Do neonicotinides cause bee decline?

[Denninmi]

1. I'm sure they probably do.

But I don't think "colony collapse" has one discrete cause. More likely a combination of things. Frankly, mite pressure is still strong. I took a beekeeping (for credit, and graded) class at Michigan State in the 1980s. Mites were known but hadn't arrived in Michigan yet at the time. Believe me, I see an overall decline in the vigor of colonies now. And, despite everything I throw at them, from Apistan to menthol to whatever, I can't eliminate mites, just keep them suppressed to tolerable levels.