The butts are undoubtedly smelly. But birds are actually quite fond of smelly chemicals, such as those found in aromatic(芳香的) plants. Some nest-building species regularly fill their nests with fresh aromatics, possibly because te chemicals are good for the immune system or the development of the chicks. Alternatively, the plant chemicals might act as insecticides.
In the study, researchers at the Autonomous University of Tlaxcala in Mexico set up heat traps, which attract harmful insects, in 55 nests around Mexico City. Some traps were lined with the stuff in smoked cigarette filters. The others were lined with the stuff from unsmoked cigarette filters, which did not contain nicotine and other smoking by-products. Whether the nest held eggs, chicks or nothing, the unsmoked cigarette traps collected more harmful insects, suggesting that it is the chemicals that drove harmful insects away.
In a second experiment, the researchers collected 28 house sparrow nests and 29 house finch( 朱雀 ) nests from Mexico City immediately after the chicks flew out for food. They found that the more smoked filter stuff filled a nest, the fewer harmful insects it had.
The missing piece of the puzzle is whether the reduced number of harmful insects in the nests actually provided any benefit to the chicks. It is also unclear if nicotine or another chemical found in cigarettes may have turned the harmful insects out of the nests.
【2017届河北省高三英语一轮复习55分钟课堂练习27 Word版含答案】相关文章:
★ 2017高考四川省广安市英语阅读理解一轮系列训练:2(含解析)
★ 重庆市2014高考英语阅读理解一轮(精品)训练题(21)附答案
★ 湖南省汝城二中2014届高考英语一轮复习阅读训练 (47)
★ 重庆市2014高考英语阅读理解一轮(精品)训练题(2)附答案
★ 【北师大版】2014届高考英语一轮复习指导课时作业:Unit 5 B卷 Word版含解析
★ 2017届高考英语二轮复习大题冲关秘籍完形填空之记叙文:名校模拟(含解析)
★ 【人教版】2014届高考英语一轮复习指导考点针对练:必修2 unit3《Computers》
★ 2017届高考英语二轮复习书面表达限时测验:3(含解析)
★ 2017届高考英语二轮复习书面表达限时测验:5(含解析)
★ 【优化方案】2017届高考英语二轮复习全国卷Ⅱ题型重组训练:第11组(含解析)
最新
2017-04-24
2017-04-24
2017-04-24
2017-04-24
2017-04-21
2017-04-21