A mutual breakdown
Nature abounds with examples of mutualistic relationships. Think of bees pollinating flowers whose nectar nourishes the bees, or clownfish that fight off predators of anemones that in turn provide habitats for the clownfish. Each species benefits the other, and together their chances of survival are better than if they lived apart. Now scientists at MIT have found that such mutualistic relationships aren’t always set in stone. Depending on environmental conditions, once-simpatico species can become competitors, and in extreme cases, one species can even drive the other to complete extinction. Studying two similar strains of yeast, the researchers found that this deterioration in relations is marked by multiple transitions in the species’ degree of codependence. What’s more, such mutualistic relations tend to break down in more “benign” environments, such as nutrient-rich conditions, in which each species isn’t required to rely solely on the other to survive. The researchers have published their results today in...