Behavioral variation in nesting phenology may offset sex‐ratio bias in tuatara. Issue 6 (25th June 2018)

• Record Type: Journal Article
• Authors: Nelson, Nicola J.; Keall, Susan N.; Refsnider, Jeanine M.; Carter, Anna L.
• Other Names: Warner Daniel A. guestEditor.; Du Wei‐Guo guestEditor.; Georges Arthur guestEditor.
• Is Part Of: Journal of experimental zoology. Volume 329:Issue 6/7(2018)
• Page Start: 373
• Page End: 381
• Publication Date: 2018-06-25
• Subjects: incubation environment -- nest site choice -- nesting phenology -- tuatara (Sphenodon punctatus); Zoology -- Periodicals; Zoology; Animal Population Groups -- physiology; Zoology; Electronic journals; Periodical; Periodicals; 590
• DOI: 10.1002/jez.2196
• Languages: English
• ISSNs: 2471-5646

Abstract

Abstract: The nest environment for eggs of reptiles has lifelong implications for offspring performance and success, and, ultimately, for population viability and species distributions. However, understanding the various abiotic and biotic drivers of nesting is complex, particularly regarding variation in nesting behavior of females and consequences for sex ratios in species with temperature‐dependent sex determination (TSD). We investigated how nest construction and nesting phenology affect the incubation environment of a reptile with TSD, the tuatara ( Sphenodon punctatus ), a species that is at risk from climate‐mediated male bias in population sex ratios. Using longitudinal behavioral data, we addressed the following questions. (1) Does nesting behavior vary with seasonal or location cues? (2) Does variation in nesting phenology or nest construction affect the incubation environment? We aimed to investigate whether female tuatara could modify nesting behavior to respond to novel environments, including a warming climate, allowing for successful incubation and balanced population sex ratios, maintaining population viability throughout their historic range. We predicted that earlier nesting after warm winters increased the likelihood that females will be produced, despite the sex determining system where males are produced from warmer temperatures. Further research is needed to understand the extent to which nesting behavior varies by individual through time, and across the range of tuatara, and the importance of habitat variability in maintaining production of females under future climate warming. GRAPHICAL ABSTRACT: Understanding the drivers of nesting behavior is complex, and their consequences for sex ratios in species with temperature‐dependent sex determination are important for viability of populations in a warming climate. In tuatara, a long‐lived reptile, earlier nesting after warm winters increases the likelihood that females will be produced, despite the sex determining system where males are produced from warmer temperatures, increasing the possibility for balanced sex ratios in the short to medium term.