Tag Archives: education

Dead Colony Forensics by Dewey M. Caron

About a dozen brave individuals gathered at the Zenger apiary colonies Sunday April 15th, during a steady Oregon liquid “sunshine” rain for dead colony forensics with Dewey.  Photo right by Mandy Shaw.

Temperature was low 50’s, with only a couple foraging bees venturing forth from 4 of 8 colonies. We hefted boxes and did autopsy on two dead-outs.

Bees die overwinter for a number of reasons. By doing a dead colony autopsy we seek to determine what might have been the likely reason for non-survivorship.  Understanding the why might help us avoid a repeat this next winter.

The first dead-out we looked at (photo above) proved to be a tough diagnosis.

The colony was a mid-May nuc donation from Beetanical apiaries of Lane Co. Hive had a standard and a shallow. The shallow frames were quite full (>3/4ths of cells) with capped honey. The shallow was lifted off and placed on upside-down cover.  There were dead brood remains on three frames of the lower standard box plus a small (<2000) number of dead adult bees on the screen bottom board and outside the entrance. Two adjacent frames had widely scattered capped brood cells extending in an oval  covering over  1/3 of the middle of the frames; there was a fist-sized patch of compact capped brood but it was not contiguous with the scattered brood of the other two frames. There was no evidence of a dead cluster but a considerable number of cells of stored pollen on 5 frames. Ample mold was evident in pollen cells and as a powdery grayish mold on surface of cells. Colony was sampled for mites with a sugar roll in September and had only 2 mites (<1%).  It was NOT treated for mites as it was a non-treatment control. Colony was alive in a mid-October inspection.

Photo of the three frames with brood shows the frame with a patch of compact brood (held  in my right hand) and two frames with very scattered brood (one in my left hand and the third on top of adjacent hive; this frame is shown isolated in photo right). Full super on ground.   Photos by Deb Caron.

So what can we diagnose? Lots of honey and pollen stores so we can likely rules out starvation. Small number of dead bee bodies suggests a small colony but if we would believe death from a too-small population of adults, there should have been evidence of a cluster with bees within cells and dead bee remains on the frame(s).  There wasn’t.

Thus our best guess is a colony that had a BEE PMS condition. The scattered brood remains on both sides of the two frames suggests this –a spotty (snot) brood situation MIGHT have been diagnosed in the October examination, but this requires a close examination of the brood; we might have noticed evidence to too few adult bees to cover the brood – both are subtle clues. The fist-sized brood area,  one frame over from the other two frames with scattered brood, might have been bees trying to escape the high mite numbers and their unhealthy brood of the 2 frames with scattered cells. Adult bees were likely dying prematurely and abandoning their (unhealthy) hive, thus the reason we saw only a smallish number of adult dead bees. The colony likely failed to rear sufficient fat, fall bees. The colony probably died within a month after the last October inspection, probably from a virus epidemic related to the mite infestation. NOTE: The September mite sample is misleading/confusing (we would expect it to have been higher); if an additional sample was taken it would perhaps have been higher?

The second dead-out was a more standard necropsy. Hive was a spring split,that struggled all season. It had 2 shallows. Colony had a 19 mite count (6%+) in September and was treated with 2 formic pads between the two boxes. It was alive in March (this spring) but noted as small. It was fed dry sugar on paper (some still remaining) and provided with a frame of sugar candy.

Opening the top and removing moisture trap, (all Zenger hives had moisture quilt traps at top) showed a dead cluster of adult bees on 3 frames in top box at top of the box extending down about ½ way on the 3 frames (see photos; in photo right, hive tool is showing the remaining dry sugar on paper – quilt trap with wood shaving lower right). The adult bees were black and showed excessive moisture; there were many maggots (scavenger fly) feeding on the dead bees. There was capped brood in compact pattern within the cluster. Dead adult population was small (perhaps 8-10,000 bees). There was NO capped honey in any of the frames of either box. Lower box was empty. There were some dead bees on solid bottom board. There was little mold.

So what was diagnosis? The dead cluster is characteristic of a colony that overwintered the tough months (Dec-Feb) and moisture of adult bees, maggots and little mold suggests recent death. The compact brood shows the colony was starting to expand in the spring (flight was noted in March). Although dry sugar (as candy and crystal sugar) was given as emergency feed (hefting would have revealed lack of enough stores), it turned out to not be enough — colony likely starved. Bee cluster too small to generate enough heat to make slurry out of dry sugar or candy so bees couldn’t use it. Photo below shows one of three frames. We see “bee butts” under the dead cluster and compact capped brood.  Photo by Deb Caron.

All frames, except one with high number of drone cells, could be reused for anew colony installation (package, swarm, split). Brush off dead cluster and from bottom board. If inclined wash mold with bleach or vinegar solution.

Bee class

Early in survey no place to explain that I was valuably helped by taking a bee class.

RESPONSE – You added into comments at end and that was good. We do have class by an association and by bee supply or garden store as possible answers. When not sure we can get this information in comments as you have done. Thanks for sharing.

Master Bee Keeper Program

Attending master bee keeper through OSU and believe my losses should greatly improve with better knowledge.
REASON: We all learn from mistakes. The OMB program has some great mentors and a generous amount to share about bees. Welcome and good luck.

Warre forum link

In the Education section, the other source of great information is the Warre forum hosted by David Heaf
RESPONSE – Thanks for sharing. We have little local expertise on Warre hives and because the management and hive are so different from movable frame Langstroth we need a good source of information. Here is a link as suggested  http://www.bee-friendly.co.uk/

Beekeeping Comparisons

I am curious about the differences in commercial beekeepers losses vs. hobbyists and urban vs. rural beekeeping losses. It seems that commercial beekeepers lose a lot. This year my very first loss was one hive, which I am proud of since I hear about veteran beekeepers of far many years experience whom loose half of their apiary to winter losses. I attribute my success to attending bee association meetings regularly and education through WA State Beekeeping program, reading sources such as books, internet and magazine subscriptions. Also the invaluable networking with other beekeepers and/or conferences.
RESPONSE – Our survey has found the opposite – commercial beekeepers have only about one-half the overwintering losses of backyard beekeepers – and this has been consistent in the PNW surveys now for a number of years. They lose heavier during the season than the backyarder beekeepers – they are requiring/expecting more from their bees and “using” them multiple times a year (for pollination primarily but also for honey production – they need more productivity to cover their time and costs.) What is “unique” about our current losses is that an individual may do the same management; same location, etc but have heavy losses one year and lighter another. Much we still don’t understand about bees – the survey effort is designed to enable you to look over your beekeeper neighbor’s fence. Networking and well-designed training materials and programs such as OR and WA Master Beekeeper programs are helping but are no substitute for the actual doing – to learn and benefit form understanding what bees are doing. I appreciate your sharing

Ending comment section purposes & beekeeping education

The survey doesn’t give an option for “I would like to…” in the question about what things have helped us. As it’s only April and we’re just starting beekeeping this year, we’re still trying to find beekeeping mentors, classes that actually fit our schedules, and other local resources, so would love to be able to indicate interest in those things 😉

RESPONSE: The last open section is exactly for your adding something like “I would like to….” Please consider adding that information. Most short courses/classes on bees are in Feb and March – there will be very few for rest of the year….and those that will be offered are often for more advance beekeepers (such as courses on queen rearing, our Journey courses in the OR Master Beekeeper program). Courses are offered early in the year so beekeepers can start this year. What is still available however are the monthly meetings of the bee associations. Many have an open Q&A session so you can ask an expert – some have a meeting before the meeting to get questions answered. Check out the OR State beekeepers site orsba.org for the nearest local group to where you live.

2015 Survey Q & A – Education

Q-Follow-up with suggested programs and classes in the area.

A – Thank you for suggestion under comments on your survey. We have many introductory courses in area – most have already taken place – but we have very little for intermediate levels – I am doing a queen rearing class end of Maya and bee Day April 25 at George Hansen’s in Colton is an event of value to those past the beginner phase. Portland Metro will have a mite intermediate workshop with me and Matt Hansen – date not yet set (likely in June or July). I agree that we need more courses!