Those wonderful wasps in your garden

Gardeners know the benefits of bees pollinating flowers and improving fruit crops, but many neglect their cousins, the wasps, who deserve the same level of kudos for ridding gardens and crops of pests.

Credit: iStock / Antagain

Gardeners and farmers all know the benefits of bees pollinating flowers and improving the quality and quantity of fruit crops, but many neglect their cousins, the wasps, who deserve the same level of appreciation and respect for ridding gardens and crops of pests.

Wasps belong to a large, diverse group of insects. Thousands of species thrive in North America, tens of thousands of species world-wide. The vast majority are solitary insects that complete their life cycle on their own. The most defining characteristic of wasps is that they are insect predators. Their “bread and butter” is eating other bugs, and many wasps are highly specialized and feed only on certain insect prey, or hunt based on the gender or specific development stage of its prey.

In 2004 many people noticed an abundance of wasps, mostly three social species: the Yellow Jacket, the Bald-faced Hornet and the Paper Wasp. Their abundance was due to the exceptional weather conditions that most of British Columbia has had since spring. The good weather enabled all kinds of insects, including wasps, to flourish and multiply.

Since many different insects are prey for wasps, their ecological role is critically important. Without them, huge insect populations would develop, including those that feed on your favorite ornamentals or fruit-bearing plants. In other words, wasps help us keep insect populations in check.

When too many wasps develop in an area, humans are mostly responsible. In July and August, at the height of barbecue season, wasp populations reach their maximum size. We support these large populations because we often leave food crumbs from picnics and barbeques and cans with sweet droplets of pop and juice remain, not to mention spilled ice cream, chicken bones and other food remnants in exposed garbage cans. Why would wasps use energy to hunt for insect prey when we set the dining table for them?

By understanding the behaviour of wasps and reducing the availability of food sources, we can prevent their nuisance and appreciate their importance in our environment.

Paul van Westendorp is the Provincial Apiculturist, BC Ministry of Agriculture, Food & Fisheries