Asphondylia floccosa

Gagné, 1986

woolly stem gall midge, Saltbush Woolly Stem Gall Midge

Asphondylia floccosa is a gall midge in the Cecidomyiidae that induces distinctive woolly stem galls on Atriplex polycarpa. The larvae develop within multi-chambered galls but do not consume plant tissue directly—instead feeding on fungi that grow inside the gall structure. This was first described by Raymond Gagne in 1986 and is known from the southwestern United States.

Pronunciation

How to pronounce Asphondylia floccosa: /æsˌfɒnˈdɪliə fləˈkoʊsə/

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Identification

Distinguished from other Asphondylia by the woolly, stem-based galls on Atriplex polycarpa specifically. The galls contain 1–15 chambers and have a fuzzy, wool-like exterior. Similar gall midges on Atriplex or related Chenopodiaceae may induce different gall morphologies or occur on different species.

Appearance

are small, delicate flies typical of gall midges, with long and reduced wing venation. The galls they induce appear woolly or flocculent on stems of the plant. Larvae are tiny, legless maggots found within gall chambers.

Habitat

Arid and semi-arid regions where the plant Atriplex polycarpa (allscale saltbush, or Cattle saltbush) grows. Found in desert scrub and dry wash environments.

Distribution

Known from Arizona and California, USA. Distribution corresponds to the range of its plant in the southwestern United States.

Diet

Larvae feed on fungi growing within the galls they induce, not on the gall tissue itself. The specific fungal associates have not been identified in the available literature.

Host Associations

Atriplex polycarpa - Induces woolly stem galls; larvae develop within galls on this plant

Life Cycle

Females induce woolly stem galls on Atriplex polycarpa. Each gall contains 1–15 chambers housing individual larvae. Larvae develop through winter, feeding on internal fungi. occurs within the gall, with emerging to mate and oviposit into new tissue.

Behavior

Larvae engage in fungal farming within galls—a mutualistic or commensal relationship where the insects create conditions favorable for fungal growth and then consume the fungi rather than plant material.

Ecological Role

Acts as a gall inducer that modifies plant growth. The fungal association within galls represents a poorly understood . May serve as a food source for or , though these have not been documented for this .

Human Relevance

No direct economic importance documented. The has been used in studies of gall induction and insect-fungus relationships.

Similar Taxa

Asphondylia ilicicolaAnother Asphondylia that induces galls, but on Ilex opaca (American holly) berries rather than Atriplex stems; produces green berries instead of red through fungal association
Other Asphondylia spp. on AtriplexMultiple Asphondylia specialize on Atriplex; distinguished by gall location (stem vs. leaf vs. flower), gall , and chamber number

More Details

Fungal Feeding

This is notable among gall midges for not feeding directly on plant tissue. Instead, larvae cultivate or exploit fungi within the gall chambers, making it a candidate for studying insect-fungus .

Chamber Variability

The 1–15 chambers per gall represents unusually high variability in gall complexity for a cecidomyiid, suggesting flexible oviposition or variable plant responses.