Abstract

The courtship song of male Drosophila melanogaster is generated by wing vibration and contains an interpulse interval (IPI) which is species-specific and usually falls in the mean range of 30–40 ms. The IPI is extremely temperature-sensitive, so we wondered whether flies collected along the eastern coast of Australia between latitudes 16.9°S and 42.9°S might have adapted to the different thermal conditions and show differences in mean IPI. We observe a significant correlation between IPI and latitude in addition to the well-known association between latitude and body size (Bergmannn’s Rule). However, somewhat surprisingly we could not detect a significant association between body size and IPI. We also examined flies collected from the North and South-facing slopes of ‘Evolution Canyon’ in Israel and observed differences in IPI that support the view that thermal adaptation can shape this important song character. We also examined the songs of flies from Kenya and observed no correlation between altitude of collection and IPI. In all three experiments, body size did not correlate with IPI. A global analysis of all three sets of populations on three continents revealed a strong association between IPI and latitude. We speculate that IPI is shaped by thermal and sexual selection whereas body size is also shaped by natural selection.

摘要

雄性黑腹果蝇求爱歌由机翼振动产生，包含一个特定于物种的脉冲间隔 (IPI)，通常在 30-40 毫秒的平均范围内。IPI 对温度极为敏感，因此我们想知道在澳大利亚东海岸在 16.9°S 和 42.9°S 之间收集的苍蝇是否可能已经适应了不同的热条件并显示出平均 IPI 的差异。除了众所周知的纬度和体型之间的关联（伯格曼法则）之外，我们还观察到 IPI 和纬度之间的显着相关性。然而，有点令人惊讶的是，我们无法检测到体型与 IPI 之间的显着关联。我们还检查了从以色列“进化峡谷”的南北斜坡收集的苍蝇，并观察到 ​​IPI 的差异，这些差异支持热适应可以塑造这一重要歌曲特征的观点。我们还检查了肯尼亚苍蝇的歌声，发现收集高度与 IPI 之间没有相关性。在所有三个实验中，体型与 IPI 无关。对三大洲所有三组人口的全球分析揭示了 IPI 与纬度之间的密切关联。我们推测 IPI 受热选择和性选择的影响，而体型也受自然选择的影响。对三大洲所有三组人口的全球分析揭示了 IPI 与纬度之间的密切关联。我们推测 IPI 受热选择和性选择的影响，而体型也受自然选择的影响。对三大洲所有三组人口的全球分析揭示了 IPI 与纬度之间的密切关联。我们推测 IPI 受热选择和性选择的影响，而体型也受自然选择的影响。