Eumenes fraternus

Geographic Range

Eumenes fraternus, a species of potter wasp, is native to the Nearctic region. It is found in eastern North America and the eastern United States, occuring as far west as Ontario in Canada, and Minnesota, Kansas, Oklahoma, Nebraska, and Texas in the United States. (Buck, et al., 2008)


Eumenes fraternus lives in temperate forests, at woodland edges, and in shrubby fields. These wasps are also found in suburban or agricultural areas. Juveniles live in small domes that the mother constructs with mud. These domes are found on shrubs, bushy plants, and various overhangs that are anywhere from less than 1 meter off the ground to about 5 meters high in the treeline. The egg domes are usually found on the outside of forest edges. (Fontenelle Nature Association, 2008; Bequaert, 1938; Hubbell, 1989)

  • Range elevation
    1 to 9 m
    3.28 to 29.53 ft

Physical Description

Eumenes fraternus is small and delicate, measuring about 9.5 to 19 mm long. The body is black and shiny, and ivory markings are present on the face, thorax, and abdomen. The first abdominal segment is long and stalk-like. Wingspan ranges from 8 to 12.5 mm and wings are a metallic bluish-brown. Females are slightly larger than males. The species can be distinguished from close relatives Eumenes crucifera and E. verticalis by a shorter pubescence of the scape, which is less than 0.8x mid ocular diameter. In the closely related species, the scape has longer hairs. This wasp undergoes incomplete metaphorphosis and has immature stages differing from adults. (Fontenelle Nature Association, 2008; "Potter Wasp", 2012)

  • Sexual Dimorphism
  • female larger
  • Range length
    9.52 to 19.05 mm
    0.37 to 0.75 in
  • Range wingspan
    8 to 12.5 mm
    0.31 to 0.49 in


Female potter wasps (Eumenes) lay fertilized eggs in a dome constructed with mud. The sex of each of these eggs is genetically determined by a single gene loci with many alleles. Once the eggs hatch, the larvae grow and develop in the pot and eat paralyzed caterpillars that the mother provides for sustenance. Potter wasp development occurs solely within a closed environment, and little is known about the metamorphosis between juvenile and adult stages. Development can be put on hiatus for overwintering. In this case, the egg remains within the mud dome until conditions are appropriate for the wasp to continue development. Once the wasp reaches adulthood, it burrows out of the nest. (Buck, et al., 2008; Hubbell, 1989; Hubbell, 1993)


Eumenes fraternus has a short life cycle, and thus can spawn two or three generations within one season. Mating occurs in the spring, summer, and fall, and the species overwinters during the colder winter months. Research has not yet determined if these wasps are polygynous or polygynandrous. (Hubbell, 1993)

Reproduction in potter wasps is not well understood. Courtship, mating, and oviposition occur in the spring, summer, and fall, and potter wasps can spawn two to three generations between winters. Females are oviparous and lays one egg in each mud pot they construct. Females may construct many pots to house all of her eggs. (Hubbell, 1993)

  • Breeding interval
    Potter wasps can breed two to three times per year, in the warmer months.
  • Breeding season
    Courtship, mating, and oviposition occur in the spring, summer, and fall.

Male Eumenes fraternus do not invest in the offspring, except to contribute gametes. Females construct mud domes where the eggs mature. They also paralyze caterpillars and deposit them into the dome for nourishment. Afterwards, female potter wasps do not tend to the pot and do not stay long enough to see the adults emerge. ("Potter Wasp", 2012)

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


Potter wasps are able to produce 2 to 3 generations within one season. (Hubbell, 1993)


Potter wasps are solitary wasps, living on their own or in groups. They are known for constructing miniature spherical pots or spheres on a variety of plants or overhangs. Like their relatives, they hunt for caterpillars and paralyze them to feed them to their young. Females are not particularly aggressive and do not defend their nests, but the males are known to defend good feeding areas quite aggressively from members of their same species. (Fontenelle Nature Association, 2008; "Potter Wasp", 2012; Bequaert, 1938; Hubbell, 1993)

Home Range

The size of the home range of potter wasps in not known.

Communication and Perception

Eumenes fraternus is a solitary wasp, and does not communicate explicitly with others of its species. However, the female potter wasp can defend herself by stinging. Male potter wasps of closely related species have been found to be quite aggressive towards other species of insects when they have located a good feeding area. Although information about perception in E. fraternus is sparse, closely related species use UV detection and photodetection to determine which spots are pollen or nectar rich and good for feeding. (Hubbell, 1993)

  • Perception Channels
  • ultraviolet
  • chemical

Food Habits

Potter wasps are omnivorous. Adults feed primarily on flower nectar from mid-summer through the fall. However, the young only eat moth and butterfuly (Lepidoptera) larvae placed in the nest by the mother. Females are known to store up to 12 caterpillars in their nests for the developing young. ("Potter Wasp", 2012; Krombein, 1979)

  • Animal Foods
  • insects
  • Plant Foods
  • nectar


Female E. fraternus can sting their predators. Their markings are imitated by a non-harmful species of Diptera, which is further evidence of their defensive properties. As juveniles, the only means of defense against predators is the mud dome in which they develop. Luckily, this is quite effective, and the hard exterior successfully protects the larvae. (Krombein, 1979; White, et al., 1998)

Ecosystem Roles

Potter wasps are both predators and prey in their ecosystem, and function to control caterpillar populations. (Tavolacci, 2003)

Economic Importance for Humans: Positive

Gardeners are especially fond of potter wasps for controlling caterpillars in the garden that would otherwise destroy their crops. (Hubbell, 1993)

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

Potter wasps will not sting humans unless they are bothered. They can be pests to humans if they build pots in garden areas or on windowsills of a home. Luckily, it is not difficult to remove an empty pot by simply scraping it away. (Krombein, 1979)

  • Negative Impacts
  • injures humans
    • bites or stings
  • crop pest

Conservation Status

This species of potter wasp is not considered endangered or threatened.


Sarah Short (author), University of Michigan-Ann Arbor, Catherine Kent (editor), Special Projects.



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


living in landscapes dominated by human agriculture.


Referring to an animal that lives in trees; tree-climbing.

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.


uses smells or other chemicals to communicate


a period of time when growth or development is suspended in insects and other invertebrates, it can usually only be ended the appropriate environmental stimulus.

  1. active during the day, 2. lasting for one day.

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

female parental care

parental care is carried out by females


union of egg and spermatozoan


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


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.


having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.


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


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


the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.


having more than one female as a mate at one time

seasonal breeding

breeding is confined to a particular season


remains in the same area


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


lives alone

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"


living in residential areas on the outskirts of large cities or towns.


uses touch to communicate


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).


Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.


A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.


2012. "Potter Wasp" (On-line). Accessed February 02, 2012 at

Bequaert, J. 1938. The three Eumenes of Canada and the northeastern United States; with notes on other North American species (Hymenoptera; Vespidae). Bulletin of the Brooklyn Entomological Society, 33: 59-70.

Buck, M., S. Marshall, D. Cheung. 2008. Identification Atlas of the Vespidae (Hymenoptera, Aculeata) of the northeastern Nearctic region. Canadian Journal of Arthropod Identification, No. 5: 1.

Fontenelle Nature Association, 2008. "EUMENES FRATERNUS" (On-line). NatureSearch. Accessed February 01, 2012 at

Gullan, P., P. Cranston. 2010. The Insects: An Outline to Entomology. Hoboken, New Jersey: Wiley-Blackwell.

Hubbell, S. 1989. A Book of Bees. New York City, New York: Ballantine Books.

Hubbell, S. 1993. Broadsides from the Other Orders: A Book of Bugs. New York City, New York: Random House.

Krombein, K. 1979. Superfamily Vespoidea. Pp. 1469-1522 in K Krombein, P Hurd, D Smith, B Burks, eds. Catalog of Hymenoptera in America north of Mexico Vol. 2, Apocrita (Aculeata). Washington: Smithsonian Institution Press.

Tavolacci, J. 2003. Insects and Spiders of the World. New York City, New York: Marshall Cavendish.

White, R., D. Borror, R. Peterson. 1998. A Field Guide to Insects: America North of Mexico. New York City, New York: Houghton Mifflin Harcourt.