Coptotermes formosanus (Isoptera: Rhinotermitidae) is a severe invasive pest species. Native to China, this termite has been introduced to many areas of the world including Hawaii and the U.S. mainland. It is generally assumed that a limited number of introductions and the occurrence of genetic bottlenecks during the invasion have resulted in reduced genetic variation in C. formosanus populations in the U.S.A. Reduced genetic variation in introduced populations could potentially affect population genetic structure, such as degrees of relatedness and inbreeding of colonies, as well as influence colony social structure, i.e. number and relatedness of reproductives. We compared the genetic variability, population structure and social organization of C. formosanus of native and introduced populations using microsatellite markers. We examined 14 colonies from a native population in China (Guangdong), and 14-20 colonies from each of three introduced populations in the U.S.A. (Oahu, Hawaii; Armstrong Park and City Park, New Orleans, Louisiana). Genotypes of one individual per colony at 12 loci are used to investigate the genetic differentiation and inbreeding of populations by calculating F-statistics. To measure coefficients of inbreeding and relatedness within and between colonies within a population we determined the genotypes for up to 24 individuals per colony at 5-8 loci. To describe the social organization of colonies we tested for deviations from Mendelian ratios expected for colonies headed by single pairs of reproductives. First results show that U.S. populations of C. formosanus have low genetic variability compared to native populations. At colony level, we found that 40-70% of the colonies from introduced populations are headed by multiple reproductives. A wide range in degrees of intracolonial relatedness indicates variable degrees of inbreeding. Sociogenetic data from Chinese termites are currently being analyzed. Comparisons of genetic patterns of native and introduced populations will allow us to shed light on the invasion biology of C. formosanus.
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA