Diversity and distribution of stored grain insects among the Soliga Tribal settlements of Biligirirangana Hills, Karnataka, India

Soligas are a tribal community living in the forest areas of Biligirirangana Hills in southern Karnataka, India. Soligas cultivate several crops in small patches located close to their settlements for subsistence. During the present investigation, the diversity, distribution and abundance of insects that infest food grains stored by Soligas were studied and the influence of biotic and abiotic factors was assessed. Grains held in storage by Soligas were found to be infested by 13 species of insects. The distribution and abundance of all the species were mapped. Among these, Sitophilus oryzae was the most widely occurring and abundant species, while, Corcyra cephalonica was the least abundant and less frequently occurring species. Species richness was influenced by the number of food grain types stored by Soligas. It was observed that the biotic and abiotic factors did not influence the diversity and distribution of stored grain insects. Instead, the observed pattern of stored grain insect distribution was found to be influenced by anthropogenic factors like food grain sharing habits among the Soligas and accessibility to the towns and cities from their settlements.