Data from: A Bayesian approach to social structure uncovers cryptic regulation of group dynamics in Drosophila melanogaster

Understanding the mechanisms that give rise to social structure is central to predicting the evolutionary and ecological outcomes of social interactions. Modeling this process is challenging, because all individuals simultaneously behave in ways that shape their social environments—a process called Social Niche Construction [SNC]. In previous work we demonstrated that aggression acts as an SNC trait in fruit flies (Drosophila melanogaster), but the mechanisms of that process remained cryptic. Here, we analyze how individual social group preferences generate overall social structure. We use a combination of agent-based simulation [ABS] and Approximate Bayesian Computation [ABC] to fit models to empirical data. We confirm that genetic variation in aggressive behavior influences social group structure. Furthermore, we find that female "decamping" due to male behavior may play an under-appreciated role in structuring social groups. Male-male aggression may sometimes destabilize groups, but may also be an SNC behavior for shaping desirable groups for females. Density intensifies female social preferences, thus the role of female behavior in shaping group structure may become more important at high densities. Our ability to model the ontogeny of group structure demonstrates the utility of the Bayesian model-based approach in social behavioral studies.

解析催生社会结构的内在机制，是预测社会互动进化与生态结局的核心要务。对该过程开展建模颇具挑战，原因在于所有个体均会同时以塑造自身社会环境的方式开展行为——这一过程被称为社会生态位构建（Social Niche Construction, SNC）。在既往研究中，我们已证实攻击行为在黑腹果蝇（*Drosophila melanogaster*）中属于一类社会生态位构建性状，但该过程的具体机制仍晦暗不明。本文中，我们针对个体社会群体偏好如何塑造整体社会结构展开分析。我们结合基于智能体的模拟（Agent-Based Simulation, ABS）与近似贝叶斯计算（Approximate Bayesian Computation, ABC），将模型拟合至实证数据。我们证实，攻击行为的遗传变异会对社会群体结构产生显著影响。此外，我们发现雌性因雄性行为而发生的“弃迁”现象，可能在群体结构塑造中发挥了此前被低估的重要作用。雄性间的攻击行为有时可能会破坏群体稳定性，但同时也可作为一种社会生态位构建行为，为雌性塑造更适宜的群体。种群密度会强化雌性的社会偏好，因此在高密度种群环境下，雌性行为对群体结构塑造的作用可能更为突出。我们能够对群体结构的个体发生过程进行建模，这一成果证明了基于贝叶斯模型的研究方法在社会行为学研究中的应用价值。