Boerlijst Sam P, Boelee Eline, van Bodegom Peter M, Schrama Maarten
Department of Environmental Biology, Center for Environmental Research Leiden University of Leiden Leiden the Netherlands.
Division of Inland Water Systems Deltares Delft the Netherlands.
Ecol Evol. 2024 Aug 27;14(8):e70124. doi: 10.1002/ece3.70124. eCollection 2024 Aug.
Temperature is commonly acknowledged as one of the primary forces driving ectotherm vector populations, most notably by influencing metabolic rates and survival. Although numerous experiments have shown this for a wide variety of organisms, the vast majority has been conducted at constant temperatures and changes therein, while temperature is far from constant in nature, and includes seasonal and diurnal cycles. As fluctuating temperatures have been described to affect metabolic processes at (sub)cellular level, this calls for studies evaluating the relative importance of temperature fluctuations and the changes therein. To gain insight in the effects of temperature fluctuations on ectotherm development, survival, and sex ratio, we developed an inexpensive, easily reproducible, and open-source, Arduino-based temperature control system, which emulates natural sinusoidal fluctuations around the average temperature. We used this novel setup to compare the effects of constant (mean) temperatures, most commonly used in experiments, block schemes, and natural sinusoidal fluctuations as well as an extreme variant with twice its amplitude using the cosmopolitan mosquito species s.l. as a study organism. Our system accurately replicated the preprogrammed temperature treatments under outdoor conditions, even more accurately than traditional methods. While no effects were detected on survival and sex ratio within the ranges of variation evaluated, development was sped up considerably by including temperature fluctuations, especially during pupation, where development under constant temperatures took almost a week (30%) longer than under natural fluctuations. Doubling the amplitude further decreased development time by 1.5 days. These results highlight the importance of including (natural) oscillations in experiments on ectotherm organisms - both aquatic and terrestrial - that use temperature as a variable. Ultimately, these results have major repercussions for downstream effects at larger scales that may be studied with applications such as ecological niche models, disease risk models, and assessing ecosystem services that rely on ectotherm organisms.
温度通常被认为是驱动变温动物媒介种群的主要因素之一，最显著的是通过影响代谢率和存活率。尽管大量实验已针对多种生物证明了这一点，但绝大多数实验是在恒定温度及其变化条件下进行的，而自然界中的温度远非恒定，包括季节性和昼夜循环。由于已描述温度波动会影响（亚）细胞水平的代谢过程，因此需要开展研究来评估温度波动及其变化的相对重要性。为了深入了解温度波动对变温动物发育、存活和性别比例的影响，我们开发了一种基于 Arduino 的廉价、易于重现且开源的温度控制系统，该系统能模拟围绕平均温度的自然正弦波动。我们使用这个新颖的装置，以广泛分布的蚊虫种类作为研究对象，比较了实验中最常用的恒定（平均）温度、分段方案、自然正弦波动以及振幅加倍的极端变体的影响。我们的系统在户外条件下准确复制了预先设定的温度处理，甚至比传统方法更精确。虽然在评估的变化范围内未检测到对存活率和性别比例的影响，但温度波动显著加快了发育速度，尤其是在化蛹期间，恒温条件下的发育时间比自然波动下长了近一周（30%）。将振幅加倍进一步使发育时间缩短了 1.5 天。这些结果凸显了在以温度为变量的变温动物（包括水生和陆生）实验中纳入（自然）振荡的重要性。最终，这些结果对更大尺度的下游效应具有重大影响，这些效应可通过生态位模型、疾病风险模型以及评估依赖变温动物的生态系统服务等应用进行研究。
