Pandey Atul, Motro Uzi, Bloch Guy
Department of Ecology, Evolution, and Behavior, The Hebrew University of Jerusalem, Jerusalem, Israel.
The Federmann Center for the Study of Rationality, The Hebrew University of Jerusalem, Jerusalem, Israel.
Neurobiol Sleep Circadian Rhythms. 2020 Aug 24;9:100056. doi: 10.1016/j.nbscr.2020.100056. eCollection 2020 Nov.
The circadian and endocrine systems influence many physiological processes in animals, but little is known on the ways they interact in insects. We tested the hypothesis that juvenile hormone (JH) influences circadian rhythms in the social bumble bee . JH is the major gonadotropin in this species coordinating processes such as vitellogenesis, oogenesis, wax production, and behaviors associated with reproduction. It is unknown however, whether it also influences circadian processes. We topically treated newly-emerged bees with the allatoxin Precocene-I (P-I) to reduce circulating JH titers and applied the natural JH (JH-III) for replacement therapy. We repeated this experiment in three trials, each with bees from different source colonies. Measurements of ovarian activity suggest that our JH manipulations were effective; bees treated with P-I had inactive ovaries, and this effect was fully recovered by subsequent JH treatment. We found that JH augments the strength of circadian rhythms and the pace of rhythm development in individually isolated newly emerged worker bees. JH manipulation did not affect the free-running circadian period, overall level of locomotor activity, sleep amount, or sleep structure. Given that acute manipulation at an early age produced relatively long-lasting effects, we propose that JH effects on circadian rhythms are mostly organizational, accelerating the development or integration of the circadian system.
昼夜节律系统和内分泌系统影响着动物的许多生理过程，但它们在昆虫体内的相互作用方式却鲜为人知。我们检验了一个假设，即保幼激素（JH）会影响群居大黄蜂的昼夜节律。保幼激素是该物种中的主要促性腺激素，它协调着诸如卵黄生成、卵子发生、蜡分泌以及与繁殖相关的行为等过程。然而，它是否也会影响昼夜节律过程尚不清楚。我们用早熟素-I（P-I）对新羽化的蜜蜂进行局部处理，以降低循环中的保幼激素滴度，并应用天然保幼激素（JH-III）进行替代疗法。我们在三个试验中重复了这个实验，每个试验使用来自不同来源蜂群的蜜蜂。卵巢活动的测量结果表明，我们对保幼激素的操作是有效的；用P-I处理的蜜蜂卵巢不活跃，而随后的保幼激素处理完全恢复了这种效应。我们发现，保幼激素增强了单独隔离的新羽化工蜂的昼夜节律强度和节律发展速度。保幼激素操作并未影响自由运行的昼夜周期、总体运动活动水平、睡眠量或睡眠结构。鉴于早期的急性操作产生了相对持久的影响，我们提出保幼激素对昼夜节律的影响主要是组织性的，加速了昼夜节律系统的发育或整合。
