Homosexual Behavior Among Fish Increases Attractiveness to Females

Credit: David Bierbach/University of Frankfurt

In many species, females are attracted to large, conspicuous males. But among animals that mate with many partners, males that manage to mate with more than one female can increases their chances of attracting others, even if they aren’t as conspicuous.

The scientists published their findings in the journal Biology Letters. In some species of fish, smaller, less flashy males can win over females by flirting with larger males. Researchers worked with the tropical freshwater fish Poecilia mexicana. Females were shown video footage of small, drab-colored males nipping the genital openings of larger, brightly colored males, an action which precedes mating in opposite-sex fish pairs.

After witnessing this behavior, the female fish indicated their newly awakened interest by spending more time swimming near the images of the less impressive males. The finding suggests that homosexual behavior can enhance a male’s ability to pass on his genes by attracting females that wouldn’t be interested in him otherwise.

Mollies aren’t the only fish that exhibit homosexual behavior. There are documented cases of at least 15 different species doing the same. Whether all of these species do so in an effort to attract more females hasn’t yet been determined.

Reference: “Homosexual behaviour increases male attractiveness to females” by David Bierbach, Christian T. Jung, Simon Hornung, Bruno Streit and Martin Plath, 23 February 2013, Biology Letters.
DOI: 10.1098/rsbl.2012.1038