Browsing by Author "Kosgamage, K.R.K.A."

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    Occurrence and Species Diversity of Ground-Dwelling Worker Ants (Family: Formicidae) in Selected Lands in the Dry Zone of Sri Lanka
    (University of Kelaniya, 2012) Dias, R.K.S.; Kosgamage, K.R.K.A.
    Ants are an essential biotic component in terrestrial ecosystems in Sri Lanka. Worker ants were surveyed in six forests, uncultivated lands and, vegetable and fruit fields in two Districts of the dry zone, Anuradhapura and Polonnaruwa, from November, 2007 to October, 2008 by employing several sampling methods simultaneously along five, 100 m transects. Soil sifting, litter sifting, honey-baiting and hand collection were carried out at 5 m intervals along each transect. Twenty pitfall traps were set up throughout each site and collected after five hours. Air and soil temperatures, soil pH and soil moisture at each transect were also recorded. Use of several sampling methods yielded a higher value for species richness than just one or two methods; values for each land ranged from 19 – 43 species. Each land had its own ant community and members of Amblyoponinae, Cerapachyinae, Dorylinae, Leptanillinae and Pseudomyrmecinae were recorded for the first time from the dry zone. Previous records of 40 species belonging to 23 genera in 5 subfamilies for the Anuradhapura District are updated to 78 species belonging to 36 genera in 6 subfamilies. Seventy species belonging to thirty one genera in 9 subfamilies recorded from the first survey of ants in Polonnaruwa lands can be considered a preliminary inventory of the District; current findings updated the ant species recorded from the dry zone to 92 of 42 genera in 10 subfamilies. Consequent to this sum, the estimate of ant diversity of Sri Lanka rises to 202 species in 64 genera while 12 subfamilies remain unchanged.
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    Species of fungi and bacteria transmitted by the workers of two household ant species, Anoplolepis gracilipes Jerdon and Monomorium pharaonis Linne
    (Research Symposium 2010 - Faculty of Graduate Studies, University of Kelaniya, 2010) Kosgamage, K.R.K.A.; Dias, R.K.S.; Jayaratne, D.L.
    Workers of several ant species are considered as nuisance insects and household pests. Anoplolepis gracilipes and Monomorium pharaonis are two such species that attend food and this study was carried out to investigate if the workers of the two species contaminate food by transmitting any species of fungi or bacteria. Worker ants of A. gracilipes and M. pharaonis were collected in to sterilized Petridishes from a cafeteria of University of Kelaniya using a pair of sterilized forceps around 10 a.m. on the 24th of March, 2009. Five workers of each ant species were introduced to each of the five petridishes containing two culture media; Potato Dextrose Agar (PDA) for isolation of fungi and Nutrient Agar (NA) for isolation of bacteria under aseptic conditions. Both introductions were done within ten minutes after the collection of ants. Ants were allowed to crawl for five minutes in each petridish. Five petridishes containing PDA and five petridishes of NA but without introduction of ants were also maintained in each experiment. The PDA plates contaminated by ants and the control PDA plates were incubated at room temperature (28 °C) for a week. The NA plates contaminated by ants and the control NA plates were incubated at room temperature overnight. Microorganisms observed in each plate were identified according to the standard procedures. Five microorganisms transmitted by A. gracilipes included three fungi species; Aspergillus niger, Curvularia sp., Helminthesporium sp. and two bacteria species; Salmonella sp. and Micrococcus sp. In addition, four microbes, transmitted by M. pharaonis were identified as three species of fungi; Aspergillus niger, Aspergillus sp., Mucor sp. and a species of bacteria; Micrococcus sp. The identification of bacteria was done at Medical Research Institute in Colombo. The results indicated the possibility of food contamination by the workers of the two ant species.
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    Systematics and community composition of foraging worker ants (Family: Formicidae) collected from three habitats in a dry zone region of Sri Lanka
    (University of Kelaniya, 2008) Dias, R.K.S.; Kosgamage, K.R.K.A.
    Ants (Order: Hymenoptera, Family: Formicidae) are an important and common biotic component in the wet zone of Sri Lanka. Eleven subfamilies, 57 genera and 123 morphospecies of ants have been recorded from the wet zone recently, but little is known about the ants that inhabit dry zone of Sri Lanka. A survey on the dry zone worker ants was carried out from 2"d to 3'd of November, 2007 in three types of habitats, a forest, Kahalla - Pallekele forest (N 08° 311 and E 080° 301), a bitter gourd cultivation (N 07° 511 and E 080° 3 71) and in an uncultivated land (N 07° 511 and E 080° 3 71) in Dam bulla by soil sifting, litter sifting, honey baiting and pitfall trapping along 'five transects laid in each of them. A 100 m transect was laid in the forest whereas a 50m transect was laid in the other two habitats due to the smaller area of the two lands. Soil sifting and litter sifting were carried out at 5 m distance along each transect. Ten honey baits were placed at 5 m intervals along each transect and the baits were collected after an hour. Tw enty, honey-baited pitfall traps were fixed randomly in the sampling area of each habitat and the traps were collected after five hours. All samples were preserved in 85% ethanol in the field. Worker ants were sorted and identified to the furthest possible taxonomic levels in the laboratory. Air (27 °C- 32 °C) and soil temperatures (27 °C- 33 °C) and soil moisture content (8.6% - 14.5%) of each habitat were also measured. Worker ants belonging to five subfamilies, Dolichoderinae, Formicinae, Myrmicinae, Ponerinae and Pseudomyrmecinae and, 4 1 species and morphospecies of ants were recorded from the three habitats. The dolichoderines, Tapinoma indicum, Tapinoma melanocephalum, Technomyrmex albipes, the formicines, Anoplolepis gracilipes, Camponotus sp. 1, Camponotus sp. 2, Camponotus sp. 3, Camponotus sp. 4, Oeco'f.hylla smaragdina, Paratrechina longicornis, Polyrhachis sp. 1, Pseudolasius sp. , the myrm1cines, Calyptomyrmex sp. 1, Crematogaster sp. 1, Crematogaster sp. 2, Lophomyrmex sp. 1, Meranoplus bicolor, Monomorium destructor, Monomorium sp. 1, Pheidole sp. 1, Pheidole sp. 2, Pheidole sp. 3, Pheidole sp. 4, Pheidole sp. 5, Pheidole sp. 6, Solenopsis geminata, Solenopsis sp. 1, Strumigenys sp. 1, Tetramorium sp. 1, Tetramorium sp. 2, Tetramorium sp. 3, Tetramorium sp. 4, Tetramorium sp. 5, Tetramorium sp. 6, Tetramorium sp. 7, the ponerines, Anochetus sp. 1, Hypoponera sp. 1, Pachycondyla sp. 1, Platythyrea sp. 1 and the pseudomyrmecines, Tetraponera allaborans and Tetraponera rufonigra were observed in these three types of habitats. Tapinoma melanocephalum, Anoplolepis gracilipes, Paratrechina longicornis, Crematogaster sp. 1, Solenopsis geminata, Tetramorium sp. 1, Tetramorium sp. 3 and Tetramorium sp. 7 were observed m considerable proportions whereas others were found in less than 4% proportions. Significant differences were observed among the frequencies of ant species recorded in this study (Chi-square test; p< 0.05) and, Tetramorium sp. 7 (28%), Tetramorium sp. 3 ( 13.4%) and Solenopsis geminata ( 10.9%), were the dominant species observed in Dambulla region. The ponerines were observed in the forest and the uncultivated land but they were not observed in the bitter gourd cultivation. The pseudomyrmecines were not observed in the uncultivated land. Tapinoma melanocephalum, Paratrechina longicornis, Crematogaster sp.l, Meranoplus bicolor, Monomorium destructor, Pheidole sp. 1, Tetramorium sp. 1, Tetramorium sp. 3 and Tetramorium sp. 4 were common to these sites. W hen compared with the prevwus record on dry zone ants, the presence of two pseudomyrmecines is a new observation and the absence of aenictines in current habitats was also noticeable.