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- Ecology of Coelomomyces Indicus Lyengar
Ecology of Coelomomyces Indicus Lyengar
Dissertation Abstract:
Surveys were conducted in Thailand and the Philippines for Coelomomyces indicus on anopheline hosts.
In Thailand, only Anopheles vagus vagus Donits was observed to be infected with C. indicus. The percentage of infection was found in the provinces near the country's border, namely Rayong, Surin, Chiangrai, and in rice fields that were newly transplanted and with stagnant water. Five species of copepod were found in the same habitat, namely: Mesocyclops leukarti pilosa Keifer, Microcyclops varicans Sar., Neodiaptomus botulifer Keifer, N. Mephistopheles Brehm, and Thermocyclops crassus (Fischer).
In Luzon, Philippines, four species of anopheline infected with C. indicus were found, namely: Anopheles vagus vagus Donits, An. lesteri Biasas and Hu, An. indefinitus (ludlow), and An. philippinensis Ludlow. Infection percentage varied from 0 to 78.9. High percentage of infection was found in locations near houses or large animals and also in newly transplanted and stagnant rice fields. Three species of copepod were found, namely Mesocyclops leukarti Keifer, Cryptocyclops bicolor linjanticus Keifer, and Microcyclops varicans Sar. Some M. varicans from field collections were infected with C. indicus. Coelomomyces-infected mosquito larvae were collected from either clear or turbid water and in partially-shaded or fully-sunlit areas. Water pH and water temperature were of similar levels in all collection sites. Field observations indicated that the appearance of infection corresponded with anopheline development in the area, where an alternate host was present.
For physical factors, neutral condition and higher pH (7-10) of water media stimulated the germination of C. indicus on thin-walled sporangial germination up to three weeks. The species of the chemical on thick-walled sporongial germination showed a highly significant difference between dosages used, which are as follows: carbofuran at 10 ppm stimulated 12.3 percent germination on the sixth week; butachlor at 20 ppm and 40 ppm stimulated 16.7 and 11.7 percent germination, respectively; and ammonium sulfate 21 percent N at 10 ppm stimulated 12.0 percent germination.
Laboratory infection trials of C. indicus on anopheline host occurred ony when infected and field-collected M. varicans was included in the medium. Artificial infection of laboratory-reared M. varicans was unsuccessful.