Soravia Camilla, Bisazza Angelo, Cecere Jacopo G, Rubolini Diego
Centre for Evolutionary Biology (M092), University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia.
Department of General Psychology, University of Padova, via Venezia 8, Padova I-35131, Italy.
Curr Zool. 2022 Mar 24;69(1):66-75. doi: 10.1093/cz/zoac021. eCollection 2023 Feb.
Costs and benefits of brain lateralization may depend on environmental conditions. Growing evidence indicates that the development of brain functional asymmetries is adaptively shaped by the environmental conditions experienced during early life. Food availability early in life could act as a proxy of the environmental conditions encountered during adulthood, but its potential modulatory effect on lateralization has received little attention. We increased food supply from egg laying to early nestling rearing in a wild population of lesser kestrels , a sexually dimorphic raptor, and quantified the lateralization of preening behavior (head turning direction). As more lateralized individuals may perform better in highly competitive contexts, we expected that extra food provisioning, by reducing the level of intra-brood competition for food, would reduce the strength of lateralization. We found that extra food provisioning improved nestling growth, but it did not significantly affect the strength or direction of nestling lateralization. In addition, maternal body condition did not explain variation in nestling lateralization. Independently of extra food provisioning, the direction of lateralization differed between the sexes, with female nestlings turning more often toward their right. Our findings indicate that early food availability does not modulate behavioral lateralization in a motor task, suggesting limited phenotypic plasticity in this trait.
大脑偏侧化的成本和收益可能取决于环境条件。越来越多的证据表明，大脑功能不对称的发展是由生命早期所经历的环境条件适应性塑造的。生命早期的食物可获得性可以作为成年期所遇到的环境条件的一个指标，但其对偏侧化的潜在调节作用却很少受到关注。我们增加了对野生种群红脚隼（一种两性异形的猛禽）从产卵到雏鸟早期饲养阶段的食物供应，并对其理毛行为（头部转动方向）的偏侧化进行了量化。由于偏侧化程度更高的个体在高度竞争的环境中可能表现得更好，我们预计额外提供食物，通过降低雏鸟间对食物的竞争水平，会降低偏侧化的程度。我们发现额外提供食物促进了雏鸟的生长，但并没有显著影响雏鸟偏侧化的程度或方向。此外，母体身体状况并不能解释雏鸟偏侧化的差异。与额外提供食物无关，偏侧化的方向在两性之间存在差异，雌性雏鸟更频繁地向右侧转头。我们的研究结果表明，生命早期的食物可获得性并不会调节运动任务中的行为偏侧化，这表明该性状的表型可塑性有限。
