Department of Entomology, Michigan State University, East Lansing, Michigan, USA.
McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida, Gainesville, Florida, USA.
Insect Sci. 2020 Jun;27(3):583-612. doi: 10.1111/1744-7917.12653. Epub 2019 Jan 7.
Polymorphisms for melanic form of insects may provide various selective advantages. However, melanic alleles may have significant/subtle pleiotrophic "costs." Several potential pleiotrophic effects of the W (=Y)-linked melanism gene in Papilio glaucus L. (Lepidoptera) showed no costs for melanic versus yellow in adult size, oviposition preferences, fecundity, egg viability, larval survival/growth rates, cold stress tolerance, or postdiapause emergence times. Sexual selection (males choosing yellow rather than mimetic dark females) had been suggested to provide a balanced polymorphism in P. glaucus, but spermatophore counts in wild females and direct field tethering studies of size-matched pairs of virgin females (dark and yellow), show that male preferences are random or frequency-dependent from Florida to Michigan, providing no yellow counter-advantages. Recent frequency declines of dark (melanic/mimetic) females in P. glaucus populations are shown in several major populations from Florida (27.3°N latitude) to Ohio (38.5° N). Summer temperatures have increased significantly at all these locations during this time (1999-2018), but whether dark morphs may be more vulnerable (in any stage) to such climate warming remains to be determined. Additional potential reasons for the frequency declines in mimetic females are discussed: (i) genetic introgression of Z-linked melanism suppressor genes from P. canadensis (R & J) and the hybrid species, P. appalachiensis (Pavulaan & Wright), (ii) differential developmental incompatibilities, or Haldane effects, known to occur in hybrids, (iii) selection against intermediately melanic ("dusty") females (with the W-linked melanic gene, b+) which higher temperatures can cause.
昆虫黑变形式的多态性可能提供了各种选择优势。然而，黑变等位基因可能具有显著/微妙的多效性“代价”。几种潜在的多效性影响Papilio glaucus L.（鳞翅目）中 W（=Y）连锁黑变基因在成虫大小、产卵偏好、繁殖力、卵活力、幼虫存活率/生长速度、耐冷胁迫或滞育后出现时间方面没有代价。性选择（雄性选择黄色而不是模仿深色雌性）被认为在 P. glaucus 中提供了一种平衡的多态性，但在野外雌性的精子计数和大小匹配的处女雌性（深色和黄色）的直接野外系泊研究中，显示雄性偏好是随机的或依赖频率的，从佛罗里达州到密歇根州，没有提供黄色的劣势。在几个主要的种群中，从佛罗里达州（27.3°N 纬度）到俄亥俄州（38.5°N），都显示出 P. glaucus 种群中深色（黑变/模仿）雌性的最近频率下降。在此期间，所有这些地点的夏季温度都显著升高（1999-2018 年），但深色形态是否更容易（在任何阶段）受到这种气候变暖的影响仍有待确定。还讨论了模拟雌性频率下降的其他潜在原因：（i）来自 P. canadensis（R & J）和杂交种 P. appalachiensis（Pavulaan & Wright）的 Z 连锁黑变抑制基因的遗传渗入，（ii）已知在杂种中发生的发育不相容性或 Haldane 效应，（iii）对中间黑变（“灰尘”）雌性的选择，较高的温度可能导致这种雌性出现。
