Nutrient enrichment of ecosystems by fungus-growing versus non-fungus-growing termites
Résumé
Fungus-growing termites (Macrotermitinae) collect water to air-condition their fungi and have been recorded tunnelling deeper than 80 m for groundwater. This collection of water ultimately results in solute accumulation and nutrient enrichment of their termitaria. We consequently hypothesized that nutrient enrichment of termitaria constructed by fungus-growing termites would be greater than by non-fungus-growing termites. To test this, we compared nutrient enrichment of termitaria of fungus-growing Macrotermes spp. in Namibia and termitaria of two non-fungus-growing termites – Trinervitermes trinervoides in South Africa and Nasutitermes triodiae in Australia. Compared with adjacent topsoils, Macrotermes termitaria were significantly enriched in 18 elements whereas T. trinervoides and N. triodiae termitaria were enriched in only one and five elements, respectively. Nutrients particularly enriched in Macrotermites termitaria included Ca (an enrichment factor of 12), Mg (2.9), Co (2.8), Fe (2.4), Mn (2.3), Se (2.2) and Cu (2.0). We suggest that fungus-growing termites that collect water for air-conditioning their fungi have the potential to inadvertently boost – to a far greater degree than non-fungus-growing termites – the availability of nutrients to local plants and herbivores.