Browsing by Author "Udayakantha, W.S."

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    The ant community observed by the repeated quadrat sampling in a selected region of the Meethirigala Forest Reserve, Sri Lanka
    (Department of Zoology and Environmental Management, University of Kelaniya, 2015) Udayakantha, W.S.; Dias, R.K.S.
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    The Ants (Hymenoptera, Formicidae) of Sri Lanka: a taxonomic research summary and updated checklist
    (ZooKeys 967, 2020) Dias, R.K.S.; Guénard, B.; Akbar, S.A.; Economo, E.P.; Udayakantha, W.S.; Wachkoo, A.A.
    An updated checklist of the ants (Hymenoptera: Formicidae) of Sri Lanka is presented. These include representatives of eleven of the 17 known extant subfamilies with 341 valid ant species in 79 genera. Lioponera longitarsus Mayr, 1879 is reported as a new species country record for Sri Lanka. Notes about type localities, depositories, and relevant references to each species record are given. Accounts of the dubious and some undetermined species from Sri Lanka are also provided. 82 species (24%) are endemic whereas 18 species that are non-native to Sri Lanka are recorded. The list provides a synthesis of the regional taxonomical work carried out to date and will serve as a baseline for future studies on the ant fauna of this biodiversity hotspot.
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    Discovery of three new Tetraponera species (Formicidae; Pseudomyrmecinae) from Sri Lanka.
    (International Research Symposium on Pure and Applied Sciences, 2017 Faculty of Science, University of Kelaniya, Sri Lanka., 2017) Dias, R.K.S.; Udayakantha, W.S.; Thotagamuwa, A.; Fernando, K.S.S.D.; Madushani, N.
    Tetraponera F. Smith is the sole genus of subfamily Pseudomyrmecinae recorded from Sri Lanka and very little is known about the diversity of the arboreal genus in the country. Nests of Tetraponera species were collected by checking the worker trails and locating them followed by severing the nests from the host trees. Colony members in (i) a nest in a cashew tree branch from Delgoda (7º 00.395´N and 80º 00.96´E) Udupila in Gampaha District in March, 2015 (ii) three nests of Tetraponera from two jack trees in the premises behind the Department of English language Teaching (6º58´ 35.94" N and 79º54´ 58.8"E), University of Kelaniya in March, 2015 and (iii) a nest in a dry rubber branch from Gulanakanda (6°35'01.7"N 80°00'36.7"E), Bombuwala, Kalutara in August, 2016 were preserved in 70 % ethanol for the identification and listing of Tetraponera species. Fifteen morphometric parameters of each adult caste of each species, if present, were measured using a calibrated micrometre eyepiece fixed to a stereo-microscope and total length of the adult castes were measured by a ruler in mm scale, which was kept under the stereo-microscope. Cephalic Index (CI=HW/HL), Scape Index (SI=SL/HW) and Relative Eye Length (REL=EL/HL) were also calculated. Worker ants were identified to the species level refering to the relevant literature; T. extenuata Ward, T. microcarpa Wu and Wang and T. modesta (F. Smith) in Tetraponera allaborans-group were identified from the nests (i), (ii) and (iii), respectively. Black or dark brownish black worker with the contrasting brownish orange post-petiole, tibiae, tarsi and scapes, taller and more slender propodeum and more convex and soft-edged pronotal margins characterized T. extenuata workers. Workers of T. microcarpa were of black or brownish black, with lighter brown petiole, post-petiole and appendages, bidentate median clypeal lobe, short and broad profemur and quadrat-shaped propodeum. Small size, orange-brownish colour of the body with lighter colour appendages and relatively slender profemur characterized T. modesta workers. Colony demography of each nest recorded by counting the number of each adult caste with the naked eye and that of larvae, pupae and eggs under the stereo-microscope indicated that workers generally had the highest percentage abundance whereas eggs or larvae were also present in higher percentages. Very low percentage of dealate queen was observed in each nest. Four Tetraponera species, T. rufonigra (Jerdon), T. allaborans (Walker), T. nigra (Jerdon) and T. nitida (Smith) recorded previously from Sri Lanka rose to seven with the current findings. A taxonomic key that distinguish all Tetraponera species recorded from Sri Lanka is prepared with the colour images to facilitate quick identification of workers of each species.
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    Nest density and other observations on a population of Aneuretus simoni Emery, 1893 (Formicidae, Aneuretinae) and other ants in Indikada Mukalana Forest Reserve in Sri Lanka
    (Journal of Insect Biodiversity, 2016) Dias, R.K.S.; Udayakantha, W.S.
    The Sri Lankan Relict Ant, Aneuretus simoni Emery, survives in several wet zone and intermediate zone forests in Sri Lanka. Nests of this species and other ants were surveyed at 159 m and 291 m elevations in Indikada Mukalana Forest Reserve by laying 20 quadrats of 1 m × 1 m at two plots of each locality in December, 2015. The number of ant nests within each quadrat was recorded; then the frequency of nest occurrence out of 40 quadrats, percentage nest abundance and mean nest density of A. simoni, as well as associated ant fauna were calculated. Percentage frequency of worker ant occurrence was also investigated using pitfall traps. Eighteen genera and 21 species in Aneuretinae, Dolichoderinae, Formicinae, Myrmicinae and Ponerinae were recorded from the two methods. Nests of A. simoni were found only in the locality at 291 m altitude in the forest; 17.5 % of quadrats with an A. simoni colonies, 9.7% of nest abundance in relation to that of other ant species and 0.18 m2 of mean nest density were observed. Nest density of A. simoni had the fourth rank among that of the other species. Frequency of occurrence of A. simoni workers in the pitfall traps at lower and upper elevations was 2% and 3%, respectively. An actualized map showing the current distribution of A. simoni is produced.
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    New Records of Ants (Hymenoptera: Formicidae) from Sri Lanka, Including Four Tramp Species
    (Sociobiology, 2018) Dias, R.K.S.; Udayakantha, W.S.; Wachkoo, A.A.; Akbar, S.S.
    Five ant species are reported for the first time from Sri Lanka: Ooceraea alii (Bharti & Akbar, 2013); O. biroi (Forel, 1907); Prionopelta kraepelini Forel, 1905; Strumigenys emmae (Emery, 1890) and S. membranifera Emery, 1869. Among the newly reported species, four species (O. biroi, S. membranifera, S. emmae and P. kraepelini) are known for their invasive and tramping nature, spreading via human commerce and have attained broad cosmopolitan distribution. Impact of these ants on regional fauna is not known and needs immediate attention. A brief diagnosis, distribution, and illustrations are provided for each species.
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    Tetraponera modesta, a new pseudomyrmecine ant record (Hymenoptera: Formicidae) for Sri Lanka
    (Ukrainska Entomofaunistyka 2020, 2020) Dias, R.K.S.; Udayakantha, W.S.; Thotagamuwa, A.; Akbar, S.A.
    Tetraponera modesta (F. Smith, 1860) is herewith recorded for the first time from Sri Lanka. With this addition number of known Sri Lankan species for the genus becomes five. The other four species are T. allaborans (Walker, 1859), T. nigra (Jerdon, 1851), T. nitida (Smith, 1860), and T. rufonigra (Jerdon, 1851). Among the known regional species, T. modesta is easily separable by smaller size, yellow to orange brown colouration of the head and mesosoma, and relatively slender petiole.
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