Mating dynamics and multiple paternity in a long‐lived vertebrate

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.

Incubation Temperature and Maternal Resource Provisioning, but Not Contaminant Exposure, Shape Hatchling Phenotypes in a Species with Temperature-Dependent Sex Determination

“…Many theories regarding the adaptive value of TSD rely on the presence of a sex-specific effect of incubation temperature on offspring fitness (Charnov and Bull, 1977;Valenzuela and Lance, 2004;Schwanz et al, 2016). For example, in the American alligator, it is plausible that males benefit disproportionately from increased size and energy reserves resulting from intermediate incubation temperatures, because males must attain larger sizes (and older ages) in order to reach reproductive maturity compared to females (Wilkinson et al, 2016;Zajdel et al, 2019). As such, TSD would serve as an adaptive sex allocation strategy in this species.…”

Do female amphibians and reptiles have greater reproductive output if they have more mates?

“…2), which implied that multiple paternity may incur costs for Crocodylia (e.g. Zajdel et al 2019). Results…”

“…The summary effect size for three species of Crocodylia (McVay et al 2008;Lance et al 2009;Lafferriere et al 2016;Zajdel et al 2019) was non-significant, lacked heterogeneity and showed a negative trend (Fig. 2; Table 3).…”

Evidence of multiple paternity for the endemic Xingu River stingray

“…Multiple paternity (MP) is a phenomenon when two or more males contribute genetically to a litter (Daly‐Engel et al ., 2010). Several species from different vertebrate taxa are known to adopt this strategy (Correia et al ., 2021; Gayet et al ., 2021; Zajdel et al ., 2019). Hypotheses for the widespread occurrence of MP encompass the points of view of both genders.…”

“…genetics, microsatellites, polyandry, Potamotrygonidae, reproduction Multiple paternity (MP) is a phenomenon when two or more males contribute genetically to a litter (Daly-Engel et al, 2010). Several species from different vertebrate taxa are known to adopt this strategy (Correia et al, 2021;Gayet et al, 2021;Zajdel et al, 2019).…”