Arachnospila arcta (Cresson)

Kurczewski, Frank E., West, Rick C. & Waichert, Cecilia, 2024, New host records for Nearctic and Neotropical spider wasps (Hymenoptera: Pompilidae), Insecta Mundi 2024 (34), pp. 1-32 : 25

Arachnospila arcta (Cresson)

OREGON: Clackamas County, West Linn; 14 July 2022, 1535 PDT; M. D. Barton. Host: Callobius severus Simon ( Amaurobiidae ), adult or penultimate male. The spider was dragged backwards through dense grasses, being held cephalothorax upright and grasped with the wasp’s mandibles by its right forecoxa-trochanter joint or end of right pedipalp ( Barton 2022).

Callobius severus is a new host species for A. arcta . Arachnospila arcta is strongly polyphagous in host selection having been reported with seven families of host spiders, including Amaurobiidae ( Evans and Yoshimoto 1962; Kurczewski and Kiernan 2015, Kurczewski et al. 2017).

OREGON: Marion County, Salem; 29 August 2015, 2040 PDT; S. Braden. Host: Eratigena duellica (Simon) ( Agelenidae ), subadult female. The wasp, walking backwards up the siding of a house or garage, grasped the immobilized giant house spider by the base of its left hind coxa or pedicel with her mandibles ( Braden 2015).

Eratigena duellica is a new host spider species for A. arcta . Kurczewski et al. (2017) reported Arachnospila arcta provisioning with Eratigena agrestis Walckenaer (hobo spider) in Portland, Multnomah County, OR. Other recent records for A. arcta from the West Coast include other genera of Agelenidae ( Hololena sp. , Novalena pina Chamberlin and Ivie ) and Segestriidae ( Segestria sp. ), other funnel-web and tube-web spiders ( Kurczewski et al. 2017).