Ancistrocerus parietum

Linnaeus, 1758

Wall Mason Wasp

Ancistrocerus parietum is a solitary mason wasp native to Europe that was introduced to North America, first recorded from Ithaca, New York in 1916. It has since gradually extended its range across the northeastern United States and into Canada. The is associated with dead deciduous wood for nesting and has shown decline in parts of its native range, possibly due to loss. Populations in southern Finland may produce two per year.

Ancistrocerus parietum by the Smithsonian. Used under a CC0 license.Ancistrocerus parietum by the Smithsonian. Used under a CC0 license.Ancistrocerus parietum by the Smithsonian. Used under a CC0 license.

Pronunciation

How to pronounce Ancistrocerus parietum: //ænˌsɪstroʊˈsɪrəs ˌpæriˈiːtəm//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Members of the Ancistrocerus can be identified by a prominent transverse carina (ridge) on the base of the first abdominal segment, creating an abrupt angle where the meets the . Specific identification of A. parietum requires examination of color pattern details; the has been historically confused with similar . Males have hooked tips on the , a characteristic shared with other male eumenine .

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Habitat

Associated with dead deciduous trees and wood, which provide nesting cavities. Uses pre-existing cavities such as old borings in logs, hollow twigs, and similar structures.

Distribution

Native to Europe; introduced to North America with first record from Ithaca, New York in 1916. In North America: northeastern United States west to Michigan, south to Ohio and New Jersey, and Canada (Quebec, with range extension reported). In Europe: present in Belgium, Finland, and northwestern Russia; declining in parts of native range.

Seasonality

Active season extends into summer; possibly (two per year) in southern Finland, suggesting period from spring through mid-summer.

Diet

feed on nectar and other sources. Females provision nests with paralyzed caterpillars (larvae of Lepidoptera) as food for developing offspring.

Life Cycle

Solitary. Females nest in pre-existing cavities, partitioning them with mud into individual . Each cell receives one and multiple paralyzed caterpillars as provisions. Possibly in southern Finland, producing two per year; elsewhere.

Behavior

Females hunt caterpillars on vegetation, paralyzing them with stings to provision nest . Nesting involves collecting mud to partition cavities and seal nest entrances.

Ecological Role

of caterpillars, contributing to natural regulation of . Nesting in dead wood makes the dependent on decaying timber .

Human Relevance

Non-aggressive solitary that does not defend nests; stings only if handled. May benefit gardens and landscapes through caterpillar .

Similar Taxa

  • Ancistrocerus unifasciatusSimilar size range and general appearance; distinguished by abdominal color pattern (A. unifasciatus has single yellow band on first abdominal segment versus different pattern in A. parietum) and geographic range (A. unifasciatus is native North American, not introduced)
  • Ancistrocerus campestrisSimilar cavity-nesting and use; distinguished by abdominal coloration (A. campestris has yellow hind margins on first three abdominal segments) and native North American distribution
  • Ancistrocerus waldeniiSimilar -level with transverse carina on first abdominal segment; A. waldenii constructs free-form mud nests attached to hard surfaces rather than using pre-existing cavities, and has white markings with spot on sixth abdominal segment in females

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Sources and further reading