Environmental and hormonal correlates of immune activity in a cooperatively breeding tropical bird
Environmental and hormonal correlates of immune activity in a cooperatively breeding tropical bird
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DOI：
10.1016/j.ygcen.2008.07.013
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发表时间：
2008-10-01
影响因子：
2.7
通讯作者：
Martin, Lynn B., II
中科院分区：
文献类型：
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作者：
Rubenstein, Dustin R.;Parlow, A. F.;Martin, Lynn B., II
由于温带地区的气候模式通常是可预测的，物种可以在环境条件变化之前在相互竞争的生理过程中自适应地分配资源。在半干旱的热带地区，环境是季节性的，但高度不可预测，分配决定可能对条件的短期波动更加敏感。我们询问(I)对免疫功能的投资是否会受到降雨量年际变化的影响，以及(Ii)皮质酮和催乳素这两种调节其他脊椎动物免疫活动的激素是否可以预测合作繁殖的超级八哥(Lamprotomis Superbus)在环境中引起的免疫活动变化。优秀的八哥生活在非洲稀树草原上，其特点是降雨量年间变化很大，这会影响它们的繁殖生活史和激素水平。我们量化了血浆杀菌能力，或细菌杀灭，以及在繁殖前旱季四年期间采集的血液样本中催乳素和皮质酮的浓度，因为这是决定该物种生殖作用的时期，也是降雨量最大的时期。我们发现细菌杀灭在研究最干燥的年份最弱，我们检测到细菌杀灭与催乳素呈正相关，而与皮质酮没有负相关。综上所述，这些结果表明，催乳素可能介导了降雨引起的超级八哥免疫活性的变化。这项研究首次研究了催乳素与鸟类固有免疫指标之间的关系，并表明，即使是生活在不可预测的环境中的物种，也可能通过催乳素来调整其生理优先顺序，以适应环境条件。(C)2008 Elsevier Inc.保留所有权利。
Because climatic patterns in temperate regions are generally predictable, species can allocate resources adaptively among competing physiological processes before environmental conditions change. In the semi-arid tropics where environments are seasonal, but highly unpredictable, allocation decisions may be more sensitive to short-term fluctuations in conditions. We asked (i) whether investments in immune function were affected by inter-annual variation in rainfall and (ii) whether corticosterone and prolactin, two hormones that modulate immune activity in other vertebrates, predict environmentally induced alterations in immune activity in cooperatively breeding superb starlings (Lamprotomis superbus). Superb starlings inhabit African savannas characterized by high among-year variation in rainfall, which influences their breeding life histories and hormone levels. We quantified bactericidal capacity of plasma, or bacterial killing, and prolactin and corticosterone concentrations in blood samples collected over a four year period during the dry season prior to breeding, as this is the period when reproductive roles are determined in this species and when rainfall is most variable. We found that bacterial killing was weakest in the driest year of the study, and we detected a positive relationship between bacterial killing and prolactin, but not a negative relationship with corticosterone. Together these results suggest that prolactin may mediate rainfall-induced changes in immune activity in superb starlings. This study is the first to examine relationships between prolactin and an index of constitutive, innate immunity in birds, and suggests that even species inhabiting unpredictable environments adjust their physiological priorities to environmental conditions, perhaps via prolactin. (C) 2008 Elsevier Inc. All rights reserved.