Diaugia angusta Perty, 1833

Nihei, Silvio Shigueo & Pavarini, Ronaldo, 2011, Taxonomic redescription and biological notes on Diaugia angusta (Diptera, Tachinidae): parasitoid of the palm boring weevils Metamasius ensirostris and M. hemipterus (Coleoptera, Dryophthoridae), ZooKeys 84, pp. 23-38 : 25-30

Diaugia angusta Perty, 1833 Figures 111

Diaugia angusta Perty 1833: 187, plate 37, fig. 9, type locality: Brazil, Minas Gerais, syntype male (lost sec Reiss and Schacht 1983: 308, formerly at the Zoologischen Staatssammlung München), syntype male (USNM, #A16608, also from Minas Gerais, not examined)

Redescription.

Male: Body length: 13.5 mm (11.5-15.0), wing length: 11.0 mm (10.0-12.0) (n=20).

Colouration (Figures 1-7): Frontal vitta dark-brown to black (Figure 3); head silver or light-golden pruinose but gena with reddish dark brown area from the eye lower margin to vibrissal angle (Figures 1). Antenna dark-brown. Palpus yellowish brown; proboscis dark-brown. Thorax dark-brown to black with silver or light-golden pruinosity (Figure 6); the scutum with 4 dark stripes not reaching the scutellum, and the remaining scutum silver pruinose. Wing hyaline, the membrane tinged with light-brown or at least along the veins (Figure 5); calypteres and halter brown. Legs dark brown with silver pruinosity on coxae and femora. Abdomen (Figures 5 and 7) dark brown to black with silver pruinosity on anterior margin of tergites 3 to 5, and with extensive yellow areas on sides of syntergite 1+2 and tergites 3 and 4, both dorsally and ventrally.

Head (Figures 1, 3): Eye apparently bare, with very short and sparse setulae. About 14 pairs of frontal setae. Two minute proclinate fronto-orbital setulae; fronto-orbital plate bare and narrower than frontal vitta and parafacial. Parafacial bare. Facial ridge with few weak setulae near vibrissa. Postpedicel slender, 4x the length of pedicel; arista long plumose, with 2-3 dorsal and 2 ventral rows (but one single ventral row on basal half), with about same length of postpedicel, and the length of longest cilia about 5x the basal width of arista. Vibrissa fine and long, inserted at level of lower facial margin. Genal dilation covered by fine pale setulae. Palpus filiform; labella developed, slightly shorter than prementum, which is as long as palpus.

Thorax (Figure 6): Acrostichals 3+1, but a weak pair before the postsutural pair. Dorsocentrals 3+4, but seems 3+3 as the second postsutural is weakly developed or indistinct from ground setulae in some specimens. Posthumerals 2, aligned with the intralar row, the posterior seta stronger and the anterior located lateral to the postpronotum. Presuturals 2, the posterior stronger. Postpronotals 3. Notopleurals 2. Postutural intra-alars 2, the anterior weak; intra-postalar absent. Postsutural supra-alars 3, the anteriormost (prealar) weakly developed, about 1/3 the length of the strongest supra-alar and shorter than the first postsutural intra-alar and dorsocentral. Prosternum and proepisternum bare. Six strong anepisternal setae. Katepisternals 2, but some specimens with a reduced lower anterior seta is present. Katepimeron (barette) setulose anteriorly. Scutellum with one basal, one lateral, one apical and one discal pairs of setae.

Wing (Figure 5): costal spine undeveloped; base of R4+5 setulose dorsally and ventrally; M vein bent forward to R4+5, and convex after bend.

Legs: Fore tibia with 2 posterior setae. Mid femur with 2 anterior setae on median third, 2 dorsal preapical setae, and one posterodorsal preapical setae. Mid tibia with 1 submedian anterodorsal seta, 2 posterior setae on apical and basal third (the basal seta weak), and one ventral seta on apical third. Hind tibia with an anterodorsal row of irregularly sized and spaced setae but one strong submedian seta; with one submedian anteroventral and two posterodorsal seta (the submedian stronger).

Abdomen (Figure 7): Abdomen elongate and tapering to apex in dorsal view. Syntergite 1+2 and tergite 3 each with one lateral marginal seta. Tergite 4 with a marginal row of setae, the ventral setae reduced. Tergite 5 with marginal row of setae, with the ventral setae reduced; no discal setae but the ground setulae rather developed dorsally.

Terminalia (Figures 8-10): Cercal plate enlarged at base and tapering to the apex in posterior view (Figure 9), with long setulae mostly on base, the tip long and narrow and slightly curved inwards, ending before apex of surstylus (Figure 8). Surstylus broad and the apex rounded, with subparallel margins in lateral view (Figure 9), while in posterior view tapering slightly to the subtruncate apex, the inner surface of surstylus concave. Pregonite and postgonite widely fused as a single piece on each side and firmly connected to the hypandrium (Figure 10); pregonite+postgonite somewhat stout at basal 2/3, strongly curved downwards at middle and tapering to the apex. Aedeagal apodeme straight, with subparallel margins, and elongate, longer than hypandrium (Figure 10). Epiphallus enlarged at base but uniformly narrow until a subtruncate apex, a little longer than half length of aedeagal apodeme. Distiphallus composed of a dorsal sclerite, long, straight and quite narrow, and anteriorly to it, a ventral membrane narrow and extremely elongate. The latter curved at apical half and bearing spinulae all along, these spinulae with their points upwardly oriented and becoming tinier towards the apex (Figure 10).

Female: Body length: 11.0 mm (11.5-15.0), wing length: 9.0 mm (7.5-10.5) (n=12). Differs from male in the following: two strong proclinate fronto-orbital setae (Figures 2, 4); fronto-orbital plate as wide as both frontal vitta and parafacial; fore tibia with 1 posterior seta; abdomen oblong in dorsal view, not elongate as in males, with the yellow areas on sides of syntergite 1+2 and tergites 3 and 4 less extensive than in male; tergite 3 with a median marginal pair; and tergite 5 with the ground setulae weakly developed.

Intraspecific variation.

Within the examined material, the specimens showed some significant intraspecific variation in colouration: body colouration varied from dark brown to black (compare Figures 3 and 4); head and thorax with silver to light-golden pruinosity (compare Figures 1 and 2, and 3 and 4); wing always hyaline but the membrane tinged throughout with light-brown (Figure 5) or infuscated at least along the veins, and in some specimens with no noticeable infuscation.

Examined material.

BRAZIL: Goiás, Anápolis, 1 male, 3.iii.1937, 1 male, vii.1934, Serviço Febre Amarela M.E.S. leg. (MZSP); Rio de Janeiro: Itatiaia, 700m, 1 male, 28.iv.1941, J. F. Zikán leg. (MZSP); Rio de Janeiro, Corcovado (Paineiras), 2 males (MZSP), 1 male (MNRJ), iii.1934, L.T. [Travassos] leg. (MZSP); idem, 1 male, xi.1935, L. Travassos leg. (MNRJ); idem, 1 male, 19.i.1938, Oiticica leg. (MZSP); Rio de Janeiro, Jardim Botânico, 1 male, vi.1935[? year hardly readable], H. S. Lopes leg. (MZSP); São Paulo: Barueri, 1 male, 3.iv.1957, 1 male, 20.iv.1957, 1 male, 20.vi.1957, 1male, 28.xii.1965, 2 males, 15.i.1966, 1 male, vii.1966, K. Lenko leg. (MZSP); Juquiá, 3 males and 3 females, i.2006, R. Pavarini leg. (ex. Metamasius sp. in “pupunha” crop [ Bactris gasipaes Kunth]) (MZSP); Pariquera-Açu, 8 males and 11 females, iv-xii.2007, P.H. Silva & R. Pavarini leg. (ex. Metamasius hemipterus in “pupunha” crop - Bactris gasipaes ) (MZSP); Araçatuba, Sítio Santo Amaro, 1 male, 6.i.1963, Rabello leg. (MZSP); Salesópolis, Boracéia, 1 male, 10-14.xi.1947, L. Trav. F., G. Ramalho & E. Rabello leg. (MZSP); idem, 2 males, 14.viii.1947, E. Rabello, Trav. F. & J. Lane leg. (MZSP); São Paulo, Ipiranga, 1 male, i.1932, R. Spitz leg. (MZSP); Paraná, Rio Negro, 1 male, 7.i.1929, no collector (MZSP); Santa Catarina: Blumenau, 1 male, xii.1924, Luederwaldt leg. (ex. Metamasius ensirostris ) (MZSP); Nova Teutônia, 1 male, iv.1964, 1 male, viii.1967, F. Plaumann leg. (MZSP).

On the type material.

Perty (1833: 187) described Diaugia angusta without mentioning the composition of the type-series and with no reference to a holotype. Townsend (1939: 77) provided a diagnosis of Diaugia in his "Manual of Myiology" and deliberately referred to a ‘holotype’ and a ‘paratype’ (deposited at “Munich” and “Washington” respectively). Quite possibly he had not examined the supposed ‘holotype’ (perhaps only the ‘paratype’ at the USNM), as there is no clear statement in the brief pages about Diaugia . The male syntype deposited at the Zoologischen Staatssammlung München is lost ( Reiss and Schacht 1983: 308), and the only type-material remaining is the male syntype at USNM.

Distribution.

BRAZIL (states of Goiás, Minas Gerais, Rio de Janeiro, São Paulo, Paraná, Santa Catarina) (Figure 11).

Habitat characterization.

Based on geographical data of the examined material, Diaugia angusta has been recorded in areas covered by Atlantic Forest (Figure 11). Most areas are characterized by dense evergreen ombrophilous tropical forests, whereas there is a single record in semi-deciduous forest (Brazil: São Paulo: Araçatuba). Outside the Atlantic Forest, this species also occurs in drier biomes such as Cerrado (Brazil: Goiás: Anápólis), however, it is very likely that it actually inhabits the gallery forests (humid forests accompanying riverine systems). Additionally, based on the known records, the altitude ranges from sea-level to 900 meters.

Hosts:

i) Metamasius ensirostris (Germar, 1824) ( Coleoptera : Dryophthoridae ) (new record) from Blumenau, state of Santa Catarina;

ii) Metamasius hemipterus (Linnaeus, 1758) (new record) from Pariquera-Açu, state of São Paulo;

iii) Metamasius sp. (new record) from Juquiá, state of São Paulo.