A major question in evolutionary biology is how mutualistic symbioses evolve and remain stable over long periods of time. Classic theory predicts that mutualisms will tend to become parasitic over time, but fossils and molecular dating indicate that some mutualisms have been stable for tens of millions of years.
Herder ants, those that tend other insects as ‘livestock’, offer keys to the evolution of animal-to-animal symbioses. The relationship between Acrophyga ants and mealybugs is fascinating and has lasted at least 20 million years.
The ants, whose only nutritional input comes from the feces of the ants called “honey dew”, rely completely on the mealybugs for survival. In return, the mealybugs, which subsist on root material found in the underground colonies, are cared for, protected, and cleaned by the ants.
When new colonies are formed, an unmated queen leaves her home carrying a single pregnant adult mealy bug in her mandibles. The single mealybug is the seed individual for the next generation of symbionts in the new colony.
Dr. John LaPolla has studied biodiversity his professional life, even discovering new species of ant. Ants have fascinated John LaPolla since he was a boy, leading him to become a myrmecologist, a scientist who specializes on ants. His research focuses on the discovery and description of ant biodiversity both of the past and present. This has taken him around the globe in search of ants, but has also brought him face to face with the challenges the 21st century presents to biodiversity. He received his Ph.D. from Rutgers University in 2004, completed a two-year postdoctoral fellowship at the Smithsonian Institution, and has been a faculty member in the Department of Biological Sciences at Towson University since 2006