How bee pandemics spread

I’m writing this in the midst of the COVID-19 emergency as a way of helping everyone distract themselves but yet provide some relevant content. It is always easy and simple to read about someone else’s problems! Hence, I’m bringing you this edition of my beekeeping newsletter, social isolation version.

Bees are not very good at social isolation

Honeybees are social creatures. If you think humans are social creatures, multiply it many times over. Bees are extremely dependent on one another. The queen (one per hive) and the drones (these are the male bees) can’t feed themselves and depend on the workers for being fed. Even these workers, who feed the queen and the drones, are not the ones collecting the food, as they are “house bees” as opposed to the “field bees”.

A bee queen surrounded by workers

Each bee has a little role to play within the hive, and it depends on each of the other bees doing their role. A bee cannot self-isolate more than one organ of your body can function on its own. The intra-hive interaction is never-stopping and essential, it encopasses everything from the bee-dance to many different pheromones – those secreted by the queens, by the workers, or even by the developing bee larvae and pupae.

Thus, a hive lives and dies together. There is no possibility of putting one part of the hive in quarantine. If a part of the hive gets a disease, the entire hive is likely to get it soon. In essence, the hive is one nuclear family, but in fact they’re even closer than your typical nuclear family, as the children essentially never leave the nest (I guess they earn their keep by doing all the chores).

Isolation between hives

For the most part, bees stick to their own hive and don’t move from one hive to another. Furthermore, bees from one hive have very limited interaction with bees from other hives. You won’t see bees playing around the way dogs play when they meet other dogs. There’s very little bee-to-bee interaction outside the hive, and hives are mostly kept isolated from one another.

If this was truly 100% true, there would be no bee pandemics. Bee pathogens would be limited to one hive, and possibly other descendant hives of that infected one, and hive-to-hive contamination would never happen. This would have been nice, unfortunately that’s rarely how it works.

Drones – the breakers of rules

“Drones” are just male bees. The majority of honeybees are workers – infertile female bees who perform the different hive tasks. Most of the eggs laid by the queen are female eggs, but a small portion of them are drones. Drones are used to spread the queen’s genome to other hives, by sending these drones to mate with virgin queens during their nuptial flight, an act that will cost these drones their lives as they die at the instance of mating.

Each hive prevents workers from other hives from wandering in. There are guard bees at the entrance to the hive, enforcing a bee equivalent of a “authorized personnel only” policy. Drones are excluded from that policy, and they frequently go into hives other than their own. This way they can spread their queen’s genome even farther, by gradually wandering away from their original hive. It’s in the best interest of the species, as it encourages genetic diversity and reduces the chances of a drone mating with a sister-queen.

It’s great, except for diseases. Some diseases tend to be carried by these drones. That’s how the horrible, terrible Varroa Mites are spread, these mites commonly carry with them bunch of other pathogens which are then transmitted to the new hive, so in a way, it’s the gift that keeps on giving. Varroa mites originate from Pacific Asia and gradually spread (almost) throughout the world, responsible for much of the decimation of both cultivated and wild colonies in the 1990s and 2000s. They are still a major problem to this day.

It’s a stick-up

As mentioned above, beehives are “authorized personnel only” areas. Only bees who grew up in that hive are welcome to enter. The main reason for that bee-enforced policy is that given the opportunity, hives will rob one another of resources, mostly honey. If you leave a jar of honey outside around the end of August, you can see that yourself (please don’t, for multiple reasons – for example store-bought honey could contain pathogens imported from another country).

One deadly bee disease is the feared American Foulfrood, or AFB. This disease is caused by a bacteria, back in the 1960s and 1970s it was the true fear of beekeepers for their hives to be infected with AFB. The disease does not affect the adult bees, only the larvae and pupae in the hive. As adult bees eventually die of old age (an adult bee lives 6-8 weeks), but the brood is consumed by the disease, there are fewer and fewer adult bees in the hive, until it cannot be properly guarded and is typically raided and robbed by neighboring hives. Unbeknown to these bees, they also take something else home, other than the sweet, robbed honey – they are now covered with tiny AFB spores, which they will carry to their home hive, thus continuing the chain.

AFB is extremely resilient in spore form. They can live up to 50 years inside abandoned beekeeping equipment. This is why AFB is required to be reported, the hives have to be killed and the equipment destroyed, typically burned. It’s a true tragedy for a beekeeper to have to kill a seemingly healthy hive which was diagnosed with AFB.

The mite bomb

Yet another disease carrying mode is one that was nicknamed “the mite bomb”, named after a common transmittal method of the good old varroa mites, but also applicable to some of the other diseases.

When a hive is infested with more and more mites, the hive becomes weaker, bother due to the direct effect of the mites on the bees (a bee that feeds a mite parasite is proven to be weaker), but also due to the many diseases the mites are known to carry (among those deformed wing virus and several different types of bee paralysis viruses… Can you tell I don’t like mites?). The hive becomes weaker, other than being robbed regularly, eventually the hive will completely collapse as it will be unable to sustain itself. Each of the adult bees would abscond, looking for another hive. Some would be turned back at that hive, but especially if they’re carrying nectar or pollen with them, they might be allowed in, bringing in mites with them and thus spreading the infection.

This is the reason why beekeepers are encouraged to monitor and keep their mite counts low, as a mite-infested collapsing hive might subsequently bring down many other neighboring hives (we would have loved to keep mite-free hives, but that would be unrealistic).

Isolate, and bee safe!

These are trying times for everyone, bees and humans alike (for different reasons though). I hope you and your loved ones are doing well, so stay safe and healthy everyone!!!