Hydrelliaeucoila egeria Díaz and Gallardo, 2009

Reche, Vanina & Gallardo, Fabiana, 2022, Two new species of the Neotropical genus Hydrelliaeucoila (Cynipoidea: Figitidae: Eucoilinae), Journal of Natural History 56 (1 - 4), pp. 227-239 : 230-231

publication ID

https://doi.org/ 10.1080/00222933.2022.2064249



persistent identifier


treatment provided by


scientific name

Hydrelliaeucoila egeria Díaz and Gallardo, 2009


Hydrelliaeucoila egeria Díaz and Gallardo, 2009

( Figure 1 View Figure 1 )


Female. ARGENTINA. Buenos Aires, Otamendi , - 38.1122339S, - 57.8456287W. January 2007, Cabrera coll., obtained from puparium of Hydrellia sp. , on Egeria densa (MLP). GoogleMaps

Paratypes. Females and males: same data as holotype: 15♀, January 2007; 68♀, 5♂, May 2008 GoogleMaps .

Additional material

ARGENTINA. Buenos Aires, La Plata , -34.9206797”S, -57.9537638W, 22 April 2015. Aquino and Gallardo colls. on crop squash type Butternut ‘ Anco’ , Cucurbita moschata Duchesne ex Poir (3♀ MLP) . Misiones, Yacutinga , - 27.4889S, - 55.41109722W. 29 August 2006, Cabrera coll., obtained from puparium of Hydrellia sp. (3♀ MLP). GoogleMaps

Diagnosis. This species can be characterised by the following features: Body length 1.40–1.80 mm. Head and mesosoma shiny black. Lateral and inferior area of face striated; in frontal view with strong dorso-ventral ridge adjacent to torulus. Female antenna with last seven or eight flagellomeres with rhinaria. Occiput smooth. Pronotal plate slightly striated. Inferior part of pronotum side slightly striated. Dorsal surface of scutellum ( Figure 1b View Figure 1 ) coarsely sculptured, reticulate-rugose. Scutellar foveae ( Figure 1b View Figure 1 ) at base slightly sculptured, oval, shorter than wide. Lateral bars of scutellum with foveae beneath. Scutellar plate ( Figure 1c View Figure 1 ) without a dark impression on the entire edge. Middle and ventral part of mesopleuron, above mesopleural carina with few striations. Metapleuron slightly sculptured. Marginal cell of fore wing partially open ( Díaz et al. 2009).

Description. In Díaz et al. 2009.

Biology. Hydrelliaeucoila egeria Díaz and Gallardo parasitises pupae of Hydrellia egeriae . These pupae are found fixed to the stems of E. densa at the leaf axils of the last leaf the fly larva fed on. The gravid female parasitoid lays an egg in the host pupa, and continues exploring the stem for more pupae. During the warm season, the parasitoid takes around one month to develop. Parasitoids that have not emerged by the end of fall diapause as larvae in the host puparium until the following spring. Laboratory observations reveal that the female parasitoid sometimes explores branches devoid of fly pupae, so apparently it selects E. densa branches at random, and not by detecting the presence of the host fly ( Cabrera Walsh and Mattioli 2007, 2008; Díaz et al. 2009).

Distribution. ( Figure 4 View Figure 4 ). Argentina. Recorded from Otamendi ( Diaz et al. 2009) and La Plata (new record), Buenos Aires province and Yacutinga (new record), Misiones province. This distribution belongs to the Pampean province for Buenos Aires and Parana Forest for Misiones (Chacoan subregion).

Comments. Hydrelliaeucoila egeria differs from the other two species known from Argentina by presenting the following combination of characters: head and mesosoma black (reddish brown in H. rufa sp. nov.; dark brown in H. nonstriata sp. nov.); lateral and inferior area of face striated (smooth in H. rufa sp. nov. and H. nonstriata sp. nov.); head in frontal view with ridge adjacent to torulus (absent in H. nonstriata ); medial bridge of pronotal plate broad (narrow in H. rufa sp. nov. and H. nonstriata sp. nov.); without a dark impression on the entire edge of scutellar plate (with a dark impression on the entire edge in H. rufa sp. nov.).