The Influence of Multiple Paternity on Genetic and Morphological Variation in Leatherback Hatchlings (Dermochelys coriacea) at Sandy Point National Wildlife Refuge

Molecular techniques can reveal information about mating systems and paternal identity in cryptic species. Leatherback turtle hatchlings exhibit variation in body size at Sandy Point National Wildlife Refuge (SPNWR), St. Croix, USVI, sometimes within one clutch. When maternal identity is known, microsatellites can be used to determine the number of fathers contributing to a nest and to assign paternal identity to hatchlings. I measured body size and collected skin from leatherback hatchlings at SPNWR and found that hatchlings weighed 45.3 +/- 3.5 g, were 59.1 +/- 2.4 mm long (SCL), and had an average body condition index (BCI) of 2.2 x 10-4 +/- 2.4 x 10-5 g/mm3 (n =3,293). I used maternal and hatchling genotypes to reconstruct paternal genotypes, assigning fathers to each hatchling. I found multiple paternity in five of 16 nests, and compared mass, SCL, and BCI of hatchlings from different fathers and the same mothers. I found no significant differences between sizes of hatchlings based on paternal identity. I compared hatchling size variation for nests with and without multiple paternity and found a tendency for multiple paternity nests to have greater hatchling size variation, although this tendency was not statistically significant. Therefore, I found no direct evidence for paternal genetic influence on body size within a clutch. I also examined opportunistically collected dead embryonic twins and found they were genetically identical. Understanding factors affecting hatchling body size, and other possible measures of fitness, may reveal insights into the reproductive biology and development of cryptic leatherbacks.