Termites play a significant part in the savanna ecosystem. Their collective biomass in these landscapes can even surpass that of large mammals. These insects are considered ecosystem engineers, shaping their surroundings through their activities. Understanding their diet is fundamental to appreciating their extensive influence on the savanna’s ecological balance.
Primary Food Sources: Grasses and Dead Plant Material
Savanna termites primarily consume dead plant matter rich in cellulose, a complex carbohydrate forming plant cell walls. This diet includes abundant dried grasses, fallen leaves, and various forms of dead wood such as twigs and branches. Termites also feed on decomposing organic matter within the soil, known as humus, and even animal dung. Their feeding habits are crucial for breaking down vast amounts of organic material that would otherwise accumulate.
To process these cellulose-rich foods, termites rely on a specialized digestive system. Many species harbor symbiotic microorganisms, including bacteria and protozoa, within their guts. These microbes produce enzymes that break down cellulose into simpler sugars, which the termites can then absorb for energy. Some higher termite species have also evolved to produce their own cellulolytic enzymes to aid in this process. Foraging termites remove substantial quantities of wood and leaf litter from the savanna landscape.
Specialized Diets: Fungus Cultivation
A distinct feeding strategy employed by many savanna termites, particularly those belonging to the Macrotermitinae subfamily, involves cultivating symbiotic fungi. These termites construct elaborate nests that house “fungus gardens” or “fungus combs.” The cultivation process begins with worker termites collecting plant material like wood, grass, and leaf litter.
After collecting, the termites chew the plant material and pass it through their digestive tracts, mixing it with their feces. This processed material then serves as a substrate for growing specific species of Termitomyces fungi within their nests. The fungi, in turn, pre-digest the cellulose and other complex plant compounds, making the nutrients more accessible and enriching the material with nitrogen. The termites then consume the fungal biomass as their primary food source. This symbiotic relationship allows these termites to recycle dead plant material in their environment.
Ecological Role: Nutrient Cycling and Soil Health
The feeding activities of termites significantly influence the savanna ecosystem by driving nutrient cycling. As decomposers, they break down vast amounts of dead organic material, preventing its accumulation across the landscape. This decomposition process releases essential nutrients, such as nitrogen, phosphorus, carbon, calcium, potassium, and magnesium, back into the soil. Termite mounds, in particular, become “islands of fertility” due to this nutrient enrichment.
Beyond nutrient release, termite tunneling and mound-building activities significantly improve soil health. Their subterranean networks enhance soil aeration, allowing air to penetrate deeper into the ground. These tunnels also improve water infiltration, increasing soil moisture retention. The improved soil structure and nutrient availability support greater plant growth on and around termite mounds, contributing to the overall resilience of the savanna biome.