Taxodiomyia

Gagné, 1968

cypress gall midges

Species Guides

Taxodiomyia cupressi(Cypress Twig Gall Midge)
Taxodiomyia cupressiananassa(cypress twig gall midge)
Taxodiomyia taxodii(cypress leaf gall midge)

Taxodiomyia is a of gall midges in the Cecidomyiidae that induce galls on cypress trees (Taxodium spp.). The genus contains at least three described , all specialized to form distinctive twig or leaf galls on their coniferous . These tiny flies are rarely observed directly, with their presence most commonly detected through the abnormal plant growths they induce.

Taxodiomyia by (c) Amber M. King, some rights reserved (CC BY), uploaded by Amber M. King. Used under a CC-BY license.

Taxodiomyia taxodii by (c) Amber M. King, some rights reserved (CC BY), uploaded by Amber M. King. Used under a CC-BY license.

Taxodiomyia taxodii by (c) ncb1221, some rights reserved (CC BY), uploaded by ncb1221. Used under a CC-BY license.

Pronunciation

How to pronounce Taxodiomyia: /tæksəˌdaɪoʊˈmaɪə/

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

Identification

Identification of Taxodiomyia relies primarily on examination of the galls they produce rather than the insects themselves. Adults are minute, delicate flies typical of Cecidomyiidae, with long, and reduced wing venation. Species-level identification requires examination of larval or adult by , or association with their characteristic gall types on specific plants. The galls of T. cupressiananassa are globular, spongy, initially snow-white and turning rusty-brown with age, with numerous spike-like projections.

Images

Habitat

Associated with wetland and riparian forests where cypress trees (Taxodium spp.) occur. The is found in supporting bald cypress (Taxodium distichum) and pond cypress, including swamps, floodplains, and pond margins.

Distribution

Eastern and central North America, with records from the southeastern United States north to central Illinois. Distribution follows that of cypress , with bald cypress native to the southeastern coastal plain and Mississippi Valley.

Seasonality

Galls are visible on trees from late spring through fall. may emerge from galls still on the tree later in the season. In temperate regions, larvae typically overwinter inside fallen galls and pupate in spring, with adult timed to host plant .

Host Associations

Taxodium distichum - gall inducerbald cypress; primary for T. cupressiananassa
Taxodium ascendens - gall inducerpond cypress

Life Cycle

Females lay in cypress twigs. Larvae induce formation of spongy, globular galls within which they develop. Larvae feed on gall tissue, then pupate inside the gall. emerge through exit holes in the gall wall. In T. cupressiananassa, galls detach and fall with leaves; larvae overwinter in fallen galls and complete development the following spring.

Behavior

females use their ovipositor to inject directly into twig tissue. Larvae secrete plant growth regulators that hijack host developmental , causing the plant to form a specialized nutritive structure (gall) that shelters and feeds the developing insect.

Ecological Role

As gall inducers, these act as specialized herbivores that manipulate plant growth. The galls provide for and , though specific associates are poorly documented. Damage to host trees is generally minor and cosmetic rather than causing significant tree mortality.

Human Relevance

Considered a minor pest of ornamental bald cypress in urban and suburban plantings. The galls, while conspicuous, do not threaten tree health. Management is rarely necessary; natural enemies and tree vigor typically keep in check.

Similar Taxa

DasineuraAnother of Cecidomyiidae containing numerous gall-inducing ; distinguished by gall and plant associations rather than fly appearance
ContariniaLarge of gall midges with similar ; Taxodiomyia is distinguished by specialization on Cupressaceae

Misconceptions

The galls of T. cupressiananassa are frequently mistaken for cypress cones by casual observers, and have also been misidentified as fungal (particularly rust fungi in the Gymnosporangium) due to their rusty coloration and spiky appearance.

More Details

Gall morphology

Galls of T. cupressiananassa are among the most distinctive of any cecidomyiid: globular, 1–2 cm in diameter, with a soft spongy texture and numerous pointed projections. The white galls turn brown and woody with age.

Taxonomic history

The was established by Gagné in 1968 to accommodate cypress-associated gall midges previously placed in other genera. The type is Taxodiomyia cupressi (Schweinitz, 1822), originally described as Cecidomyia cupressi.