The seasonal natural history of Pheidole morrisi forel revealed by wax-casting

The small golden ant Pheidole morrisi Forel is the most common ant of the Apalachicola National Forest, a typical longleaf pine flat-woods ecosystem and is found in pine forests across the eastern U.S. P. morrisi likely plays a significant role in these important North American ecosystems, yet many aspects of the ant's life history, including its annual cycle, remain un-investigated. To determine the annual cycle and life history of P. morrisi a range of colony sizes were censused by wax-casting entire nests, excavating the casts, segregating sections of the casts by their depth from the surface, and retrieving the ants by melting the wax. This technique provided data on the numbers of the different colony members as well as their locations in the nest. This procedure was repeated throughout the year to capture major phases of the seasonal cycle, along with changes in colony demography. In addition to this, the sampling of a range of sizes revealed differences between mature and immature colonies. Colonies were found to produce two cohorts of brood annually and to overwinter larvae. These phases of worker brood production are separated by a phase of alate production. Soil temperatures at the time of casting showed that the brood were usually kept in the warmest regions of the nest, which varied seasonally from 18 to 26 ^oC. The proportion of the colony composed of majors was different between colonies at different stages of growth, but did not change seasonally. A number of other colony-level attributes were related to season, depth, or colony size.