Data from: Different ultimate factors define timing of breeding in two related species

Correct reproductive timing is crucial for fitness. Breeding phenology even in similar species can differ due to different selective pressures on the timing of reproduction. These selection pressures define species’ responses to warming springs. The temporal match-mismatch hypothesis suggests that timing of breeding in animals is selected to match with food availability (synchrony). Alternatively, time-dependent breeding success (the date hypothesis) can result from other seasonally deteriorating ecological conditions such as intra- or interspecific competition or predation. We studied the effects of two ultimate factors on the timing of breeding, synchrony and other time-dependent factors (time-dependence), in sympatric populations of two related forest-dwelling passerine species, the great tit (Parus major) and the willow tit (Poecile montanus) by modelling recruitment with long-term capture-recapture data. We hypothesized that these two factors have different relevance for fitness in these species. We found that local recruitment in both species showed quadratic relationships with both time-dependence and synchrony. However, the importance of these factors was markedly different between the studied species. Caterpillar food played a predominant role in predicting the timing of breeding of the great tit. In contrast, for the willow tit time-dependence modelled as timing in relation to conspecifics was more important for local recruitment than synchrony. High caterpillar biomass experienced during the pre- and post-fledging periods increased local recruitment of both species. These contrasting results confirm that these species experience different selective pressures upon the timing of breeding, and hence responses to climate change may differ. Detailed information about life-history strategies is required to understand the effects of climate change, even in closely related taxa. The temporal match-mismatch hypothesis should be extended to consider subsequent critical periods when food needs to be abundantly available.精准的繁殖时机对个体适合度至关重要。即便亲缘关系相近的物种，其繁殖物候也可能因繁殖时机所承受的选择压力不同而存在差异。这些选择压力决定了物种对春季变暖的响应模式。时间匹配-失配假说（temporal match-mismatch hypothesis）指出，动物的繁殖时机会被自然选择塑造为与食物可获得性相匹配（即同步性）。与之相对，依时间变化的繁殖成功率（即日期假说，the date hypothesis）则可由其他随季节恶化的生态条件导致，例如种内/种间竞争或捕食作用。本研究以两种亲缘关系相近的林栖雀形目鸟类——大山雀（Parus major）和沼泽山雀（Poecile montanus）的同域种群为研究对象，通过长期标记重捕数据构建招募模型，探究了繁殖时机的两个终极影响因素：同步性与其他依时间变化的因素（即时间依赖性）。我们提出假说：这两个因素对这两个物种的适合度具有不同的影响权重。研究结果显示，两个物种的局部招募率均与时间依赖性和同步性呈二次相关关系。但这两个因素的重要性在两个物种间存在显著差异。鳞翅目幼虫食物资源是预测大山雀繁殖时机的主导因素。与之相反，对于沼泽山雀而言，以同种个体繁殖时机为参照的时间依赖性，对局部招募率的影响程度要高于同步性。在雏鸟出飞前及出飞后阶段遭遇的高鳞翅目幼虫生物量，均提升了两个物种的局部招募率。这些相悖的研究结果证实，这两个物种在繁殖时机上所承受的选择压力存在差异，因此它们对气候变化的响应模式也可能有所不同。即便对于亲缘关系相近的类群，要理解气候变化的影响，也需要掌握其详细的生活史策略信息。时间匹配-失配假说应当得到拓展，以纳入食物需要充足供应的后续关键时期。