Influence of short‐term temperature drops on sex‐determination in sea turtles. Issue 8 (26th July 2021)

• Record Type: Journal Article
• Authors: Porter, Ellen; Booth, David T.; Limpus, Colin J.; Staines, Melissa N.; Smith, Caitlin E.
• Is Part Of: Journal of experimental zoology. Volume 335:Issue 8(2021)
• Page Start: 649
• Page End: 658
• Publication Date: 2021-07-26
• Subjects: climate change -- global warming -- incubation -- incubation temperature -- marine turtles -- sex‐ratio; Zoology -- Periodicals; Zoology; Animal Population Groups -- physiology; Zoology; Electronic journals; Periodical; Periodicals; 590
• DOI: 10.1002/jez.2509
• Languages: English
• ISSNs: 2471-5646

Abstract

Abstract: All sea turtles exhibit temperature‐dependent sex‐determination, where warmer temperatures produce mostly females and cooler temperatures produce mostly males. As global temperatures continue to rise, sea turtle sex‐ratios are expected to become increasingly female‐biased, threatening the long‐term viability of many populations. Nest temperatures are dependent on sand temperature, and heavy rainfall events reduce sand temperatures for a brief period. However, it is unknown whether these short‐term temperature drops are large and long enough to produce male hatchlings. To discover if short‐term temperature drops within the sex‐determining period can lead to male hatchling production, we exposed green and loggerhead turtle eggs to short‐term temperature drops conducted in constant temperature rooms. We dropped incubation temperature at four different times during the sex‐determining period for a duration of either 3 or 7 days to mimic short‐term drops in temperature caused by heavy rainfall in nature. Some male hatchlings were produced when exposed to temperature drops for as little as 3 days, but the majority of male production occurred when eggs were exposed to 7 days of lowered temperature. More male hatchlings were produced when the temperature drop occurred during the middle of the sex‐determining period in green turtles, and the beginning and end of the sex‐determining period in loggerhead turtles. Inter‐clutch variation was evident in the proportion of male hatchlings produced, indicating that maternal and or genetic factors influence male hatchling production. Our findings have management implications for the long‐term preservation of sea turtles on beaches that exhibit strongly female‐biased hatchling sex‐ratios. Abstract : Can sea turtle eggs exposed to short periods of male inducing temperatures create male hatchlings? Research Highlights: We incubated sea turtle eggs at female temperatures except for brief periods when they were incubated at male temperatures. Exposing eggs to male temperatures for 3 days can induce some male hatchling production.