Literature Review: Carefully Assessing Hazards

by Carl Strang

The Internet is a tremendous resource, providing ready access to all kinds of information. It also has become the foundation for significant social networking. Those two benefits have their dark side, however, as rumors and half-baked ideas spread readily and take on a semblance of fact. These might be amusing, except that they can take a nasty political turn, as in the attack on the American president’s legitimate citizenship, or unsupported fears regarding vaccines or genetically modified crop plants. Concerns about the measured declines in pollinator insects have drawn a lot of attention, and a wide range of hypotheses. This is good, as science works from hypotheses. The next step is to test these, but as is the case for the speculations listed above, lots of people want to jump directly from possibility to voting decisions or legislation without waiting for the results to come in. This week’s selected study from the 2013 scientific literature is an example of how possibilities need to be tested and sorted out. The results are not simple and straightforward the way Internet fear- and rumor-mongers would have it. The study focused on certain insecticides, white clover and our most common species of bumble bee.

Bombus impatiens worker. This is practically the only species of bumble bee we see in the Chicago area from August on.

Bombus impatiens worker. This is practically the only species of bumble bee we see in the Chicago area from August on.

White clover flower. This introduced legume has flowers strongly attractive to bees.

White clover flower. This introduced legume has flowers strongly attractive to bees.

Larson JL, Redmond CT, Potter DA (2013) Assessing Insecticide Hazard to Bumble Bees Foraging on Flowering Weeds in Treated Lawns. PLoS ONE 8(6): e66375. doi:10.1371/journal.pone.0066375

They looked at Bombus impatiens colony responses to lawns with white clover that were treated with two different lawn insecticides. Neither insecticide affected the bees if flowers present at spraying time were mowed from the plants. One of the insecticides (chlorantraniliprole) did not affect the bees, the other (chlothianidin, a neonicotinoid) affected bees that visited flowers that had been sprayed. New flowers opening after spray application did not affect bees.

Ecological interactions are complex. Biochemistry is complex. We humans have developed tools that help us deal with such complexity. Reason and intuition are two such tools, but when addressing real world problems involving physical entities or processes the formalized use of reason (i.e., science) is needed if we are to have clear and unambiguous answers. The fear-mongers manipulate peoples’ intuition to shape statements that sound right, but without the tedious sorting out of hypotheses through scientific studies such fearsome forecasts have to be regarded as nothing more than possibilities.

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