Male sea lampreys may not be the best-looking creatures swimming in our lakes and streams, but they apparently have something going for them that the ladies may find irresistible.
Research by a team of Michigan State University scientists found that the males have a secondary sex characteristic that creates heat when they get near a female lamprey, something the females find hard to say no to.
The work of the team focused on a small bump located near the male’s anterior dorsal fin. Close examination of this bump determined that it was full of fat cells, cells that are similar to ones found in mammals, animals that need to maintain their own body temperature.
By putting a probe into the bump, the researchers found that the temperature of the bump, also known as rope tissue, increased by 0.3 degrees Celsius when the male approached a female, sometimes even more, depending upon the female.
The role this “bump” played in spawning was not known until now. Scientists had thought it merely as ornamental or playing some other minor role.
“We thought it was just a structure that was used for some kind of mechanical stimulation that they needed to trigger the female to lay eggs,” said Weiming Li, a professor of fisheries and wildlife and a team member.
Until now it was believed that males attracted females by releasing pheromones.
Read more at: Phys.org