Turns out they’ve figured what was killing the honeybees, incidentally, and it was a fungus-virus combination. (Also wreaks havoc on college freshmen.) For what it’s worth, I read not long ago that it’s entirely possible — and maybe even likely — that these types of temporary fluctuations in the populations of different species have happened before, we just weren’t around or didn’t have the technology to pay such close attention. Now some subset of bees resistent to the fungus or the virus survives and multiplies to fill the honeybee niche.