Yellowjacket Wasps Crash the Party

It's that time of year again when you start seeing the wasps take an interest in your cookouts and seem to be everywhere. You haven't seen them all summer, and then unexpectedly, they're all over the place, irritating everybody, causing panic, and swatting hands. Remember now?

August is the time of year when people ask, "What's the point of wasps?" The answer may surprise you.

Did you know there are approximately 4,000 species of wasps in the US alone? These include the parasitic wasps, some so small they are like pin heads. Most of the 200 larger wasps with a stinger are solitary and cause no problems for humans. For many of these, only the female wasp has the stinger.

However, when we talk about wasps, we're almost undoubtedly talking about one specific species, the Yellowjacket wasp (Family Vespidae). To understand why these wasps become bothersome this time of year, you first need to understand their lifecycle.

Yellowjacket wasps live in social colonies like some bees, but unlike social bees, they haven't evolved a way of saving food to allow the colony to survive the winter. The only survivors are the young, fertilized queens who hibernate over winter. They appear in the spring to build little walnut-sized nests where they lay approximately 20 eggs.

The queen feeds those larvae that ha until around May when they become workers. Then she focuses on egg-laying, and the workers focus on feeding them, growing the nest as they go along. By this time of year, the nest has grown to around 16 inches in diameter, often larger, and that nest can have up to 15,000 wasps!

Change of Plans

Then, in August and September, a dramatic shift takes place. The queen quits her egg-laying (save a few that will go on to be future queens and males to fertilize them) and no longer releases the pheromone that causes the workers to work.

This change makes these workers redundant, leaving them jobless and disorientated. The problem for us is that although adult wasps are insect predators, those insects feed the larvae, not themselves. In their adult form, wasps cannot digest solid food and need sugary liquid to survive. Now, with fewer larvae to feed, they become uncontrollably and insatiably hungry.

Wasps love easy food such as over-ripe fruit and fizzy drinks. Towards the end of their brief lives, their hunger drives them to search for easy sugar at precisely the time when we are more likely to be using our gardens and outdoor spaces for eating sweet things. The timing couldn't be better for them or worse for us.

So why are those who panic and try to swat them away more likely to be stung than those who remain calm?

Well, the problem is that these redundant workers have their own pheromone, which helps protect the nest from attackers earlier in the year, and that's essentially a chemical rallying cry to other workers that the nest is under attack.

So when you swat that annoying wasp, and it feels under attack, that rallying cry will go out. Suddenly, it all kicks off, and loads more wasps will start coming in aggressive mode, fired up and ready to defend their nest. The best advice is to stay calm.

Think of it this way: from May, that wasp has been working its socks off, helping keep things nice on Earth. Now it's going to die. So why not give it a break, save your swats, put a bowl of sugary drink somewhere out of your way, and let it go out on a nice sugar high!

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