Fancy furniture and flashy home decor can impress a first date. Now, it seems the same is true for fish.
In the springtime, some male fish make nests out of algae. Females visit the nests and sometimes lay eggs there. Scientists assumed that the best nest designs are dark and well-camouflaged—perfect for hiding eggs from predators.
A male three-spined stickleback (arrow) carries a brightly colored strip of foil for decorating its nest.
|Ostlund-Nilsson and Holmlund
But something fishy off the coast of Sweden caught the eyes of Sara Ostlund-Nilsson of the University of Oslo in Norway and Mikael Holmlund of the University of Stockholm in Sweden. The researchers noticed male three-spined sticklebacks tending greenish nests with flecks of red and orange algae at their entrances.
To figure out what was going on, the scientists put male sticklebacks in an aquarium with shiny, colored strips of foil made for Christmas candies along with a variety of sequins. The fish weren’t interested in the sequins, but they went gaga over the strips, especially the red ones. They promptly took the gaudy strips home to put in their nests.
Female fish loved the colorful designs, too, the researchers report. Male sticklebacks turn red during breeding season, which may have something to do with female preferences for red nests.
Some birds, too, use decorations to impress members of the opposite sex. Male bowerbirds, for instance, adorn their nests with feathers and other colorful things—even plastic pen caps—that they pick up. People aren’t the only animals who appreciate a little glitz and glitter now and then.