Data from: Sex-specific variation in foraging behavior is related to telomere length in a long-lived seabird

Foraging during breeding is a demanding activity linked to breeding
investment and possibly constrained by individual quality. Telomere
length, the protective nucleoproteins located at the ends of the
chromosomes, is considered a trait reflecting somatic maintenance and
individual quality. Therefore, foraging effort and parental investment may
be positively related to telomere length, if individuals with longer
telomeres are of better quality and thus able to maintain better body
condition and allocate more resources to parental activities. In the brown
booby (Sula leucogaster), we investigated if telomere length is related to
body mass (a proxy of condition) and whether variation in foraging
behavior and provisioning effort is related to telomere length or body
mass. Then, we explored whether variation in foraging and provisioning
influences the chick mass growth rate. In 34 pairs nesting in Isla de San
Jorge, in the Gulf of California, México, we sampled their blood to
estimate telomere length, measured their body mass, and for 10 days,
recorded their foraging behavior via global positioning system (GPS)
loggers and their chick provisioning rate and chicks’ mass growth rate. We
found a positive relationship between parents’ body mass and telomere
length. Body mass did not affect foraging behavior. Females with longer
telomeres were more prone to travel longer distances towards offshore and
deeper waters than females with shorter telomeres. In contrast, males with
longer telomere lengths performed more nearshore foraging trips than males
with shorter telomeres. Chick provisioning rate was unrelated to telomere
length or body mass, but females fed the chick at a rate 2.4 times greater
than males. Females’ offshore foraging, but not males’, was positively
related to chick mass growth rate. Our results suggest that individual
quality, indicated by telomere length, is an important driver of
sex-specific, between-individual variation in foraging behavior,
indirectly affecting offspring condition.

繁殖期的觅食活动是一项高消耗行为，与亲本投入密切相关，且可能受个体自身素质制约。端粒（telomere）是位于染色体末端的保护性核蛋白结构，被视为反映躯体维持能力与个体素质的性状。因此，若端粒更长的个体素质更佳，能够维持更优身体状态并为亲本抚育活动分配更多资源，那么觅食投入与亲本投入或与端粒长度呈正相关。

我们以褐鲣鸟（Sula leucogaster）为研究对象，探讨端粒长度是否与体重（身体状态的替代指标）相关，以及觅食行为与抚育投入的变异是否与端粒长度或体重有关联。随后，我们进一步探究觅食与抚育行为的变异是否会影响雏鸟的体重生长速率。

在墨西哥加利福尼亚湾圣乔治岛的34个筑巢繁殖配对中，我们采集其血液样本以估算端粒长度、测量体重，并通过全球定位系统（GPS）记录仪连续10天记录其觅食行为，同时记录雏鸟的抚育频次与体重生长速率。

研究结果显示，亲本的体重与端粒长度呈显著正相关关系。体重并未对觅食行为产生显著影响。端粒更长的雌性个体，相比端粒较短的雌性，更倾向于前往更远的远洋与深水区域觅食；与之相反，端粒更长的雄性个体，其觅食行程相较于端粒较短的雄性更贴近近岸区域。雏鸟的抚育频次与端粒长度或体重均无关联，但雌性的育雏频次是雄性的2.4倍。雌性的远洋觅食行为（而非雄性）与雏鸟体重生长速率呈正相关。

本研究结果表明，以端粒长度为表征的个体素质，是驱动觅食行为存在性别特异性个体间变异的重要因素，并间接影响后代的身体状态。