In the referenced Nature paper, the authors describe measurements they made on honey bee and bumble bee neurons in response to sugar with and without the neonicotinoid compounds. As I also stated, they also checked if the presence of the insecticides had any impact on the way the insects detect sugar. It did not.
Understand this: they inserted electrodes into nerve fibers that bees use to "taste" what they are consuming. Using these electrodes they monitored the nerve signals going to the bees brain. By varying the concentration of insecticides over a range starting at zero, they were able to show that there was no difference in the response related to the amount of the chemical they were testing. The paper has charts and graphs with error bars and correlation (p) values. It's real science done by real scientists, who know that their academic reputation depends on avoiding mistakes.
This is not a high school "science experiment" with a bunch of bees free flying in a cage with two sources of sugar and a student counting the number of bees going to one or the other. The experiment is based on a fundamental understanding at the neurological level of how bees function. It has nothing to do with nectar.
Your criticism is based on a level of understanding that is extremely childish. Are you actually that uninformed? You are not asking relevant question, but making assertions based in ignorance. Even given the generally low quality of analytical thinking shown on Slashdot, you lack of knowledge is pathetic. Normally I would say that you should look at the paper, but in your case I expect that there are too many big words that you would not understand.