The role of cuticular hydrocarbons in adaptations to changing climatic conditions and in sexual communication of Anopheles mosquitoes

疟疾是一种媒介传播的疾病，目前威胁着世界一半的人口。按蚊传播疟疾，并且已经开发了许多防止蚊虫叮咬的工具，例如驱蚊剂和经杀虫剂处理的蚊帐。尽管千禧年以来疟疾大幅减少，但目前的控制方法停滞不前，部分原因是疟疾蚊子媒介出现了抗药性。此外，蚊子侵入了世界上新的地区，从而增加了人类感染疟疾的风险。对蚊虫生物学和生态学的深入了解有助于开发新的蚊虫媒介控制方法。在这里，我们将重点关注按蚊的两种/种复合物，并将研究在其身体上发现的一类化合物如何帮助蚊子识别交配伴侣并在新地区定居。这些化合物是角质层的碳氢化合物，它们在蚊子的角质层上形成一层蜡质层——它们的皮肤类似物。在其他昆虫中，角质层的碳氢化合物已知有两个作用。它们可以防止水分流失——干燥，这在蚊子生活的炎热热带环境中很可能发生。它们也被用作一种迷人的香水，用来识别合适的交配伴侣。然而，角质层碳氢化合物在疟疾蚊子中的作用还不为人所知，而这个项目打算对此进行测试。我们将重点介绍我们选择的两种按蚊，因为它们表现出了特殊的兴趣。第一个物种是斯氏按蚊，原产于印度，但在过去10年里入侵了非洲之角。从印度迁徙过来后，这些蚊子必须适应和生存在阿拉伯半岛和东非的干热气候中。因此，任何对不同环境条件的适应也必须是最近发生的，而且发生得非常迅速。我们现在有机会研究这种独特的生物过程，我们预测表皮碳氢化合物的变化有助于这些蚊子入侵非洲。此外，安。斯氏蚊还必须将它们潜在的交配对象与非洲本土的按蚊区分开来。这意味着，如果他们使用这些诱人的香水，它们可能已经被修改过了——这再次让我们研究角质层的碳氢化合物。第二个感兴趣的物种是法劳按蚊，生活在澳大利亚北部、巴布亚新几内亚、所罗门群岛和瓦努阿图。事实上，这不是一个物种，而是一个由8个密切相关的物种组成的复合体，其中一些出现在同一地点，还有一些生活在与亲戚隔绝的岛屿上。到目前为止，我们已经研究了居住在澳大利亚北部的8个物种中的1个。我们发现该物种雄性和雌性的表皮碳氢化合物有很大的不同。这一令人兴奋的发现表明，它们可能确实利用表皮上的碳氢化合物作为香水来选择配偶，正如许多其他昆虫物种所显示的那样。我们现在想把我们的研究扩展到其他兄弟物种，看看它们的角质层碳氢化合物在雄性和雌性之间是否不同。我们预测它们是，但当蚊子的亲属生活在同一地点时，它们会略有改变。安的发现。farauti和/或An。斯蒂芬氏蚊利用化合物寻找配偶将对其他蚊子种类和蚊子控制策略产生深远的影响。负责表皮碳氢化合物产生和感知的蚊子基因和蛋白质可能会以各种方式成为目标，从而导致我们迫切需要的疟疾病媒控制的新方法。此外，如果我们发现快速变化的表皮碳氢化合物有助于蚊子适应不断变化的气候的证据，这将有助于科学家预测蚊子种群未来如何在世界各地迁移和入侵。这可能会指导预防战略，从而挽救数百万人的生命。

Malaria is a vector-borne disease that currently threatens half of the world population. Anopheles mosquitoes transmit malaria, and many tools have been developed to prevent mosquito bites, such as mosquito repellents and insecticide-treated bed nets. Despite the huge reductions in malaria since the millennium, present control methods have stalled, partly due to emerging insecticide resistance in malaria mosquito vectors. In addition, mosquitoes invade new regions of the world, thus increasing the risk of malaria to people. Better understanding of mosquito biology and ecology could lead to the development of novel methods of mosquito vector control.Here we will focus on two species/species complexes of Anopheles mosquitoes, and will study how a class of chemical compounds that is found on their bodies helps mosquitoes to recognize mating partners and to colonize new areas. These compounds are cuticular hydrocarbons, and they form a waxy layer on the mosquito cuticle - their analogue of skin. In other insects, cuticular hydrocarbons are known to have two roles. They prevent water loss - desiccation, which is likely to occur in hot tropical environments where mosquitoes live. They are also used as an attractive perfume for recognizing appropriate mating partners. However, the role of cuticular hydrocarbons in malaria mosquitoes is not well known, and this project sets out to test it.We will focus on the two Anopheles species that we selected because of the special interest that they present.The first species, Anopheles stephensi, are native to India, but have in the past 10 years invaded the Horn of Africa. Upon migration from India, these mosquitoes had to adapt to and survive in dry and hot climate of the Arabian peninsula and East Africa. Thus, any adaptations to different environmental conditions must also be extremely recent and are happening very rapidly. We have a chance now to study this unique biological process as it occurs, and we predict that changes in cuticular hydrocarbons help these mosquitoes in their invasion of Africa. In addition, An.stephensi also have to distinguish their potential mating partners from the native African Anopheles species. This means that their attractive perfumes, if they use them at all, might have been modified - this again brings us to study cuticular hydrocarbons. The second species of interest, Anopheles farauti, inhabits northern Australia, Papua New Guinea, the Solomon islands and Vanuatu. In fact, this is not one species but a complex of 8 closely related species, some of which occur at the same locations, and some live on islands in isolation from their relatives. We so far have studied 1 of the 8 species that inhabits Northern Australia. We found that cuticular hydrocarbons of the males and females of this species are very different. This exciting finding implies that they may indeed use cuticular hydrocarbons as the perfume to select their mates as it has been shown in many other insect species. We now want to extend our study to the other sibling species, and see whether their cuticular hydrocarbons are different between males and females. We predict that they are, but are modified slightly when the relatives of the mosquitoes live at the same location. The finding that An.farauti and/or An.stephensi use chemical compounds to find their mates will have profound implications for other mosquito species and mosquito control strategies. Mosquito genes and proteins, responsible for production and perception of cuticular hydrocarbons, may then be targeted in a variety of ways, leading to novel methods of malaria vector control that we urgently need. In addition, if we find evidence that rapidly changing cuticular hydrocarbons helps mosquitoes adapt to changing climate, this will help the scientists predict how mosquito populations may migrate and invade around the world in the future. This may guide prevention strategies that will save millions of human lives.