Highlights

In this work, we discovered that Nasutitermes corniger soldiers, when isolated, produced Methyl Salicilate, whereas when aerated with an individual from another colony, produced a great amount of Eugenol.

Abstract

Chemicals involved in communication between organisms are called infochemicals, which can be classified as intraspecific (phemoromes) or interspecific (alelochemicals).¹ For eusocial insects, such as termites, pheromones are involved in every aspect of live, as reproduction, foraging, defense, orientation, and every other interaction in the colony.² Termites, for example, produce alarm, sexual, trail and aggregation, among others pheromone classes.³ In this work, we identified volatile compounds produced by soldiers of N. corniger from four different nests in a 100 m² area in the city of Campo Formoso-BA. Prior to volatiles extraction, we performed behavioral tests. Ten soldiers of each nest were placed in a petri dish and then ten soldiers of another nest were placed in the same petri dish. All nest combinations were tested, and, in every experiment, termites showed aggressive behavior. For volatiles extraction there were two different treatments: 1) around 100 isolated soldiers from each nest and 2) about 100 soldiers of one nest with 5 soldiers of a different colony. Individuals were placed in aeration chambers for 24h and the volatiles were trapped on a 0.4 cm long bed of Super Q resin (Allthec, Deerfield, Illinois USA), which was latter eluted with hexane. Extracts were concentrated as required under Ar and were analyzed by GC-MS. On the first treatment, all colonies’ soldiers produced mainly Methyl Salicilate. For the second treatment, Methyl Salicilate was still produced but there was also production of Eugenol in a greater amount (87%). Although behavior tests are still up to be done, we can infer that Methyl Salicilate may be an aggregation pheromone and Eugenol may be an alarm pheromone or a defensive compound. Those behavior tests may determine the real function of each compound.

References

1. DICKE, M.; SABELIS, M. W. Infochemical terminology: based on cost-benefit analysis rather than origin of compounds? v. 2, p. 131–139, 1988.
2. LEONHARDT, S. D. et al. Ecology and Evolution of Communication in Social Insects. Cell, v. 164, n. 6, p. 1277–1287, 2016.
3. COSTA-LEONARDO, A. M.; CASARIN, F. E.; LIMA, J. T. Chemical communication in isoptera. Neotropical Entomology, 2009.

Acknowledgements

The authors thank CNPq and FAPESB for scholarships. We also thank ITCBio for the GC-MS analysis.