Dasineura gleditchiae

Adults are tiny, delicate flies typical of gall midges, with reduced wing venation and long, bead-like antennae. The species is most readily identified by its distinctive galls: small, pod-shaped or berry-like structures that form on honey locust leaflets. These galls are green when young and may turn brown with age; they contain a single larva each. The galls superficially resemble fruits but are attached to leaf tissue rather than stems.

Associated with honey locust trees in urban plantings, parks, and ornamental landscapes. The species thrives in temperate climates where its host is cultivated. In North America, it occurs in natural and planted stands of Gleditsia triacanthos; in Europe, it is restricted to urban and suburban environments where ornamental honey locusts are grown.

Native to North America: recorded from California, Idaho, North Dakota, Oregon, South Dakota, Wyoming (USA), and Ontario (Canada). Introduced to Europe: established in Austria, Belgium, Croatia, Czech Republic, Denmark, France, Greece, Hungary, Italy, Luxembourg, Netherlands, Poland, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, and the United Kingdom (England and Wales). Also recorded in Turkey.

Adults emerge in spring and early summer, coinciding with honey locust leaf development. Gall formation occurs as new foliage expands. Larvae develop within galls through summer, with mature larvae dropping to the soil to pupate. Pupation occurs in soil, with adults emerging the following spring.

Larvae feed on plant tissue within galls induced on honey locust leaflets. Adults do not feed; their mouthparts are reduced or non-functional, as is typical for many Cecidomyiidae.

• Gleditsia triacanthos - gall inducerThe sole known host; larvae induce pod-shaped galls on leaflets.

Eggs are laid on developing honey locust leaflets. Larvae hatch and induce gall formation, developing within individual pod-like galls. Mature larvae exit galls and drop to the ground, burrowing into soil to pupate. Pupae overwinter in soil. Adults emerge in spring, often synchronizing with host bud break.

Females oviposit on young leaf tissue, triggering gall induction through chemical manipulation of plant growth. Larvae are sedentary, developing entirely within their individual galls. Mature larvae actively exit galls and burrow into soil for pupation. Adults are weak fliers and likely disperse short distances; long-range spread occurs primarily through human transport of infested plant material.

Acts as a phytophagous specialist on honey locust, with minimal apparent impact on native ecosystems in its introduced range due to restriction to cultivated hosts. The galls may provide microhabitats for incidental inquilines or parasitoids, though specific associates are poorly documented.

Considered a minor ornamental pest due to gall formation on honey locust foliage, which can cause aesthetic damage and premature leaf drop in heavy infestations. Management in urban settings may involve pruning of infested branches or soil treatments targeting pupae, though the species is rarely a priority for intensive control.

• Dasineura investitaAlso in Cecidomyiidae and induces similar berry-like galls, but on wood nettle (Laportea canadensis) rather than honey locust; host plant distinguishes the species.
• Other Dasineura spp. on GleditsiaSome congeners may occur on honey locust; precise identification requires examination of adult morphology or molecular analysis, as gall morphology alone may not distinguish all species.
• Contarinia spp.Related gall midges that may cause similar foliar distortions on leguminous hosts; distinguished by gall structure details and adult genitalia.

• gall midge
• Cecidomyiidae
• invasive species
• urban pest
• Gleditsia
• phytophagy
• gall induction
• ornamental pest

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• Catalogue of Life
• Cecidomyiidae | Beetles In The Bush
• Ted C. MacRae | Beetles In The Bush | Page 5
• Dasineura gleditchiae . [Distribution map].