Too Many Dead Bees!

The dark spots are the dead bees.
(Click to view larger)

Wednesday all three hives were observed bearding in the evening as our temps have been very hot. I don't remember looking at the bees Thursday evening but I usually do and it is entirely possible that, because everything looked normal, nothing registered with me.

But Friday evening it was easy to see that something was very wrong with the Dmitry hive - No bearding as with the other hives, no bees flying, no orientation flights, nothing. And then I looked down...

Thousands of dead bees lay in front of the hive filling a mulched space of three feet or so in length. My mind began a mental checklist as I searched for a possible cause. The bees were not chalky, their wings were not crinkly or 'K' shaped. It was almost as it someone came along and sprayed pesticide on them and they fell from the front of the hive. But if that were the case, why would vandals harm just the center hive of my three?

There were so few bees in the hive, I didn't bother with a veil or gloves as I opened it, expecting to find it empty. Instead, I did find healthy looking bees but zero brood. The queen looked fine but she isn't laying. She had been laying well since she was installed back in April.

So, what the heck is going on with this hive? I believe I have two separate issues:

Issue One:
I had quit feeding the hive as they were growing in population and had built up a good reserve of pollen and nectar. However, we're in a full dearth now and what are the three things a hive needs to thrive?

1. Space
2. Ventilation
3. Food

There was plenty of space and ventilation thanks to modifying the inner cover. But I had neglected to ensure the hive had food! It is common knowledge that a queen will cease laying if food becomes unavailable. So I put the top feeder on and filled it with 1:1 sugar syrup. Will check back in a few days to see if the queen has resumed laying.

Issue Two:
I'm stumped what happened to the dead bees outside the hive but a likely culprit is pesticides. I live in a rather rural area with small farms, pastures, homes and gardens. It is highly likely the foraging bees found a good food source that was tainted and led many other bees to it, who in turn, brought the tainted pollen and nectar back to the hive.

I gave the hive a couple frames of brood and nurse bees from the Sasha hive, leaving the OV hive alone so as to not harm it's new queen as she matures.