Warm weather sets lowland skink sex

SNOW skinks can base their gender on either genes or temperature. Which strategy they choose appears to depend on the weather.


Ido Pen of the University of Groningen in the Netherlands and colleagues studied two clans of snow skinks, Niveoscincus greeni, living at low or high altitude in the mountains of Tasmania, Australia. The team captured pregnant skinks from each clan and allowed half of each group to lie in the sun for 10 hours per day, while the others were restricted to 4 hours. When the skinks gave birth, the scientists sexed their offspring.

Litters born to the lowland clan had a greater proportion of females after long days in the sun, compared to short days. In contrast, the sex ratio of the highland litters remained equal (Nature, DOI: 10.1038/nature09512). This suggests that temperature drives the sex of low altitude litters, while genes determine gender further up the mountain.

Pen thinks climatic pressures are behind these different systems. At low altitudes, females born early under warm conditions have more time to grow large and produce offspring, so it is advantageous for these skinks' gender to be temperature-sensitive. At higher altitudes, however, erratic annual temperatures mean that the timing of birth may not affect reproduction rates, so the skinks rely on genes to produce a balanced sex ratio.

http://www.newscientist.com/article/mg20827844.300-warm-weather-sets-lowland-skink-sex.html