Browsing by Author "Perera, A.P.S."

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Arboreal ant assemblages (Formicidae) and importance of Oecophylla smaragdina (Fabricius) occurrence in a wet zone cashew field in Sri Lanka
(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Dias, R.K.S.; Perera, A.P.S.
Many ant species (Hymenoptera, Formicidae) have the potential to control herbivore abundance, reducing the plant damage while increasing plant growth, reproduction and yield in agro-ecosystems. Ant assemblages on six cashew trees in Delgoda, Gampaha District were recorded throughout three phenological phases by visiting the field six times from March to June in 2015. Seven to 15 baited traps were set 25 cm apart on the branches of each small, medium and large tree and collected after three hours. Worker ants seen on the main trunk and four major branches of each tree during a five minute period were hand-collected 5 to 9 times from small to large trees on each occasion. Collected ants were preserved in 70% ethanol, identified and listed. Number of Oecophylla smaragdina (Fabricius) nests observed on the same trees was recorded from April to June in 2015. The materials carried by O. smaragdina workers on cashew tree branches were also collected, preserved in 70% ethanol and identified to the possible levels using a Low Power Stereo-microscope. Fourteen ant species in five subfamilies were recorded. Species richness observed on each occasion ranged from 7 – 11 while O. smaragdina was the only species on all cashew trees. Nests of the species of O. smaragdina were observed only on one or two large and medium-sized trees. Various plant and animal materials carried by O. smaragdina workers confirmed that the species is an omnivore and a generalist predator. Presence of ant assemblages on cashew trees in the absence of any insecticide application in the current cashew field may have contributed to an observed absence of serious damage by cashew insect pests elsewhere.
Colony demography in the differently colored leaf nests of Oecophylla smaragdina Fabricius collected from the premises of Kelaniya University, Sri Lanka
(Department of Zoology and Environmental Management, University of Kelaniya, 2015) Perera, A.P.S.; Dias, R.K.S.
Species richness of arboreal ant assemblages (Hymenoptera, Formicidae) and frequency of Oecophylla smaragdina (Fabricius) occurrence in a wet zone cashew (Anacardium occidentale L.) field in Sri Lanka
(University of Kelaniya, 2016) Dias, R.K.S.; Perera, A.P.S.
Ant assemblages on cashew trees in the wet zone of Sri Lanka were recorded throughout three phenological phases from March to June in 2015. Baited trapping and hand collection recorded fourteen ant species in five subfamilies and species richness observed on each occasion ranged from 7 to 11. Absence of serious cashew pests was noticeable in the current phenological cycle. Oecophylla smaragdina (Fabricius) was the only species recorded on all trees. Number of O. smaragdina nests observed on the same cashew trees in the two plots was recorded from April to June in 2015 and nests of the species were observed only on large and medium-sized trees. The materials carried by O. smaragdina workers on cashew tree branches were also collected, preserved in 70% ethanol and identified as far as possible using a Low Power Stereo-microscope and various plant and animal materials carried by workers confirmed that the species is an omnivore and a generalist predator. In the current study absence of serious damages caused by the cashew insect pests even without any insecticide application might be due to the presence of ant assemblages on cashew trees.