Neuroterus fragilis

Bassett, 1900

succulent gall wasp

Neuroterus fragilis, commonly known as the succulent gall wasp, is a of oak gall wasp in the Cynipidae. It induces distinctive galls on California oak species, with only the spring bisexual currently documented. The species is notable for its relatively large galls compared to its tiny body size.

N fragilis from Report of the State Entomologist on injurious and other insects of the state of New York (1917) (14781149311) by Edna Libby Beutenmüller. Used under a Public domain license.N fragilis adult by EponineBunnyKickQueen. Used under a CC BY 4.0 license.Report of the State Entomologist on injurious and other insects of the state of New York (1917) (14781149311) by New York (State). State Entomologist; Felt, Ephriam Porter, 1868-1943. Key to American insect galls. Used under a No restrictions license.

Identification

Distinguished from other Neuroterus by the large (10–30 mm), succulent swellings on petioles and midribs of oak leaves, rather than smaller or differently positioned galls. The combination of yellow legs and specific association with California oak species aids identification. Only the spring bisexual is known, unlike many which have documented parthenogenetic summer generations.

Images

Appearance

are minute measuring 0.7–1.2 mm in body length. The legs are distinctly yellow. The galls induced by this are 10–30 mm in size, appearing as succulent swellings on leaf petioles and midribs.

Habitat

Associated with oak woodlands in California. Galls develop on the leaves of oak trees, specifically on petioles and midribs.

Distribution

to California, USA. Documented from oak including leather oak (Quercus durata), California scrub oak (Quercus berberidifolia), blue oak (Quercus douglasii), and valley oak (Quercus lobata).

Seasonality

Spring active; specific timing of not detailed in available sources. The spring bisexual generation is the only confirmed generation.

Host Associations

  • Quercus durata - gall inducerleather oak
  • Quercus berberidifolia - gall inducerCalifornia scrub oak
  • Quercus douglasii - gall inducerblue oak
  • Quercus lobata - gall inducervalley oak

Life Cycle

Only the spring bisexual , with both males and females, is documented. A parthenogenetic summer generation, common in related oak gall wasp , is hypothesized but unconfirmed.

Ecological Role

Gall inducer on California oak . Creates microhabitats that may support associated , though specific or for this species are not documented in available sources.

Similar Taxa

  • Other Neuroterus speciesMany induce smaller or differently structured galls on oaks; N. fragilis is distinguished by its large, succulent petiole and midrib swellings and specific range in California.

More Details

Generational uncertainty

While most oak gall wasps have a documented parthenogenetic summer , this has not been confirmed for N. fragilis despite being considered possible.

Tags

Sources and further reading