Behavioral responses of the arboreal termite Nasutitermes corniger (Isoptera: Termitidae) to wood extracts

The termite Nasutitermes corniger is attracted to weathered wood, but it is not known whether this attraction is of chemical or physical nature. This work examines whether wood extracts can change the attraction of N. corniger to a food substrate. In a first experiment, filter paper impregnated with a eucalyptus extract, Eucalyptus grandis, and another one with a solvent were placed in the foraging arena of N. corniger nests under laboratory conditions. The extracts used were from weathered or unweathered wood. During the second experiment, two tests were performed using eucalyptus wood. First, a piece of unweathered wood was impregnated with an extract of weathered wood (treatment) or solvent (control). In the second test, a piece of weathered wood was impregnated with an extract of unweathered wood (treatment) and another one with solvent (control). At the end of the tests, the number of termite recruitment on each substrate was quantified. Filter paper recruited more termites when treated with unweathered wood extracts or with extracts of weathered wood than when impregnated with the solvent. Unweathered wood treated with extracts of weathered wood recruited more termites than the control. However, weathered wood impregnated with extracts of unweathered wood recruited similar numbers of termites as the same wood impregnated with the solvent. It was verified that chemicals from weathered or unweathered wood increased the foraging activity of N. corniger in neutral substrates, but only chemicals from weathered wood altered the attraction of N. corniger to eucalyptus wood.