Adler Peter H, Borkent Art, Hamada Neusa, McCreadie John W
Department of Plant and Environmental Sciences, Clemson University Clemson, SC, 29634-0310, USA.
Research Associate of the Royal British Columbia Museum, 691-8th Ave SE, Salmon Arm, British Columbia, V1E 2C2, Canada.
Acta Trop. 2017 Sep;173:171-179. doi: 10.1016/j.actatropica.2017.06.017. Epub 2017 Jun 15.
The polytene chromosomes of 130 larvae of the Neotropical Simulium metallicum complex from Brazil, Costa Rica, and Ecuador revealed five cytoforms, including three ('M', 'N', and 'O') that are new and two ('B' and 'J') that represent range extensions of up to 850km. The discovery of three new cytoforms brings the total number in the complex to 17. Cytoforms 'B', 'J', and 'N' are reproductively isolated from one another, and their species status is corroborated by morphological evidence. None of the three new cytoforms is known from current or historical onchocerciasis foci, although 'M' inhabits the periphery of the former Ecuadorian Santiago onchocerciasis focus a mere 30km to the west. The number of fixed chromosomal differences, as many as 24, separating some members of the S. metallicum complex far exceeds that known between members of any other simuliid species complex. Two distinct groupings can be diagnosed within the S. metallicum complex, based on at least eight fixed chromosomal rearrangements and structural characters in the larval stage. Consequently, a recommendation is made to recognize the S. horacioi complex and the S. metallicum complex sensu stricto. Recognition of two separate complexes provides potential phylogenetic content with predictive power for understanding biological phenomena such as vector potential.
对来自巴西、哥斯达黎加和厄瓜多尔的130只新热带区金属蚋复合体幼虫的多线染色体研究发现了5种细胞型，其中包括3种新的细胞型（“M”、“N”和“O”）以及2种细胞型（“B”和“J”），后者代表了长达850公里的分布范围扩展。3种新细胞型的发现使该复合体中的细胞型总数达到17种。细胞型“B”、“J”和“N”彼此之间存在生殖隔离，其物种地位得到形态学证据的证实。尽管细胞型“M”栖息在前厄瓜多尔圣地亚哥盘尾丝虫病疫点以西仅30公里处的边缘地带，但目前或历史上的盘尾丝虫病疫点均未发现这3种新细胞型中的任何一种。金属蚋复合体某些成员之间存在多达24个固定的染色体差异，这远远超过了已知的任何其他蚋科物种复合体成员之间的差异。基于幼虫阶段至少8种固定的染色体重排和结构特征，在金属蚋复合体中可以诊断出两个不同的分组。因此，建议认可霍氏蚋复合体和狭义的金属蚋复合体。认可两个独立的复合体为理解诸如媒介潜能等生物学现象提供了具有预测能力的潜在系统发育内容。
