It appears that part of the problem with the  neonicotinoid pesticides,  and bees is that bees react in the same way to the pesticides as a smoker does to nicotine, and preferentially select contaminated nectar.  (Research articles is here and here)

This has the effect of increasing their exposure to these pesticides, which have been tied to colony collapse disorder:

Bees prefer food containing neonicotinoid pesticides, research suggests.

They may “get a buzz” from the nicotine-like chemicals in the same way smokers crave cigarettes, according to scientists at Newcastle University.

The experiments raise the question of whether bees can be exposed to harmful doses of pesticides because they are attracted to the chemicals.

Another study found neonicotinoids had a negative effect on bees in the wild.

The Crop Protection Association, which represents pesticide producers, questioned the findings of the studies, published in the journal, Nature.
Scientific controversy

Bees are in decline in Europe and North America due to a number of factors, including pesticides, habitat loss and diseases.

In 2013, the EU imposed a two-year ban on using three neonicotinoid pesticides on flowering crops amid concern about their effects on bees.

Neonicotinoids contain synthetic chemicals similar to nicotine, which as a plant toxin is damaging to insects.

Neuroscientists at Newcastle University tested whether honeybees and bumblebees preferred food containing neonicotinoids over untreated food in the laboratory.

They were surprised to find that sugar solution containing two of three neonicotinoid pesticides appeared to be attractive to bees and “may act like a drug” targeting the brain.

This sh%$ is getting very real.

We need to stop pandering to the Ag chemical companies of the world, and review these chemicals with a lot more rigor.