How important is the ant-termite interaction in African rain forests?

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Natural ecosystems provide important services to humans, such as the generation of food, the prevention of flooding, and carbon sequestration. However, they are increasingly under threat from global changes, such as habitat destruction and global warming. In order to maintain natural ecosystems it is vital to understand how they work. Trophic interactions between groups of organisms - interactions involving one organism eating another - are one of the main factors determining how these ecosystems are structured. But the nature of these interactions is poorly known, even in well-studied systems. One such key trophic interaction is that between ants and termites. Both groups make up a large proportion of the biomass in tropical ecosystems across the world, and are known to be 'ecosystem engineers' i.e. they are one of the main contributors to the structure of the ecosystem. Termites do this by moving soil around, and eating large amounts of dead leaves, wood and even soil. Ants also move soil around, and also consume a wide variety of animals and some plants. Since a majority of the species of ants are at least partly predatory, and termites are a highly abundant and moderately nutritious, it has often been assumed that ants eat a lot of termites. However, this has only been demonstrated for a small number of species, as much predation of termites by ants takes place underground. We propose to quantify the interaction between ants and termites not by direct observation of predation events, but by looking for termite genetic material in the guts of ants. We already have collections of ants and termites from soil cores taken in rain forest in Gabon. The different species of ant present have already been identified morphologically (from their appearance). For each species of ant we will search for termite DNA in the guts of up to 30 individuals. For certain parts of their genetic material, each termite species has its own unique sequence of base pairs. Consequently we can tell not only that a particular species of ant has eaten a termite, we can also tell which species of termite it has eaten. This will allow us to divide up the species of ant into three different categories: 1. Those that do not eat termites 2. Those that do eat termites, but do not have any preference for a particular termite species, or group of termite species 3. Those that specialise on a particular termite species or group of termite species The resulting data will allow us to construct a partial food web for the different species of ants and termites, and will allow us to make predictions about the impacts of processes such as habitat conversion and climate change on the structure of natural ecosystems.