COLLEGE STATION, Feb. 9, 2011 When you've got to go, you've got to go upstream, that is, if you are a male swordtail fish seeking a mate, according to research from Texas A&M University.
A recent study led by Texas A&M biologists Dr. Gil Rosenthal and Dr. Heidi Fisher in collaboration with scientists at Centro de Investigaciones Cientificas de las Huastecas in Hidalgo, Mexico, and Boston University has determined that the fish use chemical cues in their urine to elicit sexual responses from their downstream female counterparts.
In a study funded by the National Science Foundation and the American Livebearer Association, Rosenthal and his team found that male swordtail fish strategically release pheromone-packed urine in the presence of females as a display of courtship, indicating that they have evolved a temporal and spatial control of their pheromone release. The findings, which are featured in the current issue of the journal "Public Library of Science (PLoS) ONE," contradict previous assumptions that male pheromones in fish are passively released, given that most fish lack specialized scent glands or scent-marking behavior.
"We showed that male swordtail fish use chemicals in the urine as mating signals," Rosenthal says. "There's been relatively little work on how pheromones shape the lives of aquatic creatures."
The team studied wild-caught swordtail adults from the Rio Atempa in Huitznopala, Mexico, to determine whether females were attracted by passively produced cues or to pheromones as a form of communication. Using fluorescein dye injections to visualize urine release inside an aquarium, the researchers were able to determine that male swordtails relieved themselves more frequently in the presence and proximity of females than when females were absent altogether. In the wild, males court females in much the same way, but by swimming further upstream to ensure their scent is detected in the current by the
|Contact: Chris Jarvis|
Texas A&M University