Identification
La guêpe commune américaine est un maillon important de la chaîne alimentaire: elle régule les insectes ravageurs tout en participant à la pollinisation accessoire.
An imposing colony
A mature colony can reach 800 to 3,000 workers in August, making it one of the most abundant social wasps in Quebec.
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AAbdomen
Very crisp alternating lemon-yellow and black bands; well-marked petiole; smooth stinger allowing repeated stings.
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BHead
Clypeus with a distinctive central black mark; large mandibles; well-developed compound eyes.
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CWings
Two pairs of transparent membranous wings; folded along the body at rest.
Worker
Handles cell building, insect hunting, sugar gathering and nest defence. Very active from July to September.
Life cycle
From the new nest to the autumn die-offAn overwintering queen comes out of dormancy in May, chooses a cavity (burrow, stump, wall cavity) and founds the nest on her own.
The workers hatch in June and July and speed up growth; the nest can reach 800 to 3,000 individuals in August.
In August and September, the colony produces males and new queens; the workers become more aggressive toward any disturbance.
Frost kills the workers and males in October; the mated queens overwinter alone and will start a new nest in spring.
Do not confuse it with
Several Vespula species share a very similar yellow and black striped pattern.
Signs of activity
Underground or cavity nest
Built in burrows (mice, weasels), wall cavities, crawl spaces or attics. The entrance is often hidden and hard to spot.
Intense late-summer activity
Large numbers around garbage bins, meat, sweet drinks and fallen fruit from mid-August on; the workers are looking for carbohydrates for the future queens.
Patrol flights
Workers actively patrolling around the nest within a radius of 5 to 10 m; noticeable defensive behaviour if you approach the entrance.
Aggressiveness increases considerably in autumn, when food resources become scarce.
Treatment
DIY sugar trap
- 1 L Water Base of the liquid
- 4 tbsp Sugar or fruit juice Powerful sweet attractant
- 1 tsp Cider vinegar Repels bees while still attracting wasps
- Mix the water, the sugar (or juice) and the vinegar in a narrow-necked bottle.
- Place the trap at least 5 m away from eating areas to draw the wasps away from your guests.
- Empty and refill the trap every 48 hours to keep it effective.
Wasps are drawn to floral fragrances and to yellow or white clothing. Wearing neutral colours and skipping perfume significantly reduces encounters.
A crushed worker releases alarm pheromones that can trigger a collective aggressive response from the other members of the nest.
Locating and assessing the nest
Methodical observation to pinpoint the exact location
Watch the flight paths at ground level or along walls; the workers return to the nest in a straight line after foraging.
The entrance is often a 2-4 cm hole in the ground, in a foundation crack or under siding; mark it with something visible.
Count the trips over 1 minute: fewer than 10 = a modest colony; more than 30 = a large colony that calls for a risk assessment.
Prevention
- Seal the entry points
Seal foundation cracks, crawl spaces and siding openings with caulking or polyurethane foam before the month of May.
Foundation - Waste management
Use airtight garbage bins and rinse sweet containers before throwing them out. The smell of food waste is the main attractant.
Yard - Spring inspection
Inspect the perimeter in May to detect founding queens before they establish a colony; nests that are just starting out (the size of a golf ball) are easy to remove.
Outdoors
Frequently asked questions
Is the common yellowjacket aggressive?
It becomes aggressive near the nest and in late summer, when it hovers around food and sweet drinks. It can sting several times.
Where does it nest?
Often in the ground, a low wall, a wall cavity or an attic. The nest entrance is a simple hole with heavy worker traffic.
Why is it circling my patio?
Late in the season it is looking for sugars and protein: fruit, drinks, meat. Colonies are then at their population peak.
How do I eliminate a nest?
Find the entrance without blocking it, keep your distance and call in an exterminator, especially if the nest is inside a wall or near a walkway.