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Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/22/2002 Publication Date: 2/20/2003 Citation: Morales Ramos, J.A., Rojas, M.G. 2003. Nutritional ecology of the formosan subterranean termite (isoptera rhinotermitidae) growth and survival of incipient colonies feeding onpreferred wood species. Journal of Economic Entomology 96:106-116. Interpretive Summary: Since its introduction to the United States during the 1940's, the Formosan subterranean termite, Coptotermes formosanus, has been one of the most destructive termites in the continental U.S. It is estimated that the Formosan termite cause damage of several millions of dollars annually to houses, other buildings, utility poles, railway sleepers, boats and ships, paper, and living trees. Baits are one of the most effective methods of control for subterranean termites. Baits are currently the only method proven to kill entire subterranean termite colonies. The development and improvement of termite baits depend on our knowledge of termite nutrition. The objectives of this research were to study the value of different wood species as food sources for colony growth and survival of the Formosan subterranean termite and its relationship to the feeding preferences shown by this insect. New colonies of the Formosan termite were started in the laboratory by collecting and pairing alate stages from the field by using light traps. Each termite pairs were fed with one of 10 wood species or a nutritionally supplemented mix. The growth and survival of these incipient termite colonies was monitored and compared among the different food source treatments. Results showed that termite colonies fed on pecan, red gum, and aspen survived better and/or showed more growth than colonies feeding on other woods. These same wood species are highly preferred by the Formosan termite. This knowledge will increase our understanding of the mechanisms of termite foraging choices allowing for the improvement of current bait systems. Technical Abstract: Wood species as food source significantly impacted growth and survival of incipient colonies of Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). Colonies of C. formosanus feeding on pecan (Carya illinoensis (Wangenh.)) and red gum (Liquidambar styraciflua L.) produced significantly more progeny than colonies feeding on 9 other wood species tested. Progeny of colonies feeding on pecan and American ash (Fraxinus americana L.) had significantly higher survival than progeny of colonies feeding on other 9 wood species. Colonies feeding on a nutritionally- supplemented cellulose based matrix showed similar fitness characteristics as colonies feeding on the best wood treatments. This indicates that differences observed on colony fitness (Cf) can be partially explained by nutritional value of the food treatment, raising the possibility that wood from different tree species posses different nutritional value to the Formosan subterranean termite. Colonies feeding on loblolly pine (Pinus taeda L.) and ponderosa pine (P. ponderosa Laws.) had significantly lower survival and produced significantly fewer workers and soldiers than colonies feeding on other wood species. Colony survival from 90 to 180 d of age and from 90 to 360 d of age was significantly correlated with the number of workers present at 90 d of colony age indicating that colony survival depends on the presence of workers. Wood consumption in a multiple-choice study was significantly correlated with the colony fitness value (Cf). This suggests that feeding preference of C. formosanus is at least partially influenced by the nutritional value of the food source. |
