Battle of the bedbugs

They feast on盡情享受 our blood while we sleep - leaving itchy, red welts傷痕 as their calling card. Bedbugs are an insect that many would like to see the back of. But in North America, Europe and Australia,infestations蟲害 are on the rise - and our insecticides殺蟲劑 are losing their bite. 

Researchers at the University of Kentucky in the US have found 14 genes associated相關地 with resistance抵抗 to these chemicals. They're causing a number of biological changes in the bedbugs. These include the development of a thicker skin that stops the poisons from penetrating透入 and mutations突變 within the insects' bodies that prevent the toxins from hitting the nervous system. 

The genes linked to these changes are active in the insect's tough outer shell外殼 - creating a formidable強大的 first line of defence. These findings could help scientists to develop new insecticides that could either turn these genes off or bypass繞過 the pest's害蟲 molecular shields防衛(盾牌).

But until these substances are developed, exterminators滅蟲 are having to resort採取 to more primitive tactics.
http://www.bbc.co.uk/worldservice/learningenglish/language/wordsinthenews/2013/03/130315_witn_bed_bugs.shtml