Do migrant moth species have adaptations that reduce the cost of long distance flight on future reproduction?

对几种表现出翅膀多态性（有翼和无翼）的昆虫物种的研究表明，无翼成虫的繁殖产量高于从恶化的栖息地迁移出来的有翼成虫。这些结果被解释为支持这样一种观点，即飞行是以繁殖为代价的。然而，在所有成年鸟都有翅膀，需要飞行寻找食物、配偶和产卵地点的物种中，这一点还没有得到仔细的研究。此外，有假设认为，迁徙物种已经进化出了一些特征，以减少在随后的繁殖产出中维持飞行装置的成本。在我的研究小组中，我们一直使用真正的粘虫P. unipuncta作为模型系统来研究信息素介导的交配，并表明迁徙（北美）和非迁徙（亚速尔群岛）种群之间存在显着的行为和生理差异。我们将使用北美（NA）移民人口，以及来自亚速尔群岛（AZ）和夏威夷（HA）的非移民人口，来检查单态物种的飞行繁殖成本，并检验移民进化特征以降低迁移成本的假设。我们将比较在实验室不同控制条件下饲养的NA个体和在自然野外条件下饲养的NA个体（昆虫），分别在夏季（非候鸟）和秋季（候鸟）食用人工饲料和天然寄主植物。我们将测试形态学上的差异（翅膀大小、胸围质量），以确定飞行机械（肌肉/翅膀）的分配是否存在差异，并检查不同飞行时间对非迁徙鸟和迁徙鸟在飞行前后喂食不同糖分的繁殖力的影响。这些实验将使我们能够确定是否存在与迁徙相关的生殖成本，以及迁徙后的喂养和交配是否可以减轻这些成本。我们还将检查胸肌，以确定居民和迁徙者（来自自然种群和野外饲养）之间是否存在结构和/或生理差异，以确定迁徙者是否有改变，从而降低飞行繁殖的成本。这些实验将在来自AZ和HA的非移民个体中重复进行，因为AZ成年个体体型较小，性成熟年龄较小，但一生的生殖产量明显高于NA。

Studies on several insect species exhibiting wing polymorphism (having both winged and wingless morphs) have shown that the reproductive output of wingless adults is higher than their winged counterparts that migrate out of deteriorating habitats. These results have been interpreted as supporting the idea that flight comes at a cost to reproduction. However, this has not been examined carefully in species where all adults are winged and require flight for the location of food, mates and oviposition sites. Furthermore, it has been hypothesized that migrant species have evolved traits to reduce the cost of maintaining flight apparatus on subsequent reproductive output. In my research group we have been using the true armyworm, P. unipuncta, where all adults have functional wings, as a model system to study pheromone mediated mating and have shown there are marked behavioural and physiological differences between migratory (North America) and non-migratory (Azores) populations. We will use the North American (NA) migrant population, and non migrant populations from the Azores (AZ) and Hawaii (HA), to examine the cost of flight on reproduction in a monomorphic species and to test the hypothesis that migrants have evolved traits to reduce the costs of migration. We will compare NA individuals reared under different controlled conditions in the laboratory and under natural field conditions (insectary) on both artificial diet and natural host plants during the summer (non-migrants) and fall (migrants). We will test for differences in morphology (wing size, thoracic mass) to determine if there is differential allocation to flight machinery (muscle/wings) and examine the effect of flight of different durations on the fecundity of non-migrants and migrants fed different sugar regimes before and after flight. These experiments will allow us to determine if there are reproductive costs associated with migration and whether post-migratory feeding and mating might mitigate them. We will also examine thoracic muscle to determine if there are structural and/or physiology differences between residents and migrants (from natural populations and field rearings) to determine if migrants have modifications that reduce the costs of flight on reproduction. These experiments will be repeated with non migrant individuals from AZ and HA, as AZ adults are smaller and become sexually mature at a younger age, yet have a significantly higher life time reproductive output than those from NA. Our recent work has shown that the behaviours associated with pheromone mediated mating in three unrelated species changed in response to short term changes in atmospheric pressure (AP). We will now test the hypotheses that flight propensity of adult armyworm moths will be not only be affected by cues associated with seasonal change, but also in response to daily fluctuations in AP that provide reliable indicators of flight conditions.