# Lesser Maple Spanworm Moth (*macaria pustularia*) The Lesser Maple Spanworm Moth (Macaria pustularia) is a charming and common Geometrid moth native to eastern North America. Named for its caterpillars' favorite food and their characteristic "looping" crawl, this delicate white moth is a frequent visitor to deciduous forests and suburban yards alike. During the summer, it plays an important role in the local ecosystem, serving as a vital food source for nesting birds and acting as a key indicator of forest health. Though small, its abundance makes it a staple of North American woodlands. - **Category:** [Insects](https://www.snappit.app/explore/categories/insect) - **Rarity:** Common - **Danger:** 1/5 · Very low - **Snaps:** 4 - **Habitat:** Found primarily in deciduous and mixed forests, particularly where maple trees are abundant, as well as in wooded suburban parks and gardens. ![Lesser Maple Spanworm Moth](https://inaturalist-open-data.s3.amazonaws.com/photos/4723485/medium.jpeg) Photo: Nick Block, CC BY 4.0 · [iNaturalist](https://www.inaturalist.org/photos/4723485) ## Appearance Adults are small, delicate moths with a wingspan of 2 to 3 cm. Their wings are mostly pure, chalky white to light cream, decorated with three distinct orange-yellow or light brownish transverse lines crossing the forewings. A notable diagnostic feature is a tiny, bright orange or brownish spot or smudge located near the middle of the forewing's outer margin. When resting, they hold their wings flat against the surface, showcasing their triangular profile and hiding their light-colored legs beneath. ## Taxonomy - **Kingdom:** Animalia - **Phylum:** Arthropoda - **Class:** Insecta - **Order:** Lepidoptera - **Family:** Geometridae - **Genus:** Macaria ## Interesting facts - Despite their small size, their caterpillars can occasionally experience massive population booms, temporarily defoliating small stands of maples. - The common name 'spanworm' comes from the caterpillar's unique walking pattern, which makes it look as though it is measuring the earth inch by inch. - They are highly attracted to ultraviolet light sources, making them a common subject for backyard moth-watching setups. ## Special abilities - **Looping Locomotion:** The caterpillar lacks middle prolegs, forcing it to draw its rear up to its front legs to form a loop before extending forward, a highly efficient crawling technique. - **Bark Mimicry:** When resting on birch or light-colored tree trunks, the flat, white-and-orange wings of the adult moth blend seamlessly with the bark patterns to avoid detection. - **Selective Feeding:** Caterpillars selectively feed on maple leaves with lower tannin levels, maximizing nutrient absorption while minimizing defensive chemical intake. ## Measurements & details - **Length:** 1-2 cm - **Wingspan:** 2-3 cm - **Weight:** 0.0001-0.0003 kg - **Clutch Size:** 50-150 - **Incubation:** 5-14 days ## Diet & Feeding Caterpillars feed on the foliage of deciduous trees, specifically maples, while adult moths rarely feed, occasionally sipping nectar. - **Age differences:** Caterpillars feed continuously on leaves, whereas adult moths have reduced mouthparts and feed minimally or not at all. - **Primary Foods:** Red Maple leaves, Sugar Maple leaves, Silver Maple leaves, Boxelder leaves - **Foraging Method:** Grazing ## Ecological connections - **Host plant:** [Red Maple](https://www.snappit.app/explore/red-maple) (*Acer rubrum*) — The primary larval host tree where females lay eggs and caterpillars feed on foliage. - **Eaten by:** [Tufted Titmouse](https://www.snappit.app/explore/tufted-titmouse) (*Baeolophus bicolor*) — Birds heavily prey upon the caterpillars and resting adult moths during the summer breeding season. - **Parasite:** Braconid Wasp (*Cotesia congregationis*) — A parasitoid wasp that lays eggs inside the caterpillars, controlling their population. ## Safety **Danger:** 1/5 · Very low No special safety notes yet. ## Frequently Asked Questions ### How to identify Lesser Maple Spanworm Moth? Compare resting wing shape, forewing markings, antennae and body build. Small brown moths can hinge on fine details a phone photo can't always catch. Moth Identifier: upload a photo and compare the visible details. ### How long is Lesser Maple Spanworm Moth? 1-2 cm ### What is Lesser Maple Spanworm Moth's wingspan? 2-3 cm ### How much does Lesser Maple Spanworm Moth weigh? 0.0001-0.0003 kg ### What does Lesser Maple Spanworm Moth eat? Caterpillars feed on the foliage of deciduous trees, specifically maples, while adult moths rarely feed, occasionally sipping nectar. ### Where is Lesser Maple Spanworm Moth usually found? Found primarily in deciduous and mixed forests, particularly where maple trees are abundant, as well as in wooded suburban parks and gardens. ### How does Lesser Maple Spanworm Moth hunt? Grazing ### How many eggs does Lesser Maple Spanworm Moth lay? 50-150 ## Where to spot - [Battle Creek Cypress Swamp Sanctuary](https://www.snappit.app/guides/places/battle-creek-cypress-swamp-sanctuary) — Maryland, US · Nature Reserve - [Chatham Arch](https://www.snappit.app/guides/places/chatham-arch) — Indiana, US · Neighborhood - [Mystic River Reservation](https://www.snappit.app/guides/places/mystic-river-reservation) — Massachusetts, US · Nature Reserve - [Reading Public Museum](https://www.snappit.app/guides/places/reading-public-museum) — Pennsylvania, US · Botanical Garden - [Spy Pond Field](https://www.snappit.app/guides/places/spy-pond-field) — Massachusetts, US · Park - [New Milford Center Historic District](https://www.snappit.app/guides/places/new-milford-center-historic-district) — Connecticut, US · Historic District [View all places to see Lesser Maple Spanworm Moth](https://www.snappit.app/guides/where-to-see/lesser-maple-spanworm-moth) ## More Insects - [Common Eastern Bumble Bee](https://www.snappit.app/explore/common-eastern-bumble-bee) (*Bombus impatiens*) - [Spotted Lanternfly](https://www.snappit.app/explore/spotted-lanternfly) (*Lycorma delicatula*) - [Brown-belted Bumble Bee](https://www.snappit.app/explore/brown-belted-bumble-bee) (*Bombus griseocollis*) - [Eastern Carpenter Bee](https://www.snappit.app/explore/eastern-carpenter-bee) (*Xylocopa virginica*) --- Source: [Lesser Maple Spanworm Moth: Facts & Places to See — Snappit](https://www.snappit.app/explore/lesser-maple-spanworm-moth)