page_title: Vespula pensylvanica
section_title: Foraging
hierarchical_section_title: Vespula pensylvanica / Behavior / Foraging
caption_attribution_description: English: Western yellowjacket (Vespula pensylvanica) on a fennel flower (Foeniculum vulgare) Location: near Robber's Peak, Orange, CA, USA Identification: "This is the only species which has a complete yellow eye ring around each compound eye." From: http://academic.evergreen.edu/projects/ants/TESCBiota/kingdom/animalia/phylum/arthropoda/class/insecta/order/hymenoptera/family/Vespidae/Kweskin97/Vespula/pensylvanica/pensylvanica.htm Also based on images from this site: http://nathistoc.bio.uci.edu/hymenopt/Vespula.htm
context_page_description: The western yellowjacket is a Nearctic species of wasp in the genus Vespula. It is native to regions of North America, largely in areas with northern temperate climates. Its reproductive behavior is constrained by cold weather, which successfully reduces the number of western yellowjackets in cold months. However, in the absence of cold weather, this wasp's population can explode. The western yellowjacket has become particularly invasive in the Hawaiian Islands, resulting in their label as a major pest.
context_section_description: The western yellowjacket foraging behavior is similar to other Vespula species. Yellowjackets forage for insects and dead animals for meat and  plant nectar for carbohydrates. The captured prey is typically taken to a more vertical surface and malaxated by chewing off legs and wings. In larger insects, the head is typically removed first. Foraging for prey requires visual cues, but odors can be used when scavenging for protein. Hunting for prey and dead animals occurs individually because yellowjacket workers are unable to communicate the location of food to other workers in the colony. All workers forage for honey, water, and fiber. In Hawaii, yellowjackets rob honey bee colonies through two major types of raids. Sometimes, yellowjackets enter and leave in a slow but steady traffic faced by opposition from honey bee workers. In the more common raid, yellowjackets enter individually and experience no apparent opposition. V. pensylvanica utilize their mandibles to scrape weathered wood and dried herbaceous stems to obtain resources rich in fiber. 
  Most yellowjackets forage relatively close to the nest. The foraging distance ranges between 540 and 1800 feet. The average foraging distance is within 1,100 feet of the nest. In addition to visual and olfactory cues, learning also plays a role in foraging.  They rarely return to a constant location for protein and shift foraging patterns when necessary.
caption: Western yellowjacket (V. pensylvanica) on a fennel flower (Foeniculum vulgare), near Robber's Peak, Orange, California
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