A preliminary study on Collembolans associated with three vegetable crops grown at selected locations in Southern Sri Lanka

Abstract

Collembolans are one of the invertebrate groups inhabiting in soil. They serve as decomposers and are important as soil quality indicators. To date, Collembolans in vegetable fields are poorly known in Sri Lanka. Collembolans inhabited each of the three, Brinjol, Okra and Tomato fields, in Denipitiya, Labuduwa and Ridiyagama, respectively, were investigated, during July- September 2013. At each location, a 100m2 plot was selected with respect to each vegetable field and ten soil corer samples, each of 500g, were taken at random, fortnightly. The Collembolans in all these soil samples were extracted using floatation method and numbers in the supernatant was counted using a stereo-microscope in a well plate. Identification of Collembolan was done upto the generic level using taxonomic keys. Eight genera, Cyphoderus, Entomobrya, Folsomia, Guthriella, Isotomodes, Neaura, Podura and Tullbergia in six families, Cyphoderidae, Entomobryidae, Isotomidae, Neuridae, Onychiuridae and Poduridae, were detected.The highest Collembolan diversity (6.33 ± 0.17) and abundance (395.33±0.90) were recorded at Labuduwa followed by Denipitiya. Cyphoderus, Folsomia, Guthriella, Isotomodes, Neaura and Tullbergia were common at all the three locations. In contrast, Entomobrya was restricted to Labuduwa. Podura occurred in Labuduwa and Ridiyagama

while Tullbergia was prevalent at Folsomia, Guthriella, Isotomodes,

Labuduwa and Denipitiya. Cyphoderus, Neaura, Podura and Tullbergia were

common at three vegetable fields. Cyphoderus showed the highest abundance (234 ± 4.09) at Labuduwa (P<0.002) whereas Folsomia acquired the second highest (219.1 ± 1.12) at the same location. The abundance of Isotomodes (19.33 ± 0.66) Podura (51.6±1.21) and Entomobrya (9.66 ± 0.06) was the lowest (P<0.0001) at all locations.