International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya.
Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745, Jena, Germany.
BMC Ecol Evol. 2021 May 4;21(1):78. doi: 10.1186/s12862-021-01810-z.
In holometabolous insects, environmental factors experienced in pre-imaginal life stages affect the life-history traits within that stage and can also influence subsequent life stages. Here, I assessed tolerance to water immersion by the larval instars of the stable fly, Stomoxys calcitrans L. (Diptera: Muscidae) and its impact on the life-history traits of their subsequent life stages.
After submerging the three larval instars of S. calcitrans in distilled water, I found that the first instar larvae remained active for longer as compared to the second and third instar larvae. Also, the first instar larvae took a longer period to recover from the stress-induced immobility when removed from the water and returned to ambient temperature. When I followed the development of individuals of each larval instar that survived from water immersion, I found that their developmental time, weight, pupation percentage, adult emergence percentage and adult weight were negatively affected by this stressor. However, the weight of S. calcitrans adults developed from immersed first larval instar individuals was not affected by water immersion whereas their counterparts developed from immersed second and third larval instars had lower body weight. This suggests that in S. calcitrans, water immersion stress at the earlier stage is less detrimental than that experienced at late stages.
This study provides a comparative overview of the fitness consequences associated with water immersion stress during S. calcitrans larval ontogeny. The results prove that the fitness shift induced by water immersion in S. calcitrans is stage-specific. My results illustrate the importance of considering each larval instar when assessing the impact of environmental factors on holometabolous insect performance as these may be decoupled by metamorphosis.
在完全变态的昆虫中，在预蛹期经历的环境因素会影响该阶段的生活史特征，也会影响后续的生命阶段。在这里，我评估了稳定蝇（Stomoxys calcitrans L.）幼虫期对水浸的耐受性及其对后续生命阶段生活史特征的影响。
将稳定蝇的三个幼虫期浸入蒸馏水后，我发现第一龄幼虫比第二龄和第三龄幼虫更能长时间保持活跃。此外，第一龄幼虫从应激诱导的不动状态中恢复所需的时间更长，当它们从水中取出并恢复到环境温度时。当我跟踪每个幼虫期幸存下来的个体的发育时，我发现它们的发育时间、体重、化蛹率、成虫出现率和成虫体重都受到了这种胁迫的负面影响。然而，从浸水的第一龄幼虫发育而来的稳定蝇成虫的体重不受水浸的影响，而从浸水的第二和第三龄幼虫发育而来的稳定蝇成虫的体重则较低。这表明，在稳定蝇中，早期阶段的水浸应激比晚期阶段的应激危害小。
本研究提供了稳定蝇幼虫发生期间与水浸应激相关的适合度后果的比较概述。结果证明，水浸在稳定蝇中引起的适合度转移是特定于阶段的。我的结果说明了在评估环境因素对完全变态昆虫性能的影响时考虑每个幼虫期的重要性，因为这些因素可能会因变态而脱钩。
