Shaw K L, Lugo E
Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
Mol Ecol. 2001 Mar;10(3):751-9. doi: 10.1046/j.1365-294x.2001.01219.x.
Based on studies from native Hawaiian Drosophila, a model was proposed to explain sexual isolation and mating asymmetry, from which one could potentially infer the 'direction of evolution'. We examined sexual isolation between allopatric cricket species of the genus Laupala, another endemic Hawaiian insect with an elaborate mating system, to begin to explore the nature of sexual isolation and mating asymmetry in closely related Hawaiian organisms. We studied sexual isolation and mating asymmetry in two contrasts. First, an inter-island comparison, including L. makaio from the older island of Maui and L. paranigra from the younger island of Hawaii, and second, an intra-island (Hawaii) comparison, including L. nigra from the older volcano of Mauna Kea and L. paranigra with a primary distribution on the younger volcanoes of Mauna Loa and Kilauea. We used a 'no-choice' experimental design, pairing individual males and females in homospecific or heterospecific combinations. Several behavioural aspects of courtship (proportion of male singing, latency to male singing, production of spermatophores and courtship initiation speed) were quantified as well as the success or failure of matings. We demonstrate asymmetry in sexual isolation between reciprocal combinations of L. makaio and L. paranigra. This result is examined in light of the differences in courtship behaviour manifest in the experiments with these two species. We did not find evidence of asymmetry in sexual isolation between L. nigra and L. paranigra, although differences in courtship initiation speed were evident between reciprocal combinations of these two species. In addition to the geological argument that species on older islands and older volcanoes give rise to species on younger islands and younger volcanoes, we discuss phylogenetic evidence consistent with these biogeographic hypotheses of relationships among the focal taxa. The patterns of asymmetrical sexual isolation and mating asymmetry are consistent with those found in the native Hawaiian Drosophila.
基于对夏威夷本土果蝇的研究，提出了一个模型来解释性隔离和交配不对称现象，从中有可能推断出“进化方向”。我们研究了Laupala属异地分布的蟋蟀物种之间的性隔离，Laupala是夏威夷另一种具有复杂交配系统的本土昆虫，以此开始探索亲缘关系较近的夏威夷生物中性隔离和交配不对称的本质。我们在两种对比情况下研究了性隔离和交配不对称。第一，进行岛屿间比较，包括来自较古老的毛伊岛的马凯奥Laupala和来自较年轻的夏威夷岛的拟黑Laupala；第二，进行岛内（夏威夷岛）比较，包括来自莫纳克亚山较古老火山的黑Laupala和主要分布在莫纳罗亚山和基拉韦厄较年轻火山的拟黑Laupala。我们采用“无选择”实验设计，将个体雄性和雌性以同种或异种组合配对。对求偶行为的几个方面（雄性鸣叫比例、雄性鸣叫潜伏期、精包产生情况和求偶起始速度）以及交配的成功或失败进行了量化。我们证明了马凯奥Laupala和拟黑Laupala相互组合之间性隔离的不对称性。根据这两个物种实验中表现出的求偶行为差异对这一结果进行了研究。我们没有发现黑Laupala和拟黑Laupala之间性隔离不对称的证据，尽管这两个物种的相互组合之间求偶起始速度存在明显差异。除了从地质学角度认为较古老岛屿和较古老火山上的物种衍生出较年轻岛屿和较年轻火山上的物种外，我们还讨论了与这些关于重点分类群之间关系的生物地理学假设一致的系统发育证据。不对称性性隔离和交配不对称的模式与在夏威夷本土果蝇中发现的模式一致。
