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（有翅和无翅变种）的昆虫物种的研究表明，无翅成虫的生殖产量高于从恶化的生境中迁移出来的有翅成虫。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，这还没有仔细研究的物种，所有的成年人都有翅膀，需要飞行的食物，交配和产卵地点的位置。此外，有人假设，迁徙物种已经进化出的性状，以减少成本，维持飞行器在随后的生殖输出。在我的研究小组中，我们一直在使用真正的粘虫，P. unipuncta，其中所有成年人都有功能性翅膀，作为研究信息素介导的交配的模型系统，并表明迁移（北美）和非迁移（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）的移民人口，和非移民人口从亚速尔群岛（AZ）和夏威夷（HA），研究成本的飞行繁殖的单态物种和测试的假设，移民已演变的特征，以减少迁移的成本。我们将比较NA个人饲养在不同的控制条件下，在实验室和自然的野外条件下（昆虫）人工饲料和天然寄主植物在夏季（非移民）和秋季（移民）。我们将测试形态的差异（翅膀大小，胸部质量），以确定是否有差异分配到飞行机械（肌肉/翅膀），并检查不同持续时间的飞行对非移民和移民的繁殖力的影响喂养不同的糖制度飞行前后。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，以及迁徙后的进食和交配是否可以减轻这些成本。我们还将检查胸肌，以确定居民和移民（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，以确定移民是否有减少繁殖飞行成本的修改。将对来自AZ和HA的非迁移个体重复这些实验，因为AZ成体较小并且在较小的年龄时性成熟，但具有比来自NA的个体显著更高的终生生殖输出。 我们最近的工作表明，与信息素介导的交配在三个不相关的物种的行为发生变化，在短期内的大气压力（AP）的变化。我们现在将测试的假设，即成年粘虫蛾的飞行倾向不仅会受到与季节变化相关的线索，但也在响应AP的日常波动，提供可靠的指标飞行条件。

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.