Brief Natural History on the Ant Odontomachus Brunneus (Patton)

A population of Odontomachus brunneus, a primitive species of Ponerine ants, located in north Florida was studied for a one-year period. Through nest excavation and colony census, the annual cycle of reproduction and colony growth was determined with nests exiting a period of winter inactivity in late April and beginning brood production. Early brood is a combination of both sexuals and workers, with sexuals present in nests during June and July. After production of sexuals in May and June, all subsequent brood produced were found to be workers through dissection of pupal cocoons. Brood production ceased in October, with the final pupae eclosing in November at which time the colonies began a four month period of relative inactivity. Within-nest seasonal energy allocation was determined by fat extraction. Seasonal energy stores coincided with the annual cycle of reproduction, with workers declining in energy stores (fat) during initial brood production and regaining these stores after production of brood in preparation for the winter season during which colonies are primarily inactive. Comparison of body fat provided the relative ages of worker ants, which suggested that O. brunneus nests display internal age stratification throughout the majority of the year with older, leaner workers being found in the upper chambers of most nests and younger, fatter workers in the lower chambers. Using a combination of mark-recapture of foragers and nest excavation, the proportion of foragers per colony was shown to include a mean of 77% (S.D. 22) of the workforce. This proportion was not related to colony size. Female alates were also found to be a part of the foraging population of colonies.