Emersonella curculiovora, Hansson, Christer & Nishida, Kenji, 2004

Hansson, Christer & Nishida, Kenji, 2004, A new species of Emersonella (Hymenoptera: Eulophidae), parasitoid on weevil eggs (Coleoptera: Curculionidae), from Costa Rica, Zootaxa 607, pp. 1-6 : 3-6

Emersonella curculiovora sp.nov. Hansson and Nishida

Figs 1–10

Diagnosis. Notaular depressions large, round and distinct ( Fig. 3 ); female with final gastral tergite about six times as long as width at base ( Fig. 4 ); vertex with a groove from lateral ocellus towards eye, groove does not reach eye but continues along and close to eye towards frontal suture and continues a bit below suture ( Figs 1, 2 ); malar sulcus absent ( Fig. 1 ); thoracic dorsum convex; propodeum with two large anterolateral foveae ( Fig. 3 ). This species is easily separated from all known species of Emersonella by the distinct and large notaular depressions.

Description (imagines). Length of body female 1.0 mm (excl. last gastral tergite), male 0.9–1.0 mm.

Scape yellowish­white, remainder of antenna dark brown with metallic tinges. Frons metallic bluish­green. Vertex metallic bluish­purple. Mesoscutum golden­purple. Scutellum brownish with golden­purple tinges, i.e. paler than mesoscutum. Propodeum metallic bluish­green to golden­purple. Coxae dark and metallic; femora and tibiae predominantly dark brown with apices yellowish­white; tarsal segments 1­3 white, segment 4 pale brown. Wings hyaline. Petiole dark. Female gaster with 1st tergite metallic bluish­purple, remaining tergites golden­purple; male with anterior of gaster white, posterior metallic bluishpurple.

Antennae as in Figs 5, 6 . Frons and vertex smooth and shiny; frontal suture slightly down­curved laterally. Malar sulcus absent. Occipital margin rounded. Eyes with scattered hairs. Ratios of height of head/width of head 0.8; height of eye/malar space/width of mouth opening: female 1.9/1.0/1.5, male 1.9/1.0/1.4; distances between posterior ocelli/ between posterior ocellus and eye/between posterior ocelli and occipital margin 4.6/1.7/ 1.0; width of head/width of thorax across shoulders 1.2.

Thoracic dorsum convex. Pronotum well developed, with a strong carina close to posterior margin. Mesoscutum with rather strong reticulation; notaular depressions large, round and smooth. Scutellum convex and shiny with weak and engraved reticulation medially, with a median groove in anterior 1/4. Dorsellum flat and smooth. Fore wing speculum closed below; with 9–10 admarginal setae. Propodeum with a small anteromedian fovea and two large anterolateral foveae, foveae with longitudinal carinae; with curved carinae from upper corners of petiolar foramen; propodeal callus with two setae. Petiolar foramen rounded. Ratios of: length of fore wing/length of marginal vein/height of fore wing 1.8/ 1.0/1.0; length of postmarginal vein/length of stigmal vein 0.8.

Petiole about as long as wide in both sexes, with rather strong small meshed reticulation and irregular sculpture. Female gaster ovate. Ratio of length of mesosoma/length of gaster: female 1.2–1.4 (excl. elongate last gastral tergite), male 1.2–1.3.

Mature larva ( Fig. 8 ). Subspherical. Translucent to pale brown. Length ca. 0.75 mm. Head width ca. 0.08 mm. Head capsule translucent pale brown. Mandibles brown, crossing over each other at apex when closed.

Pupa ( Figs 9, 10 ). Dorsoventrally flattened. Creamy white (brown to dark brown sclerotized parts were seen as it developed). Female, ca. 0.9 mm long, 0.5 mm wide, 0.3 mm thick (n = 1); male, ca. 0.7 x 0.5 x 0.3 mm (n = 1).

Biology. Parasitoid in eggs of Camptocheirus sp. ( Coleoptera : Curculionidae ) in stems of Cinnamomum cinnamomifolium . Fifty percent (n = 32) of the weevil cement­enclosures collected contained Emersonella larvae, pupae, or adults. A mature larva ( Fig. 8 ) and several pupae ( Fig. 10 ) were observed in the cement­enclosures of the hosts eggs ( Fig. 7 ). Some of the cement­enclosures had a small hole, indicating that Emersonella adults had emerged. Several cement­enclosures contained dead and dried adults of Emersonella . The cause of this mortality is unknown but is possibly due to unsuccessful emergences. We have found that the parasitism typically occurs as one Emersonella individual per host egg. In two cases we have observed two individuals, in both cases a male and female, per host egg. The pupal stage lasted approximately 12 days. Information on the duration of the larval stage was not obtained.

Distribution. Costa Rica.

Material examined. Holotype female labelled “ Costa Rica: San José, San Pedro, UCR Campus, 1150 m, 13.xi­16.xii.2002, K. Nishida, ex eggs of stem gall inducer Camptocheirus sp. ( Coleoptera : Curculionidae ) on stems of Cinnamomum cinnamomifolium (Kunth) ” (BMNH). Paratypes: 7 females 3 males with same label data as holotype (BMNH, CH, INBio, MIUCR).

Etymology. From the Latin curculio, weevil, and voro, eat, i.e. “weevil­eater”, in reference to the preferred host.

Figures

FIGURES 1 – 4. Emersonella curculiovora sp. nov. 1. Head frontal, female. 2. Head and pronotum dorsal, female. 3. Mesosoma dorsal, female. 4. Apical gastral tergite dorsal, female.

FIGURES 5 – 6. Emersonella curculiovora sp. nov., antennae lateral. 5. Female. 6. Male.

FIGURES 7 – 10. Juvenile stages of Emersonella curculiovora sp. nov. 7. Host egg case (arrow) on stem of Cinnamomum cinnamomifolium. 8. Mature larva (arrow) in situ (host’s cement­enclosure partially removed). 9. Dorsal view of a female pupa (note meconium around the ovipositor). 10. Mature pupa (arrow) in situ (host’s cement­enclosure cement partially removed).