these species the body uses more of its energy to enhance the testes and lacks the energy it needs to further develop the brain.
The yearlong study was funded by the National Science Foundation
www.statesman.com/life/content/life/stories/other/01/15BATBRAINS.html
By Sarah Moses
NEWHOUSE NEWS SERVICE
Sunday, January 15, 2006
SYRACUSE, N.Y. — It turns out size does matter.
At least, according to a recent study, when it comes to bats, their brains and their testes.
Syracuse University biology professor Scott Pitnick found that male bats can develop either big brains or big testes.
"The larger the testes, the smaller the brains," said Pitnick.
He also found that in species with promiscuous females, male bats have relatively smaller brains — but larger testes — than in species with females that are faithful to their mates, according to the study published in the current issue of Proceedings of The Royal Society: Biological Science. Pitnick said the study does not relate to humans.
Evolutionarily speaking, big testes win when female mates are promiscuous because larger testes allow male bats to fertilize more females, he said.
"If female bats mate with more than one male, a sperm competition begins," Pitnick said. "Males want to make sure their genes make it to the next generation. And evolution is all about tradeoffs."
The study has received news coverage in Europe.
"A lot of the newspapers have used the research as a punch line, but for me, any way to get science to the public is an accomplishment," he said.
Pitnick looked at 334 species of bats, about one-third of the known number of bat species. He said he found an "outrageously" large contrast in testes sizes.
In species with faithful females, males had testes starting at 0.11 percent of their body weight. But in species where the females had a large number of mates, Pitnick found testes that were as big as 8.5 percent of the males' body weight.
Pitnick's research found that in these species the body uses more of its energy to enhance the testes and lacks the energy it needs to further develop the brain.
The yearlong study was funded by the National Science Foundation
www.statesman.com/life/content/life/stories/other/01/15BATBRAINS.html