Facultatively social animals adaptively match social strategy to environmental context; as such, they offer unique insights into the ecological factors facilitating social evolution. We investigated temporal (seasonal) and spatial (nest architectural) factors governing flexible social behavior in the carpenter bee Xylocopa varipuncta Patton using repeated, non-destructive computerized tomography scans of nesting logs. We tested the hypothesis that group living is mediated by environmental factors, specifically ecological constraints and phenological parameters. These imaging data support a facultative social organization strongly influenced by seasonal shifts in life-history strategy. Our results also illuminate patterns of structural change associated with nest inheritance and eventual nest abandonment. This dynamic use of space mediates the within-nest interactions that determine social organization. Furthermore, constraints on the usefulness of inherited nest structures compound an existing limitation on nest sites that may underlie the origins of this flexible social strategy. These findings emphasize the importance of including spatial dynamics in considerations of the ecological contexts in which sociality evolved.

中文翻译：

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CT成像揭示的木蜂社会性的时空动态

兼性社会动物适应性地将社会策略与环境背景相匹配；因此，它们为促进社会进化的生态因素提供了独特的见解。我们使用重复的、非破坏性的计算机断层扫描对筑巢原木进行了重复、无损的计算机断层扫描，研究了控制木蜂 Xylocopa varipuncta Patton 灵活社会行为的时间（季节性）和空间（巢建筑）因素。我们检验了群体生活是由环境因素介导的假设，特别是生态约束和物候参数。这些影像数据支持兼性社会组织受到生活史策略季节性变化的强烈影响。我们的结果还阐明了与巢穴继承和最终巢穴遗弃相关的结构变化模式。这种空间的动态使用调节了决定社会组织的巢内互动。此外，对遗传巢穴结构有用性的限制加剧了对巢穴地点的现有限制，这可能是这种灵活社会策略起源的基础。这些发现强调了将空间动态纳入考虑社会发展的生态环境的重要性。