Multiple paternity and population genetic structure in natural populations of the poeciliid fish, Heterandria formosa

Abstract

Heterandria formosa Agassiz, exhibits internal fertilization, internal brooding of embryos, sperm storage and an extreme level of superfetation. In this study we used microsatellite markers to examine variation among seven populations that exhibited significant variance in their histories of population density. We found that the populations were genetically distinct and that the heterozygosity increased as population density increased. We also examined paternity in three of those populations and found that the number of sires per female and the number of sires per brood increased with population density. Overall, the rates of multiple paternity are quite low relative to other species. The correlations with population density suggest that contact rates play a critical role in the breeding system in this species but the low rates of multiple paternity suggest that females may exert control over fertilization of their ova.

Shape variation in the least killifish: ecological associations of phenotypic variation and the effects of a common garden

“…Second, the genetic distinctions among populations in male size are likely greater than these common garden results suggest. Males grow more slowly and are smaller at higher densities and the densities at lotic springs are, on average, higher than those at lentic ponds (Leips and Travis 1999; Soucy and Travis 2003; Richardson et al. 2006; MacRae and Travis 2014).…”

“…Females carrying one or no broods appear streamlined and thin, while females carrying multiple broods have a distended abdomen and females with especially large broods can have a grossly distended abdomen. Moreover, local populations vary in body size and in their levels of matrotrophy and superfetation, both of which influence the shape of adult females, and this variation makes it easy to confound shape variation with life history variation (Soucy and Travis 2003). …”

“…We included this variable because it is implicated as a driver of sexual selection. In this species, there is sperm competition and competition among males for mating opportunities (Soucy and Travis 2003; Schrader et al. 2011).…”

“…2000; Leips et al. 2000, 2009; Soucy and Travis 2003; Richardson et al. 2006; Schrader and Travis 2009; Schrader et al.…”

Spatial and temporal variation in superfoetation and related life history traits of two viviparous fishes: Poeciliopsis gracilis and P. infans

“…An additional set of equivalent linear models were conducted on untransformed data to generate graphs and least-square means in the original scale of the variables in order to facilitate interpretation. Leastsquare means derived from general linear models represent values adjusted for the effect of the covariates (Sokal and Rohlf 2012). Hence, hereafter, we report mean values per month, population and species adjusted for the effect of female mass (all traits) and developmental stage (individual embryo mass).…”