Peto Blanca R, Costa Claudinéia P, Moore Meghan E, Woodard S Hollis
Department of Entomology, University of California, Riverside, Riverside, CA, USA.
BMC Ecol Evol. 2025 Apr 9;25(1):30. doi: 10.1186/s12862-025-02364-0.
Evolution has shaped diverse reproductive investment strategies, with some organisms integrating environmental cues into their reproductive decisions. In animal societies, social cues can further influence reproductive decisions in ways that might support the survival and success of the social group. Bumble bees are a lineage of eusocial insects wherein queens initiate nests independently. Bumble bee queens enter their eusocial phase only after successfully rearing their first offspring and thereafter exhibit an increased rate of egg-laying. We tested the idea that during bumble bee nest initiation, queen reproduction is socially context-dependent and under the control of social conditions in the nest.
Our findings reveal that in the bumble bee Bombus impatiens, queen egg-laying follows a dynamic, stereotypical pattern and is also heavily influenced by social group members. During the initial stages of nest initiation, accelerated egg-laying in queens is associated with the presence of workers or older larvae and pupae. Moreover, workers are required for queens to maintain increased levels of egg laying across the nest initiation stage. We also confirmed a previously-described pattern where queens temporarily decelerate egg-laying early in nest-founding, only to increase it again when the first adult workers are soon to emerge. This "pause" in egg-laying was observed in all B. impatiens queens as well as in additional species examined.
Our results support the idea that eusocial systems can employ socially context-dependent control of queen egg-laying as a reproductive strategy. In some solitary-founding lineages, including bumble bees, queens may reach their full reproductive potential only after the emergence of the first adult workers, who then take over brood care. This stands in contrast to the hyper-reproductivity observed in some eusocial species. The presence of workers and older brood (who will soon eclose) not only alleviates queen brood care responsibilities but may also provide signals that cause queens to increase their reproductive output. These phenomena may allow queens to adapt their reproductive output to the conditions of the colony. Broadly, these findings highlight the dynamic interplay between social conditions and reproduction in bumble bees.
进化塑造了多样的繁殖投资策略，一些生物会将环境线索纳入其繁殖决策中。在动物群体中，社会线索能够以可能支持社会群体生存与成功的方式进一步影响繁殖决策。大黄蜂是一类群居性昆虫，其中蜂后独立建立巢穴。大黄蜂蜂后只有在成功养育出第一批后代后才进入群居阶段，此后产卵率会增加。我们检验了这样一种观点，即在大黄蜂筑巢初期，蜂后的繁殖受到社会环境的影响，并受巢内社会条件的控制。
我们的研究结果表明，在美洲大蜂螨（Bombus impatiens）中，蜂后的产卵遵循一种动态的、刻板的模式，并且也受到社会群体成员的严重影响。在筑巢的初始阶段，蜂后加速产卵与工蜂或大龄幼虫及蛹的存在有关。此外，在整个筑巢阶段，蜂后需要工蜂来维持较高的产卵水平。我们还证实了之前描述的一种模式，即蜂后在筑巢初期会暂时减缓产卵，而当第一批成年工蜂即将出现时又会再次增加产卵。在所有美洲大蜂螨蜂后以及其他所研究的物种中都观察到了这种产卵“暂停”现象。
我们的结果支持了这样一种观点，即群居系统可以采用依赖社会环境的蜂后产卵控制作为一种繁殖策略。在一些独自筑巢的谱系中，包括大黄蜂，蜂后可能只有在第一批成年工蜂出现后才达到其全部繁殖潜力，然后工蜂接管育雏工作。这与一些群居物种中观察到的超高繁殖力形成对比。工蜂和大龄幼虫（即将羽化）的存在不仅减轻了蜂后的育雏责任，还可能提供信号促使蜂后增加其繁殖产量。这些现象可能使蜂后能够根据蜂群的状况调整其繁殖产量。总体而言，这些发现突出了大黄蜂社会条件与繁殖之间的动态相互作用。
