Nesting behavior, ecology, and functional morphology of the trapdoor spider-hunting spider wasp \u3ci\u3eAporus (Plectraporus) hirsutus\u3c/i\u3e (Banks) (Hymenoptera: Pompilidae)

Abstract

Macrophotographs in series taken by Alice Abela on sandy coastal dunes in Santa Barbara and San Luis Obispo Counties, CA in 2010–2021 supplement and enhance F. X. Williams (1928) study of the ecol­ogy and nesting behavior of the trapdoor spider-hunting spider wasp Aporus (Plectraporus) hirsutus (Banks) (Hymenoptera: Pompilidae: Aporini). Abela’s macrophotographs and observations provide new details of adult wasp feeding, functional morphology, hunting, digging and prey transport, and host spider trapdoor, entrance, burrow structure, host capture and escape activity. Newly reported host records from this study and online photographs expand A. hirsutus host selection in the large wafer-lid trapdoor spider genus Aptostichus Simon (Araneae: Mygalomorphae: Euctenizidae). The A. hirsutus California geographic distribution map by Wasbauer and Kimsey (1985) is updated, thereby providing a broader definition of intraspecific variation in this species. Aporus (Plectraporus) hirsutus (Banks) (Hymenoptera: Pompilidae: Aporini) is black, its body, antennae, legs and forewings rendered brilliant bluish, greenish or violaceous by its pubescence (Evans 1966; Wasbauer and Kimsey 1985) (Fig. 1). Females of A. hirsutus are 6.5–13.0 mm in body length, their size depending on the size of the host spider on which they fed as a larva (Evans 1966; F. E. Kurczewski pers. obs.). Females have the appropriate structural characteristics for preying on the wafer-lid trapdoor spider genus Aptostichus Simon (Araneae: Myga­lomorphae: Euctenizidae) in loose sand of active and relict coastal sand dunes and deserts in the western U. S. (Williams 1928; Wasbauer and Kimsey 1985). Aporus hirsutus ranges from Oregon and California eastward to Idaho, Nevada and western Arizona, and southward into Sonora and Baja California, Mexico (Evans 1966; Was­bauer and Kimsey 1985) (Fig. 9; Table 1)