Data from: Kin discrimination increases with odor distance in the German cockroach

Kin recognition mediates altruistic behavior and inbreeding avoidance in many animal societies. So far, evidence for accurate kin recognition, when individuals distinguish fine scale differences in genetic relatedness, in social insects is mixed. Although this ability should be counter selected to reduce risks of nepotism in eusocial colonies, accurate kin recognition may be beneficial in less integrated societies where genetic conflicts are reduced. Here we show that gregarious cockroaches Blattella germanica discriminate multiple levels of relatedness and identify inherited cuticular odors as potential kin recognition cues. When given a choice between aggregation sites containing either full siblings or less related conspecifics, cockroaches showed an increasing preference for resting with full siblings with increasing genetic distance between stimuli groups, from 50% of choices in the presence of half siblings or cousins, to 60.7% with less related cockroaches from the same strain, and 72.9% with cockroaches from a different strain. Examination of the cuticular hydrocarbon profiles of 288 nymphs and their 54 parents revealed that the chemical distance between cockroaches was negatively correlated to their relatedness. Using a Bayesian animal model approach for quantitative genetic analyses, we identified several highly heritable methyl-branched alkanes as good candidates for kin recognition cues. Our results suggest that kin recognition is based on genetically inherited odors in this gregarious insect and highlight mechanistic similarities with nestmate recognition in eusocial species.亲缘识别（kin recognition）介导了诸多动物社会中的利他行为（altruistic behavior）与近交回避（inbreeding avoidance）。迄今为止，关于社会性昆虫中存在能够精准区分遗传亲缘关系细微差异的精准亲缘识别的相关证据仍莫衷一是。尽管在真社会性（eusocial）蚁群中，该识别能力本应因降低裙带关系风险而遭到反选择，但在遗传冲突得以缓解的低度整合社会中，精准亲缘识别或许反而具备优势。本研究证实，群居性德国小蠊（Blattella germanica）能够区分多个层级的亲缘关系，并确定可遗传的表皮气味（cuticular odors）为潜在的亲缘识别线索（kin recognition cues）。当在分别包含全同胞与远缘同种个体的聚集位点间开展选择实验时，随着刺激组间遗传距离的增加，德国小蠊对与全同胞共处的偏好逐渐提升：当刺激组为半同胞或表亲时，全同胞选择占比为50%；同品系远缘个体组占比达60.7%；不同品系个体组则达到72.9%。通过对288只若虫（nymphs）及其54只亲本的表皮碳氢化合物谱（cuticular hydrocarbon profiles）进行分析，研究发现德国小蠊个体间的化学距离与亲缘关系呈负相关。借助贝叶斯动物模型（Bayesian animal model）开展数量遗传分析（quantitative genetic analyses），本研究鉴定出数种高遗传力的甲基支链烷烃（methyl-branched alkanes），可作为亲缘识别线索的优质候选物。本研究结果表明，这种群居昆虫的亲缘识别基于可遗传的气味信号，并揭示了其与真社会性物种的巢友识别（nestmate recognition）机制存在相似性。