Ceratomia amyntor

(Geyer, 1835)

Elm Sphinx, Four-horned Sphinx

Ceratomia amyntor is a North American hawkmoth with a wingspan of 8.2–11.5 cm. Larvae feed primarily on elm but also use birch, basswood, and cherry. The is notable for its four horns—additional to the caudal horn typical of sphingids—giving rise to the "four-horned sphinx." are gray-brown with wavy forewing markings and a small white dot characteristic of the . The species has one in northern regions and up to five in the southern United States.

Ceratomia amyntor by no rights reserved, uploaded by jeffcherry. Used under a CC0 license.Ceratomia amyntor by (c) Kevin Ripka, some rights reserved (CC BY). Used under a CC-BY license.Ceratomia amyntor BMNHE273956 male un by The Trustees of the Natural History Museum, London. Used under a CC BY 3.0 license.

Pronunciation

How to pronounce Ceratomia amyntor: /ˌsɛrəˈtoʊmiə əˈmɪntɔr/

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Identification

Distinguished from similar Ceratomia by four horns on larvae (vs. two in C. undulosa). recognized by gray-brown wavy forewings with small white dot; combination of broken body bands and plain gray hindwings with dark marginal band separates from . Larger size and more pronounced white head marking in some specimens may cause confusion with C. undulosa, but wing pattern details differ.

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Habitat

Deciduous forests and woodlands, suburban areas with trees present. Associated with elm, birch, basswood, and cherry stands.

Distribution

North America: Nova Scotia west to Alberta, western North Dakota, and Colorado; south to Florida, Gulf Coast, Georgia, Texas, Louisiana, and New Mexico.

Seasonality

Northern range: single , June–July. Southern range: two broods flying later in season; Louisiana records five broods March–October.

Diet

Larvae feed on leaves of Ulmus (elm), Betula (birch), Tilia (basswood), and Prunus (cherry). Has been observed on tomato and pepper plants.

Host Associations

  • Ulmus - primary
  • Betula - secondary
  • Tilia - secondary
  • Prunus - secondary
  • Solanum lycopersicum - occasional tomato
  • Capsicum - occasional pepper

Life Cycle

Complete with five larval instars completed in approximately one month. Larvae descend tree and burrow underground to pupate; may overwinter as pupae if late in season. Multiple in southern portion of range.

Behavior

Larvae exhibit "wandering" phase prior to , ceasing feeding and descending tree. , attracted to light.

Ecological Role

Herbivore in deciduous forest ; larval defoliation can be substantial on trees. Serves as prey for and other natural enemies.

Human Relevance

Occasional pest of vegetable crops (tomato, pepper) due to larval feeding. Otherwise not economically significant. Not threatened.

Similar Taxa

  • Ceratomia undulosaSimilar size and coloration; distinguished by larval horn count (two horns vs. four in C. amyntor) and subtle wing pattern differences
  • Ceratomia catalpaeShared and general ; C. catalpae specialized on Catalpa, lacks four horns as larva
  • Smerinthus spp.Similar gray-brown hawkmoth appearance; distinguished by eyespot patterns on hindwings and lack of broken body bands

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