Schizura ipomaeae

The caterpillar is distinguished from similar Schizura species by the single horn-like projection on the head (versus paired projections in some congeners) and association with morning glory hosts. Adults require genital dissection or molecular analysis for reliable separation from closely related Schizura species, as external morphology is highly variable and overlapping. The similar Schizura unicornis (unicorn caterpillar) has a more eastern distribution and different host preferences.

Found in open habitats including fields, roadsides, gardens, and agricultural areas where morning glory and bindweed occur. Also present in disturbed woodlands and forest edges. The species thrives in both natural and anthropogenic environments due to the widespread distribution of its host plants.

United States and southern Canada. Records from Vermont and throughout eastern and central North America. Absent from western regions where related species occur.

Adults are active from late spring through summer, with peak flight typically in June-July depending on latitude. Multiple generations may occur in southern portions of the range. Caterpillars are present from summer through early fall.

Caterpillars feed on leaves of morning glory (Ipomoea species) and related plants in the Convolvulaceae family, including bindweeds (Calystegia, Convolvulus). They are specialist herbivores on this plant family.

• Ipomoea - primary hostMorning glory species, primary larval food plant
• Calystegia - hostBindweeds, secondary host
• Convolvulus - hostField bindweed and relatives

Complete metamorphosis with four stages: egg, larva, pupa, and adult. Females deposit eggs on host plant leaves. Larvae feed externally on foliage, progressing through five instars. Mature larvae descend to the ground to pupate in silken cocoons among debris or in shallow soil. Adults emerge the following season; some populations may have partial second generation in favorable climates.

Caterpillars are solitary feeders that rest along leaf midribs or stems, relying on camouflage. When disturbed, they may thrash or drop from foliage on silk threads. Adults are nocturnal and come to light. The horn-like head projection in larvae is a defensive structure, though the specific defensive compounds have not been characterized for this species.

As a specialist herbivore, the caterpillar contributes to nutrient cycling in early successional habitats and serves as prey for generalist predators and parasitoids. The species may help regulate morning glory populations in natural settings.

Occasional pest of cultivated morning glories and sweet potatoes (Ipomoea batatas), though rarely reaching economically damaging populations. The caterpillar's distinctive appearance makes it a subject of interest for naturalists and photographers. The species has been used in studies of plant-insect coevolution due to its specialized host relationships.

• Schizura unicornisSimilar caterpillar with head projection, but typically has more eastern distribution and feeds on different host plants including oaks and other woody plants
• Schizura concinnaRedhumped caterpillar with bright red head and hump behind head, feeds on redbud, walnut, plum, and other trees; western and eastern North American distribution with different host preferences
• Schizura leptinoidesOverlapping range and similar adult morphology; requires dissection for reliable identification

• Notodontidae
• Lepidoptera
• North America
• specialist herbivore
• morning glory
• agricultural pest
• false unicorn caterpillar

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