Department of Biology, University of California, Los Angeles, California 90095-1606.
Integr Comp Biol. 2002 Feb;42(1):43-50. doi: 10.1093/icb/42.1.43.
I used three innovative, nondestructive field methods (gas dilution, doubly labeled water and radiography) to measure individual energy and water budgets of wild, female desert tortoises (Gopherus agassizii). With these budgets, I evaluated whether body reserves help females produce eggs independent of rainfall and food availability. Female desert tortoises used large seasonal and annual changes in metabolism and body water, protein and energy reserves to survive and produce eggs. Although lipid reserves are important to female desert tortoises, nitrogen or crude protein appears to be the primary limiting resource for producing eggs. By reducing metabolic rates 90%, females conserved enough body reserves to produce eggs during extreme drought conditions; this is an effective bet-hedging reproductive pattern in an extreme and unpredictable environment.
我使用了三种创新的非破坏性野外方法（气体稀释法、双标记水法和射线照相法）来测量野生雌性沙漠龟（Gopherus agassizii）的个体能量和水分预算。根据这些预算，我评估了身体储备是否有助于雌性在不受降雨和食物供应影响的情况下产卵。雌性沙漠龟在新陈代谢和身体水分、蛋白质和能量储备方面经历了季节性和年度性的巨大变化，以维持生存和产卵。尽管脂质储备对雌性沙漠龟很重要，但氮或粗蛋白似乎是产卵的主要限制资源。通过将代谢率降低 90%，雌性龟在极端干旱条件下仍能储存足够的身体储备来产卵；这是在极端和不可预测的环境中一种有效的风险分散繁殖模式。
