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Dolichovespula maculata

By Deena Hauze

Geographic Range

Bald-faced hornets, (Dolichovespula maculata), are a species of wasp. They belong to the group of bees known as yellow-jackets. They are found across the United States and Canada, except for the driest parts of the Great Plains region. (Buck, et al., 2008; Jacobs, 2015)

Habitat

The gray, papery nests of bald-faced hornets are aerial. They are built above the ground in trees, bushes, and shrubbery. Nests can also be found on rocks and man-made structures. The large nests are spherical or egg-shaped. They are up to 60 cm in height and 45 cm across. Bald-faced hornets are common on flowers. (Jacobs, 2015; Mullen and Durden, 2019)

  • Range elevation
    1 to 20 m
    3.28 to 65.62 ft

Physical Description

Bald-faced hornets get their name from the white markings on the face, legs, thorax, and abdomen. The rest of the body is dark black. They have brown wings and brown eyes. Bald-faced hornets are the largest species in the Dolichovespula genus. Workers are 12-14 mm long, while queens are 18-20 mm long. Males have white markings on the first segment of the abdomen. Females have 6-segmented abdomens and 12-segmented antennae, while males have 7-segmented abdomens and 13-segmented antennae. (Buck, et al., 2008; Jacobs, 2015)

  • Sexual Dimorphism
  • female larger
  • sexes colored or patterned differently
  • Range length
    13 to 20 mm
    0.51 to 0.79 in

Development

Bald-faced hornets undergo complete metamorphosis like other bees in the order Hymenoptera. Larvae hatch from an egg, then pass through several stages of growth. Once the larvae have fully matured, they begin the pupal stage. During this phase, pupae transform into adult bees. (Foster, et al., 2001; Jacobs, 2015)

Reproduction

Bald-faced hornets are a eusocial species. The queen is fertile, while the female workers are varying degrees of sterile. Some workers may even reproduce. Like many other eusocial species, bald-faced hornets are found in colonies and has a reproductive division of labor. The workers tend to the young and offspring help the parents. (Foster, et al., 2001; Mullen and Durden, 2019)

New queens and males are produced during the late summer to autumn. They leave the nest and mate after they are fully grown. Most queens in the genus Dolichovespula mate only once. Males die after mating. After storing the sperm, the queens seek out a place to wait out the winter. In the spring, they craft a nest and lay their first brood of eggs. Eggs fertilized by the queen produce female bees, while unfertilized eggs produce male bees. (Foster, et al., 2001)

Female workers are able to produce male offspring. Conflicts between queens and workers over male production are common. Nests with no queen have been reported, which may be due to the workers killing the queen. (Foster, et al., 2001)

  • Breeding interval
    Bald-faced hornet queens breed once yearly.
  • Breeding season
    Dolichovespula maculata queens and males mate during summer to early fall.
  • Range eggs per season
    100 to 400

Fertilized queens build nests during the spring. The queens deposit their eggs and feed the larvae once they hatch. The first group of offspring builds and protects the nest, gathers food, and tends to the new larvae. (Foster, et al., 2001; Jacobs, 2015)

  • Parental Investment
  • female parental care
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

Queens and males hatch in the late summer to early fall, pupate, then fly off to mate. Males die soon after mating. The fertilized queens find shelter and wait out the winter. In the spring, the adult queens begin to build their nests and lay their first group of eggs. These eggs become workers after hatching. The second group of eggs includes the males and new queens. The original queen will die with the rest of the nest during autumn, while the new queens live through the winter. (Foster, et al., 2001; Jacobs, 2015)

  • Range lifespan
    Status: wild
    1 (high) years

Behavior

Bald-faced hornets are a colonial species. Despite their large size, they are less aggressive than some smaller species of yellowjacket. Each nest is created by a dominant queen bee that produces most of the offspring. The queen chews fibers from old wood and adds her saliva, making a paste. The paste dries into the papery material that makes up the nest. (Arnett, 2000; Buck, et al., 2008; Mullen and Durden, 2019)

Communication and Perception

Like other social bees, bald-faced hornets communicate using touch, vision, chemicals called pheromones, and wing vibrations. Bees communicate about the safety of the nest, where food is, and what they should do. Like other bees, bald-faced hornets can see ultraviolet light.

Food Habits

Bald-faced hornets are predators of insects, including arthropods, flies, and other yellow-jackets. They also feed on pollen, nectar, and fruits. (Buck, et al., 2008; Mullen and Durden, 2019)

  • Animal Foods
  • insects
  • Plant Foods
  • fruit
  • nectar

Predation

Bald-faced hornets have a venomous stinger that they use to attack. Their stings are painful and are used to defend themselves and their nests (Mullen and Durden, 2019)

Ecosystem Roles

Bald-faced hornets are important pollinators that play a big role in the survival of their ecosystems. In addition to pollinating, they eat other types of insects. Bee moths are known to lay their eggs in bald-faced hornet nests. Once the eggs hatch, the larvae will feed on the eggs, larvae, and materials stored by the wasps. (Gambino, 1995)

  • Ecosystem Impact
  • pollinates
Commensal/Parasitic Species

Economic Importance for Humans: Positive

Bald-faced hornets pollinate flowers while seeking out nectar. Adults mainly eat insects. The large number they eat helps control populations of unwanted insects. (Jacobs, 2015)

  • Positive Impacts
  • pollinates crops
  • controls pest population

Economic Importance for Humans: Negative

Bald-faced hornets sting to protect themselves. They attack when their nest is disturbed. Large hives may sting many times in a swarm. These bees are able to squirt venom at threats. They are most dangerous to people allergic to bee stings. (Barlett, 2017)

  • Negative Impacts
  • injures humans

Other Comments

Yellow-jacket is an American common name for wasps in the genera Dolichovespula and Vespula. (Mullen and Durden, 2019)

Contributors

Deena Hauze (author), Animal Diversity Web Staff.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

delayed fertilization

a substantial delay (longer than the minimum time required for sperm to travel to the egg) takes place between copulation and fertilization, used to describe female sperm storage.

dominance hierarchies

ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

eusocial

the condition in which individuals in a group display each of the following three traits: cooperative care of young; some individuals in the group give up reproduction and specialize in care of young; overlap of at least two generations of life stages capable of contributing to colony labor

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

infrared/heat

(as keyword in perception channel section) This animal has a special ability to detect heat from other organisms in its environment.

internal fertilization

fertilization takes place within the female's body

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

parthenogenic

development takes place in an unfertilized egg

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

sperm-storing

mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

venomous

an animal which has an organ capable of injecting a poisonous substance into a wound (for example, scorpions, jellyfish, and rattlesnakes).

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

References

Arnett, R. 2000. American Insects: A Handbook of the Insects of America North of Mexico. Boca Raton: CRC Press.

Barlett, T. 2017. "Species Dolichovespula maculata - Bald-faced Hornet" (On-line). BugGuide. Accessed May 09, 2020 at https://bugguide.net/node/view/2890.

Buck, M., S. Marshall, D. Cheung. 2008. Identification Atlas of the Vespidae (Hymenoptera, Aculeata) of the northeastern Nearctic region. Canadian Journal of Arthropod Identification, 5: 492. Accessed May 09, 2020 at http://cjai.biologicalsurvey.ca/bmc_05/bmc_05.html.

Foster, K., F. Ratnieks, N. Gyllenstrand, P. Thorn. 2001. Colony kin structure and male production in Dolichovespula wasps. Molecular Ecology, 10: 1003-1010.

Gambino, P. 1995. Dolichovespula (Hymenoptera: Vespidae), Hosts of Aphomia sociella (L.) (Lepidoptera: Pyralidae). Journal of the New York Entomological Society, 103(2): 165-169.

Jacobs, S. 2015. "Baldfaced Hornet" (On-line). PennState Department of Entomology. Accessed May 09, 2020 at https://ento.psu.edu/extension/factsheets/baldfaced-hornet.

Mullen, G., L. Durden. 2019. Medical and Veterinary Entomology (Third Edition). London: Academic Press.

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