Why Are My Bees Suddenly Aggressive?

Sudden aggressive behavior in bees can occur for a number of reasons. However, a usually calm colony of bees that have turned aggressive is almost always due to a change in circumstances that has made their life more difficult.

You see, bees become aggressive because they have the need to defend and protect their hive from a situation that threatens the wellbeing of the colony.

Bees landing at the hive entrance

Here’s Why Your Bees May Be Suddenly Aggressive:

The Hive Is Queenless

If your bees have suddenly become aggressive, your colony may have no queen present – either because she has been accidentally killed or removed from the hive.

This is an event that the bees have not planned for. Within a few hours, they will realize there is no queen pheromone in the hive and therefore no queen. They must then nurture eggs or very young larvae into queens to bring the hive back to order.

Because there is no queen present, the colony can become aggressive until a new queen emerges and begins to lay eggs. Once the colony detects the new queen’s pheromone, calm will be restored.

Bad Weather

Inspecting your hive when the weather is too cold can cause your bees to suddenly become aggressive. Opening your hive during cold, windy, or rainy weather means the entire colony is inside and you’ll have to deal with more bees than usual, who are likely to become aggressive because they are trying to maintain the warmth in the hive.

Ideally, inspections should take place on a warm, calm day when the air temperature is above 16°C (60°F), between 10 am and 5 pm. Thousands of worker bees will be out foraging then, leaving you with fewer bees in the hive to disturb.

Using The Smoker Incorrectly Or Not At All

Using the smoker too little or not at all during inspections can cause aggressive behavior in your bees. Bees are naturally defensive and may react with aggression if you try to conduct an inspection without using smoke.

Smoke changes the bees’ behavior by masking the alarm pheromones given off by the worker bees when the hive is opened.

Using the smoker too much can be a problem too, especially if you’re a new beekeeper. Because of your inexperience, you are more likely to be nervous when opening the hive. Don’t use so much smoke that you deprive them of air altogether! Just a few puffs will be enough to let the guard bees know you are there.

Poor Inspection Technique

As a beginning beekeeper, your inspection technique will not be perfect. When opening the hive the first few times you may be nervous and your movements a little clumsy.

You might accidentally squash a few bees, make sudden, jerky movements or a frame may slip from your hands accidentally. All of these events will disturb the workings of the hive and can make your bees act aggressively.

As your technique becomes more refined, you will find you can do a hive inspection without creating too much aggression within the hive. You will only improve your inspection technique by practice. Getting a few tips from an experienced beekeeper can help too.

Nectar Dearth

A nectar dearth or nectar shortage occurs when there aren’t enough nectar-producing flowers for the bees to visit. As a result, the bees can become stressed and aggressive without enough suitable flora. You may find they buzz more loudly and fly around flowering plants in a more agitated manner.

Nectar is the sweet sugary liquid that supplies carbohydrates to the bee and is found generally in the deepest part of the flower, but not all flowers provide enough nectar for the worker bee to collect.

A nectar dearth often occurs during the transition from one season to the next. To help your colony in the short term, you can feed them sugar syrup from a feeder placed under the lid of your hive.

In the longer term, plant more flowering plants that provide bees with nectar throughout the year. Bees prefer simple flowers with open, cup-like petals where the nectar is readily accessible.

Red flowers known Corymbia ficifolia
My bees love this Corymbia ficifolia because the open petals make it easy to reach the nectar

Aggressive Queen

Aggression in a colony can also be due to the genetic traits of the queen. In this case, the aggressive behavior is not sudden, but inbuilt. The colony will always be aggressive, regardless of the season or situation.

You may find walking past the hive, even at a reasonable distance may cause a guard bee or two to follow you and buzz loudly.

The queen in your hive will have mated with a number of drones at a drone congregation site. The genetic background of the drones is unknown and some aggressive traits may have been passed on.

To rectify this situation, you need to requeen the hive. A mated queen can be purchased from a reputable queen breeder in Spring and Autumn. Ask the breeder for a mated queen that has been bred with minimal aggressive tendencies.


It is natural for bees to become suddenly aggressive from time to time. With honey stored away for the Winter months, it’s understandable that your colony wants to defend itself against anything that threatens it food supply.

The aggressive behavior may be temporary and alleviate itself over time.

However, if you notice your bees becoming too aggressive for too long, it’s important to find out why.

By observing and conducting routine inspections you will be able to work out what is going on and take the necessary steps to fix the situation, therefore ensuring the wellbeing of your colony.

Scroll to Top