… you’re not coming in!

Watch this short film to see the fascinating behaviour of guard bees. They move forward to ‘greet’ incoming bees (or possibly other insects like wasps) and very quickly, make a decision about whether the newcomer is friend or foe. Friends are allowed to pass and others are quickly repelled. What is going on bottom right? There was a hornet hawking around when I was there but she didn’t dare!

It’s a shame really, the guarding behaviour was even more in evidence yesterday, 23 September but I didn’t have my phone.

The entrance to a hive is vulnerable to attack, especially in autumn, so it’s often targeted by predators and ‘robber’ bees from other colonies. But honey bees are having none it! They’ve developed a guarding behaviour to protect the colony. A group of bees, stationed at the entrance, ‘check IDs’ and expel any undesirables.

It’s known that social insects are covered in a blend of waxy chemicals called cuticular hydrocarbons to identify members of the colony. Research shows that individual bees make their own blend of chemicals. As a bee ages, she makes a different blend of cuticular hydrocarbons and by the time she starts to leave the hive to forage, she makes a blend that is specific to the colony she belongs to. The production of this final blend is influenced by the environment within the hive. Researchers Vernier et al. have concluded that honey bees guarding the entrance can only identify non-colony members, which they then treat as intruders.

The number of bees employed in guarding activities varies according to the strength of the colony; from zero to a few dozen. The role is usually carried out by worker bees aged between fourteen and twenty-one days; that’s bees in their last week of house duties. The guard bees monitor the entrance, scrutinising bees or other insects attempting to enter. If a potential entrant is deemed a threat they will be ‘roughed up a bit’ by one or more of the guard bees. In cases where the colony is more defensive, the intruder may be stung. The aggressiveness of the would-be entrant also seems to be a factor; a bit like a bouncer at a club! Wasps for instance, often resist the initial response and are then met with a stinging reaction. A straying worker from another colony is likely to be more gentle and may be allowed to enter.

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