Spatial distribution patterns and structure of epigeal nests of soldierless termites in livestock systems in the northwestern Colombian Amazon

Abstract

Soil-feeding termites have adapted to homogeneous and highly disturbed landscapes such as pastures dedicated to cattle ranching, where they build numerous mounds that can affect the useful area of pastures due to the high density of nests. This study evaluated the spatial distribution pattern and structure of the mounds built by two species of soil-feeding termites Patawatermes turricola and Rustitermes boteroi. This work was carried out in pastures of livestock systems in El Doncello municipality in acid soils and low fertility, twenty-five plots of 400 m2 were established where the mounds number present were counted and georeferenced, and the basal perimeter, height, and distance to the nearest neighbor were measured to determine the density of mounds and spatial distribution pattern. Results show a high nest density of 62.5 mounds/ha; however, the presence of these mounds does not compromise the useful area of the pastures due to their low percentage of total area (0.08%). The study showed two distribution patterns (random and regular) that can be related with intraspecific and interspecific competition, environmental conditions and flight distance of the species. P. turricola presented higher mounds and moved the greatest amount of soil; in contrast, R. boteroi presented nests with greater volume and basal perimeter. In general, study showed that presence of numerous mounds in livestock systems does not affect useful area of pastures, since they occupy less than 1% of the area that freely allows livestock activity without any affectation.