Petrarca V, Sabatinelli G, Touré Y T, Di Deco M A
Department of Genetics and Molecular Biology, University La Sapienza, Rome, Italy.
J Med Entomol. 1998 Jan;35(1):16-25. doi: 10.1093/jmedent/35.1.16.
The Afrotropical complex of sibling species Anopheles gambiae Giles includes the most efficient vectors of human malaria south of the Sahara. Anopheles arabiensis Patton and An. gambiae s.s. Giles are the members of the complex more adapted to the human environment. They are sympatric and synchronic over most of their distribution range; however, they show a different involvement in malaria transmission, with An. gambiae being more anthropophilic and endophilic than An. arabiensis. Discriminating between them is essential for a correct assessment of epidemiological parameters. The identification is currently achieved through recognition of species-specific chromosomal inversions or by molecular biology techniques. Both methods require considerable technical resources, not always available in the field. We carried out a morphometric analysis of field and laboratory samples of An. arabiensis and An. gambiae s.s. from sites in Madagascar, Burkina Faso, Mali, and Liberia to evaluate the degree of morphological differentiation. We examined 17 morphometric characters in samples representing each of the geographic sites. All of the measures were significantly larger for An. arabiensis (regardless of the collection site), demonstrating an intrinsic greater body size of this species. To assess the reliability associated with the multivariate statistic, we applied the discriminant function analysis, which provided a method for predicting to which group a new case will most likely be assigned. In a blind experiment, the morphometric method correctly identified approximately 85% of field-collected An. arabiensis and An. gambiae s.s., which provided a relatively simple method to approximate the relative frequencies of the 2 species in areas in which their concurrent presence was already known. The influence of laboratory conditions on the morphometrics of the 2 species was also analyzed.
冈比亚按蚊吉尔斯种复合体中的非洲热带近缘种包括撒哈拉以南地区最有效的人类疟疾传播媒介。阿拉伯按蚊帕顿亚种和冈比亚按蚊指名亚种是该复合体中更适应人类环境的成员。它们在大部分分布范围内同域且同期存在；然而，它们在疟疾传播中的作用不同，冈比亚按蚊比阿拉伯按蚊更嗜人血且喜室内栖息。区分它们对于正确评估流行病学参数至关重要。目前通过识别物种特异性染色体倒位或分子生物学技术来进行鉴定。这两种方法都需要大量技术资源，而这些资源在野外并不总是可得的。我们对来自马达加斯加、布基纳法索、马里和利比里亚等地的阿拉伯按蚊和冈比亚按蚊指名亚种的野外及实验室样本进行了形态测量分析，以评估形态分化程度。我们检查了代表每个地理地点的样本中的17个形态测量特征。所有测量结果显示，阿拉伯按蚊（无论采集地点如何）的各项指标都显著更大，表明该物种本身体型更大。为了评估与多元统计相关的可靠性，我们应用了判别函数分析，该分析提供了一种预测新样本最可能归属哪个组的方法。在一项盲测实验中，形态测量方法正确识别了约85%的野外采集的阿拉伯按蚊和冈比亚按蚊指名亚种，这提供了一种相对简单的方法来估算这两个物种在已知它们同时存在的地区的相对频率。我们还分析了实验室条件对这两个物种形态测量的影响。
