Dixon Luke, Kuster Ryan, Rueppell Olav
Department of Biology, University of North Carolina at Greensboro, 1000 Spring Garden Street, 312 Eberhart Building, Greensboro, NC, 27403, USA.
Age (Dordr). 2014 Feb;36(1):89-101. doi: 10.1007/s11357-013-9546-7. Epub 2013 Jun 14.
While a negative correlation between reproduction and life span is commonly observed, specialized reproductive individuals outlive their non-reproductive nestmates in all eusocial species, including the honeybee, Apis mellifera (L). The consequences of reproduction for individual life expectancy can be studied directly by comparing reproductive and non-reproductive workers. We quantified the life span consequences of reproduction in honeybee workers by removal of the queen to trigger worker reproduction. Furthermore, we observed the social behavior of large cohorts of workers under experimental and control conditions to test for associations with individual life expectancy. Worker life expectancy was moderately increased by queen removal. Queenless colonies contained a few long-lived workers, and oviposition behavior was associated with a strong reduction in mortality risk, indicating that a reproductive role confers a significant survival advantage. This finding is further substantiated by an association between brood care behavior and worker longevity that depends on the social environment. In contrast, other in-hive activities, such as fanning, trophallaxis, and allogrooming did not consistently affect worker life expectancy. The influence of foraging varied among replicates. An earlier age of transitioning from in-hive tasks to outside foraging was always associated with shorter life spans, in accordance with previous studies. In sum, our studies quantify how individual mortality is affected by particular social roles and colony environments and demonstrate interactions between the two. The exceptional, positive association between reproduction and longevity in honeybees extends to within-caste plasticity, which may be exploited for mechanistic studies.
虽然繁殖与寿命之间通常呈负相关，但在所有群居昆虫物种中，包括蜜蜂（西方蜜蜂），专门负责繁殖的个体比不繁殖的同巢伙伴寿命更长。通过比较繁殖型和非繁殖型工蜂，可以直接研究繁殖对个体预期寿命的影响。我们通过移除蜂王来触发工蜂繁殖，从而量化了蜜蜂工蜂繁殖对寿命的影响。此外，我们在实验和对照条件下观察了大量工蜂群体的社会行为，以测试其与个体预期寿命的关联。移除蜂王适度延长了工蜂的寿命。无王蜂群中有一些长寿工蜂，产卵行为与死亡风险的大幅降低有关，这表明繁殖角色赋予了显著的生存优势。育雏行为与工蜂寿命之间的关联进一步证实了这一发现，这种关联取决于社会环境。相比之下，其他蜂巢内活动，如扇风、交哺和互理，并没有始终如一地影响工蜂的预期寿命。觅食的影响在不同重复实验中有所不同。与之前的研究一致，从蜂巢内任务过渡到外出觅食的年龄越早，寿命总是越短。总之，我们的研究量化了特定社会角色和蜂群环境如何影响个体死亡率，并证明了两者之间的相互作用。蜜蜂繁殖与长寿之间这种特殊的正相关关系延伸到了种内可塑性，这可能被用于机制研究。
