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　　Ladybugs love to snack and feast on other pests, so people began importing in Asian species called hollyqueen ladybugs as natural pest control. But in their new environments the hollyqueens wiped out native ladybugs and they have their parasites² to thank. That's according to a research in the journal Science.

　　A parasite¹ called microsporadia lies dormant³ in the circulatory systems of hollyqueen ladybugs. But when scientists inject microsporadia into a common European ladybug species, the insects die within two weeks. When the ladybugs were injected with deed microsporadia or a control substance, most survive. Hollyqueen ladybugs' immune systems on the other hand have learned to deal with micro sporadia, which lets the insects use them as biological weapons. Because one way ladybugs compete is by consuming the eggs and larva of rival species. When European ladybugs eat the hollyueen ladybugs' eggs and larva they also consuming the microsporadia and die. The discovery demonstrates an important role of the immunity⁴ in evolutionary⁵ selection and shows there are many ways to lose a food fight.

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1 parasite
n.寄生虫；寄生菌；食客
参考例句：
The lazy man was a parasite on his family.那懒汉是家里的寄生虫。 I don't want to be a parasite.I must earn my own way in life.我不想做寄生虫，我要自己养活自己。

2 parasites
寄生物( parasite的名词复数 )；靠他人为生的人；诸虫
参考例句：
These symptoms may be referable to virus infection rather than parasites. 这些症状也许是由病毒感染引起的，而与寄生虫无关。 Kangaroos harbor a vast range of parasites. 袋鼠身上有各种各样的寄生虫。

3 dormant
adj.暂停活动的；休眠的；潜伏的
参考例句：
Many animals are in a dormant state during winter.在冬天许多动物都处于睡眠状态。 This dormant volcano suddenly fired up.这座休眠火山突然爆发了。

4 immunity
n.优惠；免除；豁免，豁免权
参考例句：
The law gives public schools immunity from taxation.法律免除公立学校的纳税义务。 He claims diplomatic immunity to avoid being arrested.他要求外交豁免以便避免被捕。

5 evolutionary
adj.进化的；演化的，演变的；[生]进化论的
参考例句：
Life has its own evolutionary process.生命有其自身的进化过程。 These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。