Western Paper Wasp

Appearance

Paper wasps typically have long and slender bodies with trailing hind legs. The color of their body is generally brownish. Specifically, ''M. flavitarsis'' is divided into five races based on coloration.

Distribution

''M. flavitarsis'' is found in the western United States and Canada, ranging from southern California to British Columbia. Typically, the wasps build nests in riparian forests at elevations of 1500 to 2700 meters. At lower elevations, the nests are located in deciduous and hard evergreens, and at higher elevations in conifers. Nests are typically found within 50 meters of rivers.

M. flavitarsis is also known to nest in the built environment, particularly in protected spaces such as wall voids, the underside of eves, etc.

Behavior

During the summer season, males can be found in female foraging areas attempting to mate. However, as fall approaches, males will begin to set up leks near female hibernation sites. Fall mating occurs during September and October.

Males will choose perch sites near areas frequented by females, sometimes changing sites up to 3 times per day. However, after six to seven days of waiting, the male will then remain at his perch site for the rest of the 6–7 weeks of mating. Once a site is chosen, the male will drag his abdomen along the surface of the perch site for scent marking.

When a female comes to mate, she lands on the perch site. The male will then either lunge or walk slowly toward the female. The male mounts the female for approximately 8 seconds and extends its curled antennae and draws the female antennae upward in a behavior called lassoing.

Following mating, females will walk over the surface of the perch site, dragging their abdomens, before flying off. Typically, female ''M. flavitarsis ''will remain with its nest for the duration of their life. On the other hand, males remain on the natal nest for only a few days. Following departure from the colony, they spend the rest of their lives attempting to attract a mate.

Habitat

''M. flavitarsis'' is found in the western United States and Canada, ranging from southern California to British Columbia. Typically, the wasps build nests in riparian forests at elevations of 1500 to 2700 meters.

At lower elevations, the nests are located in deciduous and hard evergreens, and at higher elevations in conifers. Nests are typically found within 50 meters of rivers. M. flavitarsis is also known to nest in the built environment, particularly in protected spaces such as wall voids, the underside of eves, etc.

Food

''M. flavitarsis ''forage for arthropods like flies and caterpillars to feed to larvae. They will also feed upon fresh meat and hides of animals or fish. Adult wasps will drink nectar for themselves, to feed to larvae, or to store in cells.

Predators

Birds such as flickers, acorn woodpeckers, Mexican jays, and flycatchers are typical predators of ''M. flavitarsis''. In addition to birds, ants will often try to invade the wasp nests. The wasps fight back by attempting to drive and throw the ants off the nest. They will also rub their abdomen on nest surfaces to deter ants from approaching. One final predator of ''M. flavitarsis'' is the praying mantis, which will eat perching males during mating season.

Defense

When another wasp attempts to land on an occupied perch site, the owner is alerted to the intruder. If the intruder does not fly away right away, then the owner will lunge and grapple the other wasp.

Typically the two wasps will fight on the perch site and often fall off the site and land on the ground to finish fighting. Following the fight, the owner returns to its perch site, and again, rubs its abdomen to secrete its scent and ward off future intruders.

The defensive behavior of ''M. flavitarsis'' is dependent on which phase the colony cycle is in. If the nest is in the emergence phase or later, ''M. flavitarsis'' are more likely to sting a predator or intruder as a form of altruistic suicide because of colony size. However, typically the species is less prone to attack and will opt to ram the attacker as if to frighten it.

When disturbed, ''M. flavitarsis ''will stand high on their mid and hind legs with their forelegs and abdomen raised and antennae forward. They then show displeasure by buzzing their wings to produce a sound audible from several meters away.