Loose cocoon vs. whole (inspected) tube management - which do you do?
What experience have you folks had with loose cocoon vs whole tube management?
In both cases, the pre-condition for my question is that both methods involve inspection to remove or control parasites. The tube I used last year were either pre-slit (so you could peek inside) or rolled parchment (so you could unroll and re-roll.) I did not keep any sealed tubes that I was unable to inspect.
For the tubes that had any parasites in them (mostly mites) I scraped them out, cleaned them, and kept them as loose cocoons. This was about 90% of the tubes. For tubes that were completely parasite free (about 10%) I kept them as whole tubes. They're are all roughly 6" paper tubes of slightly varying diameter.
I read in the SARE "How to manage the Blue Orchard Bee" guide that bees who chew their way out of their natal tubes have much lower pre-nesting dispersal. Up to 80% of them stay and nest. (see page 46 of the guide here: http://www.sare.org/Learning-Center/...ue-Orchard-Bee) They also say that loose cocoons have much higher (50%) dispersal. That makes a heck of a difference when you are trying to build your population year over year.
What has happened so far?
1. Loose cocoons emerged as planned.
2. Whole tubes showed activity MUCH later than the loose cocoons--almost two weeks later. When I inspected them, I found very frequently that the first male had emerged and escaped the tube, but many other bees had emerged and were still stuck in the tubes. As soon as I pried them open, they flew out immediately. They seemed simply unable to get out---five bees in a row would appear emerged, but trapped in place
With our record-cold and record-rainy weather in Seattle, I have a very high dispersal rate (75%) --even more than last year. With my multiple houses located within 50 feet of each other, it's impossible to determine which bees stayed vs which bees dispersed.
For people who inspect their cocoons, which do you use and what's your experience with minimizing dispersal?