Monday, August 4, 2008 - 4:20 PM

COS 14-9: Niche partitioning among subterranean termite species, Coptotermes formosanus and Reticulitermes spp. (Isoptera: Rhinotermitidae)

Beverly A. Wiltz and Alan R. Lax. USDA-ARS

Background/Question/Methods Co-existence of ecologically similar species is only possible if some degree of niche partitioning occurs among them. Factors that can result in ecological separation include character displacement, habitat and microhabitat selection, and diet. Differences between ecologically similar species in any one of these factors may allow them to share a common resource. Co-existence of subterranean termite species is likely due to a combination of factors. Differential adaptedness by termite species to environmental conditions may reduce the level of competition.

In some areas where it has become established, the Formosan subterranean termite Coptotermes formosanus dominates the landscape because of its large colony size, greater tendency to infest living trees, and ability to maintain aerial colonies independent of ground contact. However, at some sites, it co-exists with native termite species. Several studies have identifed differences among native subterranean termite (Reticulitermes) species in their response to environmental conditions, including temperature, humidity, flooding, and food size. Most of the work on the Formosan termite has focused on its control and role in the urban environment. Landscape ecology in forested habitats and differences in resource use between the Formosan subterranean termite and native species are not as well known.


The current studies examine termite occurrence at sites in New Orleans, LA and southwestern Mississippi where both C. formosanus and Reticulitermes spp. occur. Sampling was conducted by driving wooden stakes into the ground in either a grid pattern or adjacent to trees. Stakes were examined at least every three months. Patterns in termite presence were examined, with reference to elevation, land use, species of infested trees, seasonality, and proximity to other termite and ant species.

Results/Conclusions We found that within sites, C. formosanus was found at higher elevations than Reticulitermes spp.  Formosan termites were found in association with at least 23 tree species, compared to the 14 species having Reticulitermes spp. Boundaries of the species collected shifted with season. At one site, only Formosan termites were collected in the summer, while only native termites were collected in the winter. Additional sites are being added to the project and long-term monitoring will continue to determine if the species will continue to co-exist.