Interactions of photoperiod, size-rank in the litter, and sex on development, stability and fitness components of the behavioural phenotype

生态和社会条件有可能影响行为表型的个体发生发展。然而，迄今为止，很少有实验工作旨在确定和解开这些对行为表型发展的早期影响。我们选择光周期——作为预期生态条件的预测因子——和窝中兄弟姐妹的相互作用作为可能影响广泛物种行为表型发展的因素。我们已经证明，正如预期的那样，光周期强烈地影响了洞穴（Cavia aperea）行为表型的发展，尽管这种影响可能是可逆的。现在，我们将通过配对错配实验来研究由此产生的适应性效应，我们将实验室中在人工春季光周期下饲养的动物置于室外相同或秋季光周期中，反之亦然。除了光周期外，我们还发现窝仔的大小等级和性别对决定行为表型也有影响。这种兄弟姐妹效应在动物（和人类）中广为人知，但很少进行实验研究。我们现在建议通过交叉培养实验来研究这些影响。我们会将一窝中最大或较小的幼崽交换给其他幼崽，通过这种方式，这些幼崽要么发现自己与原窝中相同的大小等级，要么在其他位置，并确定这如何影响它们行为表型的发展。这些实验将使我们能够解开光周期、窝中大小等级和性别之间的相互作用如何影响发育中的行为表型。此外，这些实验应该使我们能够评估母系和遗传效应对发育中的行为表型的影响。通过与晚育田鼠的数据比较，我们希望更好地了解不同亲代养育模式对幼鼠生活史和行为表型的影响。为了将这些研究的发现纳入一个总体框架，我们计划对环境和社会因素与行为表型发展之间的联系和相互作用进行建模。通过这种方式，我们的研究将为行为表型的个体发生、稳定性和适应性贡献大量知识。

Ecological and social conditions have the potential to influence the ontogenetic development of behavioural phenotypes. However, there has so far been little experimental work aiming at determining and disentangling these early influences on the development of behavioural phenotypes. We chose photoperiod - as a predictor of expected ecological conditions - and sibling interactions within a litter as factors that are likely to influence the development of behavioural phenotypes in a wide spectrum of species. We have shown that photoperiod, as expected, strongly influences the development of behavioural phenotypes in cavies (Cavia aperea), even though the effects may be reversible. We will now study the resulting fitness effects through match-mismatch experiments where we place animals, reared under an artificial spring photoperiod in the lab, into the same or into an autumn photoperiod outdoors and vice versa with animals reared under autumn conditions. Besides photoperiod, we found size-rank in the litter and sex also influential in determining behavioural phenotypes. Such sibling effects are widely known among animals (and humans), but have hardly been studied experimentally. We now suggest to investigate these influences through cross-fostering experiments. We will exchange the largest or smaller pups in a litter to other litters in such a way that these pups either find themselves in the same size-rank as in their litter of origin or in the other position and will determine how this influences the development of their behavioural phenotypes. These experiments will enable us to disentangle how the interactions between photoperiod, size-rank in litter, and sex contribute to the developing behavioural phenotype. Additionally, these experiments should enable us to assess the influence of maternal and genetic effects on the developing behavioural phenotype. Through comparison of our data with those on altricial voles we expect to get a better understanding of the effects of different parental care patterns on the life history and behavioural phenotypes of young. To put the findings of these studies into a general framework we plan to model the connections and interactions between environmental and social factors and the development of behavioural phenotypes. In this way, our study will contribute substantial knowledge to the ontogenetic emergence of behavioural phenotypes, their stability and adaptiveness.