Can larval rearing temperature alter the outcome of intraspecific competition in mosquitoes?

Intraspecific competition is one of the mechanisms that regulate natural populations but its effects may be confounded by other biotic and abiotic factors. To examine the effect of larval rearing temperature on the outcome of intraspecific competition, three intraspecific densities (10, 20 and 40 larvae) of Culex pipiens pipiens were reared at 20 °C or 30 °C and the effect on survival, development time, adult wing length and estimated finite rate of increase (λ') determined. Survival to adulthood was inversely associated with both temperature and larval density except in the high density treatment where survival was positively associated with temperature. Female development times and wing lengths were inversely associated with both temperature and larval density while a significant interaction of temperature and density was observed for male development times and wing lengths. Negative density-dependent effects on male development time were eliminated at high but not at low temperature but regardless of temperature treatment, higher density resulted in smaller males. The estimated finite rate of increase was significantly higher at high than at low temperature and at low and intermediate larval densities compared to high larval densities. Results suggest that temperature and perhaps other abiotic factors experienced by mosquito larvae may modify outcome of intraspecific competition.