Here we have the poisoned nest of the Asian Honeybee (Apis cerana). If you’re wondering why the nest was poisoned, it’s because this species is actually quite damaging to this area. The Asian Honeybee not only leaves in competition with native bees over nesting areas and food, but they may also carry a certain nasty mite known as the ‘Varroa mite’ (genus Varroa), which can be detrimental to European Honeybee populations (Apis mellifera) (1).
Lets take a closer look at this nest shall we. First we’ll start off with the eggs. You can see an egg inside a brood cell in picture 9. The eggs are very small, and take about three days to develop. After which the fat little larvae emerge, curling up and waiting to be fed by the worker bees. When the larva becomes large enough, the brood cell will be sealed, so the larva’s pupation will be undisturbed. The adult bee will chew its way out of the cell after emerging from the pupae (2).
You can tell which brood cell belongs to which kind of bee based on its appearance. The drones have a distinctly dome-shaped cap with a large pour in the center (pic. 7). Then, of course, there’s the queen’s brood cell, which is large, round and on the edge of the nest (pics 5-6) (3).
When it comes to this species, it’s important to stay informed about the ways in which they are damaging for the environment.
So there's a kickstarter happening soon for a beekeeping book on how to breed honey bees for resistances to a really bad parasite called Varroa destructor. This is important because this parasite has been devastating beekeeping for decades, adapting to chemical treatments, and now it's just landed in Australia. The kickstarter itself boasts super cool rewards like this adorable custom honey bee plush toy:
Please share it if you can, the info's all on the pre-launch page linked here:
Die Varroamilbe ist eine große Gefahr für Honigbienen. Ein gängiges Mittel gegen die Schädlinge: Säure. Diese belastet aber die Bienenvölker
Die Varroamilbe ist eine große Gefahr für Honigbienen. Ein gängiges Mittel gegen die Schädlinge: Säure. Diese belastet aber die Bienenvölker. Die Bienensauna ist eine Alternative, um die Milben los zu werden.
A while back I finished Michigan State University’s “Heroes to Hives” program, learning about honeybees. I’ve been fascinated by honeybees for a long time, and it was a really interesting course (and it’s free for veterans and their dependents -- Google “Heroes to Hives Michigan” if you’re that and you’re interested).
At any rate, I think that one of the biggest things I took away* was that Varroa destructor, aka the Varroa mite, is an insidious little bastard, and probably the primary enabling cause of Colony Collapse Disorder. So I’m going to talk about that, in this very long post, below the cut.
* How could I not? The primary instructor, Dr. Adam Ingrao, is extremely passionate (and dramatic) about the topic. So take it all with a grain of salt, but he did back it up with some quality info, which I’ll include below.
[ Image description: a photograph of a V. destructor mite on honeycomb(1). It is a hairy ovoid creature, brownish-red in color, with hair little legs sticking out along one of its long sides. It is such a small little beast that the hexagonal shape of the comb is not apparent in the photograph. End ID. ]
Varroa destructor is a mite that arrived in Europe in the 1970s, and made its way to the US in force in the late 1980s(2). By 2007, it was established in the entire United States, including all of the islands of Hawai’i(3). This is important, because a lot of the beekeeping practices that are based on the natural lives of the honeybees (such as the Warré Hive) were developed prior to the mite’s arrival.
I myself am passionate about the importance of knowing how bees live in the wild if you’re going to have an apiary -- I know not all beekeepers are like this, for various reasons (e.g., if you’re a commercial beekeeper who’s working with orchard growers to pollinate trees under contract, you need to both have a lot of bees, and you need to be able to transport them, so you’re going to necessarily have different needs & a different perspective than, say, a hobbyist like me). I think it’s okay: the important thing is: we need bees. And we need to understand what Varroa’s doing to our bees.
Varroa evolved with a different species of honeybee: Apis cerana, or the Asian honeybee. In the west, the primary species that beekeepers keep is Apis mellifera. This means that the Varroa was able to hop right on over onto a species that had not evolved defenses to it. The results have been devastating -- let me tell you why.
Until very recently, most researchers would tell you (and probably still will) that Varroa feed on the bees’ hemolymph -- their version of blood. In 2019, a number of researchers demonstrated that this is not the case: what the Varroa are feeding on is a honeybee organ called the fat body(4). The fat body is something akin to our liver, in that it (among many other things) functions as a filter, which is why I jokingly call these little bastard mites “the Hannibal Lecters of the honeybee”. But the fat body does a lot more: it both acts as an energy store, which I probably don’t need to tell you is important, is a major piece of the bees’ immune system, and it produces a complex called Vitellogenin (I’m gong to refer to it as “Vg” for short).
Vg is critically important to the honeybee. It is has a three-in-one function: as a protein complex, it contains proteins, but it also lipids and carbs. It’s vital to the bee’s ability to synthesize proteins, it supports the immune system’s response, and it is what determines a honeybee’s longevity: a queen bee, who lives for 2-3 years, is packed with it, whereas your regular honeybee worker doesn’t have a lot, and conversely lives for 45-60 days.
Who else has a relatively high level of Vg? Winter bees, which is why Dr. Ingrao refers to them as the fourth honeybee caste: in addition to workers, drones, and the queen, you have these “winterover” bees with their high Vg level. What’s their purpose? To live. In particular, to live for 4-6 months during the winter, when they’ll have no access to food outside the hive, and during which time they’ll be keeping the nest (and queen) alive by keeping it warm. They do this by clustering tightly (insulation) and shivering (thermoregulation), which requires a lot of energy. So they need that fat body both for its energy stores, as well as for the Vg so that they live long enough to keep the colony alive (they also eat honey, of course, which is why it’s important for beekeepers to leave honey in place, and also to leave honey in certain places, since the cluster will not expand in cold temperatures, so they’ll never get to honey stored too far away from the center).
This is why Varroa mites are so awful: they eat that fat body away to practically nothing. The little bastards grow at an exponential rate: in the beginning of the season, their numbers are low enough that they’re not going to have a lot of impact on the bees. But if a beekeeper does nothing, their population will explode in the months of August and September. This is precisely when the colony is beginning to develop the generation of winter bees it’s going to need to make it through the cold. That explosion of mites gets into the brood of baby winter bees and feeds on the larvae’s fat bodies, so when the winter bees finally emerge, their fat bodies are fatally compromised: they haven’t developed the necessary levels of Vg, meaning they won’t live very long. Their immune system is compromised, leaving them vulnerable to the many myriad viruses that the Varroa mite carries. Because their energy system is compromised, they can’t thermoregulate effectively.*** And their fat body can’t filter environmental toxins(5), making them more vulnerable to pesticides such as neonicotinoids**, which are most likely in the honey that’s been put away for the winter.
** This family of pesticides is in fact banned in Europe because of their impact on pollinators (but, sadly, not yet across the US).
*** I believe that this is not helped by thin-walled beehives. But that’s a topic for another article.
With all this in mind, it’s absolutely no wonder that Colony Collapse Disorder occurs, and that whole colonies die before the winter is out (and sometimes in the middle of summer).
What to do? Well, there’s been some stellar work in breeding Varroa-resistant strains of Apis mellifera, which is great news for beekeepers. Also, Dr. Thomas Seeley discovered that evolution is working as it should in Cornell Universty’s Arnot Forest, a research preserve in New York State, as he recounts in The Lives of Bees. However, this resistance has game at the cost of a mitochondrial bottleneck, though fortunately overall genetic diversity had increased -- while the number of queens had been drastically reduced, the dying colonies had apparently still produced enough drones to spread their genes throughout the forest’s bee populations(6). But critically, his research pointed towards the evolution of the mites versus the bees (in other words, the mites’ overall success depended on them becoming less lethal to the bees)(7). At any rate, some beekeepers advocate doing nothing: just let the bees sort it out on their own, and develop resistance through evolutionary processes.
I personally have a couple of issues with this: first, unless you are specifically breeding bees for resistance (in other words, you’re artificially speeding up the evolutionary process), this is going to take a long time, and you’re going to lose most of your bees. Also, if you’re not pursuing the treatment-free process correctly (i.e., monitoring, and then killing the colonies that experience mite explosion, so that only the colonies that are able to control the mite population on their own survive to reproduce), you’re selecting for successful mites instead of successful bees(8).
If you’ve got a ton of money and can afford buying new bee packages every year (at something like $150 to $200 a pop) until you’ve built up an apiary of successful bee colonies, that’s okay, but there is yet another problem: swarming.
This is a colony’s means of reproduction: a strong colony will cast of one or more swarms -- children, sort of***. This is one of the ways that wild bees actually manage their Varroa loads: the departing bees take a bunch of Varroa with them. The problem with this for beekeepers is that a) they generally keep steps to prevent bees from swarming, which means more Varroa remains in their really big hives or b) if the bees do swarm, and there are other beekeepers in the area, some of those bees are probably going to make their way into their hives, taking your problem into their apiaries, which imo is not cool unless you absolutely know they’re okay with it, and which means that on top of everything else, you have to be completely invested in swarm control. It’s a lot of work!
** I say “sort of” because the primary swarm is actually the old queen leaving with a bunch of bees, leaving a bunch of bees in the original nest/hive along with a virgin queen. It would be roughly analogous, in humans, to the parents of a child moving out of the family home when it’s time for the child to be on their own, and the brand new queen there now has to fly out on a mating flight and successfully make it back to the nest in order for this next generation to survive (in their childhood home). Subsequent swarms, if the colony is big enough to support them, will consist of yet more bees departing with newly-hatched virgin queens, who not only have to fly their mating flights, but have to establish a completely new household somewhere.
Knowing what Varroa does to bees, I’m personally not at all cool with these parasitic bastards. They’re awful, and I don’t want to do that to any colonies of mine. To me, it’d be like not vaccinating a pet for a nasty virus (like FIV for a cat) and then potentially letting that cat run around outdoors where it can not only pick it up, but also spread it to other cats in the neighborhood, all in the name of “letting cats develop FIV resistance naturally”. It’s just not for me, at least, not right now.
There are, fortunately, a ton of ways to knock down the mite load in honeybees, many of which are natural but all of which you need to actually understand before you utilize. Some beekeepers will simply treat with one or more method on a regular schedule -- this is called “prophylactic treatment”, and I personally am not a fan of it: I’m concerned that this will allow mites to built up resistance to them. I’m also not a fan of doing nothing, for the above reasons: potential impact on my neighbors, and I just don’t want to be losing bees all the time. So if I actually ever set up any hives, I’m going to go for an Integrated Pest Management solution: I’ll monitor my colonies for Varroa, and then treat them with the appropriate treatment when (and only when) the mite load is high enough to call for it (I’ll check 300 bees with either a sugar role or alcohol wash method and if I find 9 or more mites, I’ll treat).
I'd originally been very interested in the Warré Hive for its emphasis on beekeeping that operated in accordance with the bees’ own natural inclinations. But the need to be able to inspect the hive for pests, particularly Varroa, means that for me at least, I need to have moveable frames. So I’m probably going to go with a Langstroth-style hive, with some modifications for experimental purposes, which I might talk about later, if I get around to it.
As always, thank you for reading my book!
Citations (unlinked to ensure the post shows up in the applicable tag feeds)
Note: where information, above, is uncited, I’ve obtained it from the “Heroes to Hives” course material. Most of it’s easily available in the applicable Wikipedia articles.
(1) User Wasp32, “Varroa destructor”. - https://commons.wikimedia.org/wiki/File:Varroa-destructor.jpg
(3) Texas Invasive Species Institute, “Varroa Mite” (2014). - http://www.tsusinvasives.org/home/database/varroa-destructor
(4) Ramsey, Samuel, et al. “Varroa destructor feeds primarily on honey bee fat body tissue and not hemolymph” (2019) - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6358713/
(5) Ibid, figure S5 of the supplementary file (page 6).
(6) Seeley, Thomas. The Lives of Bees: The Untold Story of the Honey Bee in the Wild (2019). Princeton University Press. Also available in the original research paper by Dr. Selley:
(7) Seeley, Thomas, “Honey bees of the Arnot Forest: A population of feral colonies persisting with Varroa destructor in the northeastern United States“ (2007) - https://www.researchgate.net/publication/226076088_Honey_bees_of_the_Arnot_Forest_A_population_of_feral_colonies_persisting_with_Varroa_destructor_in_the_northeastern_United_States
(8) Seeley, Thomas. “Darwinian Beekeeping“. American Bee Journal, March 2017. Reproduced with permission at https://www.naturalbeekeepingtrust.org/darwinian-beekeeping
Varroa destructor, the leading cause of beekeeper angst.
This relatively large mite parasitizes honeybees from adults to larvae. Crab-like aren't they? Specimen provided by Krisztina Christmon from the University of Maryland where she studies the life history of these tricky beings. Oh, that is the tip of an insect pin you see in the picture.
Beekeepers Seek to Save Honeybees From a Colony-Invading Pest
“Female Varroa mites lurk in the darkness of a honeybee hive, waiting for the right moment to slip into the wax cells where young bees spend their youth, growing from egg to larva to pupa to adult. As larvae, the bees are ravenous, and their adult sisters, the nurse bees, visit them and provide food more than a thousand times a day. As a larva approaches its next life stage, it sends out a pheromonal signal; the nurse bees know they’ll soon need to put a waxen cap on the cell, so the young bee can complete its metamorphosis.
The problem is that the scent signal also reaches the Varroa mites, who enter the cells and hide under the larval bees’ goopy food, sending up a snorkel so they can breathe. After the cells are capped, a mite will give birth, her daughters will mate with their brothers, and the whole family will have up to two weeks to feed on the unguarded bee.”
Colonies suffered from parasitic, disease-spreading Varroa mites. Floods and fire didn’t help.
U.S. honeybees just weathered an unusually bad winter.
About 38 percent of beekeepers’ colonies died between October 1, 2018, and April 1, 2019, the Bee Informed Partnership estimates. While it wasn’t the worst recent year overall for honeybee losses — that was 2012–2013 — preliminary results released June 19 show it is the worst winter die-off recorded over the University of Maryland–based nonprofit’s 13 years of surveying bee populations.
Beekeepers should be able to rebuild those numbers this year, but such ongoing winter losses raise deep worries about the future of crop pollination. On average over the 13 years, about 29 percent of colonies have died each winter. The 2018–2019 numbers came from nearly 4,700 beekeepers, representing about 12 percent of the estimated 2.69 million U.S. hives.
Bee gone: Beekeepers say they could accept some percentage of loss in colonies during winter (gray bars), but actual winter losses (yellow) estimated over the past 13 years have been higher, according to an annual survey by the nonprofit Bee Informed Partnership. Colonies die in summer too, so starting in 2010, the survey included estimated colony losses during a whole year (orange).
Annual estimated U.S. honeybee colony losses, 2006–2019
CREDIT: THE BEE INFORMED PARTNERSHIP
Some floods and fires this year destroyed colonies, but “the take-home worry for me is Varroa [mites],” says the Partnership’s Dennis vanEngelsdorp, a bee-health entomologist at the University of Maryland in College Park. The invasive mite species Varroa destructor clamps its tiny pimple-shaped body onto bees just as they’re turning into adults (SN: 2/16/19, p. 32). Mites sap bee strength and spread disease, yet remedies against the pests seem to be losing their power. “Ideally in the long-term, we would have a bee that was resistant,” vanEngelsdorp says.
While winter bee colony die-offs are worrisome, beekeepers can split surviving bee colonies and add new queens. Replacing winter-killed colonies this way, however, takes labor, time and money.
Only 5 percent or so of U.S. beekeepers work at the commercial scale that supplies 90 percent of bees pollinating the nation’s crops, vanEngelsdorp says. If the relentless drain of replacing winter losses drives them out of business, “it’s very hard to replace that group of beekeepers.”
