Direct and indirect genetic effects in life history traits of flour beetles (Tribolium castaneum)

Indirect genetic effects (IGEs) are the basis of social interactions among conspecifics, and can affect genetic variation of non-social as well as social traits. We used flour beetles (Tribolium castaneum) of two phenotypically distinguishable populations to estimate genetic (co)variances and the effect of IGEs on three life-history traits: development time (DT), growth rate (GR), and pupal body mass (BM). We found that GR was strongly affected by social environment with IGEs accounting for 18% of the heritable variation. We also discovered a sex-specific social effect: male ratio in a group significantly affected both GR and BM. That is, beetles grew larger and faster in male-biased social environments. Such sex-specific IGEs have not previously been demonstrated in a non-social insect. Our results show that beetles that achieve a higher BM do so via a slower GR in response to social environment. Existing models of evolution in age-structured or stage-structured populations do not acco...间接遗传效应（Indirect genetic effects, IGEs）是同种个体间社会互动的基础，可同时影响非社会性状与社会性状的遗传变异。我们以两个表型可区分种群的赤拟谷盗（Tribolium castaneum）为实验对象，估算了遗传（共）方差以及间接遗传效应对3种生活史性状的影响：发育时间（development time, DT）、生长速率（growth rate, GR）与蛹体质量（pupal body mass, BM）。我们发现，生长速率显著受社会环境调控，间接遗传效应可解释18%的可遗传变异。我们还发现了性别特异性社会效应：种群内的雄性比例可显著影响生长速率与蛹体质量。换言之，在雄性占比偏高的社会环境中，甲虫的体型更大、生长速度更快。此类性别特异性间接遗传效应此前尚未在非社会性昆虫中被证实。我们的研究结果显示，能够获得更高蛹体质量的甲虫，会通过减缓生长速率来响应社会环境。现有针对年龄结构或阶段结构种群的进化模型尚未考虑……