What s new in 2017 for TSD? Marc Girondot

What s new in 2017 for TSD? Marc Girondot

Temperature effect on embryo growth Morales-Merida, B. A., Bustamante, D. M., Monsinjon, J. & Girondot, M. (2018) Reaction norm of embryo growth rate dependent on incubation temperature in the Olive Ridley sea turtle, Lepidochelys olivacea, from Pacific Central America Journal of Embryology, 1(1), 12-24. Monsinjon, J., Jribi, I., Hamza, A., Ouerghi, A., Kaska, Y., et al. (2017) Embryonic growth rate thermal reaction norm of Mediterranean Caretta caretta embryos from two different thermal habitats, Turkey and Libya. Chelonian Conserv. Biol., 16(2), 172-179.

Temperature effect on survival Kobayashi, S., Wada, M., Fujimoto, R., Kumazawa, Y., Arai, K., et al. (2017) The effects of nest incubation temperature on embryos and hatchlings of the loggerhead sea turtle: Implications of sex difference for survival rates during early life stages. J. Exp. Mar. Biol. Ecol., 486, 274-281.

General methodology for TSD studies Monsinjon, J., Guillon, J.-M., Hulin, V. & Girondot, M. (2017) From air temperature to sex ratio for Emys orbicularis in natural conditions. Acta Zool. Bulg., Supplement 10, 105-113. Air temperatures Soil temperatures Nest temperatures TSP temperatures Embryo growth model Sex ratio

TSD pattern description Hernández-Montoya, V., Páez, V. P. & Ceballos, C. P. (2017) Effects of temperature on sex determination and embryonic development in the redfooted tortoise, Chelonoidis carbonarius. Chelonian Conserv. Biol., 16(2), 164-171 Parachú Marcó, M. V., Leiva, P., Iungman, J. L., Simoncini, M. S. & Piña, C. I. (2017) New Evidence Characterizing Temperature-dependent Sex Determination in Broad-snouted Caiman, Caiman latirostris. Herpetol. Conserv. Biol., 12, 78-84.

Molecular work about TSD Radhakrishnan, S., Literman, R., Neuwald, J., Severin, A. & Valenzuela, N. (2017) Transcriptomic responses to environmental temperature by turtles with temperature-dependent and genotypic sex determination assessed by RNAseq inform the genetic architecture of embryonic gonadal development. PLoS One, 12(3), e0172044

Hydric status and TSD Sifuentes-Romero, I., Tezak, B. M., Milton, S. L. & Wyneken, J. (2017) Hydric environmental effects on turtle development and sex ratio. Zoology (Jena). Lolavar, A. & Wyneken, J. (2017) Experimental assessment of the effects of moisture on loggerhead sea turtle hatchling sex ratios. Zoology (Jena), 123, 64-70. These studies show how moisture may change the incubation conditions inside nests by changing the temperature experienced by eggs, which affects development, growth and sex ratios. The results of this study highlight the importance of including moisture conditions when predicting embryo growth and sex ratios and in developing proxies of embryonic development.

Resilience and TSD Hays, G. C., Mazaris, A. D., Schofield, G. & Laloe, J. O. (2017) Population viability at extreme sex-ratio skews produced by temperature-dependent sex determination. Proc Biol Sci, 284(1848). Only at extremely high incubation temperature does high mortality within developing clutches threaten sea turtles. Our work shows how TSD itself is a robust strategy up to a point, but eventually high mortality and female-only hatchling production will cause extinction if incubation conditions warm considerably in the future. Patrício, A. R., Marques, A., Barbosa, C., Broderick, A. C., Godley, B. J., et al. (2017) Balanced primary sex ratios and resilience to climate change in a major sea turtle population. Mar. Ecol.-Prog. Ser., 577, 189-203. The concept of TRT and pivotal are defined only for incubation at contant incubation temperatures. It is wrong to apply these concepts using mean incubation or mean TSP temperatures. The TRT as measured in this paper is simply a measure of the heterogeneity of incubation conditions and not a genetic character as when the TRT is measured with constant temperatures. This TRT can say nothing about the resilience of the population for sex ratio change because its variance is purely environmental. Almpanidou, V., Katragkou, E. & Mazaris, A. D. (2017) The efficiency of phenological shifts as an adaptive response against climate change: a case study of loggerhead sea turtles (Caretta caretta) in the Mediterranean. Mitig. Adapt. Strateg. Glob. Chang. We found that phenological changes would allow species to capture a thermal window similar to one they experience nowadays during the incubation period. Still, phenological shifts might be less adequate to follow precipitation changes, which however, were found to have a limited impact upon hatching success.

Proxies for sex ratios Carter, A. W., Bowden, R. M. & Paitz, R. T. (2017) Seasonal shifts in sex ratios are mediated by maternal effects and fluctuating incubation temperatures. Funct. Ecol., 31, 876-884. Rachel Bowden advocated that maternal investment in oestrogen in eggs can influence sex determination. Fuentes, M. M. P. B., Monsinjon, J., Lopez, M., Lara, P., Santos, A., et al. (2017) Sex ratio estimates for species with temperature-dependent sex determination differ according to the proxy used. Ecol. Model., 365, 55-67. Depending on the proxy used, sex rati oestimated from time series of temperatures can be estimated from 0 to 1! Girondot, M., Monsinjon, J. & Guillon, J.-M. (2018) Delimitation of the embryonic thermosensitive period for sex determination using an embryo growth model reveals a potential bias for sex ratio prediction in turtles. J. Therm. Biol., In press. If middle-third of incubation is used rather than true TSP, a systematic bias of sex ratio is observed Sandoval, S., Gomez-Munoz, V. M. & Porta-Gándara, M. Á. (2017) Expansion of the transitional range of temperature for sea turtle Lepidochelys olivacea from sex ratio data at controlled incubation temperatures. Herpetology Notes, 10, 63-65. Sex ratio estimated using average temperature during the middle-third of incubation compared with TSD pattern at constant temperature.

Climate change at work Jensen, M. P., Allen, C. D., Eguchi, T., Bell, I. P., LaCasella, E. L., et al. (2018) Environmental warming and feminization of one of the largest sea turtle populations in the world. Curr. Biol., 28(1), 154-159 e154. Relative proportions of male and female green sea turtles originating from the northern Great Barrier Reef (ngbr, red), and southern Great Barrier Reef/ Coral Sea (sgbr/cs, blue) as determined via mixed-stock analysis. The remaining 22 rookeries are grouped into other rookeries (black), and haplotypes not identified at any rookery are classified as orphan haplotypes (hatched lines).

Breeding sex ratio Lasala, J. A., Hughes, C. R. & Wyneken, J. (2018) Breeding sex ratio and population size of loggerhead turtles from Southwestern Florida. PLoS One, 13(1), e0191615.

Ne based on Nmales and Nfemales From conservation biology, we know that Ne should be higher than 500 for a population to persist for long term: Let take Nf=1000 500=4000*Nm/1000+Nm 4000 / 500-1= 1000/Nm 500 / 3500 = Nm / 1000 500 000 / 3500 = Nm Nm = 142

Species distribution Almpanidou, V., Schofield, G. & Mazaris, A. D. (2017) Unravelling the climatic niche overlap of global sea turtle nesting sites: Impact of geographical variation and phylogeny. J. Biogeogr., 44(12), 2839-2848. Santidrian Tomillo, P., Fonseca, L., Paladino, F. V., Spotila, J. R. & Oro, D. (2017) Are thermal barriers "higher" in deep sea turtle nests? PLoS One, 12(5), e0177256. Daniel Janzen hypothesized in his Why mountain passes are higher in the tropics that temperature gradients were effective barriers to animal movements where climatic uniformity was high. Deeper is the nest, more stable is the temperature (example, leatherbacks) and then «barrier» is higher for this species: a prediction is that embryo mortality at high temperatures should be higher in Leatherbacks than in green and still lower in olive ridleys and this is observed. But loggerheads are still more sensitive so the prediction with 3 data points is not very strong!

Evolution of TSD Pezaro, N., Doody, J. S. & Thompson, M. B. (2017) The ecology and evolution of temperature-dependent reaction norms for sex determination in reptiles: a mechanistic conceptual model. Biol Rev Camb Philos Soc, 92(3), 1348-1364.