Hughes Roger N, Roberts Derek J
Department of Zoology, University College of North Wales, LL57 2UW, Bangor, Gwynedd.
Oecologia. 1980 Jan;47(1):130-136. doi: 10.1007/BF00541788.
Reproductive effort was compared in Littorina rudis (ovoviviparous), L. nigrolineata (benthic eggs with direct development), L. neritoides and L. littorea (planktonic eggs and larvae). Three indices of reproductive effort were used: the proportion of total production committed to reproduction per unit time, the cumulative proportion of total production committed to reproduction up to a given age, and the ratio of reproductive production per unit time to somatic biomass at the beginning of the unit time interval. The indices were plotted against age and the snails ranked in order of their reproductive efforts at equivalent ages. When plotted on axes of absolute time, all three indices ranked the snails in the order L. neritoides<L. rudis≈L. littorea<L. nigrolineata. The rank order of reproductive efforts on a time axis standardized for growth rate was L. littorea<L. rudis<L. nigrolineata≈L. neritoides, and on a time axis standardized for generation time was L. neritoides≈L. rudis<L. nigrolineata. The implications and relative merits of the different expressions of reproductive effort are discussed. No general relationship was found between the magnitude of reproductive effort and either reproductive type or population ecology among the Littorina spp., or among other intertidal prosobranchs reviewed from the literature. Semelparous species had among the highest reproductive efforts, but there was no clear separation in this respect from certain iteroparous species. Parental investment, measured as the energy content of an egg plus any accompanying jelly or capsular material, was one to two orders of magnitude greater in the species with direct development than in those with indirect development. There were significant differences between egg and hatchling sizes of L. rudis from three contrasted types of shore and these differences were thought to be correlated with the intensity of desiccation and predation on hatchlings rather than with demographic factors.
对厚唇滨螺（卵胎生）、黑线滨螺（底栖卵，直接发育）、粒结节滨螺和滨螺（浮游卵和幼虫）的繁殖投入进行了比较。使用了三个繁殖投入指标：单位时间内用于繁殖的总产量比例、到给定年龄时用于繁殖的总产量累积比例，以及单位时间内繁殖产量与该单位时间间隔开始时的体细胞生物量之比。将这些指标与年龄作图，并按照相同年龄下的繁殖投入对蜗牛进行排序。当以绝对时间为轴作图时，所有三个指标对蜗牛的排序为粒结节滨螺＜厚唇滨螺≈滨螺＜黑线滨螺。在根据生长速率标准化的时间轴上，繁殖投入的排序为滨螺＜厚唇滨螺＜黑线滨螺≈粒结节滨螺；在根据世代时间标准化的时间轴上，排序为粒结节滨螺≈厚唇滨螺＜黑线滨螺。讨论了繁殖投入不同表达方式的含义和相对优点。在滨螺属物种之间，或在文献中综述的其他潮间带前鳃亚纲动物中，未发现繁殖投入大小与繁殖类型或种群生态学之间存在普遍关系。单次繁殖物种的繁殖投入最高，但在这方面与某些多次繁殖物种没有明显区别。以卵加上任何伴随的胶质或囊膜物质的能量含量衡量的亲代投资，在直接发育的物种中比在间接发育的物种中高1至2个数量级。来自三种不同类型海岸的厚唇滨螺的卵和幼体大小存在显著差异，这些差异被认为与幼体的干燥和捕食强度相关，而不是与种群统计学因素相关。
