title: Diet alters delayed selfing, inbreeding depression, and reproductive senescence in a freshwater snail.
abstract: Reproductive success is a critical fitness attribute that is directly influenced by resource availability. Here, we investigate the effects of diet-based resource availability on three interrelated aspects of reproductive success: a change in mating system based on mate availability, consequent inbreeding depression, and the deterioration of reproductive efficiency with age (senescence). We employed a factorial experimental design using 22 full-sib families of the hermaphroditic freshwater snail Physa acuta to explore these interactions. Individual snails were reared in one of two mate-availability treatments (isolated [selfing] or occasionally paired [outcrossing]) and one of two diet treatments (boiled lettuce or Spirulina, an algae that is rich in protein, vitamins, and minerals). Spirulina-fed snails initiated reproduction at a 13% earlier age and 7% larger size than lettuce-fed snails. Spirulina also resulted in a 30% reduction in the time delay before selfing. Compared to lettuce, a diet of Spirulina increased inbreeding depression by 52% for egg hatching rate and 64% for posthatching juvenile survival. Furthermore, Spirulina led to a 15-fold increase in the rate of reproductive senescence compared with a diet of lettuce. These transgenerational, interactive effects of diet on inbreeding depression and reproductive senescence are discussed in the context of diet-induced phenotypic plasticity.
authors.affiliation: Department of Biology, West Chester University 750 S. Church St., West Chester, Pennsylvania, 19383.
authors.forename: Josh R
authors.initials: JR
authors.lastname: Auld
authors.affiliation: Department of Biology, West Chester University 750 S. Church St., West Chester, Pennsylvania, 19383.
authors.forename: John F
authors.initials: JF
authors.lastname: Henkel
keywords: Age at first reproduction; aging; caloric restriction; mating system; pulmonate; transgenerational effects; waiting time