Species Composition of Ants in Cashew Plantations and their Interrelationships with Cashew

Abstract

In cashew plantations of south west Karnataka, India, foraging activity of 49 ants species belonging to 24 genera and 7 subfamilies were recorded. The study found that ants visited cashew trees regularly throughout the year. Myrmicinae ants were most dominant comprising 22 species followed by Formicinae with 13 species while, among Aenictinae and Dorylinae, only single species was found. Species richness was high in old cashew plantations recording 89.8 % of total species, while medium and young plantations recorded only 46.9 and 24.5 %. Dominance of different ant species was noticed on cashew canopy, trunk and soil in different aged cashew plantations. Old cashew plantations were characterized by Oecophylla smaragdina, followed by Anoplolepis gracillipes, while, Camponotus compressus and C. sericeus were dominant in young and medium aged plantations. Pit fall trap collection consisted mostly of Odontomachus haematodus, Lophomyrmex quadrispinosus, Technomyrmex albipes, Myrmicaria brunnea, Diacamma sp., C. compressus and C. sericeus. During flowering and fruiting period of cashew, foraging of up to 10 ant species was seen on the same tree at a time. Activities of most ant species were predominant during winter and summer which coincides with flowering and fruiting period of cashew (December–May), while during heavy down pour of south west monsoon, activities of only 10 species were seen. A significant positive correlation was found between number of ant species and maximum air temperature (0.842) and also with afternoon soil temperature (0.925).