Effects of maternal age and mass on foraging behaviour and foraging success in the northern elephant seal
Effects of maternal age and mass on foraging behaviour and foraging success in the northern elephant seal
复制标题
DOI：
10.1111/1365-2435.12108
复制
发表时间：
2013-08-01
影响因子：
5.2
通讯作者：
Costa, Daniel P.
中科院分区：
文献类型：
--
作者：
Hassrick, Jason L.;Crocker, Daniel E.;Costa, Daniel P.
1.那些表现出不确定的生长并将相对恒定比例的身体储备用于每年的繁殖努力的动物面临着在不可预测的环境中满足不断增长的能量需求的问题。我们研究了内在的特征，质量和年龄，以及外在的环境特征影响潜水和运动行为的海洋资本饲养员，北方象海豹，Mirounga angustirostris。我们评估了这种行为变化对觅食成功的影响，以海上获得的能量来衡量。采用主成分分析法将行为变量分解为三个主成分，分别描述了觅食区时间（PC1）、觅食距离（PC2）和潜水形状的结构（PC3）.内在的特征和外在的环境特征影响行为和觅食的成功。身体质量是唯一的预测停留时间在觅食区（PC1），这反过来，是最强的行为预测觅食效率和成功在短期繁殖后的季节。觅食距离（PC2）显着变化与年。由于觅食距离是海豹觅食时的水平和垂直距离的指数，我们认为它受到海洋猎物分布的年际变化的影响。年龄对行为的大多数方面的影响可以忽略不计，除了在蜕皮后觅食之旅的潜水形状的结构。所有的主成分显着影响的能量增益率繁殖后觅食旅行时，母体商店必须迅速恢复之前返回海岸换羽。年龄影响的回合结构的潜水在怀孕的女性在某种程度上影响成功，这表明以前的经验在长期的蜕皮后觅食迁移的作用。身体质量对潜水能力、觅食成功率和繁殖努力的强烈影响表明了繁殖成本权衡的近似机制。目前对后代的投资所造成的质量损失影响了母亲为未来后代积累资源的能力。
1. Animals that show indeterminate growth and put relatively constant proportions of stored body reserves towards annual reproductive effort are confronted with a problem of meeting ever-increasing energetic demands in unpredictable environments.2. We examined how intrinsic traits, mass and age, as well as extrinsic environmental features impact diving and movement behaviour in a marine capital breeder, the northern elephant seal, Mirounga angustirostris. We assessed the impact of this behavioural variation on foraging success, measured as energy gained at sea.3. We used principal component analysis to reduce behavioural variables into three principal components that described time in foraging zones (PC1), foraging distance (PC2) and bout structure of dive shapes (PC3).4. Both intrinsic traits and extrinsic environmental features influenced behaviour and foraging success. Body mass was the sole predictor of residence time in foraging zones (PC1), which, in turn, was the strongest behavioural predictor of foraging efficiency and success over the short postbreeding season. Foraging distance (PC2) significantly varied with year. Since foraging distance is an index of the horizontal and vertical distances seals travel while foraging, we suggest that it was impacted by inter-annual variation in marine prey distribution. Age had a negligible impact on most aspects of behaviour, except for the structure of dive shapes on the postmoult foraging trip.5. All principal components significantly impacted rates of energy gain for postbreeding foraging trips when maternal body stores must be recovered quickly before returning to shore to moult. Age impacted the bout structure of dives in pregnant females in a way that influenced success, suggesting a role for previous experience during the long postmoult foraging migration.6. Strong impacts of body mass on diving ability, foraging success and reproductive effort suggest a proximate mechanism for trade-offs in the cost of reproduction. Mass lost to current investment in offspring impacts a mother's ability to accrue resources for future offspring.