INTRACLUTCH EGG SIZE VARIABILITY IN HYLA-CRUCIFER (ANURA, HYLIDAE)
INTRACLUTCH EGG SIZE VARIABILITY IN HYLA-CRUCIFER (ANURA, HYLIDAE)
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作者：
CRUMP, ML
在H.一种在临时池塘中繁殖的树蛙。20窝卵的卵径变化范围为1.08-1.48 mm，卵径变异系数为2.06 ~ 5.41。卵大小的窝内变异性（通过CV测量）与雌性体长、窝卵大小或平均卵大小无显著相关性。偏度和峰度统计显示，一半的窝卵直径分布在平均值周围的非正态分布。将大鸡蛋和小鸡蛋放在单独的容器中饲养，以检查鸡蛋绝对大小的影响。尽管较大的蛋会导致孵化出的幼仔明显更大，但这些个体在变态过程中没有获得任何好处：它们没有经历过更高的生存率，没有保持它们的尺寸优势，也没有更快地变态。在理想条件下（即，没有捕食或竞争和持久性的水生网站）所有的鸡蛋大小可能是成功的。但由于自然条件很少是理想的（即，蝌蚪确实会与捕食者和同类相互作用，小池塘经常在幼虫变形之前干涸），较大的卵孵化出的较大的幼体有时可能具有优势。可变的卵子大小可能会增加雌性的适应度，因为通过产生一些小卵子，她可以增加繁殖力，这在不确定的幼虫环境中是一个重要的结果。
Egg size variability was documented in H. crucifer, a treefrog that breeds in temporary ponds. Range of egg diameter in 20 clutches from a single population was 1.08-1.48 mm. Coefficients of variation in egg size within clutches ranged from 2.06-5.41. Intraclutch variability in egg size (as measured by CV) was not significantly correlated with female body length, clutch size or mean egg size. Skewness and kurtosis statistics revealed that egg diameters of half of the clutches examined were distributed around the mean value in a non-normal fashion. Large and small eggs were raised in individual containers to examine effects of absolute egg size. Even though larger eggs resulted in significantly larger hatchlings, these individuals gained no benefit at metamorphosis: they did not experience increased survival, did not maintain their size advantage and did not metamorphose more quickly. Under ideal conditions (i.e., no predation or competition and persistence of the aquatic site) all egg sizes may be successful. But since natural conditions are rarely ideal (i.e., tadpoles do interact with predators and conspecifics and small ponds often dry up before larvae can metamorphose), larger hatchlings coming from larger eggs may sometimes have an advantage. Variable egg size may increase fitness of a female because by producing some small eggs she can increase her fecundity, an important consequence in the uncertain larval environment.