Genus Isodontia - Grass-carrying Wasps

Isodontia Patton 1880

6 spp. in 2 subgenera in our area(1), >60 spp. worldwide(2)

Medium-sized dark sphecids, often seen carrying grass to nests.

Hairs on thorax golden

Hairs on thorax pale

Hairs on thorax black

worldwide(2)

Open areas, fields, grass

in NC: I. auripes Jun-Oct, I. azteca May-Oct(3); Jul-Aug in MI(4)

Adults take nectar. Larvae are fed Gryllidae (particularly tree crickets) or other Orthoptera.(5)

Females make nests in a tree, hollow stem or other cavity, divide into sections and close with grass. They provision with Orthoptera (Tettigoniidae, Gryllidae). Can be two generations per year (I. mexicana in PA)

1. Larva 2. Cocoon and food remnants in hollow stem 3. Adult female 4. Adult male. 5. Parasitic fly's puparia.

grass-carrying habits, nest(6); nesting behavior of I. harrisi(7)

Adults emerge in early summer. Female collects blades of grass and grass and hay stems to line the nest cavity. The nest is stocked with tree crickets (Oecanthus spp.) The larvae reach the appropriate size in 4–6 days at 70–75°F and pupate. The adults emerge in 2–3 weeks. In Pennsylvania, I. mexicana typically produce two generations a year. (Jacobs 2014)

These wasps commonly make their nest in the narrow track found above outer windows.