Multiple mating and reproductive skew in Trinidadian guppies

Abstract

Male offspring production in promiscuously mating species is typically more skewed than female offspring production. It is therefore advantageous for males to seek as many mating partners as possible. However, given the documented benefits of polyandry we expect females, as well as males, to mate multiply. We tested these ideas using Trinidadian guppies, Poecilia reticulata. Fishes were collected from the wild, housed in groups of 10 males and 10 females and allowed to reproduce freely over a period of three months. We used hypervariable microsatellite loci to identify the parents of 840 offspring and to quantify the variance in mating success. As anticipated, and in line with the Bateman gradient, there was greater skew in the number of progeny produced by males. By contrast, we found no sex difference in mating partner number over the duration of the experiment. A median of two males fathered each brood and there was marked turnover in the identities of the sires of successive broods. Female partner turnover was, however, less than expected under random mating. We suggest that partner switching over time, as well as polyandry within broods, could contribute to the maintenance of genetic diversity in guppy populations.

Quantitative genetic evidence that males trade attractiveness for ejaculate quality in guppies

“…However, the sign (negative) of both relationships is consistent with prior evidence for a resource allocation trade-off between somatic growth and ejaculate investment. For example, previous work has shown that relatively small males have a competitive advantage during both controlled sperm competition trials (Evans et al 2003) and in long term and replicated mating experiments (Becher & Magurran 2004). Negative correlations between somatic growth and ejaculates are common in species in which males exhibit alternative reproductive strategies (e.g.…”

Gametic isolation in guppies ( Poecilia reticulata )

“…Novel partners are usually favoured (Hughes et al 1999). Females often mate with several males during each receptive period (Evans & Magurran 2000) and switch partners between broods (Becher & Magurran 2004;Eakley & Houde 2004). This behaviour enhances both the quality and the quantity of the resultant brood (Evans & Magurran 2000;Ojanguren et al 2005).…”

The effects of quantitative fecundity in the haploid stage on reproductive success and diploid fitness in the aquatic peat moss Sphagnum macrophyllum

“…The greater slope of the gradient in male gametophytes suggests a polygamous mating system. In many other organisms, a significant difference in slopes between the sexes on the Bateman gradient has been interpreted as a signal of sexual selection (Levitan, 1998;Becher and Magurran, 2004;Tatarenkov et al, 2008;Anthes et al, 2010).…”