Lloyd Michelle J, Gosselin Louis A
Department of Biological Sciences, Thompson Rivers University, Kamloops, British Columbia V2C 5N3, Canada.
Biol Bull. 2007 Dec;213(3):316-24. doi: 10.2307/25066649.
This study examined the role of maternal provisioning in controlling interpopulation variation in hatching size in nine isolated populations of the intertidal gastropod Nucella ostrina, in which development to the early juvenile stage takes place within an egg capsule. Variation among populations was almost entirely due to the ratio of nurse eggs to embryo, which explained 65% of the variation in hatching size. Egg size was not a significant predictor of hatching size. Differences among seven of these populations in the nurse egg/embryo ratio were entirely due to the number of nurse eggs allocated per capsule; these populations allocated different numbers of nurse eggs per capsule but allocated the same number of embryos. Intriguingly, the two most wave-sheltered populations allocated significantly more nurse eggs and more embryos to each capsule than did the seven other populations, but they maintained nurse egg/embryo ratios consistent with patterns observed in the other populations. Inter- and intrapopulation variation in hatching size appears to be controlled largely by different mechanisms: within-population variation being controlled mainly by differences in allocation of embryos per capsule, whereas most among-population variation being due to differences in allocation of nurse eggs per capsule.
本研究调查了母体供给在控制潮间带腹足动物黄口荔枝螺九个隔离种群孵化大小的种群间变异中的作用，在这些种群中，幼体早期发育在卵囊中进行。种群间的变异几乎完全归因于营养卵与胚胎的比例，这解释了孵化大小变异的65%。卵的大小并非孵化大小的显著预测因子。这些种群中有七个种群的营养卵/胚胎比例差异完全是由于每个卵囊分配的营养卵数量不同；这些种群每个卵囊分配的营养卵数量不同，但分配的胚胎数量相同。有趣的是，与其他七个种群相比，两个受海浪庇护最多的种群每个卵囊分配的营养卵和胚胎显著更多，但它们保持的营养卵/胚胎比例与其他种群观察到的模式一致。孵化大小的种群间和种群内变异似乎在很大程度上受不同机制控制：种群内变异主要由每个卵囊分配的胚胎差异控制，而大多数种群间变异则归因于每个卵囊分配的营养卵差异。
