Inter‐population variation in multiple paternity and reproductive skew in the guppy

Abstract

We use microsatellite loci to detail the multiple paternity patterns in broods from 10 wild populations of the guppy (Poecilia reticulata) found in Northern Trinidad. The populations span two major drainages comprising the Caroni and the Oropouche, and include sites that are characterized by either high or low predation. Across the populations the frequency of multiple paternity is high with 95% (range: 70%-100%) of broods having multiple sires. Broods have an average of 3.5 sires (range: 1-9) and a mixed-model analysis suggests that broods from high predation sites have marginally more sires than do those from low predation sites, but this is true only in the Oropouche drainage. There is no difference in sire number between predation sites in the Caroni drainage. Brood size, but not female body length, is correlated with the number of sires and the correlation cannot be attributed solely to the stochastic process associated with sperm competition and a 'fair raffle'. Within broods there is significant skew in reproductive success among males, which may reflect variation in sperm competitiveness or female choice. There is, however, no difference in the skew among populations from different predation regimes or drainages. Finally, high predation populations were characterized by increased genetic variability at the microsatellite loci, suggesting a larger effective population size. We discuss explanations for the high degree of multiple paternity but the general lack of any major differences among broods from ecologically different populations.

Intraspecific evidence from guppies for correlated patterns of male and female genital trait diversification

“…We used this measurement because caudal fin tissue had been taken from each female for genetic analyses in a different study [51]. This method of estimating female size was strongly correlated with standard length, as confirmed by correlating both measurements using a subsample of females (Pearson correlation: r ¼ 0.95, n ¼ 33, p , 0.0001).…”

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

“…Males can also switch from courtship to a coercive mating tactic, termed gonopodial thrusting (hereafter 'sneaking'). In the wild, females can be subjected to up to one sneaky mating attempt per minute (Magurran & Seghers 1994), which may account for the high levels of multiple paternity reported in natural guppy populations (Neff et al 2008). Both the intensity of the male's courtship displays and the area of orange in the male's colour patterns have been shown to be positively phenotypically correlated with ejaculate quality (Matthews et al 1997;Locatello et al 2006;Pitcher et al 2007; but see Skinner & Watt 2006), and these relationships are thought to explain why sperm competition favours males with relatively high levels of orange (Evans et al 2003;Pitcher et al 2003) and correspondingly high levels of courtship (Evans & Magurran 2001).…”

Do unattractive friends make you look better? Context-dependent male mating preferences in the guppy

“…In particular, female guppies prefer relatively colourful males [19,20] and importantly, female perception of male relative attractiveness influences the number of sperm transferred during copulation in favour of the more colourful male [13]. Female guppies are highly promiscuous [21], and sperm number is the most important predictor of sperm competition success in this species [22]. Since pursuing and courting females may result in significant energetic costs [23,24], and males cannot simultaneously court two different females, it can be expected that male guppies exhibit some degree of choosiness.…”