Scolia dubia haematodes

Distinguished from Scolia nobilitata by having only one pair of yellow spots on the abdomen (S. nobilitata has two pairs) and by iridescent blue-black rather than smoky brown wings. The reddish-brown terminal abdominal segments separate S. d. haematodes from other S. dubia subspecies. Flight pattern of low figure-eight loops over turf is diagnostic when grubs are present.

Medium-sized wasp with striking iridescent blue-black wings. Body predominantly black with dense hair. Terminal abdominal segments reddish-brown to reddish-orange, giving the 'blood-tailed' appearance. Abdomen with one pair of bright yellow spots on either side. Wings held flat or slightly folded at rest. Sexual dimorphism in size, with females larger than males.

Open areas with well-drained soil supporting scarab beetle populations, including residential lawns, gardens, pastures, and meadows. Requires access to nectar sources for adult feeding. Soil must be sufficiently soft to allow excavation for host location.

Eastern North America; documented from Vermont southward through the Mid-Atlantic region of the United States. Records concentrated in the northeastern and mid-Atlantic United States.

Adults active from August through autumn. Emergence timed to coincide with peak availability of scarab beetle grubs. Adults observed nectaring on late-summer and autumn-blooming plants.

Adults feed on nectar from flowers in Lamiaceae (mints, mountain mint) and Asteraceae (goldenrod, spotted horse mint). Larvae are obligate parasitoids, feeding exclusively on living scarab beetle grubs including green June beetle, Japanese beetle, Oriental beetle, Asiatic garden beetle, and other soil-dwelling scarab larvae.

• Cotinis nitida - PARASITOID_OFGreen June beetle grub
• Popillia japonica - PARASITOID_OFJapanese beetle grub
• Anomala orientalis - PARASITOID_OFOriental beetle grub
• Maladera castanea - PARASITOID_OFAsiatic garden beetle grub

Univoltine. Adults emerge in August, mate, and females hunt for scarab grubs in soil. Female excavates soil to reach grub, delivers paralyzing sting, and deposits single egg on host exterior. Larva hatches and consumes living grub over summer and autumn. Mature larva spins silken cocoon and pupates within host burrow. Overwinters as pupa. Adults emerge following August.

Females exhibit low flight pattern approximately one foot above ground, tracing figure-eight loops while searching for host vibrations or chemical cues. Non-aggressive toward humans; sting used only for prey immobilization. Adults frequently observed nectaring in groups on preferred flowers. Males patrol territories and may engage in aerial combat.

Important biological control agent of scarab beetle pests. Population dynamics track host grub abundance, functioning as density-dependent mortality factor in turfgrass and agricultural ecosystems. Adult pollination activity on late-season flowers provides secondary ecosystem service.

Beneficial insect for natural pest management in lawns and gardens. Reduces populations of destructive scarab grubs without chemical intervention. Can be encouraged through planting nectar sources (mints, goldenrods). Sting poses minimal risk to humans; not defensive. Misidentification as dangerous wasp sometimes leads to unnecessary control attempts.

• Scolia nobilitataOverlapping range and similar biology; distinguished by two pairs of yellow/off-white abdominal spots and smoky brown rather than iridescent blue-black wings

• parasitoid
• biological control
• turfgrass pest management
• scarab beetle predator
• beneficial insect
• ground-nesting
• late summer emergence

• BugGuide
• GBIF taxonomy match
• iNaturalist taxon
• Befriend wasps and they will befriend you: Digger wasps, Scolia dubia and Scolia nobilitata — Bug of the Week