ABSTRACT
Climate change is generating range shifts in many organisms, notably along the elevational gradient in mountainous environments. However, moving up in elevation exposes organisms to lower oxygen availability, which may reduce the successful reproduction and development of oviparous organisms. To test this possibility in an upward-colonizing species, we artificially incubated developing embryos of the viperine snake (Natrix maura) using a split-clutch design, in conditions of extreme high elevation (hypoxia at 2877 m above sea level; 72% sea-level equivalent O2 availability) or low elevation (control group; i.e. normoxia at 436 m above sea level). Hatching success did not differ between the two treatments. Embryos developing at extreme high elevation had higher heart rates and hatched earlier, resulting in hatchlings that were smaller in body size and slower swimmers compared to their siblings incubated at lower elevation. Furthermore, post-hatching reciprocal transplant of juveniles showed that snakes which developed at extreme high elevation, when transferred back to low elevation, did not recover full performance compared to their siblings from the low elevation incubation treatment. These results suggest that incubation at extreme high elevation, including the effects of hypoxia, will not prevent oviparous ectotherms from producing viable young, but may pose significant physiological challenges on developing offspring in ovo. These early-life performance limitations imposed by extreme high elevation could have negative consequences on adult phenotypes, including on fitness-related traits.
Subject(s)
Altitude , Colubridae/embryology , Oxygen , Adaptation, Physiological , Animals , Body Size , Colubridae/physiology , Embryo, Nonmammalian/physiology , Embryonic Development/physiology , Female , Heart Rate , Male , Swimming/physiologyABSTRACT
Nineteen polymorphic microsatellite loci were identified and developed for Natrix maura. Polymorphism was assessed for 120 individuals sampled across four sampling sites from the French Pyrenees Mountains. The number of alleles per locus ranged from 3 to 15, and expected heterozygosity per locus ranged from 0.227 to 0.863. We tested for deviation from Hardy-Weinberg equilibrium and linkage disequilibrium and assessed the presence of null alleles for all loci, resulting in a selection of 14 high-quality polymorphic markers. These markers will be extremely useful in identifying fine-scale genetic structures and providing insight into conservation management plans of this species.
