Abstract

Hybridization is a fundamental evolutionary and ecological process with significant conservation ramifications. Sea turtle hybridization occurs at unusually high frequencies along the northeastern coast of Brazil. To better understand the process, we studied the reproductive output, migration patterns (through satellite telemetry), and isotopic niches of loggerhead turtles Caretta caretta and olive ridley turtles Lepidochelys olivacea and their hybrids. We classified 154 nesting females as loggerhead (n = 91), olive ridley (n = 38), or hybrid (n = 25) based on mitochondrial and nuclear DNA. Further, we compared nesting female morphological data and reproductive parameters (clutch size, emergence success, hatchling production, incubation period) of 405 nests among hybrids and parental species. We found no significant differences among the 3 groups when hatchling production was corrected for female body size, indicating that hybrids and parental species produce similar numbers of hatchlings per clutch. Satellite tracking of 8 post-nesting hybrid females revealed shared foraging grounds with both parental species, as well as neritic migrations between foraging and nesting areas similar to those previously reported for loggerheads and olive ridleys. Analyses of 13C and 15N isotope values (n = 69) further confirmed this pattern, as hybrid isotopic niches overlapped extensively with both parental species. Thus, given the similarities presented between hybrids and their parental species in reproductive, ecological, and behavioral characteristics, we conclude that these hybrids may persist along with other sea turtle nesting populations in the area, with research and conservation implications.

Highlights

  • Species boundaries and hybridization are primary research areas in conservation, ecology, and evolutionary biology

  • The genetic data revealed that of the 113 turtles that were morphologically similar to loggerheads, 91 had only loggerhead haplotypes and were identified as loggerheads

  • This study considers the implications of hybridization for conservation, ecology, and evolutionary biology

Read more

Summary

Introduction

Species boundaries and hybridization are primary research areas in conservation, ecology, and evolutionary biology. Hybridization has been reported among most of the hard-shelled sea turtle species (Cheloniidae), usually at very low rates within populations (Bowen & Karl 2007). Loggerhead and hawksbill hybrids, for example, remarkably constitute 30−40% of the nesting population there, potentially representing significant conservation concerns. Relative to their parental species, loggerhead × hawksbill hybrids had similar reproductive parameters (clutch size, emergence success, incubation period, hatchling production, observed clutch frequency, observed annual production, observed breeding frequency, observed total production; Soares et al 2017) and exhibited no decreased fitness as expressed by hatchling viability or hybrid breakdown (Soares et al 2018)

Methods
Results
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call