Robert Kylie A, Vleck Carol, Bronikowski Anne M
Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, Iowa 50011, USA.
Horm Behav. 2009 Jan;55(1):24-32. doi: 10.1016/j.yhbeh.2008.07.008. Epub 2008 Jul 29.
During embryonic development, viviparous offspring are exposed to maternally circulating hormones. Maternal stress increases offspring exposure to corticosterone and this hormonal exposure has the potential to influence developmental, morphological and behavioral traits of the resulting offspring. We treated pregnant female garter snakes (Thamnophis elegans) with low levels of corticosterone after determining both natural corticosterone levels in the field and pre-treatment levels upon arrival in the lab. Additional measurements of plasma corticosterone were taken at days 1, 5, and 10 during the 10-day exposure, which occurred during the last third of gestation (of 4-month gestation). These pregnant snakes were from replicate populations of fast- and slow-growth ecotypes occurring in Northern California, with concomitant short and long lifespans. Field corticosterone levels of pregnant females of the slow-growth ecotype were an order of magnitude higher than fast-growth dams. In the laboratory, corticosterone levels increased over the 10 days of corticosterone manipulation for animals of both ecotypes, and reached similar plateaus for both control and treated dams. Despite similar plasma corticosterone levels in treated and control mothers, corticosterone-treated dams produced more stillborn offspring and exhibited higher total reproductive failure than control dams. At one month of age, offspring from fast-growth females had higher plasma corticosterone levels than offspring from slow-growth females, which is opposite the maternal pattern. Offspring from corticosterone-treated mothers, although unaffected in their slither speed, exhibited changes in escape behaviors and morphology that were dependent upon maternal ecotype. Offspring from corticosterone-treated fast-growth females exhibited less anti-predator reversal behavior; offspring from corticosterone-treated slow-growth females exhibited less anti-predator tail lashing behavior.
在胚胎发育过程中，胎生后代会接触到母体循环中的激素。母体应激会增加后代对皮质酮的接触，而这种激素暴露有可能影响后代的发育、形态和行为特征。我们在测定了野外的自然皮质酮水平以及到达实验室后的预处理水平后，用低水平的皮质酮处理怀孕的雌性束带蛇（西部束带蛇）。在为期10天的暴露期间（发生在4个月妊娠期的最后三分之一时间），于第1天、第5天和第10天额外测量了血浆皮质酮。这些怀孕的蛇来自北加利福尼亚快速生长和缓慢生长生态型的重复种群，相应地具有较短和较长的寿命。缓慢生长生态型的怀孕雌性的野外皮质酮水平比快速生长的雌性高一个数量级。在实验室中，两种生态型动物在皮质酮处理的10天内皮质酮水平均升高，并且对照和处理的雌性均达到了相似的平稳期。尽管处理组和对照组母亲的血浆皮质酮水平相似，但皮质酮处理的雌性产生的死产后代更多，并且总生殖失败率高于对照组雌性。在1个月大时，快速生长雌性的后代血浆皮质酮水平高于缓慢生长雌性的后代，这与母体模式相反。皮质酮处理的母亲的后代，尽管滑行速度未受影响，但表现出逃避行为和形态的变化，这些变化取决于母体生态型。皮质酮处理的快速生长雌性的后代表现出较少的反捕食者反转行为；皮质酮处理的缓慢生长雌性的后代表现出较少的反捕食者甩尾行为。
Zotero 插件