Abundance, Distribution, and Colony Size Estimates for Reticulitermes spp. (Isoptera: Rhinotermitidae) in Southern Mississippi1

Enviton. Entomol. 11: 1290-1293 (1982) A census of 24 1-ha plots indicated .an average abundance per ha of 4.42 colonies of Reticulitermes flavipes (Kollar) and 2.38 colonies of R. virginicus (Banks). Nearest neighbor analysis indicated the mean distance between colonies of R. f2avipes to be 22.48 m, between colonies of R. virginicus to be 26.19 m, and between colonies, irrespective of species, to be 16.80 m. Six R. flavipes colonies were selected by a ranked-set sampling method, and the mean colony size was estimated to be 244,445 termites. Reticulitermes flizvipes (Kollar) and R. virginicus (Banks) are important economic pests, yet little pertinent research of an ecological nature has been conducted. This perhaps reflects the long-standing availability of highly effective termiticidal soil treatments which place a chemical barrier between the wooden commodity (home) and the termite colony. Newer control techniques now being developed, however, are designed to treat specific, individual colonies; copsequently, better knowledge of termite ecology is needed. We recently initiated research on the biology, demography, and field ecology of Reticulitermes spp. in southern Mississippi. We have described the abundance of soldiers and reproductives, sex ratio of reproductives, association of soldiers with reproductives in R. flavipes (Howard and Haverty 1980), and seasonal variation in caste proportions of R. jZavipes field colonies (Howard and Haverty 1981). Here we report on the abundance and distribution of R. flavipes and R. virginicus colonies, and on the mean number of termites in mature colonies of R.flavipes, i.e., colonies in the reproductive stage of their life cycle (Oster and Wilson 1978). Materials and Methods Estimation of Colony Abunda~zce and Distribution In August 1980, a total of 104 contiguous plots (100 by 100 m; 1 ha) in the Desoto National Forest, ca. 20 krn north of Gulfport, Miss., was surveyed, and their boundaries were marked. The site consists of gently rolling hills (ca. 15to 30-m elevation) covered with a stand of predominately 50to 60-year-old naturally regenerated longleaf pine (Pinus palustris Mill.) with some slash pine (P. elliottii Engelm. var. Elliottii) at the lower elevations. The dominant understory consists of gallbeny (Ilex glabra L.), Yaupon (I . vomitoria Ait.) and dogwood (Cor~zusflorida L.). The area was control burned ca. 3 years before this study. In November 1980, four representative blocks of six 1-ha plots were selected and exhaustively examined for dead logs, standing or lying on the ground, which measured 10 cm or more in diameter at their greatest breadth. The locations and dimensions of these logs were plotted 'Received for 19 March 1982. on a topographical map. With a hand axe as a sampling tool, the presence or absence of termites, by species, was noted for all logs. All logs were disturbed as nearly alike as possible. Logs containing conspecific termites and separated by at least 15 m were assumed to represent separate termite colonies. These data were analyzed to estimate mean number of termite colonies, by species, and nearest-neighboring logs containing termites, by species. Summary statistics were calculated by plot, as well as the dispersion coefficient "a," using the formula of Wood and Lee (1971): a = m7, where m = density of logs with termites per m2, and I = mean distance (m) between pairs of nearest neighbor logs containing termites. Distance measurements were made from rnidpoint of log 1 to the midpoint of log 2. Estimation of Number of Termites in a Mature R. fla-