Aporus hirsutus

Distinguished from other Pompilidae by the combination of: short, thick antennae; thorax with gradual anterior slope toward head (not blocky); proportionately short legs; and small body size. Differs from the unrelated genus Evagetes, which shares short antennae, by its streamlined rather than blocky thorax. Within the genus Aporus, A. hirsutus is distinguished from congeners by details of pubescence density and distribution, and subtle structural features of the propodeum and petiole, though precise diagnostic characters require specialist examination.

Small spider wasp, 8-15 mm in body length. The thorax slopes gradually toward the head, creating a streamlined profile. Legs are proportionately shorter than in other spider wasps. Antennae are relatively short and thick. The species epithet 'hirsutus' suggests a hairy or setose body covering, though specific details of coloration and pubescence pattern require direct examination of specimens.

Found in association with flowers of umbelliferous plants including Queen Anne's Lace (Daucus carota), as well as buckwheat (Eriogonum spp.), rabbitbrush (Chrysothamnus spp.), gumweed (Grindelia spp.), spurge (Euphorbia spp.), and various other flowering plants. Also visits extrafloral nectaries of sunflower (Helianthus annuus), honeydew from aphids, and gall exudates on oak. The species requires habitats supporting both floral resources for adults and mygalomorph spider hosts for larval development.

Western North America. Ranges from central British Columbia south to central Baja California, eastward to western Idaho, Utah, and most of Arizona. One record from Montezuma County, Colorado.

Adults active primarily May through October, with peak activity during summer months. Single generation per year in most of range; possibly two generations in southernmost latitudes.

• Aptostichus sp. - hostwafer-lid trapdoor spider, family Euctenizidae; adult male wasp reared from this host

Adult female stings host spider into paralysis, then utilizes the spider's own burrow as a nest. A single egg is deposited on the paralyzed spider. Larva feeds on the paralyzed host. Typically one generation annually, with some indication of partial second generation in southern areas where some females may oviposit in spring producing summer larvae.

Adults frequently visit flowers for nectar, particularly umbelliferous blossoms. Constantly moving even while feeding, making them challenging photography subjects. Females hunt mygalomorph spiders, sting them into paralysis, and usurp their burrows for nesting. Males have been reared from host spiders, indicating successful larval development.

Parasitoid of mygalomorph spiders, contributing to population regulation of these soil-dwelling arachnids. Adult flower-visiting behavior may contribute to pollination of visited plants, though this has not been quantified. As a specialist parasitoid, helps maintain spider community structure in western North American ecosystems.

Not known to be of direct economic importance. Like other spider wasps, poses minimal stinging risk to humans due to small size and non-aggressive nature. Potential interest for biological control research given its specialized parasitoid biology, though no applied uses have been documented.

• Evagetes spp.Shares short, thick antennae but differs in having blocky rather than streamlined thorax; unrelated genus in Pompilidae
• Other Aporus speciesRequire detailed examination of pubescence, propodeal structure, and petiole proportions for definitive identification; A. hirsutus distinguished by denser hairiness per species epithet
• Other small PompilinaeDistinguished by the unique combination of short legs, short thick antennae, and sloping thorax profile characteristic of Aporus

• hymenoptera
• pompilidae
• spider wasp
• parasitoid
• western north america
• mygalomorph spider parasitoid
• flower visitor

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