Does polyandry really pay off?: The effects of multiple mating and number of fathers on morphological traits and survival in clutches of nesting green turtles at Tortuguero

Abstract

View the peer-reviewed version (peerj.com/articles/880), which is the preferred citable publication unless you specifically need to cite this preprint. Despite the long debate of whether or not multiple mating benefits the offspring, studies still show contradicting results. Multiple mating takes time and energy. Thus, if females fertilize their eggs with a single mating, why to mate more than once? We investigated and inferred paternal identity and number of sires in 12 clutches (240 hatchlings) of green turtles (Chelonia mydas) nests at Tortuguero, Costa Rica. Paternal alleles were inferred through comparison of maternal and hatchling genotypes, and indicated multiple paternity in at least 11 of the clutches (92%). The inferred average number of fathers was three (ranging from 1 to 5). Moreover, regression analyses were used to investigate for correlation of inferred clutch paternity with morphological traits of hatchlings fitness (emergence success, length, weight and crawling speed); and size of the mother; and an environmental variable (incubation temperature). We suggest and propose two different comparative approaches for evaluating morphological traits and clutch paternity, in order to infer greater offspring survival. First, clutches coded by the exact number of fathers and second by the exact paternal contribution (fathers who gives greater proportion of the offspring per nest). We found significant differences (P < 0.05) in clutches coded by the exact number of fathers for all morphological traits. A general tendency of higher values in offspring sired by two to three fathers was observed for the length and weight traits. Alfaro-NúñezHowever, emergence success and crawling speed showed different trends which unable us to reach any further conclusion. The second approach analysing the paternal contribution showed no significant difference (P > 0.05) for any of the traits. We conclude that multiple paternity does not provide any extra benefit in the morphological fitness traits or the survival of the offspring, when analysed following the proposed comparative statistical PrePrints 24 was three (ranging from 1 to 5). Moreover, regression analyses were used to investigate for correlation 25 of inferred clutch paternity with morphological traits of hatchlings fitness (emergence success, length, 26 weight and crawling speed); and size of the mother; and an environmental variable (incubation 27 temperature). We suggest and propose two different comparative approaches for evaluating 28 morphological traits and clutch paternity, in order to infer greater offspring survival. First, clutches 29 coded by the exact number of fathers and second by the exact paternal contribution (fathers who gives 30 greater proportion of the offspring per nest). We found significant differences (P < 0.05) in clutches 31 coded by the exact number of fathers for all morphological traits. A general tendency of higher values 32 in offspring sired by two to three fathers was observed for the length and weight traits. However, 33 eme...

A Review of Patterns of Multiple Paternity Across Sea Turtle Rookeries

“…In summary, our work helps resolve a long-standing conundrum by supporting the suggestion (Alfaro-Núñez et al, 2015;Jensen et al, 2006;Lee and Hays, 2004;Wright et al, 2013) that multiple paternity generally offers no fitness benefits to female sea turtles and simply scales with the density of turtles on the breeding grounds. The use of movement data to estimate male-female encounter rates may allow the broader applicability of this conclusion to be assessed for other taxa.…”

“…1). No evidence for genetic (indirect) benefits has so far been detected (Alfaro-Núñez et al, 2015;Lee and Hays, 2004;Wright et al, 2013) with fitness indicators such as clutch size, hatching success or offspring quality being typically compared between single-fathered clutches and those with multiple fathers. However, it has also been argued that indirect benefits may only be easily detected in genetically impoverished and inbred populations (Madsen, 2008).…”

Evidence of multiple paternal contribution in Podocnemis sextuberculata (Testudines: Podocnemididae) detected by microsatellite markers

“…Variation in the frequency of multiple paternity has also been demonstrated in studies of the mating system of marine turtle populations including Chelonia mydas (92%: Alfaro-Núñez et al 2015;61%: 75%: Pearse et al 2001;Lee and Hays 2004;9%: FitzSimmons 1998) and Caretta caretta (31%: Moore and Ball 2002;33%: Harry and Briscoe 1988), as well as the freshwater turtle, Chrysemys picta (0%: McTaggart 2000; 13%: Pearse et al 2001;33%: Pearse et al 2002). Some authors suggest that the rate of multiple paternity found in populations different factors, such a scarcity of resources, which is likely to reduce the population density and thus the number of copulations (Engqvist 2011).…”

“…The latter should aim to increase the number of males that will potentially fertilize the eggs (Alfaro-Núñez et al 2015), to provide higher rates of multiple paternity and consequently to maintain or increase intrapopulation genetic variability (Sugg andChesser 1994, Chesser andBaker 1996).…”

Does polyandry really pay off?: The effects of multiple mating and number of fathers on morphological traits and survival in clutches of nesting green turtles at Tortuguero

“…However, the application of nuclear DNA markers as an alternate tool has transformed such research, by providing direct insights into parentage in natural populations (Packer et al, 1991;Craighead et al, 1995;Keane, Dittus & Melnick, 1997;FitzSimmons, 1998;Uller & Olsson, 2008) and enabling investigation into the genetic consequences of multiple matings. For example, genetic polyandry of surveyed birds species occurs regularly in 86% of the species (Michl et al, 2002;Griffith, Owens & Thuman, 2002). As a result, sperm from different males may compete to fertilize a single clutch of eggs.…”