Now here's the interesting bit...
The swarm hive I caught last year and combined with another swarm a few weeks ago had a 3-day count of 133. I noticed several bees with DWV in this hive so was expecting some mites and a daily count of about 45 is a bit high. The following link is quite useful.
National Bee Unit - Varroa Calculator
The older established hive (that Dave has never treated or done anything with - EVER) had a 3-day count of just 13. Wow! There's something in this hive! Bees with good strong genetic traits perhaps? I know Dave thought of them as aggressive and I have heard anecdotal reports that aggressive bees (particularly Africanised bees) have greater resistance to Varroa. Well these bees aren't Africanised, but I can hope their behavior promotes some good mite control! I can but hope.
So what to do? Well I have some MAQS I can use to treat, but the weather looks a bit on the chill side for treating over the next couple of days. So I may just wait until Thursday and then treat just the swarm hive. The other I will leave alone.
If I am unlucky with the MAQS (I have lost queens in the past, but then the treatment was done in some very hot weather) I can think of worse things to do than take a frame of eggs and larvae from the established hive and pop this in the swarm hive! With luck I'll get their good genes passed on.
STOP PRESS: I added MAQS to the swarm hive on Wednesday evening. It wasn't too cold and the next few days seem to be good in respect of day time temperatures. I wanted to treat sooner rather than later.