Table1_Exposure to artificial light at night mediates the locomotion activity and oviposition capacity of Dastarcus helophoroides (Fairmaire).DOCX

Light entrains the endogenous circadian clocks of organisms to synchronize their behavioral and physiological rhythms with the natural photoperiod. The presence of artificial light at night disrupts these photoperiodic cues and is currently considered to be a major threat to key fitness-related behaviors, including sleep disruption and physiological stress. Research on the ecological influence of forest pest and their natural enemies is lacking. The wood-boring insects significantly damage forest and urban forest ecosystem functions. The parasitic beetles, Dastarcus helophoroides is an important natural enemy of wood-boring insects, especially those in the Cerambycidae family. However, the effect of artificial light at night on the locomotor rhythms and oviposition capacity of D. helophoroides has received little attention. To address this gap, diel changes in the locomotor activity and number of eggs laid by female D. helophoroides was analyzed under different light-dark (LD) cycles and temperatures. The results showed that the 24-h rhythmic of locomotor activity in these beetles was elevated in darkness and reduced under illumination, indicating that they are nocturnal insects. This activity has two major peaks, the evening (1–8 h after lights off) and morning (3.5–12.5 h after lights off) components, reflecting that light mediate regular changes in locomotor activity. Moreover, the circadian rhythms and active percentage were influenced by the illumination duration and temperature, especially constant light and 40°C. Females laid more eggs under the 16 L: 8 D cycles at 30°C than under the other combinations of photoperiod (including constant light and darkness) and temperature. Finally, the potential influence of exposure to four ecologically relevant intensities of artificial light at night (0, 1, 10 or 100 lx) on oviposition capacity was studied. The results showed that lifetime exposure to bright artificial light (1–100 lx) at night decreased the number of eggs laid relative to those laid with no lighting at night. These results demonstrate that chronic exposure to bright artificial light at night may influence the locomotor activity and oviposition capacity of this parasitic beetle.

光照可调控生物体的内源性昼夜生物钟，使其行为与生理节律与自然光周期同步。夜间人工光照的存在会干扰这些光周期信号，目前被认为是威胁生物体关键适合度相关行为的主要因素之一，这类行为包括睡眠紊乱与生理应激。目前针对森林害虫及其天敌的生态影响研究仍较为匮乏。蛀干昆虫会对森林与城市森林生态系统的功能造成显著破坏。花绒寄甲（Dastarcus helophoroides）是蛀干昆虫的重要天敌，尤其针对天牛科（Cerambycidae）昆虫。然而，夜间人工光照对花绒寄甲的活动节律与产卵能力的影响却鲜有研究关注。为填补这一研究空白，本研究在不同光暗（LD）周期与温度条件下，分析了雌性花绒寄甲的昼夜活动变化与产卵数量变化。研究结果显示，该甲虫的24小时活动节律在黑暗阶段升高、光照阶段降低，表明其为夜行性昆虫。其活动存在两个主要峰值时段：黄昏期（关灯后1~8小时）与黎明期（关灯后3.5~12.5小时），这反映出光照可介导其活动节律的周期性变化。此外，其昼夜节律与活动占比会受到光照时长与温度的影响，其中以恒光照与40℃条件下的影响最为显著。在30℃、16小时光照:8小时黑暗的光周期条件下，雌性花绒寄甲的产卵量高于其他光周期（包括恒光照与全黑暗）与温度组合。最后，本研究还探究了四种具有生态相关性的夜间人工光照强度（0、1、10或100勒克斯（lx））对其产卵能力的潜在影响。结果显示，相较于夜间无光照的对照组，终生暴露于夜间强光（1~100 lx）环境下的个体产卵量有所降低。上述结果表明，长期暴露于夜间强光环境下，可能会影响该寄生甲虫的活动节律与产卵能力。