Why Are There So Many Wasps in September? Understanding Late Summer Wasp Behaviour
As summer draws to a close, you might expect wasp activity to start disappearing. Instead, September can be one of the times when wasps become particularly noticeable around homes and gardens. You may see them hovering around outdoor tables, investigating sugary drinks, feeding on fallen fruit or spending more time around bins and food waste.
This doesn’t necessarily mean there has been a sudden increase in wasp numbers. Colonies may already be close to their seasonal peak, while changes in worker behaviour make wasps much more noticeable around people.
September often marks an important stage in the natural life cycle of a wasp colony, although the precise timing varies depending on the species, weather and development of the nest. As the nest approaches the end of its annual cycle, worker wasps begin spending less time feeding developing larvae and more time searching for sugary food for themselves. This brings them into much closer contact with people and helps explain why wasps can seem particularly persistent at this time of year.
Why does wasp behaviour change in September?
What are “tipsy wasps”?
You may have heard late-summer wasps described as “tipsy” or “drunk” wasps, and there is some truth behind the expression.
During fermentation, some of the fruit’s natural sugars are converted into alcohol. Wasps are attracted to the remaining sugars and may also consume small amounts of alcohol while feeding on the fruit.
The British Pest Control Association (BPCA) highlighted this behaviour in August 2026, warning that worker wasps feeding on fermented fruit can become inebriated and may behave more erratically.
That doesn’t mean every wasp you see in September is drunk. The more important point is that the change in the colony coincides with an abundance of ripe and overripe fruit. This gives worker wasps another readily available source of sugar and brings them closer to people.
If you have apple, pear, plum or other fruit trees in your garden, regularly removing fallen and overripe fruit is therefore a simple way to reduce one potential attraction.
