Universidad Veracruzana, Xalapa, Mexico.
Physiol Behav. 2011 Oct 24;104(5):778-85. doi: 10.1016/j.physbeh.2011.07.019. Epub 2011 Jul 23.
Many aspects of an animal's early development might potentially contribute to long-term individual differences in physiology and behavior. Here we asked whether differences among littermates of the domestic rabbit in the position in the litter huddle that they occupy during the early nest period might contribute to the development of distinct behavioral and physiological phenotypes. In each of 12 litters we determined the pup occupying the most peripheral, the most central, and an intermediate position in the huddle during the first postnatal week. We then tested the responses of these same individuals as nestlings, juveniles and young adults when confronted by a range of age-appropriate environmental challenges. Two behavioral tests appeared particularly discriminatory in identifying differences associated with early position in the huddle; latency of pre-weaning pups to jump down from a shelf, and the response of young adults to the fearful screams of a conspecific. In both cases animals that had occupied the periphery of the huddle showed behavioral responses indicative of a more proactive behavioral style than their "intermediate" or "central" littermates. We conclude that while consistent long-term differences in behavioral style associated with early position in the litter huddle exist in rabbits, future work is needed to confirm the causal nature of this association, to identify underlying mechanisms, and to refine methods of behavioral and physiological testing across the life span.
许多动物早期发育的方面可能会对其生理和行为的长期个体差异产生潜在影响。在这里，我们询问了家兔同窝仔兔在早期巢穴期所占据的巢穴堆位置的差异是否会导致不同的行为和生理表型的发展。在每 12 窝中，我们确定了在出生后的第一周内占据巢穴堆最外围、最中心和中间位置的幼崽。然后，当这些幼崽处于巢中、幼年期和年轻成长期时，我们用一系列适合年龄的环境挑战来测试它们的反应。两个行为测试在识别与早期巢穴位置相关的差异方面显得特别有区分度；未断奶幼崽从架子上跳下的潜伏期，以及年轻成体对同种动物恐惧尖叫的反应。在这两种情况下，占据巢穴堆外围的动物表现出的行为反应表明它们具有比“中间”或“中心”窝仔更积极主动的行为风格。我们得出结论，尽管家兔在早期巢穴堆位置上存在一致的长期行为风格差异，但仍需要进一步研究来确认这种关联的因果性质，确定潜在机制，并改进整个生命周期的行为和生理测试方法。
