ECOLOGY AND FIELD BIOLOGY OF CAMPONOTUS LEYDIGI (HYMENOPTERA: FORMICIDAE) IN CERRADO VEGETATION
Hélio Soares Júnior, Hélio Soares Júnior
Departamento de Biologia Animal, Universidade Estadual de Campinas, Campinas, Brazil; Departamento de Biologia Animal, Universidade Estadual de Campinas, Campinas, Brazil
Camponotus leydigi is distributed throughout the Neotropics and commonly occurs in cerrado savanna, where foragers search for solid and liquid food on the ground and on vegetation. Here, we provide a field account of the biology and behavior of this species in a cerrado reserve at Itirapina, SE Brazil. We describe the nest architecture, activity schedule, foraging behavior, diet, and home range used by foraging workers. Colony activity rhythm was monitored in the hot/rainy and cold/dry seasons (n=8 nests). Ant activity was recorded during 20-min sessions at 2-h intervals, for 24 h. Temperature and relative humidity were also recorded. Video cameras at nest entrances recorded (50 h) returning workers transporting solid or liquid food (repletes). Home ranges were estimated by following painted foragers. Entire home ranges of tagged colonies were documented with aerophotogrammetric photos (foraging routes visible by colored signs). We used orthodontal plaster to describe nest architecture. Workers of C. leydigi forage solitarily and colony activity varies seasonally, with increased numbers of workers foraging during daytime in the hot season. The species has an omnivorous diet, collecting 3.7 times more liquid (plant and insect exudates) than solid food items (mostly termites). Workers also frequently collect acid uric crystals on the ground, probably as Nitrogen supplementation. Colonies of C. leydigi are typically polydomous, with multiple satellite nests up to 30 m apart from one another. Brood transport, tandem running and replete workers are frequently seen between nests. The nest architecture in C. leydigi is simple and consists of 3 to 7 chambers, with initial tunnels superficial and parallel to the soil surface. Major workers frequently use their heads to block the nest entrance against intruders (usually other ant species). Our study adds to the natural history and field biology of C. leydigi, and highlights its ecological role in cerrado.