Eupelmus messene

Walker, 1839

Eupelmus messene is a tiny in the Eupelmidae. Females are brachypterous (short-winged) and reproduce via thelytoky, producing only daughters. The is a specialized idiobiont ectoparasitoid of the gall wasp Aulacidea hieracii, attacking both concealed and exposed larvae and pupae of its . Females possess a remarkably thin, flexible, and mobile ovipositor capable of drilling through hard substrates, including polystyrene Petri dish walls in laboratory observations.

Pronunciation

How to pronounce Eupelmus messene: /juːˈpɛlməs mɛˈsiːni/

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Identification

Eupelmus messene can be distinguished from its Eupelmus microzonus by several traits: E. messene females are brachypterous (short-winged) versus fully winged in E. microzonus; E. messene is thelytokous (all-female ) versus arrhenotokous ( with males) in E. microzonus; E. messene lays single directly onto the body versus multiple eggs placed on chamber walls in E. microzonus; and E. messene undergoes obligatory larval requiring subzero temperatures versus facultative diapause in E. microzonus.

Habitat

Associated with galls formed by Aulacidea hieracii on stems of hawkweed Hieracium × robustum.

Distribution

Southeast European Russia (Saratov region documented); broader distribution records include England and Iran (Fars province).

Host Associations

Aulacidea hieracii - primary Gall wasp forming galls on Hieracium × robustum stems; E. messene attacks larvae and pupae

Life Cycle

Hibernating individuals undergo obligatory larval requiring exposure to subzero temperatures. Females are thelytokous, producing only female offspring. Development occurs within galls of the Aulacidea hieracii.

Behavior

Females use a thin, flexible, mobile ovipositor to drill through substrate walls to locate and parasitize larvae. In natural conditions, females drill through gall walls to find Aulacidea hieracii larvae and lay single directly onto the host body. In laboratory conditions without hosts, females have been observed drilling through polystyrene Petri dish walls and laying eggs outside the dish. Drilling involves four distinct movements: pushing, rotational, ejection (observed only in plastic, likely to clear debris), and cementing. After oviposition, females seal perforations with a biological substance, possibly for protection against environmental factors.

Ecological Role

Idiobiont ectoparasitoid; acts as a local on Aulacidea hieracii. Coexists with the more Eupelmus microzonus on the same through differential resource use and life-history strategies.

Human Relevance

Research on the ovipositor drilling mechanics has potential biomimetic applications for developing minimally guided probes in neurosurgery, orthopedic surgical instruments, and needle biopsies using functionally graded tools.

Similar Taxa

Eupelmus microzonusCo-occurs on same Aulacidea hieracii; distinguished by fully winged females, arrhenotokous , multiple per host placed on chamber walls, facultative , and inability to attack exposed host larvae or pupae

More Details

Ovipositor structure

The ovipositor consists of an ovipositor , 1st valvula, and 2nd valvula; its thin, flexible, mobile structure enables drilling through hard substrates including polystyrene.

Laboratory drilling observations

Of 18 females placed in Petri dishes without galls, five drilled into dish walls. One observed individual took over two hours per perforation, pausing to feed, drink, and groom, and continued drilling even after transfer to a new dish.

Reproductive biology

produces only female offspring; males are unknown in this .