摘要
Why are sperm so variable despite having a singular, critical function and an intimate relationship with fitness? A key to understanding the evolution of sperm morphology is identifying which traits enable sperm to be successful fertilizers. Several sperm traits (e.g., tail length, overall size) are implicated in sperm performance, but the benefits of these traits are likely to be highly context dependent. Here, we examined phenotypic selection on sperm morphology of a broadcast spawning tube worm (Galeolaria gemineoa). We conducted laboratory experiments to measure the relationship between average sperm morphology and relative fertilization success across a range of sperm environments that were designed to approximate the range of sperm concentrations and ages encountered by eggs in nature. We found that the strength and form of multivariate selection varied substantially across our environmental gradients. Sperm with long tails and small heads were favored in high-concentration environments, whereas sperm with long heads were favored at low concentrations and old ages. We suggest variation in the local fertilization environment and resulting differences in selection can preserve variability in sperm morphology both within and among males.
摘要译文
为什么精子尽管有一个独特的，关键的功能，并配备了健身的亲密关系等变量？一个关键的了解精子形态的演化确定哪些特质使精子能够成功肥料。几个精子性状（例如，尾长，整体大小）有牵连的精子的性能，但这些特征的好处可能是高度依赖于上下文的。这里，我们研究了表型选择在广播产卵管虫（Galeolaria gemineoa）精子形态。愤怒的精子形态和跨范围被设计为近似精子浓度和年龄在自然界中遇到卵子的精子范围内的环境相对受精成功。我们发现，多元选择的力量和形式在我们的环境梯度变化显着。精子的长尾巴，小头被看好的高浓度的环境中，而精子的长头被看好在低浓度老年龄。我们建议的变化在当地受精环境，造成选择的差异可以内和男性中保存变异精子形态。
Darren W. Johnson[1]; Keyne Monro[2,3]; Dustin J. Marshall[2,3];. THE MAINTENANCE OF SPERM VARIABILITY: CONTEXT-DEPENDENT SELECTION ON SPERM MORPHOLOGY IN A BROADCAST SPAWNING INVERTEBRATE[J]. Evolution, 2013,67(5): 1383-1395