|scientific name Euxoa |
Open relatively xeric habitats, in particular grassland-steppe habitats with loose soils.
Adults of most species fly in late summer and early fall, although a few species emerge in spring an
The genus Euxoa belongs to the tribe Agrotini in the Noctuid subfamily Noctuinae. Members of this tribe can be identified by the following characteristics: eyes without surface hairs; lacking tuft of lash-like scales in front of eye below antennae; frons bulging with a ringlike tubercle in most species; trifid hindwing venation; all tibia with spines; middle and hind tarsi with fourth row of setae laterally on outside of first segment.
Euxoa can be distinguished from other Noctuinae by the following genital characters;
in males there is a sclerotized saccular extension below the lower margin of the cucullus, and females have elongated sclerotized plates in the dorsal and ventral wall of the ductus bursae extending anteriorly from a sclerotized ostium bursae.
Adults are medium-size (mainly 3.0-4.5 cm wingspan) stout-bodied moths in a wide variety of mostly drab earth tone colors and cryptic patterns.
Euxoa have a single generation each year. Most species overwinter as fully formed larvae within the egg, with a few species hatching in the fall and overwintering as first instar larvae. Larvae of a few species which fly in spring hatch from the egg in late summer and overwinter as partly grown larvae. All species, where known, lay the eggs in the soil. The larvae feed above the surface at night or on cloudy days, resting under clods or below the surface during the day. When fully-grown or nearly so, the larvae aestivate for a time. Pupation takes place in the soil in an earthern cell.
Mostly widespread, common species, including a number of serious economic pests.
So far as is known, larvae of the genus Euxoa are all general feeders, with most preferring to feed on low-growing broad-leaved plants, although grasses and cereal crops and occasionally tree leaves are also eaten. Several species are serious economic pests on wide variety of agricultural crops.
Primarily arid and semi-arid habitats in the Northern Hemisphere. Euxoa occur throughout North America south to Costa Rica, with the greatest diversity in the Great Plains and mountainous regions of western North America. Over half of the 300 plus described species occur in North America, and more than 80 species have been found in Alberta. It appears that soil conditions such as moisture, soil texture and exposure are the most important determinants of range for Euxoa.
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