Bracon phytophagus Quicke, 2005

Flores, Saul, Nassar, Jafet M. & Quicke, Donald L. J., 2005, Reproductive phenology and pre-dispersal seed-feeding in Protium tovarense (Burseraceae), with a description of the first known phytophagous ‘‘ Bracon’ ’ species (Hymenoptera: Braconidae: Braconinae), Journal of Natural History 39 (42), pp. 3663-3685 : 3672-3677

Bracon phytophagus Quicke sp. n.

( Figures 5–8 )

Adult female

Length. Length of body 10.5 mm, of fore wing 10.5 mm and ovipositor (part exserted beyond apex of metasoma) 9.5 mm.

Head. Antennae with 58 flagellomeres. Terminal flagellomere strongly acuminate. Median flagellomeres strongly oblique, almost diamond-shaped in dorsal aspect, slightly longer laterally than wide. First flagellomere 1.0 and 0.95 times length of 2nd and 3rd flagellomeres, respectively, the latter being 1.45 times longer (maximum length) than wide. Mandibles twisted so only a single tooth visible in anterior aspect. Inter-tentorial distance: tentorio-ocular distance51.6:1.0. Inter-tentorial distance: height of clypeus52.85:1.0. Face largely smooth and shiny, with three distinct areas of setosity on either side, one bordering the lower half of the eye and extending to the malar region, a band running dorsally from the region of the anterior tentorial pits to approximately the mid-height of the face and a single line of setae submedially. Height of eye: shortest distance between eyes: width of head51.0:1.05:2.0. Oculo-antennal groove well developed. Frons shiny, weakly impressed and weakly minutely coriaceous. Stemmaticum rather rectangular. Shortest distance between posterior ocelli: transverse diameter of posterior ocellus: shortest distance between posterior ocellus and eye51.0:1.2:3.8.

Mesosoma. Mesosoma 1.68 longer than maximally high, largely smooth and shiny. Pronotum smooth. Notauli obsolescent, weakly indicated on anterior of mesoscutum. Scutellar sulcus narrow and minutely punctate. Scutellum smooth. Median area of metanotum large, flat, without carina anteriorly. Propodeum smooth.

Wings. Fore wing: lengths of veins SR1:3-SR:r56.5:4.8:1.0. Lengths of veins 2-SR:3-SR:rm51.4:2.9:1.0. Vein 2-M 1.35 times 3-SR. Vein 1-M nearly straight. Vein 1-SR+M moderately curved posteriorly. Vein r-m with two bullae. Vein 1-SR forming an angle approximately 80 ° with vein C+SC+R. Vein m-cu 0.35 times 1-M. Vein cu-a interstitial. Hind wing: vein 1r-m:R151.0:2.0. Apex of vein C+SC+R with one especially thickened seta (basal hamule). Base of hind wing with medium-sized glabrous area distal to vein cu-a on posterior half of cell.

Legs. Claws with pointed basal lobe ( Figure 5b ). Lengths of fore femur (excluding trochantellus):tibia:tarsus51.0:1.05:1.35. Fore tibia with transverse apical row of markedly thickened bristles which curve slightly dorsally. Lengths of hind femur:tibia:basitarsus (based on male paratype)51.58:2.5:1.0

Metasoma. Smooth and shiny with seven exposed, moderately densely setose tergites. First metasomal tergite 1.2 times longer than maximally wide; median area largely smooth and shiny; dorsolateral carinae very strong and sub-lamelliform. Second tergite 1.9 times wider than medially long, with medium-sized, nearly pentagonal, smooth mid-basal triangular area formed posteriorly into a mid-longitudinal carina that extends approximately 0.6 times length of tergite; with a pair of posteriorly diverging sublateral grooves. Second suture bisinuate, strongly crenulated; abruptly terminated sublaterally. Third tergite 2.25 times wider than medially long, without transverse, subposterior groove; with very weakly indicated antero-lateral areas. Tergites 4–7 largely smooth, moderately setose. Hypopygium sharply pointed, reaching end of apex of metasomal tergites. Ovipositor sheaths 2.9 times longer than hind tibia. Ovipositor very slender, apically markedly darkened ( Figure 5c ); dorsal valve with a distinct nodus; ventral valves apically with three normal teeth and with nine more basal weaker serrations ( Figure 5d ).

Colour. Head black, with black setae but palps (except 2nd segment of maxillary palp which is largely black) and narrow marks near orbit of eye and a mark behind each antennal socket orange-yellow; mesosoma largely bright yellow, the mesoscutum more reddish yellow; metasoma largely yellow but with 4th and more posterior tergites becoming increasingly extensively black marked and hypopygium largely black; legs yellowish with telotarsi largely black, apices of mid- and hind tibiae narrowly dark brown to black; antenna and ovipositor sheathes black. Wings boldly patterned: basal 0.4 of fore wing yellowish, broad transverse band between apex of pterostigma and apex of 2nd submarginal cell pale yellow hyaline, the remainder brown to dark brown, pterostigma black with apical 0.1 yellowish; hind wing yellow with transverse dark band at level of vein R1, and narrowly dark apically.

Male

Smaller than female (7–9 mm), probably polymorphic for colour (see Figure 6 ). The yellow form has slightly more extensive dark markings with a dark patch also on the mid-ventral part of the hind tibia, and with submedial pairs of nearly black marks on the 3rd metasomal tergite ( Figure 6b, d ).

Etymology

Named because it is the first known phytophagous braconine.

Type material examined

Holotype: female; North Venezuela: Cordillera de la Costa, Altos de Pipe (10 ° 209N, 66 ° 559W); reared from fruit of Protium tovarense . The type specimen is deposited in the Natural History Museum, London . Paratypes: four males, with same data as holotype, two in the Natural History Museum , London, two in the Instituto Venezolano de Investigaciones Científicas, Venezuela .

Notes

The new species is closely related to B. flavipalpisimus replacement name (Szépligeti) (5 Iphiaulax flavipalpis Szépligeti, 1901 , n. comb., not B. flavipalpis Thomson, 1892 ) and B. glabrescens (Szépligeti) (5 Iphiaulax glabrescens Szépligeti, 1901 , n. comb.) because it is large (more than 8 mm long), has a pointed basal lobe to the claws, and has a very slender ovipositor. It can be distinguished from them in having the mesosoma red yellow rather than largely black, in having the fourth and/or fifth metasomal tergites black (at least posteriorly), and in having the hind legs largely yellow.

Two males reared from the fruits of Protium tovarense were far darker than the other males or the female (compare Figure 6a, c and Figure 6b, d ). These are excluded from the paratype series in case they are not conspecific, though they have identical ITS-2 sequences to the predominantly yellow typical forms. The ITS-2 sequences of the five sequenced individuals have GenBank/ EMBL accession numbers DQ167439 – DQ167443 ; the specimens are also in the collection of the Natural History Museum, London. These darker specimens also differ from the two Szépligeti species named above in that they have the hind legs the same colour as the middle legs .

Larval description

Final instar larva ( Figure 7a–c ). The mature larvae are white, rather ‘‘C’’-shaped, with smooth cuticle. First thoracic spiracle located near posterior margin of 1st segment. Abdominal segments 1–7 with distinct dorsal humps, these being particularly prominent on segments 2–6. The head capsule is strongly sclerotized: with a pigmented band running more or less concentrically with the epistoma from near the antennae to connect with the hypostoma, antennae papilliform but without distinct encircling ring, epistoma complete and wide, clypeus dark and sclerotized, inner pleurostomal margin and mandibular processes darkened, hypostoma with lower edge dark, hypostomal spur slender, stipital sclerite strongly ‘‘U’’-shaped, cardo large, irregular and pigmented, prelabial sclerite virtually absent, mandibles massive, virtually black, strongly hooked with four strong tooth-like processes along ventral margin. Prepupa ( Figure 8a, b ) distinctly ‘‘S’’-shaped in female, with posterior end curved dorsally as a result of development of ovipositor sheaths.

Figures

Figure 5. Habitus and details of claw and ovipositor of Bracon phytophagus sp. n., holotype female. (a) Habitus; (b) oblique ventral view of mid-telotarsus showing large basal lobe; (c) apex of ovipositor and ovipositor sheaths; (d) detail of apex of ovipositor showing extra serrations.

Figure 6. Habitus and features of the metasoma of males of Bracon phytophagus sp. n. illustrated using Automontageẹ. (a, c) Dark morph; (b, d) yellow form.

Figure 7. Features of final instar larva of Bracon phytophagus sp. n. taken from chill-killed specimens. (a) Frontal view of head capsule showing large, multi-toothed, heavily sclerotized mandibles; (b) oblique view of head showing (arrowed) the small papilliform antenna; (c) lateral view of mature larva showing large humps on abdominal segments 2–7.

Figure 8. Prepupa, pupa, and traces of silk in pupation chamber of Bracon phytophagus sp. n. (a, b) Prepupa, in lateral and ventral views, showing ‘‘S’’-shaped curvature and beginning of development of ovipositor structures posteriorly (lower left); (c) posterior of pupa in situ showing ovipositor with remains of larval skin (head capsule: arrowed) adhering to ovipositor; (d) frass from inside pupation hole with traces of thin silk-like material.