Ants And Aphids Enjoy A Mutually Beneficial Partnership
In the arthropod world it is not uncommon to find two different insect species indulging in a mutually beneficial relationship. These beneficial relationships do not always occur between two insects. For example, some termite species have been enjoying a symbiotic relationship with different fungal species for millions of years. Ant and aphids serve as an example of a symbiotic relationship between two insects. For years researchers have been aware of the symbiotic relationship between ants and aphids, but now researchers are learning that ants may wield more power in this relationship than previously thought. According to Japanese researchers, ants that indulge in symbiotic relations with aphids can determine the reproductive success of their aphid partners. Therefore, the constitution and size of aphid populations is largely determined by their ant partners. But why would ants want to influence aphid populations?
Ants and aphids have been watching each other’s backs for a long time now. Species from both of these groups have adapted to helping each other survive in the wild. For example, ants protect aphids from predatory attacks from ladybugs and wasps. In return for this protection, aphids supply ants with tasty honeydew, which ants eagerly consume. This mutually beneficial relationship helps each species to survive. However, ants prefer some types of honeydew over others.
The particular aphid species that shares a symbiotic relationship with ants is known as Macrosiphoniella yomogicola, and the ants are known as Lasius japonicus. The aphid species comes in two morphs. One group of aphids are red and the other is green. It turns out that the ant species prefers honeydew that is made by the green group of aphids over the honeydew that is made by the red group of aphids. Green colored aphids enjoyed greater protection from ants when compared to the red colored group. It is believed that the ants prefer the green colored aphid’s honeydew as it is the more nutritious of the two. In laboratory and field conditions red aphids normally reproduced at greater rates than green aphids. However, when ants were introduced into the habitat, green and red aphids began reproducing at equal rates. The ants were clearly manipulating the aphid’s reproductive success so that more green aphids would come to exist in a particular environment. By manipulating the reproductive rates of the aphids, the ants are able to secure a greater amount of nutritious honeydew produced by the green aphids. This is one of the few examples of one insect species manipulating the population numbers of another insect species.
Do you believe that nutrition is the only factor that drives ants to prefer honeydew produced by green aphids over honeydew produced by red aphids?