A year-long study has indicated that termites from China ‘smell’ other species in their environment and modify their behaviour accordingly.
In many ecosystems where termites exist, there will be several different termite species living in the same area. When there is competition over resources, each species will find its position in the dominance hierarchy. But how do the termite species decide who’s ‘top dog’? Theo Evans from the University of Western Australia and Boris Kasseney from the University of Lomé, Togo, have published their research on the dominance hierarchy of wood-eating termites from China.1
The research investigated the competition and dominance between five species of wood-eating termites found in Huangzhou, China. Using several laboratory experiments and a year-long field study, they managed to unravel the patterns of dominance.
Paired contests with equal numbers of individuals clearly demonstrated that dominance was dependent on body size, much like contests in many other animal species. However, this advantage was reduced when the paired contests were based on equal biomass rather than equal numbers of termites.
Studies using filter paper with the different termite ‘smells’, clearly demonstrated that the termites could detect the presence of other species. Smaller species would avoid filter paper that had been used by the larger species, whereas larger termite species were happy to forage through filter paper used by the smaller species.
The field study appeared to indicate that the smaller species managed to avoid the larger species by exhibiting a different foraging pattern. While the largest species, Macrotermes barneyi, was active year round, the most abundant species, Odontotermes formosanus was significantly more active in the summer and the two smaller species, Odontotermes hainanensis and Reticulitermes flaviceps were relatively more abundant in winter. The fifth species in this study, Coptotermes formosanus, was rarely found in the survey area during the field study.
Based on the laboratory data, where Macrotermes was clearly the dominant species, it would have been suspected that it would have also been dominant in the field. However, it was less common than both of the Odontotermes species. This may be explained by the fact that the study area was disturbed land (the Hangzhou Botanical Garden), rather than undisturbed native forest. Fungus-growing termites such as Macrotermes do appear to be more sensitive to disturbance. Certainly in Africa, Macrotermes bellicosus was found to be more dominant in the rich termite communities of undisturbed primary forest, but not so in more disturbed agricultural land.
Coptotermes species appear to grow in number in disturbed environments. The reduction in abundance of the more dominant fungus growing termites, better adaptation of Coptotermes to disturbed environments and a greater tolerance of Coptotermes to the higher temperatures found in urban environments, are potential reasons suggested by the authors for their success in disturbed environments. Certainly in Australia, where the fungus growing termites are absent, Coptotermes also dominates Australian forests, which is in line with the expectations from the China study.
However, as the termite fauna around the world varies, the authors note that much research needs to be carried out to uncover competitiveness and dominance hierarchies in the different geographies, in order to identify and confirm any common factors and patterns.
1 Evans, T. A. and Boris Dodji Kasseney, 2019. The Dominance Hierarchy of Wood-Eating Termites from China. Insects.
