NOCTURNAL BITING RHYTHMS OF MOSQUITOS (DIPTERA-CULICIDAE) IN SRI-LANKA

Nocturnal biting rhythms of mosquitoes in a dry zone irrigated riceland habitat in Sri Lanka, were studied by analysis of hourly-segregated bovid bait catches conducted between 18:00 and 06:00 hr during February-April 1990. Peak biting immediately after sunset was seen in Aedes lineatopennis (Ludlow 1905), Ae. pipersalatus (Giles 1902), Ae. vexans (Meigen 1830), Anopheles barbirostris Van der Wulp 1884, An vagus Doenitz 1902 and Armigeres subalbatus, (Coquillett 1898). A unimodal profile. with peak biting 2-4 hr after sunset occurred in Mansonia uniformis: (Theobald 1901), An.: annularis Van der Wulp 1884; An. aconitus:Doenitz 1902, An. jamesii Theobald 1901, An. tessellatus Theobald 1901, An. nigerrimus Giles 1900, An. pallidus Theobald 1901, An, peditaeniatus (Leicester 1908) and Culex gelidus Theobald 1901. Biphasic profiles were seen in Cx. fuscocephala Theobald 1907, Cx. tritaeniorhynchus Giles 1901, Gc. pseudovishnui Colless 1957 and Cx. whitmorei (Giles 1904). Among less abundant species, maximal biting occurred during the first quarter of the night in Ae. indicus (Theobald 1907), Ae. pallidostriatus (Theobald 1907), An. subpictus Grassi 1899 and Cx. vishnui Theobald 1901, whilst biting occurred almost uniformly throughout the night in An, varuna Iyengar 1924.