Ant - Insect Associations in Selected Sites in Matara District.

Abstract

Ants are eu-social insects and one of the most important invertebrate groups in terrestrial habitats. Many ant species make obligatory or temporary associations with other organisms especially plant sap sucking insects belong to order Hemiptera or Homoptera. Ants are important for protection and spreading of these insects and some of which are very importafft pests of many crops. Hence this ant-insect association in agricultural lands enhances the survival of associated pest species. Present study was carried out to identify the worker ant species associated with insects in selected sites namely, Thelijjawila, Palatuwa, Wellamadama and Kiralakele in Matara District. Thelijjawila and Palatuwa sites had vegetable cultivations and Wellamadama and Kiralakele had natural vegetation. Worker ants were sampled by pitfall trapping, honey baiting, honey and dry fish baiting, and hand collection. Ant species which associated with homopteran insects were collected in selected sites by using hand collecting method. Sampling was carried out twice a month from June to September in 2017. Collected ants and associated insects were identified to the possible taxonomic levels using the standard taxonomic keys of insects. Five subfamilies, 19 genera and 29 species of ants were found from all the four sites and species richness on each site ranged from 5 to 17. Natural habitats had more ant species than agricultural habitats. Fifteen ant species were identified associated with 7 different homopteran insects which include 2 species of aphids, 1 leaf hopper, 2 plant hoppers, 1 scale insect and 1 mealy bug. All of them were identified as crop pests with limited mobility. The ant species Oecophylla smaragdina, Anopholepis gracilipes and Technomyrmex sp.1 have shown high affinity to associate with Homopteran insects. Present study indicated that about 15 species of ants prefer to associate with honey dew producing insects and large ant species namely 0. Smaragdina and A. gracilipes associated with more than one homopteran insect. Ant species which associate with homopteran pests tend to protect and disperse them among the crop plant community causing adverse effects on the productivity of the crops.