Bird fertility boosted if sex expected

DALLAS (Reuters) - Fertility rates in birds can get a lift if the male anticipates that a sexual encounter is just around the corner, researchers from the University of Texas reported on Thursday.

The unorthodox study involved 28 male quails, 14 female quails, and two chambers: a green one near a noisy room and a white one on an isolated table.

The males were put into each of the chambers for a brief period daily over a period of five days. Half were given access to a female immediately after their time in the green chamber but not the white: for the other half it was the opposite.

The male quails therefore came to associate one chamber with the act of copulation.

"We can take anything and make it a romantic setting if there is the anticipation of sex," said Michael Domjan, a psychology professor at the University of Texas at Austin.

"We concluded the experiment by pairing the males with single females. One male would go into the romantic chamber and then have access to the female, then one would go into the non-romantic chamber and then have access to the same female," Domjan, one of the authors of the study, told Reuters by telephone.

Using DNA testing the researchers then tracked the paternity of the eggs and found that the males who anticipated the act of copulation fertilized 72 percent of the eggs laid by the female quail.

The study, published online on Thursday in the September issue of Psychological Science, concluded that the anticipation of mating appeared to induce them to produce more offspring.

"It shows that psychological factors impact fertility and that learning has a lot to do with successful sexual behavior," said Domjan.