Hello Echo Lake Visitors,

Thanks for taking an interest in our research! You’ve found fish enclosures that will be in the water for about 6 weeks. We are running an experiment with stickleback fish, those little prey fish that trout, loons, and sometimes dragonfly larvae like to eat.

It’s typical in many animal and plant species for males and females of the same species to differ in their anatomy. Think cardinals, peacocks, elephant seals, elk, and so on. Why? One explanation is that these differences arise because of the competition for mates. Those elk males need those big antlers, or those peacock males need those big tail feathers, to win the competition for females.

However, it may also be that males and females compete for food and other resources. If so, males and females might start using different resources and adapt by getting different anatomies. Not because of competition for mates, but competition for resources.

If resource competition is the reason for differences between females and males, then we might make a prediction. Males and females should compete less for resources than males versus males, and than females versus females.

This experiment is testing that prediction. Some enclosures have male-male pairs. Some enclosures have female-female pairs. And some enclosures have male-female pairs. (We know this because we used PCR to identify males and females based on their sex chromosomes.) We expect the individuals in the male-female pairs to compete less, and have better survival and growth. Time will tell!