Quantitative genetics of aerial dispersal behaviour and life-history traits in tetranychus urticae

Abstract

Genetic variance and covariance components of aerial dispersal behaviour, fecundity and sex ratio in a population of the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), were estimated by half-sib and full-sib analyses. Additive genetic variation was detected for the dispersal behaviour, but not for fecundity or sex ratio. The observed phenotypic variation and covariation were largely explained by non-additive genetic variation and maternal effect or common environmental variation. The existence of additive genetic variation in aerial dispersal behaviour was likely the result of opposing selection on latency or underlying traits of the behaviour, and not indirect selection on fecundity or sex ratio. Lack of significant genetic correlation between the three traits may indicate that they share few genes or underlying morphological and/or physiological traits in common. The results suggest that aerial dispersal behaviour may be an adaption to unpredictable environments. © 1993 The Genetical Society of Great Britain.