You’re in for a treat this week. Beelistener reader Dr Chris Palgrave kindly donated his time and expertise by creating this thought provoking piece for the mindful beekeeper. On top of all his other work, Chris fits in time to run Three Hares Honey https://www.facebook.com/threehareshoney. Thank you, Chris.
Dr Chris Palgrave, BSc (Hons) BVM&S PhD FRCPath FHEA MRCVS.
Chris is a beekeeper and veterinary surgeon living with his family in the Exe Valley in Devon. He is a specialist in pathology and member of the British Bee Veterinary Association He has a particular interest in sustainable, responsible and ethical beekeeping practices. Chris is a member of Exeter Beekeepers and writes regularly for the veterinary and beekeeping press, including a monthly column in BeeCraft magazine called Chasing Sunbeams https://www.bee-craft.com/about-beecraft/the-magazine.
It is easy to think of disease in simple terms. Do you have covid, yes or no? Do your bees have AFB, yes or no? And it is true, in some cases, the presence or absence of disease is binary. However, in many cases, ‘health’ and ‘disease’ are more complex to define and represent different points on a continuum.
We all know that when we get tired and ‘run down’ we are more likely to pick up the bug that has been circulating, or we may suffer from mouth ulcers, spots, thrush and various other infections. Those with chronic conditions like eczema, psoriasis and inflammatory bowel disease are also more likely to experience a flare-up.
The underlying causes are complex and multifactorial, but broadly encompass ‘stress’ in its many and varied forms, including physiological ‘body’ stress (lack of sleep, poor diet, drinking too much alcohol, pre-existing disease etc) and psychological ‘mental’ stress (work-related, family and relationships, moving house, financial concerns etc). While these are handy categories, in reality the two are closely related and intertwined.
Stress has a profound impact on our endocrine system (hormones), it changes our metabolism, inhibits our immune system and alters our emotional state; there is also increasing evidence that changes to our microbiome (bacteria living in our gut) play an important role.
In a stressed and vulnerable state, we may become infected by something that isn’t already in our body. However, we also harbour many potentially pathogenic organisms that are kept in-check by competing ‘friendly bacteria’ (our microflora) and our immune system. Disrupt that delicate balance through stress or exposure to chemicals (including antibiotics) and the pathogenic bacteria or fungi have a chance to take hold, or latent viruses ‘hiding’ from the immune system seize the opportunity to make a reappearance (e.g. cold sores).
While animals may not have money worries or suffer the ill-effects of a self-inflicted heavy night out, they too experience both psychological and physiological stress. For example, cattle, which are all too often dismissed as docile and stupid, are remarkably sensitive creatures; dairy cows can struggle to relax and allow oxytocin release and milk ‘let down’ if there is someone new in the milking parlour (new human mothers can experience a similar phenomenon when breastfeeding in an unfamiliar environment). Most herdsmen/women play the radio during milking and if someone changes the station one day, it can be enough to unsettle the cows. Likewise, owners, like enthusiastic parents-to-be, often want to see their ewe, cow, mare, sow, bitch give birth; but this is a vulnerable moment. Hence many wait until their audience finally gives up and goes to bed before doing so.
I have visited farms where there’s a lot of shouting, whistling, clanging of gates, arm waving and stick brandishing to jostle animals from one area to another. I have also visited farms which are calm and quiet, where animals are encouraged along with a gentle “Come on girls!” – calmly, but with purpose. While both approaches achieve the same end, I know where I would rather live. The things is, it’s in everyone’s interests to reduce stress. Stressed farm animals (e.g., those treated aggressively, experiencing conflict within their social group, given inappropriate space or kept in suboptimal conditions) demonstrate slower weight gain and decreased productivity. They may also exhibit aberrant behaviour – tail biting, feather plucking, aggression and, in some cases, infanticide. Similarly, companion animals stressed by insufficient exercise, long periods spent alone, inappropriate accommodation, a new pet in the house or the arrival of a baby may demonstrate compulsive chewing, lick themselves bald, destructive behaviour or mess outside the litter box. Stressed animals are also more likely to suffer from disease – especially when they are physiologically vulnerable (e.g., because they have too little food, poor quality food, poor weather, too hot/cold, are heavily pregnant, have just given birth, have pre-existing disease, multiple infections, or are in pain).
One of my lecturers at the Edinburgh vet school, a highly experienced and down-to-earth Scottish farm vet, Jim Kelly, always used to say: “A happy coo (cow) is a healthy coo”. Simple, yes, but oh so true.
So, what does this have to do with bees? Vertebrate animals and, since April this year, some groups of invertebrates (including octopus, squid, crabs, lobsters) are legally recognised as sentient (able to experience feelings such as distress, fear and joy). However, the situation with bees and other insects is less clear; they do demonstrate some behaviours that could be interpreted as emotion or intelligence, such as a calm vs defensive colony and the ability to make complex decisions as a group. However, the question as to how sentient they are remains contentious, in part because it is so difficult to measure accurately and reliably. Similarly, it is unclear how insects experience harmful stimuli and whether they ‘feel’ pain in a conscious way. Nevertheless, I prefer to give them the benefit of the doubt and treat them as sentient to avoid any potential unnecessary suffering.
Even if you are not convinced by the concept of ‘happy bees’ or their capacity to experience psychological stress or pain, they do experience physiological stress. And when they are stressed, they will be more vulnerable to disease and less productive. Some potential stressors we have very little influence over, such as the weather, but others we can control or mediate. This includes siting of hives, apiary layout, sanitary practice, biosecurity measures, type of hive, state of repair, number of colonies we choose to manage, how we manage them, and selecting for well-adapted resilient bees.
Subclinical (invisible) infections such as nosemosis, European foulbrood and chalkbrood tend to rear their heads as clinical (visible) disease at particular times of year. Spring is the main pinch point when the colony is particularly vulnerable and stressors are more likely to have a profound impact. The winter bees are getting old, the brood nest is expanding, stores may be running low, pollen needs to be collected, the weather may be cold or temperamental with bees suddenly confined to the hive, and brood cells (potentially harbouring disease) are being cleaned in preparation for laying. The second pinch point is the late summer/early autumn when Varroa load can become a particular issue as mite numbers continue to increase, but the bee population is decreasing and so there are fewer cells and bees for the mites to infest, resulting in a greater load.
We can mitigate for the spring vulnerability by doing our best to ensure the health and longevity of the winter bees. This includes controlling Varroa levels during the late summer/early autumn and making sure there is plenty of time the bees to process any supplementary syrup feed. Likewise, it is essential that we monitor stores closely and consider treatment for Varroa during the winter period, if needed.
Causes of Honey Bee Stress.
So, what kinds of colonies may experience stress?
- A colony that is handled carelessly or opened when too cold.
- A colony that is kept in an inappropriate, poorly insulated or dilapidated hive.
- A colony that is kept in a location which is too hot, too cold or too damp.
- A colony that is hungry or with inappropriate/insufficient stores.
- A colony that is split when too small.
- A colony which suddenly has its honey stores removed and/or is given a large empty space (e.g., honey supers or an empty brood box).
- A colony that is stimulated early in the season and prematurely switches its nurse bees to foragers; this may leave the brood nest short staffed and particularly vulnerable to cold snaps.
- A colony selected to collect less propolis will be more vulnerable to disease.
- A colony of diseased bees or that is infested with Varroa and associated viruses.
- A colony subjected to frequent, slow inspections.
- A colony that is smoked too heavily, or with smoke that is too hot or acrid.
- A colony subjected to manipulations which involve major disruption and/or cooling of the brood nest (e.g., splits, brood spreading, chequerboarding).
- A colony being transported between sites.
- A colony suddenly made queenless or hopelessly queenless.
- A colony exposed to noxious substances inside or outside the hive.
- A colony that is genetically/phenotypically inappropriate for a particular area.
- I suspect that a colony that is prevented from raising the number of drones it would like (worker foundation, drone culling).
- I suspect a colony which repeatedly has its swarming urge/instinct frustrated.
Of course, some degree of stress is inevitable in all animal husbandry systems and can never be completely eliminated. However, regardless of our chosen management system and personal beekeeping philosophy, it is important that we think carefully about potential “stress impact” of our actions. This is particularly important at those times of year when colonies are most vulnerable (e.g., spring). Firstly, is it really necessary? Secondly, is now the right time? Thirdly, do I have a clear plan and the necessary equipment so I can perform it quicky, carefully and in a focussed manner? Fourthly, is the colony (and any resulting splits) in a robust state and well-resourced to cope without undue stress? Finally, are the bees in a suitable hive, under an appropriate management system and well adapted for local conditions?
There is a tendency, particularly for less experienced, but conscientious beekeepers, to follow beekeeping manuals and training sessions to the letter. While this an admirable approach, every colony in every part of the country will perform differently and is subject to different stressors at different times. There is no fixed timetable. It is important to be observant and to take advice from more experienced beekeepers and adapt our practice to local conditions. However, it is equally important to keep asking questions and not be afraid to challenge the status quo, for what may seem as if it is written in stone today, is just one of many ways of doing things. By striving to remain open-minded, we are better placed to change tack if/when new information comes to light.
Ultimately, if we can align our beekeeping practice with local conditions and reduce the number and magnitude of stressors on our colonies, we are much more likely to have ‘happy’, healthy, productive bees.
British Bee Veterinary Association; see HOME link below.
I recently joined the BBVA and got cool badges and packets of seeds in my welcome pack. There’s access to some great webinars when you join, and an informative newsletter. Any beekeeper can join.