11/23/2009

New Microbes Found that Help Leaf Cutter Ants Breakdown Biomass

Summary

Tropical leaf cutter ants cultivate specific fungi to efficiently break down cellulosic plant biomass to serve as food for ant colonies. However, plant materials harvested by the ants contain relatively small amounts of nitrogen, a crucial nutrient that limits the growth of the ants’ fungal gardens and thus breakdown of plant biomass. In a paper in the November 20 issue of Science, researchers at the DOE Great Lakes Bioenergy Research Center (GLBRC) describe how bacteria colonizing the ant gardens convert atmospheric nitrogen gas into ammonia, a form of nitrogen that can be used by both the fungi and the ants. The group, led by Cameron Currie of the University of Wisconsin, Madison, estimates that over half of the nitrogen requirements of the system are met by these bacteria and that the colonies fertilize the surrounding soil, contributing to overall ecosystem productivity. These results highlight the importance of natural community interactions in the deconstruction of biomass, and suggest potential approaches for consolidated bioprocessing for biofuel production.

References

Pinto-Tomás, A. A., et al. 2009. “Symbiotic Nitrogen Fixation in the Fungus Gardens of Leaf-Cutter Ants,” Science 20(5956), 1120-23. DOI: 10.1126/science.1173036.