What are yellow jackets

• “Yellow jacket” is a common name for certain wasps, mostly in the genus Vespula.

• They are social insects, with queens, workers, and males. 

Local species around Calgary

Here are a few species known in Alberta / Calgary area:

Species

Common Name

Features / Habitat

Nesting & Diet

Vespula pensylvanica

Western Yellowjacket

Seen throughout Alberta. About 10–15 mm long. Insects of Alberta

Predatory on other insects; also scavenges. Nesting subterranean or dark cavities (logs, wall voids) etc. Insects of Alberta

Vespula acadica

Forest Yellowjacket

More in forested areas. Insects of Alberta

Nests underground and under decaying logs. Colony size can reach ~400 workers. Insects of Alberta

Vespula atropilosa

Prairie Yellowjacket

Found in prairie and open forest, southwestern Alberta. Insects of Alberta

Ground-nesting, often in old rodent burrows. Colony size maybe ~500 workers. Preys on spiders, flies, caterpillars; also nectar and sweets. Insects of Alberta

Life cycle & behaviour

• Overwintering queens: Only mated females (queens) survive through winter by hibernating; rest of colony (workers, drones) die off. In spring, queens found new nests.
  
  

• Nest growth: Nests start small, then increase in size over the spring / summer. By late summer / early fall the colony is large, more workers, more foraging, more noticeable interaction with humans.
  
  

• Diet: Adult yellow jackets often consume nectar, sweets, or anything sugary; they also scavenge (picnic foods, meats). The larvae are fed more protein (insects etc.).
  
  

Nesting habits & locations

• Many species nest underground, in rodent burrows, under stumps, logs. Some choose wall voids or dark cavities.

• Nests are more likely to be problematic or noticed when close to human structures, or in places where nests are hidden but foraging workers are visible. Insects of Alberta+
  
  

Impact & interactions with humans

• Yellow jackets are attracted to food smells (especially sweet, meat), rubbish, outdoor cooking. They can be persistent around events like picnics.
  
  

• They can sting multiple times, and are more aggressive if their nest is disturbed.