Research Training Program

Stephanie Johnson
Cornell University
Ithaca, New York

Ted Schultz, Ph.D.
Supervising Scientist
Department Entomology

“The actual research part of the
program was a very valuable
experience for my growth
as an entomologist."

Cyphomyrmex longiscapus one fungus-growing ant species or many?

Found commonly on the banks of small streams in the wet forests of Panama, Colombia, and Costa Rica, the fungus-growing ant Cyphomyrmex longiscapus is an ideal organism for the study of the evolution of fungus growing behavior and cultivar specificity. Physical characteristics, nest size and architecture, and other evidence suggest that C. longiscapus may actually be a complex of several cryptic species that are new to science. C. longiscapus specimens were collected from biological stations such as La Selva in northern Costa Rica and from Darien and Bocas del Toro, Panama. A sample of these ants was mounted on pins and a subset was selected for measurement with attention given to sampling across as many nests as possible. Standard ant measurements, such as head width and head length, length, were taken. Ants from all three castes, workers or non-reproductive females, queens or reproductive females, and males, were measured digitally using a Leica M40 microscope tethered to a JVC digital camera driven by Automontage image analysis software. The resulting data were then analyzed and compared to measurements from a previous study of the Colombian C. longiscapus type series and C. longiscapus ants from central Panama using ANOVA tests and general linear modeling with SYSTAT software. Field observations have suggested that the nest architecture of the ants in Costa Rica and those in Bocas del Toro, Panama are very different from that of C. longiscapus nests commonly found in central Panama. The number of workers per nest also differs greatly between typical C. longiscapus nests, which average approximately 20 workers, and the nests from Bocas del Toro, which have hundreds of workers. In addition, morphological analysis has shown that there are significant differences in head width, head length, and other measurements between the different populations. This evidence suggests that the populations studied may actually be different cryptic species. Combining these results with data from other studies may help to answer larger evolutionary questions about the evolution of fungus cultivation, fungus specialization, and speciation.

This research was supported by a grant from the National Science Foundation Research Experiences for Undergraduates program, Award Number DBI-02435123.

Letter of gratitude