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Sympiesis Förster, 1856 comparative info return to: prev home
Flagellum usually with 4, rarely 5 funicular segments in both sexes; basal 3 funicular segments usually branched in males. Clypeal margin truncate or slightly concave. Notauli incomplete or ending in anterior half of axillae; setae on mesoscutal midlobe usually arranged in regular longitudinal rows (if not, then propodeum without median carina or plicae); scutellum without sublateral grooves (but rarely with visible traces of these grooves), reticulate; sculpture of mesoscutum, scutellum, and axillae nearly uniform. Postmarginal vein 2x stigmal vein length or longer; disc sometimes fuscate near stigma and/or parastigma; speculum present, basal cell bare; basal and cubital veins setose. Propodeum without costula, plicae usually incomplete or absent, extending as straight diagonal lines from spiracle to nucha if present; median carina present or absent; median panels shiny to dull and reticulate. Compare with: Dahlbominus, Pnigalio, Necremnus, Notanisomorphella, Hemiptarsenus.

1a-b: Sympiesis mesosoma (left), and forewing venation (right)

      
2a-d: Sympiesis female and male antennae: typical (left), and S. sericeicornis (Nees) (right, atypical of genus)

3a-b: Sympiesis ancylae Girault propodeum (left), and S. sericeicornis propodeum (right)

4a: S. marylandensis Girault propodeum

Biology: Parasitoids of leaf-mining Lepidoptera.

Comments: Large and vaguely defined genus. Distinction from many other Eulophus-group genera is tenuous and ultimately uncertain. There is a weak division in the Eulophus-group between genera related to Eulophus (ie: Necremnus, Microlycus, Dicladocerus, etc.) and those related to Sympiesis (ie: Pnigalio, Hemiptarsenus, Notanisomorphella, etc.) based mostly on postmarginal vein length and number of funicular segments in females, but this division is not supported by strong evidence at this time and the limits of these groups are far from obvious. Sympiesis contains many distinct species groups, some of which are very similar to certain species groups in genera such as Hemiptarsenus, which make precise definition of the genus impossible. Gestalt identification in particular of Sympiesis is likely to be mistaken for these reasons.

Comparative information:

Dahlbominus: Postmarginal vein 1.7x stigmal vein length or less. Forewing almost always with vague fuscate cloud posterior to marginal and postmarginal veins. Propodeum with complete median carina, without plicae. Some Sympiesis have a similar dark cloud on the forewing, but most that do have dark spots on have them isolated near the stigma and/or parastigma. In Dahlbominus, there is either a large, uniform dark cloud or no fuscation at all. A few Sympiesis approach Dahlbominus in coloration but differ in the propodeal features (reticulate sculpture, lacking a median carina) and in that the postmarginal vein is about 2x stigmal vein length. It should also be noted that the only absolute difference between the two genera is the postmarginal vein length. These differences are very minor, but no taxonomic changes should be made until the phylogeny of Sympiesis and its relatives, including Necremnus, is better understood, to insure that the resulting changes produce monophyletic groupings.

Pnigalio: Usually with costula connecting plicae with median carina. Some species and small specimens of others do not have a costula, and are more difficult to separate: median panels of propodeum shiny and smooth, without reticulate sculpture (but transverse rugae present instead of costula in some forms), always with at least nearly complete plicae; mesoscutal midlobe with many dorsal setae arranged irregularly. Sympiesis usually do not have plicae, and median panels of propodeum are often distinctly reticulate, although some Sympiesis have plicae extending diagonally laterad anteriorly. The shape of the plicae is especially valuable when distinguishing these two genera, as they arise between the median carina and the spiracles in Pnigalio and proceed more or less straight posteriad until they meet the costula, at which point they begin converging strongly, such that there is a corner where the plicae meet the costula (in rare exceptional species without a costula, they may be straight and divergent posteriorly). In Sympiesis, the plicae, when present, arise nearly adjacent to the spiracles and proceed as essentially straight diagonal lines to the nucha (convergent posteriorly). Sympiesis usually have mesoscutal midlobe setae arranged in longitudinal rows, but this character fails in some forms, which are distinguished by propodeal features: median carina and plicae absent, median panels uniformly reticulate, propodeum distinctly convex along transverse axis (but sunken along median axis). The mesoscutal character is essential, however, in recognizing some specimens of true Pnigalio that have lost the costula. Another, less reliable, character is that Pnigalio usually has a more strongly sculpted and shiny mesoscutum than in Sympiesis.

Necremnus: Females with 3 funicular segments (male antenna essentially identical with that of most Sympiesis). Postmarginal vein less than 1.7x stigmal vein length, usually 1-1.5x stigmal vein length.   Dahlbominus may represent a transitional form between these two genera.

Notanisomorphella: Propodeum always with distinct plicae, enclosing sharply raised median panels. Median carina always distinctly complete. Plicae in Sympiesis are typically less distinct, extending diagonally when present (ie: S. marylandensis), and the median panels are not sharply raised relative to areas lateral to the plicae. A few Sympiesis, especially S. bimaculatipennis (Girault) and S. fragariae Miller, have slightly raised median panels, thus the difference between these two genera is one of continuous variation, and ultimately slight.

Hemiptarsenus: Distinguished from Sympiesis using quantitative continuous characters: Toruli very high on face, far above lower eye margin; scape distinctly exceeding vertex; forewing and costal cell unusually long and narrow: forewing at least 2.6x longer than broad and costal cell 7-15x longer than broad. In some species of Sympiesis, the scape slightly exceeds the vertex. Many Sympiesis have one or more body parts elongate, but not all in combination. Hemiptarsenus has two fairly distinct species groups. In one of these groups, easily distinguished from Sympiesis, the scape is elongate and narrow, exceeding the vertex by 2x of more scape width; these forms also have a short propodeum, it being 2x or more broader than long. In the other, more problematic, group, the scape only slightly exceeds the vertex and the propodeal length is subequal (<1.75x) its width. This group seems to overlap some species of Sympiesis, but no Sympiesis that I am aware of have a long propodeum and scape exceeding vertex at the same time. Distinction between these two genera is situational and ultimately difficult for some forms.

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References

Boucek, Z. 1988. Australasian Chalcidoidea (Hymenoptera). A biosystematic revision of genera of fourteen families, with a reclassification of species. CAB International, Wallingford, UK.

Miller, C.D.F. 1970. The Nearctic species of Pnigalio and Sympiesis (Hymenoptera: Eulophidae). Memoirs of the Entomological Society of Canada 68.

Image credits: 1a-b: Boucek (1988). 2a-d, 3a-b, 4a: Miller (1970).