Sex enhances survival inParamecium

Abstract

The pervasiveness of sex despite its well-known costs is a long-standing puzzle in evolutionary biology. Current explanations for the success of sex in nature largely rely on the adaptive significance of the new or rare genotypes that sex may generate. Less explored is the possibility that sex-underlying molecular mechanisms can enhance fitness and convey benefits to the individuals that bear the immediate costs of sex. Here we show that selffertilization can increase stress resistance in the ciliate Paramecium tetraurelia. This advantage is independent of new genetic variation, coupled with a reduced nutritional input, and offers fresh insights into the mechanistic origin of sex. In addition to providing evidence that the molecular underpinnings of sexual reproduction and the stress response are linked in P. tetraurelia, these findings supply an explanation for the persistence of selffertilization in this ciliate. on the genetic structure and reproductive strategy of the crustacean Daphnia magna. Ecology Letters 2004, 7:848-858. 10. Jokela J, Dybdahl MF, Lively CM: The maintenance of sex, clonal dynamics, and host-parasite coevolution in a mixed population of sexual and asexual snails.