Data from: Functional traits in red flour beetles: the dispersal phenotype is associated with leg length but not body size nor metabolic rate

1. Individuals vary in their ability to disperse. Much of this variation can be described by covarying phenotypic traits that are related to dispersal (constituting the ‘dispersal phenotype’ or ‘dispersal syndrome’), but the nature of the associations among these traits is not well understood. Unravelling the associations among traits that potentially constitute the dispersal phenotype provides a foundation for understanding evolutionary trade-offs due to variation in dispersal. 2. Here, we tested five predictions pertaining to the relationships among physiological, morphological and movement traits that are associated with dispersal, using a species with a long history as a laboratory model for studying ecological phenomena, red flour beetles (Tribolium castaneum). 3. We identified a dominant axis of movement ability that describes variation in dispersal-related movement traits. Individuals that scored positively on this axis moved at higher speed, travelled longer distances, had lower movement intermittency and dispersed quicker to a specified area. 4. Relative leg length, but not body size nor routine metabolic rate related positively with movement ability, indicating a likely mechanistic relationship between increased stride length and movement ability. 5. Our data suggest that the dispersal phenotype may be more strongly linked to morphological traits than physiological ones. We demonstrate that associations among many functional traits do not necessarily conform to a priori expectations, and predict that the substantial intraspecific variation in trait values may be important for selection. Movement is a complex behavioural trait, but it has a mechanistic basis in locomotor morphology that warrants further exploration.

1. 个体的扩散能力存在显著个体差异。此类差异大多可通过与扩散相关的共变表型性状进行描述，这类性状共同构成了扩散表型（dispersal phenotype）或扩散综合征（dispersal syndrome），但目前学界对这些性状间的关联本质尚缺乏充分了解。阐明潜在构成扩散表型的各性状间的关联，可为理解由扩散变异引发的进化权衡提供坚实的理论基础。
2. 本研究以长期作为生态学研究实验室模型物种的赤拟谷盗（Tribolium castaneum）为研究对象，针对与扩散相关的生理、形态及运动性状间的关联提出五项预测并开展检验。
3. 我们鉴定出一条主导性的运动能力轴，可用于阐释与扩散相关的运动性状变异。在该轴上得分较高的个体，运动速度更快、移动距离更长、运动间歇性更低，且能更快抵达指定区域。
4. 相对腿长与运动能力呈显著正相关，而体型大小与常规代谢率则无此关联，这提示步长增加与运动能力提升之间可能存在机械机制层面的关联。
5. 本研究数据表明，扩散表型与形态性状的关联可能较其与生理性状的关联更为紧密。我们的研究结果显示，诸多功能性状间的关联未必符合先验预期，并推测性状值存在的显著种内变异可能对选择作用具有重要意义。运动是一项复杂的行为性状，但其运动形态学层面存在机械基础，这一研究方向值得开展进一步探索。