Influence of mating system and variable selection on adaptive variation within and across species of cannibalistic black widow spiders

交配系统和变量选择对​​食人黑寡妇蜘蛛物种内和物种间适应性变异的影响

• 批准号: 229029-2007
• 负责人: Andrade, Maydianne
• 金额: $ 2.15万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2009
• 资助国家: 加拿大
• 起止时间: 2009-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=425399
• 关键词: Influence; mating; system; variable; selection

My research examines how social and environmental conditions affect the evolution of male reproductive traits. I propose field and laboratory studies of variation in male size, development time, and mating strategies in three closely related species of cannibalistic black widow spiders. The extreme mating system of two of these species (Redbacks and Brown Widows) involves self-sacrifice by males to their cannibalistic mates. This severely restricts male mating opportunities. Thus male fitness depends on the ability to compete successfully under a limited range of conditions experienced soon after maturity. I predict that males of these species will use cues of small-scale fluctuations in competitive challenges to adjust development of adult traits to forms that are optimal for the local environment (= developmental plasticity). In contrast, males of the third species (Western Black Widows) mate with multiple females over a longer period, and are likely to encounter a range of micro-habitat challenges. I predict these males will adopt traits that perform well on average across the most commonly encountered conditions, but will not be optimal under any one condition. My work will examine this idea by measuring spatial and temporal variation in selection pressures across local and broad geographic scales, and fitness effects of variable adult traits across widely separated populations in each species. I will answer two main questions. (1) How is fitness affected by variable selection on mating strategies, development time, and body size traits within the context of each species' mating system? and (2) Does selection for developmental plasticity in sexually-selected traits depend on mating system? Studies proposed here will shed light on causes of adaptive variation between species of black widow spiders-a group that is notable for its extreme mating systems and broad species distributions. More generally, this work will make significant contributions to our understanding of the how different levels of environmental variability affect adaptive variation within and across populations.

我的研究考察了社会和环境条件如何影响男性生殖特征的进化。我建议对三种近亲同类相食的黑寡妇蜘蛛在雄性体型、发育时间和交配策略方面的变化进行实地和实验室研究。其中两个物种（红背和褐寡妇）的极端交配制度包括雄性向同类相食的伴侣做出自我牺牲。这严重限制了雄性交配的机会。因此，雄性的适应性取决于在成熟后不久经历的有限条件下成功竞争的能力。我预测这些物种的雄性将利用竞争挑战中小规模波动的线索来调整成年特征的发展，以适应当地环境的最佳形式（=发育可塑性）。相比之下，第三种雄性黑寡妇（西部黑寡妇）与多个雌性交配的时间更长，可能会遇到一系列的微栖息地挑战。我预测这些雄性会采用在最常见的情况下表现良好的特征，但在任何一种情况下都不会是最佳的。我的工作将通过测量在局部和广泛的地理尺度上的选择压力的时空变化，以及在每个物种中广泛分离的种群中不同成年性状的适应性效应来检验这一观点。我将回答两个主要问题。(1)在各物种的交配系统背景下，交配策略、发育时间和体型特征的变量选择如何影响适合度？(2)性选择性状的发育可塑性是否取决于交配制度？这里提出的研究将揭示黑寡妇蜘蛛物种之间适应性变化的原因——黑寡妇蜘蛛以其极端的交配系统和广泛的物种分布而闻名。更一般地说，这项工作将对我们理解不同水平的环境变异性如何影响种群内部和种群之间的适应性变化做出重大贡献。