Biology of Humans 6th Edition by Judith Goodenough,Betty McGuire

Exercise 13

In this chapter we have seen that plants form the base of most food webs. Bees pollinate many plants, including agricultural plants. Indeed, bees pollinate more than 100 crop species, representing 70% of the world's agricultural product. Thus bees maintain the base of a food web that nourishes much of the world, and so their loss would be devastating.
Colony collapse disorder (CCD), a mysterious condition in which the majority of worker bees disappear from the hive, leaving behind the queen and a few nurse bees, is difficult to study because the worker bees fly off and die alone. Among the hypotheses for the cause of CCD is a member of a class of pesticide, the neonicotinoids. Studies on the role of these pesticides in CCD provide contradictory evidence.
The following is a summary of Karen Feldscher's report on a study1 by Harvard researchers. You can read her entire report here: K. Feldscher, "Pesticide found in 70 percent of Massachusetts' honey samples," Harvard Gazette, July 23, 2015, at: http://news.harvard.edu
Researchers from the Harvard Chan School examined pollen samples collected from a set of hives in 10 of 14 counties of Massachusetts from April through August 2012. They worked with 62 beekeepers who used pollen traps on beehive landings to collect monthly samples of pollen and honey. In each sample, the pollen and honey contained neonicotinoid pesticides. The researchers conclude that bees foraging in Massachusetts are always at risk of neonicotinoid exposure.
Use at least three reliable sources to find other factors implicated in CCD. For each factor you find, describe a study that supports the hypothesis that it is a possible cause of CCD. Cite your sources.