Ants are among the most important organisms found in mid- to low-latitude terrestrial ecosystems, often playing keystone roles. Their success is due largely to their highly social way of life; they live colonies ranging in size from a few dozen to several hundred million individuals. In many ways, ant colonies function like superorganisms--tasks and physiological roles (including reproduction) are divided among the queen and several types and ages of workers. My research reco gnizes the organism-like nature of ant colonies: each colony most commonly begins life as a single individual and goes through a process of growth, development, and death; specific colony functions are carried out by specialized classes of workers, larvae, or sexual individuals; competition takes place among colonies, just as it does among individuals of nonsocial animals ; nourishment must be taken in by colonies, distributed, and allocated among colony members and colony functions; colonies must produce specialized sexual indiv iduals (propagules) for reproducing themselves, and these must leave the colony, mate, and found new colonies.

Current and past research projects follow several major themes.

(1) Sociogenesis: Just as an organism results from the growth of a zygote through the rules and interactions of embryogeny, so the mature ant colo ny is produced from the single, mated queen through the rules and interactions of sociogenesis. Just as the differences among mature organisms reflect th e differences in their rules of embryogeny, so the differences among the mature colonies of species of ants reflect the differences in their rules of sociogenesis. Describing and unraveling the rules of sociogenesis is one of the broad goals of our research. Actual projects include: (a) a description of the changes in fire-ant worker size and size distribution (polymorphism) as colonies grow; (b) changes in the patterns of labor distribution as colonies grow; (c) the social regulation of egg-laying rate in fire-ant queens; (d) the rules by which work ers feed larvae; (e) the manner in which the size- and age-based division of labor among fire-ant workers translates into a force of sociogenesis.

(2) Colony reproduction: A second major theme focuses on ecological and evolutionary aspects of colony reproduction. Whereas newly mated fire-ant queens typically found colonies alone, they often cooperate with other newly mated queens during this period. Because workers will kill all but one of the queens in su ch associations, it is a puzzle that queens choose to associate. The puzzle is compounded by the existence of brood-raiding--workers from incipient colonies ste al brood from other such colonies, who steal it back, until one colony is victorious. Workers then all coalesce in the winning nest, abandoning their mothers. W e have been attempting to solve these evolutionary puzzles, as well as trying to link these colony-level phenomena to population-level outcomes.

While trying to determine whether colonies whose queens have died are able to replace them, we discovered a new mode of colony founding. Fire ant colonies overw inter a small number of sexual reproductives, and these depart on mating flights during the very early spring. The function of these overwintered queens is to s eek out orphaned colonies, enter them, and take over as functioning queens. This is an essentially parasitic mode of colony founding, because the new queen is u nrelated to the workers who will rear her offspring. We are currently estimating the proportion of mature colonies that are headed by such replacement queens.

(3) Population dynamics among colonies: Relatively little work has been done on the dynamics of populations of colonies. We (with Dr. Eldridge Adams, Uni versity of Connecticut) have established long-term mapped plots that yield data on the "birth," death, spacing, and movement of over 1000 fire ant col onies. This long-term study is coupled with determinations of territory size and study of territorial defense, giving insight into how the behavior of colonies results in the characteristics of populations and how the characteristics of neighborhoods feed back o n territory area, colony size, and fitness.

(4) The natural history of other ant species: We have an ongoing interest in the biology of several other species of Florida ants, including the Florida harvester ant (Pogonomyrmex badius), the winter-active Prenolepis imparis, several arboreal species, and any other species that strike us as " ;neat." These studies often follow the same themes established with the fire-ant research described above, e.g. the sociogenesis of harvester-ant colonies, but include many other aspects of natural history.

(5) Arboreal ant ecology: The discovery that the arboreal ant Crematogaster ashmeadi is the main food of the endangered red-cockaded woodpecker le d to a collaborative study (with Dr. Frances C. James of this department) of the ecosystem processes that link recurrent ground fires in the longleaf pine ecosystem with the well-being of the red-cockaded woodpecker, the cycling of nutrients, changes in the ground-cover vegetation, and the abundance of arboreal ants. This long-term project consists of a large experiment in which three different prescribed fire treatments are applied to about 60,000 acres of the Apalachicola National Forest and the effects on woodpeckers, vegetation, nutrients, ants, and other insects are monitored.