Biodiversity, including small predators2 such as dragonflies and other aquatic3 bugs4 that attack and consume parasites6, may improve the health of amphibians7, according to a team of researchers. Amphibians have experienced marked declines in the wild around the world in recent decades, the team added. The study suggests that dwindling8 global environmental biodiversity and worldwide spikes9 in infectious diseases may be linked, said Jason Rohr, associate professor of integrative biology, University of Southern Florida.In the last century, there has been an unprecedented10 global increase in infectious diseases and a concomitant decline in and homogenization of biodiversity, said Rohr. The controversial dilution11 effect hypothesis suggests that the two phenomena12 might be linked, or that biodiversity often decreases disease risk.In the study, which included a series of laboratory experiments, field surveys and mathematical modeling, the presence of various species of dragonfly larvae13 reduced the infections in frogs caused by parasitic14 flatworms called trematodes, said Val Beasley, professor and head of the department of veterinary and biomedical sciences, Penn State, who worked with Rohr and whose research group collaborated15 with Lucinda Johnson, senior research associate and director of the Center for Water and the Environment, University of Minnesota Duluth, to complete the field study.Beasley said that various species of trematodes penetrate16 tadpoles18, sometimes killing19 them and at other times weakening them with tissue damage, kidney failure, or severe limb deformities when the tadpoles develop into frogs. He added that other vertebrate species commonly catch trematode infections from bodies of water. These include wildlife, domestic animals and humans -- mostly children -- who are commonly affected20 by schistosomiasis in tropical parts of the world.The researchers, who release their findings in the Proceedings21 of the National Academy of Sciences, did not see a similar reduction in trematode infections in the presence of larval damselflies, which are intraguild predators, meaning they attacked and killed not only the parasites but also the tadpole17 hosts.According to Rohr, most research on biodiversity focuses on the diversity of parasite5 hosts, while this study reveals the importance of the diversity of species that attack and eat parasites.In our wetland survey, our microcosplayms and disease models, we discovered that there were fewer flatworms in frogs where there were more species of flatworm predators, said Rohr. Additionally, the field study indicated that the diversity of these predators was a better predictor of flatworm infections than nutrients22, frog immunity23 or the diversity and abundance of hosts.The researchers emphasized the similarities between their findings and research on roles of small predator1 communities that help control crop pests. They concluded that both management of crop pests and efforts to prevent parasitic disease can be guided by the need to conserve24 the biodiversity of small predators.
点击收听单词发音
1 predator n.捕食其它动物的动物；捕食者 参考例句： The final part of this chapter was devoted to a brief summary of predator species.本章最后部分简要概要了食肉动物。 Komodo dragon is the largest living lizard and a fearsome predator.科摩多龙是现在存在的最大蜥蜴，它是一种让人恐惧的捕食性动物。
相关文章推荐
