Macremphytus

MacGillivray, 1908

Dogwood Sawflies

Species Guides

4

Macremphytus is a of common sawflies in the Tenthredinidae, comprising at least four described . The best-known member is Macremphytus tarsatus, commonly called the dogwood , which is a significant defoliator of dogwood trees in North America. Sawflies in this genus are herbivorous, with larvae feeding on leaves of woody plants. The genus exhibits distinctive larval traits including waxy secretions and in wood.

Macremphytus by (c) agood, some rights reserved (CC BY). Used under a CC-BY license.Macremphytus tarsatus by (c) Kristy Morley, some rights reserved (CC BY), uploaded by Kristy Morley. Used under a CC-BY license.Macremphytus tarsatus 5429856 by Brian Kunkel, University of Delaware, Bugwood.org. Used under a CC BY 3.0 license.

Pronunciation

How to pronounce Macremphytus: /maˈkrɛm.fɪ.təs/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Larvae distinguished from caterpillars (Lepidoptera) by possessing six or more pairs of fleshy on abdominal segments versus five or fewer in caterpillars. Early instars covered in white waxy filaments; mature larvae of M. tarsatus display yellow, white, and black coloration. are small, -like insects.

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Habitat

Associated with deciduous woodlands and ornamental landscapes containing plants, particularly dogwoods (Cornus spp.) and trees in the walnut (Juglandaceae).

Distribution

North America; records include Vermont and broader United States.

Seasonality

emerge and fly from May through July. Larvae develop through summer, with mature larvae seeking sites in wood during autumn.

Diet

Larvae feed on leaves of plants including grey dogwood (Cornus racemosa), silky dogwood (Cornus amomum), flowering dogwood (Cornus florida), black walnut (Juglans nigra), butternut (Juglans cinerea), and hickories (Carya spp.).

Host Associations

  • Cornus racemosa - grey dogwood, favored
  • Cornus amomum - silky dogwood
  • Cornus florida - flowering dogwood
  • Juglans nigra - black walnut
  • Juglans cinerea - butternut
  • Carya spp. - hickories

Life Cycle

Winter spent as larva in chamber constructed in rotting wood or structural wood including siding and decks. In spring, larvae pupate. emerge May-July, mate, and females deposit in clutches of 100 or more on undersurfaces of leaves. Eggs hatch and larvae develop through multiple instars over summer. Mature larvae abandon plants in autumn to construct galleries in wood.

Behavior

Larvae initially feed gregariously, skeletonizing leaves; later instars may consume entire leaves except midveins. Early instars curl beneath leaves when disturbed. Mature larvae bore into wood to create chambers, producing sawdust-like .

Ecological Role

Herbivore and defoliator of native and ornamental trees. Larvae serve as food source for and ; waxy secretions may provide defense against and .

Human Relevance

M. tarsatus recognized as occasional pest of ornamental dogwoods and landscape plantings. Larval boring into structural wood, including decks and siding, can cause minor cosmetic damage.

Similar Taxa

  • Eriocampa juglandisButternut woollyworm, another with white waxy larval secretions; distinguished by preference (walnut ) and pupal in soil rather than larval overwintering in wood
  • Atomacera deceptaMallow sawfly, similar larval and waxy secretions; distinguished by plants (mallows/Hibiscus) and different timing

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Sources and further reading