Yes, but not in Germany

Scientists try to ask simple questions and to design a controlled experiment, with “all other things being equal.”  It’s rarely possible.

Our chief consultant writes:

Here at Five Colors we claim no expert knowledge of biological subjects.  However, they are very important, and occasionally we come upon papers that require no detailed background to read.  Two of these were published in the 30 June 2017 Science, concerning the effect of a certain class of insecticide on bees.

Bee colonies in both Europe and America have been declining alarmingly in the past few years, for reasons that are not yet clear.  And bees are important: not just producers of honey, they pollinate many crops.  It’s an exaggeration to say that if bees die off we will have nothing to eat, but not by much.  (One of our relatives raised various crops in California.  He kept bees to pollinate his almond trees, but their honey was too bitter to eat.  Orange-grove honey, on the other hand, is known for its wonderful flavor.)

Some studies have shown that a family of insecticides, the neonicotinoids, used to protect crops from pests, have bad effects on bees.  However, in-lab experiments have been criticized for various unrealistic conditions, and short-term studies in the field have yielded conflicting results.  The first paper in Science looked at 33 different rapeseed-growing sites in the UK, Germany and Hungary, each divided into one field with one neonicotinoid insecticide, another with a different one, and one with none; and at each site recorded what happened to three kinds of bees from the flowering season over the following winter.  A companion paper, using a different structure, looked at bees near corn crops in Canada and the US.

The effects of the insecticides were generally negative, not actually killing off the bees but certainly reducing their ability to survive.  The two different insecticides acted differently, though, with one having less effect than the other.  And in Germany the insecticide bees actually did better than the control bees.

As we’ve noted before, biology is complex.  We’d like a yes-or-no answer to the question: are neonicotinoid insecticides bad for bees?  What we get is: sometimes, but apparently not in Germany.  There are many factors at work, and insecticides are only one of them.  The second paper found a possible clue: one fungicide applied to the corn crop seemed to increase the negative effect of the insecticide.

The effect of neonicotinoids on bees is bad enough overall, though, to make a ban on them wise.  However, all other things are not going to stay equal in this case.  What will the farmers replace them with?  Other chemicals, other procedures?  It seems like asking a lot to require all farmers to move to Germany.