Militão Teresa, Clessin Augustin, Gamble Amandine, Granadeiro José Pedro, Boulinier Thierry, Catry Paulo
MARE - Marine and Environment Sciences Centre/ARNET - Aquatic Research Network, Ispa - Instituto Universitário, Lisboa, Portugal.
CEFE, UMR 5175, CNRS, EPHE, IRD, University of Montpellier, Montpellier, France.
Sci Rep. 2024 Dec 30;14(1):31694. doi: 10.1038/s41598-024-81608-3.
While numerous studies have established correlations between parasite load and negative effects on their hosts, establishing causality is more challenging because parasites can directly compromise host condition and survival or simply opportunistically thrive on an already weakened host. Here, we evaluated whether Ixodes uriae, a widespread seabird tick, can cause a decrease in growth parameters (body mass, bill length and growth rates) and survival of chicks of a colonially seabird, the black-browed albatross (Thalassarche melanophris) breeding on New Island (West Falkland). To investigate this, we daily removed the ticks from 28 randomly selected chicks during their first 14 days of life (treated chicks) and compared their growth and survival with 49 chicks of a control group. The tick load on control chicks correlated negatively with their body mass, growth rates and survival. Comparisons between treated and control chicks demonstrated that tick infestation depleted body mass and hampered the growth of control chicks. Treated chicks had a higher survival rate than control ones to fledgling age, but not to 14 days old, suggesting that the delayed higher mortality on control chicks was caused by the accumulation of sub-lethal effects of ticks. This study experimentally demonstrates that high tick infestation can cause reduced host growth and survival.
虽然众多研究已确定寄生虫负荷与对宿主的负面影响之间存在关联，但确定因果关系更具挑战性，因为寄生虫既可以直接损害宿主的健康状况和生存能力，也可能只是在已经虚弱的宿主身上趁机繁衍。在此，我们评估了一种广泛分布的海鸟蜱——乌喙蜱（Ixodes uriae）是否会导致在新岛（西福克兰群岛）繁殖的群居海鸟——黑眉信天翁（Thalassarche melanophris）雏鸟的生长参数（体重、喙长和生长速率）下降以及存活率降低。为了探究这一问题，我们在雏鸟出生后的头14天里，每天从28只随机挑选的雏鸟身上清除蜱虫（处理组雏鸟），并将它们的生长和存活情况与49只对照组雏鸟进行比较。对照组雏鸟身上的蜱虫负荷与它们的体重、生长速率和存活率呈负相关。处理组雏鸟与对照组雏鸟的比较表明，蜱虫感染会消耗对照组雏鸟的体重并阻碍其生长。处理组雏鸟到幼鸟期的存活率高于对照组，但到14日龄时并非如此，这表明对照组雏鸟后期较高的死亡率是由蜱虫的亚致死效应累积所致。本研究通过实验证明，高蜱虫感染会导致宿主生长和存活能力下降。
