A Beehive Autopsy

Though beekeeping is an incredibly fun, interesting and often exhilarating hobby, it certainly does have its challenges. Many beekeepers face losses of colonies each year, especially over the winter months.

Honeybee colonies are lost for various reasons, but taking the time to investigate what happened to a lost colony is an opportunity to learn what changes you can make to have more success with future colonies.

Patiently Waiting

In another Snippet, titled “Checking Your Beehive Has Signs of Life“, we discuss how you can check on your hive with little disturbance to the colony and cluster inside. If you haven’t found any signs of life, it’s best to wait a week or two and check again.

Once you’re certain that there is no longer a live colony of honeybees inside your beehive, there are steps to take to determine what may have caused their demise. Though it’s a sad and difficult task to endure, figuring out why the colony has died can help you better care for bees later on and help you decide on whether to reuse equipment from that hive.

Looking Through Equipment

You’ll want to first start by opening the hive and removing pieces of equipment one at a time. Take care to closely review and photograph each piece of equipment to see if there are any telltale signs of a problem, like dark staining (bee poop) on the frames indicating dysentery and possibly Nosema disease. 

Investigating the Cause of Death

In preparing for an inspection of a dead honeybee colony, you should think of answers to a few questions:  

-How big was this colony going into the winter?  

-How much food was stored in the colony in the fall and where was it located?

-What were varroa mite counts in the fall? 

-Was the colony in overall good health?

-Ahead of winter, was the hive prepared to prevent moisture issues? 

-Were there any recent abnormal temperature spikes? (i.e.: a day with temps more than 55 degrees F followed by a freeze overnight soon after)

For most beekeepers who lose colonies, these factors are often the main reasons that colonies perish, especially through the winter months. Ensuring you’re thinking about these issues long before the cold weather starts can help you ensure more success with future colonies.

As you’re pulling equipment apart, make note of where the dead bees and/or cluster are located. How many dead bees are inside the hive vs. outside? Are the bees dead with heads stuck inside their cells? In that case, they likely died of starvation, either because they didn’t have enough resources, or they lacked warmth to move to their honey stores.

Though it’s one of the grosser beekeeping tasks, uncapping some dead brood and pulling them from their cells can provide you with the unique chance to look for signs of Varroa Mite infestation. You may see things like actual mites on the larvae/pupae or bees with deformed wings or shortened abdomen.

Look for mite infestation signs in the brood comb, sugar-like white flecks on the outer edges of cells. This is “guano” (mite feces). Look for holes in the brood cappings or chewed-up pupae. Examine the brood pattern if it’s very spotty, but keep in mind brood rearing is limited in the winter and bees will abandon the brood if the colony is too small to keep it warm.

Another sign that Varroa can be suspected is if you only find a few dead bees in the hive and lots of honey. You can complete an alcohol wash of dead bees to check for mites.

Additionally, if you want to confirm colony death due to varroa mite infestation or Nosema disease and dead bees are not yet decaying, you can collect a sample of bees and submit it to the Bee Research Laboratory for further testing. Check out the USDA’s sample submission instruction page here to learn more. 

Whatever the reason your bees may have perished, taking these steps and asking yourself these questions as you review a dead hive can be integral in determining a better beekeeping plan for future colonies.

Cleaning It All Up

In most cases when the colony perishes, the hive equipment and frames can be cleaned up and re-used within your apiary. The exception is when the colony dies from American Foulbrood, then the whole hive and equipment must be destroyed. Colony Members can learn more in our detailed lesson here. Cleaning colonies that perished after Nosema infection requires special cleaning (fumigation). If your colony dies of starvation, cold/high moisture, varroa mite infestation, wax moth, or mice – frames and equipment may be reused after a thorough cleaning to ensure that the risk of transferring any disease or issues is mitigated as best as possible.

You’ll first want to scrape off as much “gunk” off frames as possible, broken comb, cross comb, any dead larvae or bees, and debris. Your hive tool is often the perfect one for this task. Once you’ve removed as much of that gunk as you can, you can use a bucket with a water and bleach solution to further clean equipment and frames and help avoid spreading disease. You can even soak the frames or equipment in this solution, just be sure to let it dry completely before storing or using it again.

Another great way to help ensure as much disease as possible is removed from the hive is to scorch (not burn!) your wooden bee equipment. This can be done easily with a “weed-burning torch” that hooks up to a propane tank. Quickly scorching the outside layer of the wood can help kill any disease spores that could be left behind. 

As you are scraping and cleaning your hive parts, review each piece of equipment for further clues about the bees’ demise. Pay close attention to the bottom board for signs of threats like robbing, mice, or small hive beetle infestation.

Ensure that any frames you plan to reuse are frozen for at least 2 days before reuse to avoid possible wax moth or small hive beetle larvae from persisting. You can take this as an opportunity to discard any old (very dark) and messy brood comb, too. 

Staying Positive

Though finding that one of your colonies hasn’t survived is always a tough thing to come across, it truly can be an invaluable lesson in making better beekeeping decisions and helping to protect your future colonies. Most, if not all, beekeepers lose a hive at one point or another, the important thing is to learn all that you can from it.

And keep on keeping bees! Every beekeeper can make a difference in helping to grow and sustain the honeybee population and help our environment by doing so.

Learn More

Ensuring you’re keeping track of what’s happening in your hive throughout the season and taking action when needed can help your hive thrive and hopefully mitigate future hive losses. Check out our article on Hive Inspections and Recordkeeping to learn more. 

Check out our blog post on The Value in Reviewing Losses to learn more about what to look out for and what to do when you find a deadout hive. 

Colony members can review even more details and learn more about this sad but necessary topic in the Academy lesson “Learning from Deadout Inspections“. 

Not yet a Colony member? Click here to learn more and sign up.