Pitcher TE, Stutchbury BJ
Department of Biology, York University, Ontario
Anim Behav. 2000 Jun;59(6):1261-1269. doi: 10.1006/anbe.2000.1436.
Extrapair paternity is common among many songbird species yet few studies have quantified male extraterritorial foray (ETF) effort and examined potential trade-offs. One potentially important constraint for males is the need to provide parental care. Current models of male extrapair mating tactics propose that males reduce extraterritorial foray effort later in the breeding season because they face a trade-off between feeding nestlings versus pursuing extrapair matings. However, detailed field studies examining the trade-off between paternal care and male extraterritorial forays are lacking. We used radiotelemetry to quantify male extraterritorial foray effort in hooded warblers, Wilsonia citrina, to test the widely held predictions that: (1) males make significantly fewer and shorter forays during the nestling stage relative to other stages (i.e. fertile and incubating stages); and (2) male extraterritorial foray effort is negatively correlated with parental effort. Males made 0.87+/-0.09 forays/h and spent on average 12.2% of their time foraying off territory. Results were equivocal; some data suggested male foray effort decreased in relation to parental care, while other data suggested otherwise. Pairwise tests controlling for (1) extrapair mating opportunity among males and (2) male, territory and social mate quality revealed a possible trade-off between the mean duration and percentage of time in extraterritorial foray versus providing parental care. Conversely, results also revealed (1) no difference in foray rate, foray duration or percentage of time spent off territory over the various stages of the breeding season, (2) no relationship between male foray effort and male feeding rate, and (3) no difference in foray rate in pairwise comparisons, controlling for variability in extrapair mating opportunity and male quality. Overall, the trade-off between providing male parental care and pursuing alternative mating tactics may not be as strong for male hooded warblers as once hypothesized because males dedicated relatively little time to seeking extrapair copulations off territory. Copyright 2000 The Association for the Study of Animal Behaviour.
在许多鸣禽物种中，配偶外父权现象很常见，但很少有研究对雄性越界外出行为（ETF）的程度进行量化，并探究其中可能存在的权衡取舍。对雄性而言，一个潜在的重要限制因素是需要提供亲代抚育。当前关于雄性配偶外交配策略的模型提出，雄性在繁殖季节后期会减少越界外出行为，因为它们面临着喂养雏鸟与寻求配偶外交配之间的权衡。然而，缺乏详细的实地研究来检验亲代抚育与雄性越界外出行为之间的权衡。我们使用无线电遥测技术来量化橙顶灶莺（Wilsonia citrina）雄性的越界外出行为程度，以检验广泛认可的预测：（1）相对于其他阶段（即可育期和孵化期），雄性在育雏阶段的外出次数显著减少且时间缩短；（2）雄性越界外出行为程度与亲代抚育行为呈负相关。雄性每小时进行0.87±0.09次外出，平均花费12.2%的时间在领地外活动。结果并不明确；一些数据表明雄性外出行为程度与亲代抚育有关，而其他数据则不然。控制（1）雄性之间的配偶外交配机会以及（2）雄性、领地和社会配偶质量的成对检验表明，在越界外出的平均持续时间和时间百分比与提供亲代抚育之间可能存在权衡。相反，结果还表明：（1）在繁殖季节的各个阶段，外出率、外出持续时间或在领地外花费的时间百分比没有差异；（2）雄性外出行为程度与雄性喂食率之间没有关系；（3）在控制配偶外交配机会和雄性质量变化的成对比较中，外出率没有差异。总体而言，对于橙顶灶莺雄性来说，提供亲代抚育与寻求替代交配策略之间的权衡可能不像曾经假设的那么强烈，因为雄性在领地外寻求配偶外交配的时间相对较少。版权所有2000动物行为研究协会。
