Also, the researchers found that if one male leaked semen on another male and the semen-covered male later bred with a female, the female''s eggs could become fertilized with the sperm of the male she had never encountered.

The fact that a male could inseminate a female without directly breeding with her came as a big surprise.

Thus, one can say that the flour beetles'' homosexual behaviour yields a direct reproductive benefit, allowing males to inseminate females without expending time or energy having sex with them.

"We could not believe these results when we first saw them, so we ran the experiment over and over again to make sure it was actually happening," said Lewis.

The findings of the study appear in the Journal of Evolutionary Biology.