Université de Picardie Jules Verne, EA 4698 Ecologie et Dynamique des Systèmes Anthropisés, Equipe Bio-écologie des Insectes Phytophages et Entomophages, Amiens, France.
PLoS One. 2013;8(2):e54306. doi: 10.1371/journal.pone.0054306. Epub 2013 Feb 6.
Temperature changes are common in nature and insects are particularly exposed and sensitive to such variations which can be potential stresses, ultimately affecting life history traits and overall fitness. Braconids have been widely used to study the effects of temperature on host-parasitoid interactions and the present work focused on the solitary endoparasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae Aphidiidae), an efficient biological control agent commercially used against aphids such as the potato aphid Macrosiphum euphorbiae Thomas (Sternorrhyncha: Aphididae). Contrary to previous studies using heat shocks at extreme temperatures, we evaluated the effects of mild heat stresses by transferring young parasitoid adults from the constant temperature of 20°C to either a warm (25°C) or hot (28°C) temperature, for either 1 h or 48 h. Such treatments are consistent with situations commonly experienced by parasitoids when moved from their rearing conditions to greenhouses or field conditions. The effects were evaluated both on the heat stressed A. ervi adults (G0) (immediate effects) and on their first generation (G1) progeny (trans-generational effects). G0 wasps' mortality was significantly affected by the temperature in interaction with the duration of the stress. Longevity of G0 wasps surviving the heat stress was negatively affected by the temperature and females lived longer than males. Heat stress applied to A. ervi parents also had consequences on their G1 progeny whose developmental time, rates of mummification and percentage of parasitoid completing total development were negatively affected. Surprisingly, the egg load at emergence of the G1 female progeny was increased when their mothers had been submitted to a mild heat stress of 25°C or 28°C. These results clearly demonstrate trans-generational phenotypic plasticity, showing that adaptation to thermal stresses may be achieved via maternal effects. This study also sheds light on the complexity of insect responses and underlying mechanisms to fluctuating conditions in their natural environment.
温度变化在自然界中很常见，昆虫尤其容易受到这些变化的影响，这些变化可能是潜在的压力，最终会影响其生活史特征和整体适应性。杆状病毒已被广泛用于研究温度对寄主-寄生蜂相互作用的影响，本研究集中研究了独居内寄生蜂桃蚜茧蜂 Aphidius ervi Haliday（膜翅目：Braconidae 蚜茧蜂科），这是一种有效的商业性生物防治剂，用于防治马铃薯蚜 Macrosiphum euphorbiae Thomas（半翅目：蚜科）等蚜虫。与以前使用极端温度进行热休克的研究不同，我们通过将年轻的寄生蜂成虫从 20°C 的恒温转移到温暖（25°C）或炎热（28°C）的温度下，分别处理 1 小时或 48 小时，评估了轻度热应激的影响。这些处理与寄生蜂从饲养条件转移到温室或田间条件时通常经历的情况一致。评估的结果不仅包括受到热应激的 A. ervi 成虫（G0）（即时效应），还包括它们的第一代（G1）后代（跨代效应）。G0 黄蜂的死亡率受到温度与应激持续时间相互作用的显著影响。在经受热应激后幸存下来的 G0 黄蜂的寿命受到温度的负面影响，并且雌性比雄性寿命长。对 A. ervi 亲代施加热应激也对其 G1 后代产生了影响，其发育时间、木乃伊化率和完成总发育的寄生蜂比例均受到负面影响。令人惊讶的是，当 G1 雌性后代的母亲受到 25°C 或 28°C 的轻度热应激时，其卵的负载量增加。这些结果清楚地表明了跨代表型可塑性，表明通过母体效应可以实现对热应激的适应。本研究还揭示了昆虫对自然环境中波动条件的反应和潜在机制的复杂性。
