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Hundreds of thousands of people worldwide are killed every year by malaria and other diseases that are spread through mosquito bites.
Female mosquitoes are responsible for these deadly bites because they have a special mouth design that male mosquitoes do not have.
But it has not always been that way. Researchers said they have discovered the oldest-known fossils of mosquitoes - two males located in pieces of an ancient orange-colored substance known as amber.
The male mosquitoes date to 130 million years ago. They were found near the modern town of Hammana in Lebanon. To researchers' surprise, the male mosquitoes had long mouthparts seen now only in females.
Dany Azar is a researcher at the Chinese Academy of Sciences' Nanjing Institute of Geology and Paleontology and Lebanese University. Azar said they were clearly blood-eaters. The lead writer of the study, recently published in Current Biology, added, "This discovery is a major one in the evolutionary history of mosquitoes."
The two fossilized mosquitoes, both representing the same species that has died off, are similar in size and appearance to modern mosquitoes. However, the mouthparts used for getting blood are shorter than in today's female mosquitoes.
Study co-writer André Nel of the National Museum of Natural History of Paris described the finding as "quite surprising."
The special anatomy of the two mosquitoes was beautifully saved in the fossils. Both insects had sharp and triangle-shaped jaw anatomy and a long structure with tooth-like elements.
The researchers said they suspect that mosquitoes evolved from insects that did not consume blood. They think that the mouthparts that were developed for getting blood meals were originally used to pierce plants to get nutritious fluids.
Plant evolution may have affected the differences in feeding between male and female mosquitoes. At the time when these two mosquitoes became stuck in tree sap that eventually became amber, flowering plants were beginning to spread for the first time.
From the findings, Azar said that all early mosquitoes, both male and female, were bloodsucking. And male mosquitoes lost the ability later.
The researchers said while these are the oldest mosquito fossils, mosquitoes probably appeared millions of years earlier. They noted that molecular evidence suggests mosquitoes developed from about 200 million to 145 million years ago.
There are more than 3,500 species of mosquitoes worldwide, found everywhere except Antarctica. Some species spread diseases such as malaria, yellow fever, Zika fever, dengue and others. The World Health Organization says more than 400,000 people die annually from malaria - a parasitic infection - mostly children under age 5.
I’m John Russell.
全球每年有数十万人死于通过蚊虫叮咬传播的疟疾和其他疾病。
雌性蚊子负责这些致命的叮咬，因为它们具有雄性蚊子没有的特殊口器设计。
但事情并非一直如此。研究人员表示，他们发现了已知最古老的蚊子化石——两只雄性蚊子保存在一种古老的橙色物质中，被称为琥珀。
这两只雄性蚊子可追溯到1.3亿年前。它们被发现在黎巴嫩现代城镇Hammana附近。令研究人员惊讶的是，这两只雄性蚊子具有目前仅在雌性蚊子中见到的长口器。
Dany Azar是中国科学院南京地质古生物研究所和黎巴嫩大学的研究员。Azar表示，它们显然是吸血的。这项研究的首席作者最近在《Current Biology》上发表，补充说：“这一发现在蚊子的进化历史中具有重要意义。”
这两只化石蚊子代表了同一已灭绝物种，其大小和外貌与现代蚊子相似。然而，用于吸血的口器较今天的雌性蚊子要短。
研究的合著者André Nel来自巴黎国家自然历史博物馆，他将这一发现描述为“相当令人惊讶”。
这两只蚊子的特殊解剖结构在化石中得到了完美保存。这两只昆虫都具有尖锐且三角形状的颚解剖结构，以及一个带有类似牙齿的长结构。
研究人员表示，他们怀疑蚊子是从不吸血的昆虫中演化而来的。他们认为最初用于吸血的口器是用来刺穿植物并提取有营养的液体的。
植物的演化可能影响了雄性和雌性蚊子之间进食差异。在这两只蚊子被困在最终变成琥珀的树脂中的时候，开花植物刚开始传播。
从这些发现中，Azar表示早期的蚊子，无论是雄性还是雌性，都是吸血的，而雄性蚊子后来失去了这种能力。
研究人员表示，尽管这是已知最古老的蚊子化石，但蚊子可能早在数百万年前就已经存在。他们指出，分子证据表明蚊子的演化大约发生在2亿到1.45亿年前。
全球有超过3,500种蚊子，除南极洲外随处可见。一些蚊子传播疟疾、黄热病、寨卡病毒热、登革热等疾病。世界卫生组织表示，每年有超过40万人死于疟疾——一种寄生虫感染，主要是5岁以下的儿童。
我是约翰·拉塞尔。
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Words in This Story
fossil – n. something (such as a leaf, skeleton, or footprint) that is from a plant or animal which lived in ancient times
evolution – n. an idea that the differences between plants and animals are because of changes that happened by a natural process over a very long time
species – n. a group of animals or plants that are similar and can produce young animals or plants
anatomy -- n. the parts that form a living thing
pierce -- v. to make a hole in or through something
sap – n. a watery juice inside a plant that carries the plant's food
