Eurytoma

Habitats are diverse and host-dependent, ranging from plum orchards where larvae develop inside fruit stones, to galls formed by tephritid flies on Cirsium and other plant genera. Specific habitat requirements vary by species and are determined by host availability rather than fixed environmental conditions.

Records from multiple continents including North America (Alabama, British Columbia), Europe (Czech Republic, Moldova, Romania, Turkey, Greece, Bulgaria, Russia), and Asia (India: Andhra Pradesh, Assam, Bihar). Distribution is global but patchy, reflecting collection effort and host plant distribution rather than continuous range.

• Urophora cardui - primary host (for E. serratulae and E. robusta)tephritid gall-former on Cirsium
• Prunus domestica - host plantplum; larval development in seeds
• Prunus domestica insititia - host plantmirabelle plum
• Prunus domestica syriaca - host plantmyrobalan
• Prunus cerasifera - host plant
• Prunus armeniaca - host plantapricot
• Prunus spinosa - host plantblackthorn, less preferred
• Eurytoma serratulae - host (hyperparasitized)by E. robusta
• Syntomaspis eurytomae - parasitoidTorymidae, parasitoid of E. schreineri with 1.6-3.4% parasitism rate

Life cycle varies by species. Eurytoma schreineri is univoltine: larvae overwinter in seeds, pupate when temperatures exceed 10°C, and adults emerge at 15.6°C; adults live 6-8 days (maximum 15-18 days). Larval development for this species completes during summer followed by diapause. Other species likely follow similar patterns tied to host phenology, but specific details are not established for the genus as a whole.

Behaviors are species-specific and tied to host exploitation strategy. Some species detect host larvae before visible gall formation; others oviposit only after distinct gall chambers have formed. Eurytoma robusta hyperparasitizes congeneric species within shared galls. Adults of some species are attracted to yellow visual traps. Adults of E. schreineri bore exit holes (1.0-1.8 mm diameter) in stone walls using mandibles.

Primarily parasitoids of other insects, with roles ranging from primary parasitoid of gall-formers to seed predator. Some species act as hyperparasitoids. Coexisting species may exhibit complementary host exploitation strategies that facilitate coexistence through density-dependent dominance shifts. Some species are significant agricultural pests causing up to 90% yield loss in fruit crops.

Eurytoma schreineri is an invasive agricultural pest of plum orchards causing premature fruit drop and severe yield losses; economic threshold is 1.2 larvae per tree in spring. Management relies on yellow sticky traps for monitoring and spinosad insecticide applications. The genus is taxonomically problematic due to polyphyly, complicating identification and pest management efforts.

• CynipidaeBoth families contain gall-associated wasps; Eurytoma larvae have been mistaken for cynipid larvae in galls, but differ in being parasitoids rather than gall-formers and belong to Chalcidoidea rather than Cynipoidea
• TorymidaeRelated chalcid family with similar morphology; Syntomaspis eurytomae (Torymidae) parasitizes Eurytoma schreineri, indicating close ecological and taxonomic relationship

• parasitoid
• seed wasp
• gall-associated
• agricultural pest
• polyphyletic
• Chalcidoidea

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• ID Challenge #3 | Beetles In The Bush
• Figure 5 from: Zwölfer H, Böheim M, Beck E (2015) Eurytoma serratulae and E. robusta (Hymenoptera, Eurytomidae): complementary host exploitation strategies of coexisting parasitoids and their impact on the host Urophora cardui. Journal of Hymenoptera Research 42: 47-62. https://doi.org/10.3897/JHR.42.8847
• A New Invasive Pest in Plums: Monitoring and Control of Eurytoma schreineri.