Erebidae

Erebidae

Erebidae is a large and exceptionally varied family of moths within the superfamily Noctuoidea. It includes tiger moths, lichen moths, tussock moths, underwings, litter moths, snout moths, and many other lineages once divided among several different families. In Minnesota and the Upper Midwest, erebids occur in forests, wetlands, prairies, meadows, gardens, roadsides, and other habitats where their larval host plants are present.

Erebids range from small, cryptically patterned moths to large species with bold warning colors or brilliant hindwings. Most are active at night, but some—including the Virginia Ctenucha and several other tiger moths—regularly fly during the day. The family’s diversity means that no single color pattern, body shape, or behavior identifies every member.

General Appearance

Adult erebids vary greatly in size and form. Many have broad or triangular forewings, stout thoraxes, and wings held roof-like or flat over the abdomen at rest. Others are slender, narrow-winged, heavily furred, wasp-like, or shaped to resemble dead leaves and bark.

Coloration may be gray, brown, tan, black, white, orange, red, yellow, green, or metallic blue. Some species rely on camouflage, while others display warning colors, eyespots, or brightly banded hindwings. Males and females may differ in size, color, wing development, or antenna structure.

Common field marks include:

• cryptic forewing lines, spots, bands, or marbling
• hidden hindwings that may be red, orange, yellow, black, or strongly banded
• thoracic or abdominal tufts and crests
• simple, toothed, or strongly comb-like antennae
• snoutlike labial palps in some groups
• white, orange, red, black, or metallic warning patterns in many tiger moths
• densely hairy or tufted caterpillars in Arctiinae and Lymantriinae
• variable resting postures, from tightly roofed wings to wings spread flat against a surface

Family-level recognition from a photograph may be straightforward for distinctive tiger moths or underwings, but many plain brown species require close comparison with Noctuidae, Nolidae, or other moth families.

Habitat and Behavior

Species in this family occupy a wide range of terrestrial habitats, including:

• deciduous, coniferous, and mixed forests
• prairies, meadows, old fields, and roadsides
• marshes, bogs, wet meadows, and shoreline vegetation
• gardens, parks, farms, and urban landscapes
• woodland edges, clearings, shrublands, and leaf-litter habitats

Many erebids fly after dusk and visit lights, flowers, sap flows, fermenting fruit, or sugar bait. Underwing moths often rest against bark with their cryptic forewings closed over colorful hindwings, exposing the bright pattern only when disturbed. Litter moths remain close to the forest floor, while day-flying tiger moths may nectar in sunny openings alongside butterflies.

Behavioral patterns useful for field identification include:

• daytime versus nighttime activity
• attraction to light, bait, sap, or flowers
• resting posture and choice of substrate
• sudden flashes of colorful hindwings during escape flights
• slow flight through grass versus rapid flight around trees or lights
• association with lichens, leaf litter, grasses, or a particular host plant
• seasonal timing and the condition of the wings and body scales

Adults may be found from spring through fall in Minnesota, with each species having its own flight period. Some species produce one generation per year, while others may have multiple broods when conditions allow.

Identification Characters

Key field characters include:

• Forewing pattern: ground color, transverse lines, spots, streaks, patches, and the shape of the outer margin.
• Hindwing pattern: bright color, banding, dark borders, translucence, or uniform shading hidden beneath the forewings.
• Wing shape and posture: broad, narrow, triangular, wrapped, tented, or flat wing position at rest.
• Head and palps: facial scaling and the length or angle of the labial palps, especially in snout and litter moths.
• Antennae: threadlike, serrate, pectinate, or bipectinate structure; males may have more strongly branched antennae.
• Thorax and abdomen: crests, hair, metallic scales, warning colors, bands, and overall body proportions.
• Legs: color, hair, spines, and resting position may provide supporting characters.
• Sex and age: sexual dimorphism, faded scales, and wing wear can change the apparent pattern.
• Larval form: density and arrangement of hairs or tufts, body stripes, head color, prolegs, and host-plant association.

Many boldly patterned erebids can be identified from clear photographs, especially when both the forewings and body markings are visible. Plain or worn specimens may require multiple angles, examination of small structures, or expert review. Some closely related species cannot be separated reliably without examination of genitalia or DNA barcoding.

For photographic identification, try to capture:

• a dorsal view showing the complete forewing pattern
• a side or three-quarter view showing the head, palps, thorax, abdomen, and resting posture
• the hindwings if they are exposed naturally
• antenna structure, particularly in strongly comb-antenned species
• a scale reference when practical
• date, location, habitat, time of activity, and attraction method
• the host plant and several body angles when documenting a caterpillar

Life Cycle and Ecology

Like other moths, erebids undergo complete metamorphosis: egg, caterpillar, pupa, and adult. Females usually place eggs on or near suitable larval food. Caterpillars feed on a wide range of plants, lichens, algae, fungi, or fallen plant material, depending on the lineage. Some are specialists, while others use many host species.

Larval appearance and behavior vary widely. Tiger and tussock moth caterpillars are often densely hairy, sometimes with distinctive pencils or tufts. Underwing caterpillars tend to be smooth, elongated, and barklike. Litter moth larvae live close to the ground and may feed on dead leaves or other low-growing material.

Pupation may occur underground, in leaf litter, beneath bark, or inside a silken cocoon. Hairy larvae may incorporate their own setae into the cocoon. Depending on the species, winter may be passed as an egg, caterpillar, pupa, or adult.

Erebids are important herbivores, pollinators, and prey. Caterpillars provide food for birds, predatory insects, spiders, and other animals. Adults are important prey for bats, and many erebids possess tympanal organs capable of detecting ultrasonic bat calls. Some tiger moths also produce ultrasonic signals and use warning colors or plant-derived chemicals as defenses.

Similar Families and Distinguishing Features

Other noctuoid families may closely resemble Erebidae. Useful distinctions include wing venation, tympanal structure, scaling, palps, body shape, larval form, and—when external characters are insufficient—genitalia or molecular evidence.

• Noctuidae — Owlet moths: Often stout-bodied and cryptically patterned, making some species extremely difficult to separate from erebids in photographs. Wing venation and anatomical characters are important at family level.

• Nolidae — Nolid moths: Usually small to medium-sized and often show raised scale tufts or distinctive forewing patches. Some resemble small erebids and require close inspection.

• Notodontidae — Prominent moths: Adults often have projecting wing scales or thoracic tufts that create an irregular outline. Their caterpillars may have humps, tails, or unusual defensive postures.

• Geometridae — Geometer moths: Adults are often more slender-bodied with broad wings held flat, and their caterpillars typically move with a looping “inchworm” gait because they have fewer abdominal prolegs.

• Zygaenidae and related day-flying moths: Some resemble brightly colored or wasp-like tiger moths. Antenna form, wing pattern, venation, and regional range help distinguish them.

Because Erebidae includes many formerly separate groups, a reliable identification may begin with the subfamily rather than with a single family-wide visual character.

Representative Genera

• Ctenucha — colorful, often day-flying wasp moths with dark wings, metallic bodies, and contrasting collars.
• Catocala — underwing moths with barklike forewings and brightly banded hindwings.
• Hypoprepia — lichen moths with bold red, orange, yellow, and gray wing patterns.
• Haploa — white tiger moths marked with variable black lines or spots.
• Halysidota — tussock moths whose larvae have conspicuous hair tufts and long hair pencils.
• Hyphantria — includes the Fall Webworm Moth, whose larvae build communal silk webs on host trees.
• Zale — cryptically patterned moths with broad, irregular bands and leaf- or barklike coloration.
• Hypena — snout moths with projecting palps and often angular forewing patterns.
• Idia — small litter moths commonly encountered near forest floors and at lights.
• Lymantria — tussock moth relatives that may show strong sexual differences in size, color, antennae, or flight ability.

Species Notes in This Family

• Virginia Ctenucha — Ctenucha virginica

Family overview intended for field study and photographic reference; close inspection and, when necessary, examination of wing venation, tympanal structures, genitalia, larval characters, or genetic evidence may be required for confident identification.

References

• BugGuide: Family Erebidae https://bugguide.net/node/view/43743

• Erebidae systematics: past, present, and future https://doi.org/10.1093/isd/ixaf018

• Zahiri et al. (2011): A new molecular phylogeny offers hope for a stable family-level classification of the Noctuoidea https://doi.org/10.1111/j.1463-6409.2010.00459.x