Researcher Sara Oslund-Nilsson, who works at the University of Oslo, in Norway, was studying three-spined stickleback fish. She was interested in a particular behavior that has long fascinated researchers: the tendency of sticklebacks to use colored bits of dead algae in their nests.
Why is this interesting? Well, stickleback nests tend to be simple piles of greenish fuzz. Females come by, choose a nest, and lay eggs in it. Not much color is involved anywhere. Is it possible, Oslund-Nilsson thought, that the males were using the rare opportunity for color to get the attention of the females?
To test this idea she and her co-wokers did something so simple it’s brilliant. They cut up tiny strips of colored foil from Christmas candy and dropped them in the tanks.
Sure enough, the males went bazoo when they saw these brightly colored pieces–”bazoo” is a technical term–and started stuffing them into their nests.
Now, there is debate over what the data show next–but by some measures, the strategy was a hit. That is, when the females came along, they seemed to prefer the flashy, foil-filled nests over your run of the mill brown-green shtick.
So why would a flashy nest mean a better mate? It may be that by having a snazzy nest you are advertising your fitness–look at all the stuff I have! I can go out and gather things!
Oslund-Nilsson also notes that red strips seemed to be particularly popular and that male sticklebacks turn red when it’s time to breed. She suggests this may be a way of announcing breeding status.