Effects of Low Temperature on Embryonic Development of Sceloporus Lizards

摘要: The most widely accepted explanation for the evolution of viviparity at high elevations and latitudes (cold climates) is that, by retaining eggs either short periods (in transition between oviparity viviparity) or entire gestation period, females can keep embryos warmer than they would be in nests and, thus, enhance their development. However, an increase length egg retention not only mechanism that allow squamate to cope with low ambient temperatures latitudes. We tested hypothesis short-term exposure cold has less effect on embryonic development species populations from warm climates, indicating physiological adaptation temperatures. Our experimental subjects were four (five populations) Sceloporus lizards a wide range elevations: scalaris (Arizona, 1460 m) aeneus (Mexico, 2800 group; undulatus (Virginia, 600 virgatus elevation 1800 2400 group. incubated under simulated natural temperature regimes, but exposed (8, 11, 14, 17 C) five days determine mortality delay hatching relative control same regimes. during incubation did differ eggs, vary elevation. These hatched later was again related thus rejected.