Kauppi Jenni J, Chapman Simon N, Pettay Jenni E, Lahdenperä Mirkka, Lummaa Virpi, Loehr John
Department of Biology, University of Turku, 20014 Turku, Finland.
INVEST Flagship Research Centre, University of Turku, 20014 Turku, Finland.
Evol Hum Sci. 2023 Jun 8;5:e21. doi: 10.1017/ehs.2023.16. eCollection 2023.
Dispersal does not only mean moving from one environment to another, but can also refer to shifting from one social group to another. Individual characteristics such as sex, age and family structure might influence an individual's propensity to disperse. In this study, we use a unique dataset of an evacuated World War II Finnish population, to test how sex, age, number of siblings and birth order influence an individual's dispersal away from their own social group at a time when society was rapidly changing. We found that young women dispersed more than young men, but the difference decreased with age. This suggests that young men might benefit more from staying near a familiar social group, whereas young women could benefit more from moving elsewhere to find work or spouses. We also found that having more younger brothers increased the propensity for firstborns to disperse more than for laterborns, indicating that younger brothers might pressure firstborn individuals into leaving. However, sisters did not have the same effect as brothers. Overall, the results show that individual characteristics are important in understanding dispersal behaviour, but environmental properties such as social structure and the period of flux after World War II might upend the standard predictions concerning residence and dispersal. Individual characteristics influence dispersal away from social group after a forced migration in a Finnish population.
分散不仅意味着从一个环境迁移到另一个环境，还可以指从一个社会群体转移到另一个社会群体。诸如性别、年龄和家庭结构等个体特征可能会影响个体的分散倾向。在本研究中，我们使用了一个独特的数据集，该数据集来自二战期间疏散的芬兰人口，以测试性别、年龄、兄弟姐妹数量和出生顺序如何在社会迅速变化的时期影响个体离开自己社会群体的分散行为。我们发现年轻女性比年轻男性分散得更多，但这种差异随着年龄的增长而减小。这表明年轻男性可能从留在熟悉的社会群体附近中受益更多，而年轻女性可能从搬到其他地方寻找工作或配偶中受益更多。我们还发现，有更多弟弟会增加长子比次子分散的倾向，这表明弟弟可能会迫使长子离开。然而，姐妹并没有和兄弟产生同样的效果。总体而言，结果表明个体特征在理解分散行为方面很重要，但诸如社会结构和二战后的动荡时期等环境因素可能会颠覆有关居住和分散的标准预测。在芬兰人口的一次被迫迁移后，个体特征影响了从社会群体中的分散。
