Center for Systematic Entomology, Gainesville, Florida
Nesting behavior of the spider wasp Calopompilus pyrrhomelas (Walker) (Hymenoptera: Pompilidae)
Date of this Version
Kurczewski FE, Hedin M, West RC. 2023. Nesting behavior of the spider wasp Calopompilus pyrrhomelas (Walker) (Hymenoptera: Pompilidae). Insecta Mundi 0980: 1–7.
The nesting behavior of the spider wasp Calopompilus pyrrhomelas (Hymenoptera: Pompilidae: Pepsini) is described for the first time based on independent observations and photographic series from Oakland, Alameda County, CA; Denio, Humboldt County, NV; and Tamalpais-Homestead Valley, Marin County, CA, respectively. The three wasps captured, immobilized, and provisioned the spider’s own burrows with Calisoga longitarsis (Simon) (Nemesiidae) and Antrodiaetus montanus (Chamberlin and Ivie) (Antrodiaetidae).
The genus Calopompilus Ashmead is one of the “most primitive” genera in the family Pompilidae as evidenced by its broad hind wings and anal lobe, lack of specialization in wing venation, stout “scolioid” body structure, and full complement of leg bristles (Townes 1957). Short stout legs and antenna segments, bidentate mandibles, short and wide clypeus, long and flat pronotum, and tarsal claws with an erect tooth are presumed Calopompilus adaptations for hunting trapdoor spiders and related Mygalomorphae species (Kurczewski and West 2022). Spider wasps that capture and provision their nests with trapdoor spiders and related mygalomorphs have been scarcely studied compared to pompilids that prey on araneomorph spiders (Evans and Yoshimoto 1962; Kurczewski and Kurczewski 1968; Krombein 1979; Wasbauer and Kimsey 1985; Kurczewski and Edwards 2012; Kurczewski et al. 2017, 2020, 2022). There is host mygalomorph spider association data for only two of the eight U.S. Calopompilus species, C. heiligbrodtii (Cresson) and C. pyrrhomelas (Walker) (Kurczewski et al. 2020, 2022), despite some of the species being large and attractive. This scarcity of information is probably linked to Calopompilus species capturing the host spider near its burrow and using the spider’s burrow as a nest (Kurczewski and West 2022).
The only two host records for C. heiligbrodtii, based on iNaturalist.org online photographs, are Eucteniza relata (O. P.-Cambridge) (Euctenizidae), adult male [det. R. Godwin]; and Myrmekiaphila comstocki Bishop and Crosby, adult or subadult female (Euctenizidae) [det. R. Godwin] (Kurczewski et al. 2020). Calopompilus pyrrhomelas, a much more common species than C. heiligbrodtii, has been collected or photographed with host mygalomorph spiders several times: Antrodiaetus pacificus Simon (Antrodiaetidae) (Krombein 1958; Kurczewski et al. 2020); A. pugnax (Chamberlin) (Coyle 1971); Atypoides riversi O. P.-Cambridge (Antrodiaetidae) (Kurczewski and West 2022); and Calisoga longitarsis (Nemesiidae) (Kurczewski et al. 2020, 2022; Kurczewski and West 2022). None of these observations or photographs are detailed enough to show that Calopompilus pyrrhomelas used the spider’s burrow as a nest, except for Coyle (1971). Coyle (1971) reared C. pyrrhomelas from a burrow of Antrodiaetus pugnax in Oregon (Kurczewski and West 2022). Recently, Blackwell (2022), Hedin (2022), and Wang (2022) not only confirmed that Calopompilus pyrrhomelas appropriated the burrows of Calisoga longitarsis and Antrodiaetus montanus for nests, but they independently photographed nearly the entire nesting sequence to support their observations. Theirs are the first observations of the nesting biology of C. pyrrhomelas that detail the sequence of behavioral components from the wasp finding the spider in its burrow to immobilizing it on the ground surface and pulling it inside its burrow to provide food for the future wasp larva.
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Published on March 25, 2023 by Center for Systematic Entomology, Inc. P.O. Box 141874 Gainesville, FL 32614-1874 USA http://centerforsystematicentomology.org/