Mating dynamics and multiple paternity in a long-lived vertebrate.

Joshua Zajdel,Matthew D Hale,Phillip M Wilkinson,Stacey L Lance,Thomas R Rainwater,Benjamin B Parrott

doi:10.1002/ece3.5438

Joshua Zajdel, Matthew D Hale + Show 4 more

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https://doi.org/10.1002/ece3.5438

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Abstract

Multiple paternity is relatively common across diverse taxa; however, the drivers and implications related to paternal and maternal fitness are not well understood. Several hypotheses have been offered to explain the occurrence and frequency of multiple paternity. One set of hypotheses seeks to explain multiple paternity through direct and indirect benefits including increased genetic diversity or enhanced offspring fitness, whereas another set of hypotheses explains multiple paternity as a by‐product of sexual conflict and population‐specific parameters such as density. Here, we investigate mating system dynamics in a historically studied population of the American alligator (Alligator mississippiensis) in coastal South Carolina. We examine parentage in 151 nests across 6 years and find that 43% of nests were sired by multiple males and that male reproductive success is strongly influenced by male size. Whereas clutch size and hatchling size did not differ between singly sired and multiply sired nests, fertility rates were observed to be lower in multiply sired clutches. Our findings suggest that multiple paternity may exert cost in regard to female fitness, and raise the possibility that sexual conflict might influence the frequency of multiple paternity in wild alligator populations.

Highlights

One of the most surprising discoveries resulting from modern ge‐ netic analysis of mating systems is that multiple paternity, wherein more than one male sires a clutch or litter, is relatively common across vertebrates (Birkhead & Møller, 1998; Coleman & Jones, 2011; Griffith, Owens, & Thuman, 2002; Uller & Olsson, 2008)
In an effort to further explore the potential benefits and fitness costs associated with multiple paternity, we examined whether multiple paternity influences hatchling phenotypes
It is well documented that large male alligators are better able to establish and maintain territories when compared to smaller males (Garrick & Lang, 1977; Joanen & McNease, 1971)

Summary

| INTRODUCTION

One of the most surprising discoveries resulting from modern ge‐ netic analysis of mating systems is that multiple paternity, wherein more than one male sires a clutch or litter, is relatively common across vertebrates (Birkhead & Møller, 1998; Coleman & Jones, 2011; Griffith, Owens, & Thuman, 2002; Uller & Olsson, 2008). The frequency of multiple paternity observed across crocodilian taxa ranges from 32% in the Chinese alligator (Alligator sinensis) to 100% in black caiman (Melanosuchus niger) (Muniz et al, 2011; Wu & Hu, 2010) Among crocodilians, it is not clear if the fre‐ quency of multiple paternity is driven by population density and/or mate encounter rate (Amavet et al, 2008; Budd et al, 2015; Davis et al, 2001; Lance et al, 2009; Lewis et al, 2013; McVay et al, 2008; Muniz et al, 2011; Oliveira et al, 2014; Lafferriere et al, 2016; Wu & Hu, 2010) though both have been suggested (Budd et al, 2015; Lafferriere et al, 2016). We examine mating dynamics in the American alligator with respect to the frequency of multiple paternity, the role of male characteristics in male re‐ productive output, and potential fitness benefits to females with multiply sired clutches By examining these questions within the context of the American alligator mating system, we seek to better understand whether multiple paternity is driven by evolutionary fitness advantages across sexes or is the product of population‐ specific parameters

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| DISCUSSION

CONFLICT OF INTEREST

Findings

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