Mosquito larvae (Diptera: Culicidae) in snow-melt pools in a Swedish Lapland area.

Culicid larvae were collected in snow-melt pools during the first half of June from 1975-1977 and 1995-1996 in the Abisko Valley, Torne Lapmark, northern Sweden. Twelve species were collected from 102 pools and 81 localities with 7,914 specimens (elevations from 300 to 650 m a.s.l.). Fourteen species are now known from the area. Ten types of larval habitats were classified and ten species were statistically analyzed on pooled values over all years for abundance, coexistence, and diversity. The greatest abundance of individuals had pools with Carex spp. on the bottom. Most widespread and abundant were Oc. hexodontus (Dyar), Oc. communis (DeGeer), Oc. pullatus (Coquillett), and Oc. punctor (Kirby). The two circumpolar, arctic species, Oc. nigripes (Zetterstedt) and Oc. impiger (Walker), were mainly confined to elevations above 400 m a.s.l. In such marginal habitats as these pools, exposed to variable abitotic conditions, the phenology of species was rather constant. Species diversity varied somewhat between habitats. Oc. hexodontus, Oc. communis, and Oc. pullatus most often occupied pools as single species. Oc. communis and Oc. hexodontus had the highest values for coexistence and also occurred with Oc. punctor. The habitats that were richest in species were those without vegetation or with detritus on the bottom and surrounded by Empetrum nigrum and Betula nana. These habitats contained between eight and ten species. Species abundance and coexistence over the years showed no stable species patterns for the habitat types in the area.