Entedon magnificus ( Girault & Dodd, 1913 )

Gumovsky, Alex, Little, Dave De, Rothmann, Sergio, Jaques, Lorena & Mayorga, Sandra Elizabeth Ide, 2015, Re-description and first host and biology records of Entedon magnificus (Girault & Dodd) (Hymenoptera, Eulophidae), a natural enemy of Gonipterus weevils (Coleoptera, Curculionidae), a pest of Eucalyptus trees, Zootaxa 3957 (5), pp. 577-584 : 578-584

publication ID	https://doi.org/ 10.11646/zootaxa.3957.5.6
publication LSID	lsid:zoobank.org:pub:50B6EE61-31D1-4B24-8912-B76192319754
DOI	https://doi.org/10.5281/zenodo.6109525
persistent identifier	https://treatment.plazi.org/id/3659D979-B532-FFB3-A7FD-FB0FFB73EDDC
treatment provided by	Plazi
scientific name	Entedon magnificus ( Girault & Dodd, 1913 )
status

Treatment

Entedon magnificus ( Girault & Dodd, 1913) View in CoL

( Figs 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )

Entedonella magnifica Girault & Dodd View in CoL , in Girault, 1913: 154. Syn. by Bouček, 1988: 714. Metacrias clara Girault, 1929: 324 . Syn. by Bouček, 1988: 714.

Diagnosis. Body robust, metallic green-bronze ( Fig. 1 View FIGURE 1 ); head in dorsal view wide, about 2.7× as broad as long ( Fig. 1 View FIGURE 1 D), in frontal view frons without frontal sulcus and anterior margin of clypeus somewhat produced ( Fig. 2 View FIGURE 2 B); fore wing just slightly shorter than combined length of mesosoma, metasoma and head ( Fig. 2 View FIGURE 2 A); female gaster ovate, attached by a short petiole to mesosoma ( Figs 1 View FIGURE 1 A, 2A); propodeum with channel on either side of median carina, laterally with complete, wide, antero-lateral sulcus, and smooth near flat submedian areas ( Fig. 2 View FIGURE 2 C). Male ( Figs 1 View FIGURE 1 C, D) with 4-segmented antennal funicle and 1-segmented clava; its fore wing with parastigma somewhat expanded ( Fig. 3 View FIGURE 3 C); legs pale except coxae and metafemur which broadly dark metallic in mid part ( Fig. 1 View FIGURE 1 C); and gaster without pale subbasal spot.

Description. Female. Length 1.7–1.9 mm.

Body metallic green-bronze; legs pale, except for metallic coxae and brownish pretarsi; antennae dark with metallic tint, except for pale scape; wings transparent, venation pale brown ( Figs 1 View FIGURE 1 A, B, 3C, D); OMA dark, traced mainly by sculpture.

Head in dorsal view ( Figs 2 View FIGURE 2 E, F) evenly reticulate, about 2.7× as broad as long; in frontal view ( Fig. 2 View FIGURE 2 B) 1.4× as broad as high. Ocelli relatively large in size; POL nearly 2× OOL. Occipital margin marked off by a sharp carina, notably raised along its main width ( Fig. 2 View FIGURE 2 F). MDO:OOL:OCL in ratio 12:16:11. Eye and occiput moderately pubescent; eye about 2.3× as long as malar space; interocular distance 1.3–1.4× longer than eye height. Frons without frontal sulcus, surface between scrobal depressions weakly raised, without projection. Breadth of mouth cavity ( Fig. 2 View FIGURE 2 D) about 2.3–2.5× malar space. Gena very weakly convex, with faint sculpture. Clypeus not delimited by sutures, its surface with somewhat finer reticulation than rest of face, anterior margin somewhat produced and subrectangular in shape, with four protruding setae ( Fig. 2 View FIGURE 2 D). Mandibles bidentate, with outer tooth notably longer than inner tooth; cutting margin of the teeth smooth ( Fig. 2 View FIGURE 2 D). Antennal torulus situated somewhat above lower eye margin ( Fig. 2 View FIGURE 2 B); antenna ( Figs 2 View FIGURE 2 B, 3A) with scape cylindrical, about 3.6× as long as broad in the middle, nearly (about 0.7×) as long as eye height; combined length of pedicel and flagellum about 0.7× as long as breadth of head ( Fig. 2 View FIGURE 2 E); pedicel about 1.6× as long as broad, about 0.8× as long as F1 ( Fig. 3 View FIGURE 3 A); F1–F3 subcircular, short ovate; clava two-segmented, about 1.8× as long as broad ( Fig. 3 View FIGURE 3 A).

Mesosoma 1.4× as long as broad ( Figs 1 View FIGURE 1 A, 2A). Pronotal collar weakly carinate ( Fig. 2 View FIGURE 2 E). Mesoscutum slightly more than 2× broader than long, scutellum slightly longer than broad and about 1.5× longer than mesoscutum. Axilla with one seta. Axillula present as a scale-like short projection. Dorsellum narrow, as semicircular, coriaceous area ( Fig. 2 View FIGURE 2 C). Propodeum ( Fig. 2 View FIGURE 2 C) with complete median carina continued to narrow nucha delimited by cristae, and with shallow, smooth longitudinal channel on either side; laterally with antero-lateral propodeal sulcus that continues around spiracular elevation and further along relatively flat submedian areas ventrally to supracoxal flange; each spiracular elevation with a short sharp projection ventral to spiracle; supracoxal flange relatively wide and flat; callus with 1 large and about 15 smaller setae. Fore wing ( Fig. 3 View FIGURE 3 C) just slightly shorter than combined length of mesosoma, metasoma and head ( Fig. 2 View FIGURE 2 A), slightly more than 2× as long as broad; costal cell about as long as marginal vein, about 6.4× as long as broad, bare; subcosta of submarginal vein with 2 dorsal setae; postmarginal vein about as long or somewhat shorter than knob-like stigmal vein; speculum open below; fringe of apical margin about as 1/2–2/3 as long as breadth of parastigma in its widest part; marginal vein narrowly but notably widened in place of transition into parastigma ( Fig. 3 View FIGURE 3 C). Metacoxa with dense pubescence of about 15 bristles on dorsal surface ( Fig. 2 View FIGURE 2 C).

Metasoma with petiole notably wider than broad, with distinct collar ( Fig. 2 View FIGURE 2 C); gaster about as long as broad ( Figs 1 View FIGURE 1 A, 2A).

Male ( Figs 1 View FIGURE 1 C, D, 3B, D). Similar to female, except as follows. Antennal scape with darkened extreme tip ( Fig. 1 View FIGURE 1 C, 3B), metafemur with broad dark green metallic region ( Fig. 1 View FIGURE 1 C) covering major part of dorsal and lateral surfaces (wholly pale in female). Antenna ( Fig. 3 View FIGURE 3 B) with five separate segments (clava 1-segmented); antennal scape notably wide, about 2.7 × as long as broad; pedicel slightly longer than broad; funicular segments notably longer than in female: F1 2.6 × as long as broad, slightly longer than F2, and F2, F3, F4 and clava (without long terminal spine) slightly longer than broad ( Fig. 3 View FIGURE 3 B). Fore wing ( Fig. 3 View FIGURE 3 D) with marginal vein 3 × wider in place of transition into parastigma than in place of transition to postmarginal vein. Metasomal petiole cylindrical, 1.8 × longer than broad.

Material examined. 3♀, Australia, Tasmania, Hobart, Runnymede, ex Gonipterus platensis , coll. beginning December 2011, emerged 20 December 2011 (D. de Little) ( SIZK); 4♀, 1♂, Australia, Kinglake, N.Prk., nr. Melbourne, VICT., 31.i.77 (Zd. Bouček) [identified by Zd. Bouček] ( BMNH); 7♀, 17♂, Australia, Tasmania, Hobart Area, 42.54S 147.18E, xii.1987, ex larva of Gonipterus scutellatus on eucalypt (G. Tribe) ( PPRI).

Host. Weevils of the genus Gonipterus Schoenherr ( Coleoptera : Curculionidae ) (e.g. G. platensis , G. scutellatus Gyllenhal ) on Eucalyptus trees.

Biology. Koinobiont, gregarious larval endoparasitoid; this is also the first regional host and biology record for indigenous Australian species of the genus.

Distribution. Australasian region: continental Australia and Tasmania.

Remarks. The only available descriptions are the brief ones of Girault (1913, 1915). The species was described in two different genera ( Entedonella and Metacrias ), both synonymized afterwards by Bouček (1988: 713) under Entedon . These descriptions are based on females only, are rather brief, and do not provide any dimensions. Therefore, we provided a re-description of this species based on recent examination of specimens of both sexes. Entedon magnificus is a rather distinctive species possessing wide head, bright copper coloration and predominantly pale legs and antennal scape, and short antennal segments in both sexes. No other species (described and undescribed) from Australasia studied by the first author has such combination of characters. The male has an expanded parastigma and darkened metafemora. The expanded parastigma is somewhat similar to the Palearctic E. costalis Dalman , however, it is much more evidently expanded in that species (the male of which also differs in having the fore wing densely setose basally, the clypeus with distincly produced anterior margin, and darkened legs and antennae). The darkened (bearing a dark metallic spot) metafemora of the males of E. magnificus are rather unique among species of Entedon . Generally, males of Entedon have paler coloration than females, but sexual dimorphism is opposite in E. magnificus— females have entirely pale femora, whereas males have darkened metafemora. Entedon magnificus might be confused with the Palaearctic E. pallicrus Erdős , which also has broadly pale tibiae and a bright metallic mesosoma. However, the latter species notably differs by the shorter head of both sexes (2.3× as broad as long in dorsal view, 2.7× in E. magnificus ) and wider mouth cavity (5.0× as broad as length of malar space; 2.3–2.5× in E. magnificus ). Also, both sexes of E. pallicrus possess a reduced antero-lateral propodeal sulcus, whereas in E. magnificus the sulcus is complete and extends around the spiracular elevation and further along to the supracoxal flange ( Fig. 2 View FIGURE 2 C).

Ecology. The host weevil, Gonipterus platensis ( Figs 4A View FIGURE 4. A and B , B). Adults and larvae of this species feed on new developing Eucalyptus leaves, buds and shoots, mainly on E. globulus . A female lays around 800 eggs in groups of 4–16 laid on developing shoots and leaves, and the mass is protected by a capsule made of faeces ( Loch 2008). Both males and females can live for more than one year. In laboratory conditions (20–23 °C) the larvae emerge after 7–10 days, chewing the base of the egg mass and through the leaf; there are four instars over 4–6 weeks ( Araya & Guerrero 2002; Santolamazza-Carbone et al. 2006). When the larva is fully grown, it stops eating and falls to the ground where it buries itself. The larva then makes a pupal chamber, with this stage taking almost 45–60 days ( Freitas 1991; Sanches 1993).

The parasitoid, Entedon magnificus . The available data suggest that E. magnificus is a gregarious endoparasitoid of larvae of Gonipterus weevils. The females oviposit directly into larvae of the host weevil ( Figs 4 View FIGURE 4. A and B C, D); 15– 30 larvae develop within the same host ( Figs 5 View FIGURE 5 A–E). When a parasitized mature weevil larva approaches its maximum size, the parasitoid larvae start destructive feeding. They eventually consume the entire host body and stay covered by the host skin ( Fig. 5 View FIGURE 5 A). Soon after the host skin breaks, revealing numerous mature parasitoid larvae ( Figs 5 View FIGURE 5 B–E). The emerged larvae are pale-yellow in color with darker contents in the mid gut (filled with the meconium). Soon afterwards the larvae void the meconium, turning into the prepupae and then pupate nearby ( Fig. 5 View FIGURE 5 F). The pupae stay attached to a substrate by shriveled larval skins ( Fig. 5 View FIGURE 5 G).