Termites form an essential part of the biomass of tropical and subtropical ecosystems. Their importance in tropical rainforests lies primarily in the disposal of dead organic matter. Quite a lot is known about the types of termites that eat wood. However, less is known about the so far neglected termites, so-called clay-eating. A team of experts, including Jan Šobotník from the CULS Faculty of Forestry and Wood Sciences, therefore went to French Guiana to study the diet of clay-eating species.
Ecosystem engineers, as termites are often called by experts, influence a number of important biological processes by their work in tropical forests. For example, they change the structure of the soil, transfer huge amounts of material from place to place and also serve as food for many predators. By consuming organic residues and returning nutrients back into the cycle, they change the soil's chemical composition, which positively affects the amount of water retained and, ultimately, the distribution of the surrounding fauna and flora.
In terms of the type of food they use in tropical habitats, termites can be divided into two main groups. A better-known group is termites consuming only plant materials in the initial stages of decomposition, such as wood, leaf fall or microepiphytes *. The second lesser-known group is represented by the already mentioned termites feeding on the soil or on the organic components contained in it. The importance of these termites lies, similarly to our earthworms, in making nutrients from dead tissues available in a form available to plants.
Researchers wanted to know about this group if and why they prefer different soil types. They set two basic questions: Do clay-eating termites distinguish the type of substrate consumed? And do these termites choose specific habitats to increase their energy intake?
A team of scientists was looking for answers in the Nouragues Nature Reserve, in the French department of Guyana in South America. The uninhabited area, mostly covered by tropical rainforest, is completely free of human intervention, which ensures the naturalness of the environment and the processes taking place in it.
Researchers at the site took samples of Anoplotermes-group clay-eating termites together with the substrate in which they were found. In total, the following five types of substrate were removed: rotten wood, an abandoned nest of another termite species, soil under a palm tree, soil near the base of a tree, and plain soil that was not near a larger tree in the forest. The sixth sample of the substrate was termite-free soil, only for comparison with clay used by termites as food.
Substrate samples were sent together with termites to Belgium, where subsequent tests took place. Performed chemical analyses have shown that the best predictor of the occurrence of a particular species of termite is the rough classification of the substrate (see above). "The results show that soil termites do not choose specific sites due to the higher nutrient content in the substrate, because the chemical composition of simple soil with found termites does not show statistically significant differences compared to soil not inhabited by termites. It can therefore be said that termites living in simple soil do not select nutrient-rich parts, "adds Mgr. Jan Šobotník, Ph.D.
* Microorganisms growing on living plants, which, however, feed independently and are not even partial parasites.
Mgr. Jan Šobotník, Ph.D.
In 1997 he studied biology at the Faculty of Science, Charles University in Prague. In 2003, he completed his doctoral studies with his work "Morphological and functional aspects of exocrine organs of termites of the Rhinotermitidae family" at the Department of Zoology of the same university. From 1997 to 2013 he worked at the Institute of Organic Chemistry and Biochemistry of the Academy of Sciences of the Czech Republic and since 2012 at the Faculty of Forestry and Wood Sciences of the Czech University of Life Sciences in Prague, where he deals mainly with termite biology and the structure and function of insects.
Prepared by: Jakub Málek