The biology of Culiseta morsitans and Culiseta litorea (Diptera: Culicidae) in England

Abstract

AbstractAlthough Culiseta morsitans (Theobald) is a common Holarctic mosquito very little is known about its biology so many aspects of its life-history were studied, mainly in southern England, from 1964–1987. More limited observations were made in the south on the coastal Culiseta litorea (Shute). Both species laid an average of 109 eggs as an egg raft deposited on wet mud and leaf litter. At high humidities C. morsitans eggs can remain unhatched and viable for many months. Populations of both species overwinter as fourth instar larvae, pupation occurs in April and adults start emerging in early May. The adult season lasts until September or October. Both species feed principally on birds. Serological tests, however, on blood-engorged females show that a few feed on humans, although none has been caught in human bait collections. Light-traps are not very effective in sampling adults, although a few were caught in them, as they were in non-attractant suction traps. The relative sizes of adult populations of both species were monitored in most years from 1964–1980 on Brownsea Island, Poole Harbour, England, and showed a marked decline in the proportions of C. litorea, but there was a resurgence of this species after eight years, when the population again crashed.