Data from: Pervasive indirect genetic effects on behavioral development in polymorphic eastern mosquitofish

The social environment can dramatically influence development and expression of individual behavior. Indirect genetic effects (IGE) arise when variation in the social environment depend on genotypic differences among social partners. Their role in generating variation and in influencing evolutionary dynamics has become increasingly recognized in recent years, but less attention has been paid to how indirect genetic effects arise during development. Here, we measure IGE during development using a discrete natural polymorphism in male coloration and associated behaviors in eastern mosquitofish (Gambusia holbrooki). The experiment revealed substantial IGE and direct genetic effects on behavior. For some behaviors, IGE changed and even reversed direction over the 16 weeks of the experiment, indicating important developmental dynamics. Interaction between IGE and direct genetic effects for some behaviors indicated that melanistic males were less responsive to a genetic change in their social environment than were non-melanistic males, suggesting that melanistic males were relatively inflexible in their behavior. Alternately, social partners might vary less in the behavior they direct toward these males. The color morphs differed in mating behavior and in the amount of aggressive behavior they received from their social partners, but not in direct measures of aggression. These results imply that even apparently innate differences between color morphs in behavior could arise as indirect effects of differences in behavior of social partners toward them. Deducing the developmental and social origins of these indirect effects is necessary to understand the maintenance of morphological and behavioral polymorphisms in the many species in which they occur.

社会环境可显著影响个体行为的发育与表达。当社会环境的变异源于社会伙伴间的基因型差异时，便会产生间接遗传效应（Indirect Genetic Effects, IGE）。近年来，间接遗传效应在产生变异及影响进化动态方面的作用已日益得到学界认可，但针对其在发育过程中如何产生的研究却相对匮乏。本研究以东部食蚊鱼（Gambusia holbrooki）雄性体色的离散自然多态性及其关联行为为研究对象，对发育过程中的间接遗传效应进行量化分析。实验结果显示，间接遗传效应与直接遗传效应对行为均存在显著影响。针对部分行为，在为期16周的实验过程中，间接遗传效应的作用方向甚至发生了改变与逆转，这表明发育动态具有重要意义。部分行为的间接遗传效应与直接遗传效应间存在交互作用，结果表明黑化型雄性对其社会环境中基因型变化的响应程度弱于非黑化型雄性，提示黑化型雄性的行为相对缺乏灵活性；另一方面，社会伙伴对这类雄性所表现出的行为差异可能更小。不同体色形态的雄性在交配行为以及从社会伙伴处获得的攻击行为频次上存在差异，但直接攻击行为的测量结果并无不同。上述结果表明，即便体色形态间看似先天存在的行为差异，也可能源于社会伙伴对其行为差异所产生的间接效应。要理解众多物种中形态与行为多态性的维持机制，就必须阐明这些间接效应的发育与社会起源。