In the latest phase of his research, Currie, who began this study when he was at the University of Kansas, and his team removed the external blooms of bacteria from two ant species in the genus Cyphomyrmex and examined the exoskeleton beneath with a high-powered microscope. Their investigation revealed crypts attached to endocrine glands, both of which were previously unnoticed by scientists.
In fact, the crypts are specially adapted to the type of bacteria each species harbors - evidence that the ants are capable of rapidly changing to maintain their bacterial residents.
"These two species of ants are very difficult to differentiate other than through molecular analysis," says Currie. "There are almost no morphological, or physical, differences between the two. However, the crypts in the exoskeleton are distinguishable. We can actually use them to tell the two species apart."
The degree of specialization indicates that the association between the ants and the bacteria is ancient, says Currie, and likely vital to the species' survival. The phenomenon extends beyond the two species of Cyphomyrmex to about 210 species of fungus-growing ants, which harbor many different species of a specific group of bacteria.
"For me, it shows us how little we know about natural systems and microbes in nature. Fungus-growing ants are very well studied, yet this morphological characteristic went unnoticed until now. What other organisms might be taking advantage of this type of association? What don't we know about other systems that are not as closely studied as these ants?"
Currie's collaborators include Michael Poulsen and Jacobus Boomsma of the University of Copenhagen, John Mendenhall of the University of Texas at Austin, and Johan Billen of the Cath
Source:University of Wisconsin-Madison