Kamikaze bees – why does the swarm commit suicide?

I today witnessed the most bizarre sight of a swarm apparently committing suicide which I have neither witnessed before or heard of – does anyone know what was going on? See this video & full story below:

I collected a swarm this afternoon which the caller had seen arrive this late morning. They had settled on a conifer about chest height and were acting quite normally. By the time I arrived c. 3:15 pm they had collected into a normal leg of lamb sized cluster – I’m guessing a late prime swarm. The weather was windy and unsettled – we have had several days of unseasonal wetter weather.

Having run out of Warré boxes I knocked them into a heavy cardboard box which had been used twice before this season. The queen must have been collected as they mostly fell into the box and many bees fanned when placed upturned on the floor below where they had settled. Over the course of the next hour and a half the majority went in despite it being very blustery. I don’t get suited to collect swarms and the bees were fine – no stings or warning behaviour at all was experienced from them despite many being in the air.

I would normally leave the collecting box in situ until dusk and collect then when all the bees had returned. However, as it was in a public place near a school and they were in a cardboard box, not a proper swarm box, I decided to cut and run with the bulk of the bees. I left a small box in the conifer as a shelter for any remaining bees with the intention of returning to collect in a day or two.

When I removed the box, small clusters of bees and some individual bees, about 50 in total, were noticed apparently fighting or acting as if they had been stung.

Half an hour later I was home with a cup of tea and had contacted a member of our bee group with an empty hive to arrange to drop them off where they would be “walked in” to a Warré hive. When I arrived at his house the bees were making a tremendous roaring noise, more than I’ve ever heard a swarm make before. I guessed they were getting hot though it was not a hot day and they had only been boxed c. 2 hours.

The box was opened and the bees poured onto a sheeted ramp leading up to the hive entrance – see the video. Rather than stay put to take stock then start moving upwards which is their normal behaviour, they all writhed like bees possessed and in their writhing rolled down the ramp. No bees took to the air (very unusual) and there was no fanning behaviour at all. We looked closely and could see they were all locked in a frenzy of fighting – apparently stinging each other. The queen was noticed, behaving as though she had been stung and being totally ignored by the other bees. Within less than half an hour the majority had died or were in the process of dying with the rest obviously going to do so within a short while.

I am at a loss to know what happened to them. They were fighting just as if two colonies had been mixed together, yet the swarm was behaving perfectly normally when on the tree before being shaken in. It was as if they had, as a colony, decided to commit suicide.

If you have any suggestions as to what happened or have seen this before I’d love to hear at YABeeP@gmail.com – I’m perplexed!


This entry was posted in Natural Beekeeping, Swarms, Warre Hives. Bookmark the permalink.

2 Responses to Kamikaze bees – why does the swarm commit suicide?

  1. Paul says:

    Extreme behaviour generally implies extreme conditions.

    My wife & I suspect the bees were poisoned, perhaps by some kind of spray at the location they were collected from.

    That’s a guess, but a quick search confirms that spraying with insecticide sometimes results in fighting: see list of symptoms here – http://www.norfolkbeekeepers.co.uk/spray_liaison/spray_damage.php

  2. simplebees says:


    I wonder if the box you used has become contaminated by something the bees perceive as an alarm scent. Banana would be a classic one. Go near bees after eating banana at your peril.

    Maybe a banana was placed on top of the box for a while or even transferred by hand from someone who has just eaten a banana. There could be things other than banana that might have the same effect.

    Inside the box in a closed environment, even a small amount of scent that says ‘attack’ might give rise to the behaviour you have seen.

    Edit: A number of others have suggested that the bees are not, in fact, fighting and, on a closer look, this may indeed be true. Which would bring us back to the possibility that the bees are writhing and dying due to poisoning. The question then would be: where did the toxin come from?

    BTW, the bees in this video are described as being ‘in agony’. I am not aware of any research into the question of whether bees experience what a human would call pain (and it’s a fair question to ask ‘how would you tell?’). Severe neurological disruption (which would be caused by an insecticide) would give rise to what we might see as ‘writhing’ but one should not necessarily associate this with a feeling of pain on the part of the bees. What the beekeeper might feel watching the bees is, of course, a different matter.

    Gareth, West Oxfordshire

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