Prehibernation diet and reproductive condition of female Anopheles messeae in Sweden.

1. Blood and sugar feeding in the mosquito Anopheles messeae Falleroni were investigated near Uppsala, Sweden, from 1981 to 1985, with emphasis on prehibernation diet. 2. Fructose, indicating plant feeding, was present in females of all ovarian stages, from April to October, and contributed to fat body development in non-gonoactive females before hibernation. 3. An.messeae males and females (inseminated and uninseminated) were observed feeding on floral nectaries of the plants Achillea millefolium L. and Tanacetum vulgare L. at night during August. 4. Gonotrophic dissociation started in some females in July, and by the end of September all females were inseminated and nulliparous but non-gonoactive. 5. Animal sheds were used as diurnal resting sites of non-gonoactive, prehibernating female An.messeae. Among recently fed mosquitoes in that group, 85% were gut positive for fructose and 15% for blood. Most of them showed negative host tropism, indicating that bloodfeeding is not a prerequisite for hibernation. 6. Survival rates of bloodfed (48 +/- 31 days) and non-bloodfed (42 +/- 21 days) females, collected from a cattle shed in September and kept caged without food or water in a store house, were not significantly different. This indicates that bloodfeeding may occur facultatively before hibernation but does not affect longevity and survival. 7. If overwintering is possible for bloodfed An.messeae females, they would be more likely vectors of pathogens such as Batai virus.