Passaloecus annulatus
(Say, 1837)
Passaloecus annulatus is a small solitary in the Crabronidae, Pemphredoninae. Females hunt as food for their larval offspring and also feed on aphid . The nests in pre-existing cavities such as borings in dead wood, hollow stems, or vacant , partitioning these into linear series of . It occurs across North America.
Pronunciation
How to pronounce Passaloecus annulatus: /ˌpæsəˈliːkəs ænˈjuːleɪtəs/
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Identification
Distinguished from similar small black by the or ivory . Can be separated from other Passaloecus by examination of and other subtle morphological features. The Passaloecus is recognized within Pemphredoninae by its -hunting and nesting habits.
Habitat
Found in wooded and semi-wooded areas where dead trees, standing snags, or woody debris provide exit holes and other pre-existing cavities for nesting. Also occurs in gardens and urban settings where suitable nesting substrates are available.
Distribution
North America, with records from Canada (Alberta) and throughout the continental United States. The Passaloecus has approximately sixteen in North America, collectively distributed across the entire continent.
Diet
females hunt () as food for larval offspring; adults also feed on secreted by aphids.
Life Cycle
Solitary nesting . Females construct nests in pre-existing cavities ( borings, hollow stems, vacant ), partitioning the tunnel into a linear series of with resin or -derived partitions. Each cell is provisioned with 6-60+ paralyzed or dead ; an is laid on one victim. Two per year reported for at least some (e.g., P. ithacae in New York).
Behavior
Females are known to or crush them in their before transport to the nest. frequently visit leaves bearing aphid . Highly attracted to artificial nest blocks ( blocks) drilled with holes approximately 3/16 inch in diameter. Nests are subject to by (Omalus aeneus) and ichneumon (Poemenia albipes, P. americana).
Ecological Role
of , contributing to natural of aphid . Serves as for parasitic including and ichneumon wasps.
Human Relevance
for biological pest control; can be attracted to gardens using artificial nest blocks ( blocks). Not considered a pest or nuisance .
Similar Taxa
- Passaloecus ithacaeSimilar nesting biology and appearance; both are -hunting Passaloecus with , distinguished by subtle morphological differences and geographic distribution.
- Passaloecus cuspidatusAnother congeneric hunter with similar ; identification requires examination of structural features.
- Other Pemphredoninae genera (e.g., Pemphredon, Psen)Similar small size and general appearance as or -hunting solitary ; distinguished by coloration, , and preferences.
More Details
Nesting Biology
Passaloecus annulatus exemplifies the 'housing crisis' facing solitary cavity-nesting . As property owners and park managers remove dead standing trees to avoid liability, these wasps lose essential nesting sites. Artificial nest blocks can successfully substitute for natural cavities.
Taxonomic Note
The Passaloecus is pronounced -uh-LEE-kus. It is one of approximately sixteen Passaloecus in North America, all sharing the characteristic of and or pale .