García-Moro C, Pascual J, Toja D I, Walker P L
Antropología, Facultat de Biología, Universitat de Barcelona, Spain.
Hum Biol. 2000 Aug;72(4):655-74.
The pattern of birth seasonality in California's early Spanish-Mexican colonists between 1769 and 1898 was reconstructed using genealogical data for progeny of 657 marriages. The monthly distribution of the 3,824 births in this sample shows a strong seasonal pattern, with spring and fall peaks (corresponding to peaks in conceptions during July and February) and a low point in October. This seasonal reproductive pattern is the result of a complicated set of interactions among environmental, physiological, and cultural variables. California's strongly developed winter rainfall pattern and the 19th-century agricultural cycle clearly influenced the seasonal pattern of marriages and births in this agrarian society. Several historical processes interacted with these environmental and economic factors to transform the seasonal birth pattern of the early colonists. Through time the birth pattern becomes less variable and the birth maximum shifts from spring to early winter. This appears to be, at least in part, a result of changes in labor patterns and an increase in average parity. These data suggest a multifactorial explanation for birth seasonality, in which the timing of conceptions and births is influenced by both environmental and socioeconomic factors.
利用657桩婚姻后代的家谱数据，重建了1769年至1898年加利福尼亚早期西班牙 - 墨西哥殖民者的出生季节性模式。该样本中3824例出生的月度分布呈现出强烈的季节性模式，春季和秋季为高峰（分别对应7月和2月的受孕高峰），10月为低点。这种季节性生殖模式是环境、生理和文化变量之间一系列复杂相互作用的结果。加利福尼亚州发达的冬季降雨模式和19世纪的农业周期显然影响了这个农业社会的婚姻和出生季节性模式。几个历史进程与这些环境和经济因素相互作用，改变了早期殖民者的季节性出生模式。随着时间的推移，出生模式的变化越来越小，出生高峰从春季转移到初冬。这似乎至少部分是劳动模式变化和平均生育胎次增加的结果。这些数据表明了对出生季节性的多因素解释，即受孕和出生时间受到环境和社会经济因素的影响。
