Data from: Sympatric, temporally isolated populations of the pine white butterfly Neophasia menapia, are morphologically and genetically differentiated

Temporal isolation remains an understudied, and potentially under-appreciated, mechanism of reproductive isolation. Phenological differences have been discovered in populations of the pine white butterfly (Neophasia menapia), a typically univoltine species found throughout western North America. At two locations in the Coast Range of California there are two periods of adult emergence per year, one in early summer (July) and one in late summer/autumn (September/October). Differences in flight time are accompanied by differences in wing shape and pigmentation. Here we use a combination of population genomics and morphological analyses to assess the extent to which temporal isolation is able to limit gene flow between sympatric early and late flights. Not only did we detect both genetic and morphological differences between early and late flights at the two sites, we also found that the patterns of differentiation between the two flights were different at each location, suggesting an independent origin for the two sympatric flights. Additionally, we found no evidence that these sympatric flights originated via colonization from any of the other sampled localities. We discuss several potential hypotheses about the origin of these temporally isolated sympatric flights.

时间隔离（temporal isolation）一直是一类研究不足且可能未被充分重视的生殖隔离（reproductive isolation）机制。在北美西部广泛分布的典型一化性（univoltine）物种松白粉蝶（Neophasia menapia）的种群中，已被发现存在物候差异。在加利福尼亚海岸山脉的两个采样点，该物种每年存在两个成虫羽化期：一个出现于初夏（7月），另一个则在夏末/秋季（9月/10月）。成虫飞行期的差异伴随有翅形与色素沉着的差异。本研究结合种群基因组学（population genomics）与形态学分析，旨在评估时间隔离能够在多大程度上限制同域（sympatric）早、晚飞行种群间的基因流（gene flow）。研究不仅在两个采样点的早、晚飞行种群中检测到了遗传与形态层面的差异，还发现两处种群内两飞行型间的分化模式各不相同，这表明两个同域飞行型的起源彼此独立。此外，本研究未发现任何证据表明这些同域飞行型是通过从其他采样种群扩散定植形成的。最后，本文就这类受时间隔离的同域飞行型的起源，探讨了若干潜在假说。