Nest-box temperature affects clutch size, incubation initiation, and nestling health in great tits

Prenatal maternal effects can be a source of phenotypic plasticity and may play a role in adaptation to climate change. However, we do not know how far temperature could influence such effects, if at all. We studied the influence of temperature during egg laying on maternal reproductive investment and on the phenotype of adult females, adult males, and nestlings. We expected temperature to have an effect, as it influences maintenance costs for females, who can also use it as a cue of the advancement of the breeding season. We experimentally increased night-time nest-box temperatures by approximately 1 °C throughout the entire laying period in great tits (Parus major). Clutch size was negatively correlated with laying date in heated females. Heated females did not delay incubation after clutch completion as frequently as control females did. Finally, blood sedimentation rate, which is an indicator of acute infections and inflammatory diseases, was positively correlated with hatching date...

产前母体效应（Prenatal maternal effects）可作为表型可塑性（phenotypic plasticity）的来源之一，并可能在气候变化适应中发挥作用。然而，温度（即便存在影响的话）能在多大程度上作用于此类效应，目前尚不清楚。本研究探讨了产卵期（egg laying）温度对母体繁殖投入（maternal reproductive investment）及成年雌鸟、成年雄鸟和雏鸟（nestlings）表型（phenotype）的影响。我们推测温度会产生影响，因其不仅会改变雌鸟的维护成本（maintenance costs），还可被雌鸟用作繁殖季节（breeding season）提前的信号。我们以大山雀（Parus major）为研究对象，在整个产卵期通过实验将其巢箱夜间温度提升约1℃。受热处理的雌鸟中，窝卵数（clutch size）与产卵日期（laying date）呈负相关。受热雌鸟在窝卵完成后推迟孵化（incubation）的频率低于对照雌鸟。最后，作为急性感染和炎症性疾病指标的血沉率（blood sedimentation rate）与孵化日期（hatching date）呈正相关...