Spatial Distribution of Castes Within Colonies of the Termite Incisitermes Schwarzi

In order to describe the social organization of termites with any precision, it is essential to have quantitative information on the spatial distribution of castes within the colony. Such information is important not only for descriptive purposes, but also because it can give clues to the interactions that take place within and among the different castes. Precise information on caste distribution within colonies is ordinarily not easy to obtain, because colonies are usually completely disrupted in opening them up, and because in any case the description of spatial organization in large three-dimensional or dispersed colonies in quantitative terms is difficult. But in some locations, colonies of certain kalotermitid species offer a unique opportunity to obtain just such data. In the Oleta River Mangrove Preserve just north of Miami, Florida, large numbers of Incisitermes schwarzi are found in slender, dead mangrove tree-trunks, where they form nearly one-dimensional colonies. Because the colonies are relatively small and are entirely above ground, and because the termites do not forage outside the wood, whole colonies can be collected in segments and analyzed. The results of such an analysis are the subject of this paper. While some of the findings of this study--the association of larvae with the royal pair, the aggregation of nymphs and alatesmhave been noted before in a casual way in the general descriptions of many other students of the Isoptera (e.g., Imms, 1919; Grass6, 1949), this is the first quantitative description of the spatial distribution of castes in a termite, and is worth putting on record for that reason.