The first ant survey in Ampara District and a preliminary inventory of ants (Formicidae) of paddy fields in Sammanthurai, Sri Lanka

Abstract

Ants are a very common and important biotic component in the environment which can be found on every continent on earth except Antarctica. Three hundred and forty-one valid ant species/subspecies belonging to 79 genera under 11 subfamilies have been recorded in Sri Lanka, but very little is known about the ants of the Eastern Province of the country. An ant survey in Ampara, which is one the largest districts of the Eastern Province was conducted for the first time and the first ant inventory of paddy fields of Sammanthurai was prepared. Sammanthurai in Ampara District is located 4.8 km west of the Bay of Bengal coast and lies between the towns of Ampara and Karaitivu along the A31 road. Worker ants of two selected paddy fields in Sammanthurai were surveyed on the 8th of January, 12th of March, 16th, and 17th of July by using honey baiting, soil sifting, and hand collection. In each paddy field, two 100 m transects were laid using a nylon cord. Twenty-five pieces of gauze (2 x 2 cm) with a drop of honey were placed at 4 m intervals along each transect and ants were collected into bottles containing 70 % ethanol after an hour. Soil sifting was conducted 1 m right to each transect and twenty-five samples (approximately 10 x 10 x 10 cm) at 4 m intervals taken along each transect were sifted using a sieve and white tray. All ants fallen into the white tray were preserved as above. Along each transect, worker ants crawled on the floor and the rice bushes were collected using paint brushes and a pair of fine forceps. Honey baiting and hand collection caught worker ants of 4 subfamilies, Dolichoderinae, Formicinae, Myrmicinae, and Ponerinae, and 14 genera and 14 species while soil sifting resulted in 3 subfamilies, Dolichoderinae, Formicinae and Myrmicinae, 10 genera and 12 species. Overall worker ants of four subfamilies, Dolichoderinae, Formicinae, Myrmicinae, and Ponerinae, 15 genera and 20 species were recorded and can be considered as a preliminary ant inventory of paddy fields in Sammanthurai. Tapinoma pithecorum Seifert, 2022 was recorded for the first time in Sri Lanka during this study.