“Symbiotic Evolution and Species Discovery in Fungus-Farming Ants”
Tracking these ants to their colony requires patience and dedication. To start, Dr. Shultz baits the ants with Cream of Rice and waits for an ant of interest to approach and take a bit of bait to bring back to the colony. Using a white food source makes it easier to spot the ants as they travel through the leaf litter, but it is still a difficult task. Once the ant leads him to a colony entrance, the digging starts. Fungus-farming ant colonies may be over 3 meters deep and digging requires several determined entomologists. Walls that cave in and sandy soils are no deterrents when the prize is a sample of the fungus garden and the ants that tend to it.
Fungus-Farming ants are grouped into five main categorizes based on their agricultural strategies: lower, coral, yeast, high, and leaf-cutter fungal farmers (Schultz, 2015). While interested in cladistics, Dr. Schultz’ main research focus is on the strength of the symbiont fidelity these ants have with their associated fungi. During a recent talk at University of Maryland, Dr. Schultz described how these five different groups cultivate five different types of fungi. Interestingly, the relationships between ants and their fungi vary in strength across the agricultural groups. For instance, in the higher attine fungal farmers and leafcutter ants, their fungal species have such a strong symbiotic relationship that these fungi can only be found living in ant colonies. On the other hand, the fungi associated with lower attine fungal farmers can be found both within a colony and free-living. However, some of his most recent work on the Apterostigma megacephala has brought this longstanding belief into question (Schultz et al. 2015).
A. megacephala, like many newly described and potentially undiscovered fungus-farming species, can provide scientists with clues about insect evolutionary life histories. Understanding how these ants speciate, develop mutualisms, and persist through time will be crucial to determine how they persevere in the face of global climate change and widespread deforestation. As a leader in his field, Dr. Schultz and his team will have a lifetime of work discovering new ant species, tracking the evolution of ant-fungus mutualisms, and digging giant holes in the forests of South America.
Schultz, T. 13-MAR-2015. Lecture on Symbiotic Evolution and Species Discovery in Fungus-Farming Ants. University of Maryland, College Park.
Schultz, T., Sosa-Calvo, J., Brady, S. G., Lopes, C. T., Mueller, U. G., Bacci Jr., M., & Vasconcelos, H. L. The ant equivalent of a relict colony of Neanderthals cultivating GMO crops. March 11, 2015. American Society of Naturalists. http://www.amnat.org/an/newpapers/MaySchultz.html
Gussie Maccracken is a first year PhD student in the Department of Entomology, University of Maryland, College Park (UMD). Her research explores plant interactions in the fossil record of Cretaceous North America. Specifically, she studies how insect communities change spatially and temporally using insect damaged leaves. Gussie is co-advised by Charlie Mitter (UMD) and Conrad Labandeira (Smithsonian Institution National Museum of Natural History).