螨虫通常被认为是一种肮脏的寄生虫，然而它们中的一些实际上正在扮演着清洁工的角色。

图片左边为汗蜂，右边为蜜蜂螨

据美国《科学》杂志在线新闻报道，德克萨斯大学的研究人员发现，蜜蜂螨（Laelaspoides，如上图）能够帮助汗蜂（Megalopta）清除巢中的真菌，作为回报，前者可以一直安全地住在蜂巢中，甚至被后者带到它们的新家。如果将螨虫拿走，则蜂巢中的真菌会感染并杀死大多数幼蜂。然而螨虫如何消灭真菌却依然是个谜——它们或许分泌有毒的化学物质，或许能够将真菌吃掉。研究人员在《美国博物学家》杂志网络版上报告了这一发现。

生物谷推荐原始出处：

The American Naturalist，Natalia B. Biani ，William T. Wcislo

Cleaner mites: sanitary mutualism in the miniature ecosystem of neotropical bee nests

Natalia B. Biani (University of Texas at Austin), Ulrich G. Mueller (University of Texas at Austin), and William T. Wcislo (Smithsonian Tropical Research Institute)

Contrary to popular belief that mites are nasty parasites, there are some mites that are actually beneficial and help bees clean their nest of microorganisms. Scientists at the University of Texas at Austin and at the Smithsonian Tropical Research Institute tested this idea in Panama. They studied the partnership between Megalopta bees and their mite associates. These bees nest in dead branches and each nest is a miniature ecosystem that is not only inhabited by the bees and their brood, but also by an extensive array of organisms, such as tiny flies, spiders, velvet ants, fungi, round worms, and of course, mites. Biani and colleagues discovered through a series of natural observations and bee-rearing experiments in the lab that there is much less fungi growing when mites are present in the nests, and also that bees are able to survive better than without mites. What do the mites get in exchange for this cleaning service? "A good, safe place to live and free rides on the back of the bees to new nests," says Biani.

Cleaning mutualisms have been known from coral reefs where small fish and shrimps get their food by removing parasites of bigger fish's gills and mouth. This study soon to be published in The American Naturalist constitutes one of the few examples of terrestrial cleaning mutualisms. It shows how some animals join forces with other species in order to protect their brood and their food from potential pathogens.