[MARMAM] differences in male V female breeding intervals

Graeme Hays g.hays at deakin.edu.au
Tue Sep 23 16:32:47 PDT 2014


The following paper has recently been published and I hope proves useful for those looking at operational sex ratios and investigating differences in male V female behaviour through long-term satellite tracking.

Hays GC, Mazaris AD and Schofield G (2014). Different male vs. female breeding periodicity helps mitigate offspring sex ratio skews in sea turtles. Front. Mar. Sci. 1:43. doi:10.3389/fmars.2014.00043

http://journal.frontiersin.org/Journal/10.3389/fmars.2014.00043/abstract

This paper is free to download from the journal website. The paper show how the interval between breeding seasons is shorter for male turtles than for females. We show this by long-term satellite tracking of males and females and through an energy balance model which suggests our finding will apply generally to sea turtle populations. We review all the published studies to show that that female biased hatchling sex ratios dominate across the World but then show how these hatchling sex ratio skews will translate into far more balanced adult sex ratios on the breeding areas.

ABSTRACT
The implications of climate change for global biodiversity may be profound with those species with little capacity for adaptation being thought to be particularly vulnerable to warming. A classic case of groups for concern are those animals exhibiting temperature-dependent sex-determination (TSD), such as sea turtles, where climate warming may produce single sex populations and hence extinction. We show that, globally, female biased hatchling sex ratios dominate sea turtle populations (exceeding 3:1 in >50% records), which, at-a-glance, reiterates concerns for extinction. However, we also demonstrate that more frequent breeding by males, empirically shown by satellite tracking 23 individuals and supported by a generalized bio-energetic life history model, generates more balanced operational sex ratios (OSRs). Hence, concerns of increasingly skewed hatchling sex ratios and reduced population viability are less acute than previously thought for sea turtles. In fact, in some scenarios skewed hatchling sex ratios in groups with TSD may be adaptive to ensure optimum OSRs.


All best wishes, Graeme

Professor Graeme Hays
Alfred Deakin Professor of Marine Science

School of Life and Environmental Sciences, Deakin University
Warrnambool Campus, PO Box 423, Warrnambool, VIC 3280 (+61 3 55633311)
http://scholar.google.co.uk/citations?user=7rc3SmAAAAAJ&hl=en&oi=ao
http://www.deakin.edu.au/about-deakin/careers-at-deakin/your-employer-of-choice/alfred-deakin-professor

Recent highlights:

Hays GC, Christensen A, Fossette S, Schofield G, Talbot J, Mariani P. (2014). Route optimisation and solving Zermelo's navigation problem during long distance migration in cross flows. Ecology Letters 17, 137-143. doi: 10.1111/ele/12219

Laloë J-O, Cozens J, Renom B, Taxonera A, Hays GC (2014). Effects of rising temperature on the viability of an important sea turtle rookery. Nature Climate Change 4, 513-518. doi: 10.1038/NCLIMATE2236

Hinder SL, Gravenor MB, Edwards M, Ostle C, Bodger OG, Lee PLM, Walne AW, Hays GC (2014). Multi-decadal range changes vs thermal adaptation for north east Atlantic oceanic copepods in the face of climate change. Global Change Biology 20, 140-146. doi: 10.1111/gcb.12387


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