Traffic fumes render the scent of flowers barely recognizable to honeybees and could have a serious impact on their ability to find food, new research has found. Scientists discovered that reactive pollutants in diesel (柴油) destroyed key chemicals in the odour of oilseed flowers making them smell different to the bees. "Honeybees have a sensitive sense of smell and an exceptional ability to learn and memorize new odours," said Tracey Newman, a neuroscientist at the University of Southampton. "The effect of diesel fumes on flower scent could have serious detrimental effects on the number of honeybee colonies and pollination (授粉) activity." Three-quarters of the world's food crops rely on bees and other natural pollinators " Pollinator services are crucial to humankind," said Newman. But there have been serious declines in natural pollinators in recent decades. A combination of factors is blamed, including the huge loss of the flower-rich habitats that sustain bees, as well as disease, and the impact of agricultural insecticides. The revelation that traffic fumes could be adding to the problems is significant, said Guy Poppy, a professor and ecologist at Southampton, who also worked on the research. He said, "Diesel exhaust is not the root of the problem, but clearly, with all the other stressors, adding another one is likely to be detrimental to bee health."The study, published in the journal Scientific Reports, tested bees' ability in the laboratory to recognize the aroma of oilseed rape flowers. Bees were strapped down and taught to associate floral scents with food in the form of sugar solutions. Once the bees learned the connection they began sticking their tongues out in anticipation of food even if it was not offered—an indication that they recognized the smell. When the scent was presented without pollutants the bees recognized it 98% —99% of the time. But after the scent was mixed with levels of diesel exhaust matching those found at roadsides, the bees only recognized it 30% of the time.

【正确答案】 B

【答案解析】解析：根据文章第一段第二句Scientists discovered that reactive pollutants in diesel destroyed key chemicals in the odour of oilseed flowers making them smell different to the bees可知，“柴油的活性污染物破坏了油菜花气味中关键的化学物质，让蜜蜂闻到的是不同的气味”。因此可以选出B选项，柴油的活性污染物改变了油菜花的香味。A选项“破坏了油菜花”的信息不够细化。C选项“污染了空气”并未在文章中描述。D选项“损害了蜜蜂的嗅觉”是断章取义，也不对。