Dobzhansky T, Judson C L, Pavlovsky O
Proc Natl Acad Sci U S A. 1974 May;71(5):1974-6. doi: 10.1073/pnas.71.5.1974.
When tested in Hirsch-Hadler mazes, Drosophila pseudoobscura descended from natural populations is phototactically and geotactically neutral on the average. Decidedly positive and negative populations have been obtained by artificial selection. The behavior is independent of temperature (15-27 degrees ) and age (2-17 days). The flies perceive light as weak as 0.2 lux; from 7 to 3000 lux the behavior difference between positive and negative strains increases little, and perhaps decreases at 8000 lux. A remarkable transformation occurs with red light; the population that is negatively phototactic with shorter wave lengths or with white light becomes photopositive.
在赫希 - 哈德勒迷宫中进行测试时，源自自然种群的拟暗果蝇平均在趋光性和趋地性方面呈中性。通过人工选择已获得明显的正向和负向种群。该行为与温度（15 - 27摄氏度）和年龄（2 - 17天）无关。果蝇能感知低至0.2勒克斯的光；在7至3000勒克斯范围内，正向和负向品系之间的行为差异增加不大，在8000勒克斯时可能会减小。红光会引发显著的转变；对较短波长或白光呈负趋光性的种群会变为正趋光性。
