Gonulkirmaz-Cancalar Ozlem, Bloch Guy
Department of Ecology, Evolution, and Behavior, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
The Federmann Center for the Study of Rationality, The Hebrew University of Jerusalem, Jerusalem, Israel.
J Biol Rhythms. 2024 Dec;39(6):594-606. doi: 10.1177/07487304241283863. Epub 2024 Oct 6.
Mating success depends on many factors, but first of all, a male and a female need to meet at the same place and time. The circadian clock is an endogenous system regulating activity and sex-related behaviors in animals. We studied bumble bees () in which the influence of circadian rhythms on sexual behavior has been little explored. We characterized circadian rhythms in adult emergence and locomotor activity under different illumination regimes for males and gynes (unmated queens). We developed a method to monitor adult emergence from the pupal cocoon and found no circadian rhythms in this behavior for either males or gynes. These results are not consistent with the hypothesis that the circadian clock regulates emergence from the pupa in this species. Consistent with this premise, we found that both gynes and males do not show circadian rhythms in locomotor activity during the first 3 days after pupal emergence, but shortly after developed robust circadian rhythms that are readily shifted by a phase delay in illumination regime. We conclude that the bumble bees do not need strong rhythms in adult emergence and during early adult life in their protected and regulated nest environment, but do need strong activity rhythms for timing flights and mating-related behaviors. Next, we tested the hypothesis that the locomotor activity of males and gynes have a similar phase, which may improve mating success. We found that both males and gynes have strong endogenous circadian rhythms that are entrained by the illumination regime, but males show rhythms at an earlier age, their rhythms are stronger, and their phase is slightly advanced relative to that of gynes. An earlier phase may be advantageous to males competing to mate a receptive gyne. Our results are consistent with the hypothesis that sex-related variations in circadian rhythms is shaped by sexual selection.
交配成功率取决于许多因素，但首先，雄性和雌性需要在同一时间和地点相遇。生物钟是调节动物活动和性行为的内源性系统。我们研究了生物钟节律对性行为的影响鲜有人探索的大黄蜂（ ）。我们对雄性和雌性（未交配的蜂王）在不同光照条件下的成虫羽化和运动活动的昼夜节律进行了表征。我们开发了一种监测成虫从蛹茧中羽化的方法，发现雄性和雌性在这种行为中均不存在昼夜节律。这些结果与生物钟调节该物种蛹羽化的假设不一致。基于这一前提，我们发现雌性和雄性在蛹羽化后的前3天运动活动中均未表现出昼夜节律，但在不久后就形成了强大的昼夜节律，且很容易因光照条件的相位延迟而改变。我们得出结论，在受保护和受调控的巢穴环境中，大黄蜂在成虫羽化和成年早期不需要强烈的节律，但在安排飞行和与交配相关的行为时确实需要强烈的活动节律。接下来，我们测试了雄性和雌性的运动活动具有相似相位可能会提高交配成功率的假设。我们发现，雄性和雌性都有强大的内源性昼夜节律，且受光照条件的影响，但雄性在更早的年龄就表现出节律，它们的节律更强，并且相对于雌性，它们的相位略有提前。较早的相位可能对竞争与处于接受状态的雌性交配的雄性有利。我们的结果与昼夜节律的性别相关差异是由性选择塑造的假设一致。
