Illinois Natural History Survey, University of Illinois at Urbana-Champaign, 1816 South Oak Street, Champaign, Illinois 61820, USA.
Ecol Appl. 2011 Oct;21(7):2576-86. doi: 10.1890/10-1870.1.
One source of uncertainty in predicting the response of populations to exploitation is individual differences within a population in both vulnerability to capture and contribution to population renewal. For species with parental care, individuals engaged in nesting behavior are often targeted for exploitation, but predicting outcomes of this nonrandom vulnerability will depend in part on an understanding of how parental traits are related to potential for brood contribution to the population. Variation in brood-specific contribution to recruitment of largemouth bass (Micropterus salmoides), a fish species with extended parental care, was quantified to determine if differences in mating success, parental care behaviors, and timing of reproduction influenced offspring recruitment. Dependence of these relationships on brood predation was tested in communities that differed in the presence of bluegill, Lepomis macrochirus, an important nest predator. Daily snorkel surveys were conducted in experimental ponds during spring to monitor male spawning and parental care behaviors in populations of largemouth bass. Tissue samples collected from larvae in nests were used to develop brood-specific DNA fingerprints for determining nest origins of fall recruits. Largemouth bass spawning period in bluegill ponds was longer and more variable in duration, with lower, more variable mating success, than in ponds without bluegill. In all populations, only one or two broods provided the majority of recruits, and these were broods produced during the earliest days of spawning by the oldest, largest males. In bluegill ponds, brood contribution from earliest nests also increased with brood size. Earliest nesters were the oldest males, and recruits from these nests were often above average in body size. Offspring needed to be guarded to at least swim-up larval stage to contribute any recruits. Termination of parental protection before offspring were free swimming mainly occurred with broods guarded by smaller males in ponds with brood predators. These age- and size-specific differences in timing of spawning and duration of parental care are consistent with influences of residual reproductive value and energetic constraints on reproductive behavior. Furthermore, these patterns of individual contribution to recruitment imply that fisheries that selectively target either nesting individuals or larger, older males could potentially decrease recruitment at the population scale.
在预测种群对开发的反应时，一个不确定的来源是种群内个体在易捕获性和对种群更新的贡献方面的差异。对于具有亲代照顾的物种，参与筑巢行为的个体通常是开发的目标，但预测这种非随机脆弱性的结果将部分取决于对亲代特征与潜在繁殖贡献的关系的理解。通过量化具有延长亲代照顾的鱼类大口黑鲈（Micropterus salmoides）的特定繁殖贡献的变化，来确定交配成功率、亲代照顾行为和繁殖时间的差异是否会影响后代的招募。在蓝鳃太阳鱼（Lepomis macrochirus）存在与否的群落中测试了这些关系对后代捕食的依赖性，蓝鳃太阳鱼是一种重要的巢捕食者。在春季，通过潜水员每日在实验池塘中进行调查，监测大口黑鲈种群的雄性繁殖和亲代照顾行为。从巢中的幼虫收集组织样本，用于开发特定繁殖的 DNA 指纹，以确定秋季新兵的巢起源。有蓝鳃太阳鱼的池塘中大口黑鲈的繁殖期更长，持续时间更具变异性，交配成功率更低，变异性更大，而没有蓝鳃太阳鱼的池塘则相反。在所有种群中，只有一个或两个繁殖群体提供了大多数新兵，而且这些都是由最老、最大的雄性在繁殖的最早几天产生的繁殖群体。在蓝鳃太阳鱼池塘中，最早的巢穴的繁殖贡献也随着繁殖群体的大小而增加。最早筑巢的是最老的雄性，这些巢穴的后代通常在体型上高于平均水平。后代需要被保护至少到游泳幼虫阶段才能贡献任何新兵。在有巢捕食者的池塘中，当小鱼保护的繁殖群体的后代在还未自由游动时，亲代保护就会终止。这种与年龄和大小有关的产卵时间和亲代照顾持续时间的差异与剩余繁殖价值和生殖行为的能量限制有关。此外，这种个体对招募的贡献模式意味着，选择性地针对筑巢个体或更大、更老的雄性进行捕捞的渔业可能会在种群规模上降低招募率。
