Allorhogas lavraensis Oliveira, Samacá-Sáenz & Zaldívar-Riverón, 2024

Oliveira, Tamires Camila Talamonte De, Sáenz, Ernesto Samacá, Faria, Lucas Del Bianco & Riverón, Alejandro Zaldívar, 2024, Two new species of Allorhogas (Hymenoptera, Braconidae, Doryctinae) from southeast Brazil reared from seed pods of Inga vera Willd. and Anadenanthera colubrina (Vell.) (Fabaceae), Zootaxa 5415 (1), pp. 106-116 : 108-111

Allorhogas lavraensis Oliveira, Samacá-Sáenz & Zaldívar-Riverón sp. nov.

( Figs 1A–F ).

Diagnosis. Allorhogas lavraensis sp. nov. and Al. hansoni , the latter described from Costa Rica, are associated with seed galls of I. vera . L, both forming galls “in the aril or nutritious layer outside of the seed” ( Marsh 2002). However, Al. lavraensis sp. nov. can be morphologically distinguished from Al. hansoni mainly by having 1) a body yellow with at least lateral mesoscutal and anterior part of the median mesoscutal lobes dark brown (entirely yellow in Al. hansoni ); 2) tarsomeres brown to dark brown (yellow, occasionally apical tarsomeres brown in Al. hansoni ); 3) ovipositor about 0.8 × as long as metasoma (almost twice longer than metasoma in Al. hansoni ); and 4) propodeum strongly rugose-areolate, slightly rugose-coriaceous basally (basal median areas smooth to slightly coriaceous, lateral areas rugose in Al. hansoni ).

Allorhogas lavraensis sp. nov. can be distinguished from the remaining described species of Allorhogas that are known to attack seeds of Fabaceae ( Al. brasiliensis , Al. mineiro , Al. spermaphagus , Al. vulgaris and to Al. aff argentinus from Costa Rica) and other morphologically similar species without rearing records ( Al. amuzgo Martínez & Zaldívar-Riverón 2013 ; Al. infuscotarsus Marsh 2002 ) by the combination of the above and the following features: 1) fore wing vein r 0.7 × as long as 3RSa; 2) fore wing vein m-cu interstitial to 2RS; and 4) second and basal half of third metasomal tergites costate-carinate, apical half of third and remaining tergites finely coriaceous.

Description. Female. Body size 3.3 mm ( Fig. 1A ), fore wing 3.0 mm. Colour: body entirely yellow, lateral mesoscutal and anterior part of median mesoscutal lobes dark brown; scape and pedicel light brown, flagellomeres dark brown to black; eyes silverish black; ocelli brown, area surrounding ocelli dark brown to black; palpi yellow; tarsomeres brown to dark brown; claws dark brown; wings hyaline; fore wing veins brown, stigma brown; hind wing veins brown; ovipositor sheaths dark brown to black, ovipositor yellow, apex strongly sclerotised.

Head: transverse in dorsal view, 2.3 × wider than its median length (dorsal view) ( Fig. 1B ), and 0.8 × as long as high (lateral view); occipital carina complete and reaching hypostomal carina before mandible; post ocellar line (POL) as long than ocellar diameter (OD), 0.4 × ocular ocellar line (OOL); vertex, frons, and temple coriaceous, gena coriaceous—slightly rugulose; face sparsely pilose, coriaceous-slightly transversally rugose ( Fig. 1B ); frons excavation distinct, with a median longitudinal carina, not defined by sharp lateral margins; coriaceous clypeus with dense and long pilosity; eye 1.6 × longer than wide; eye width 1.5 × longer than temple in dorsal view; malar space 0.5 × eye height and 1.5 × longer than width of hypoclypeal depression; mandibles tridentate; antenna with at least 19 flagellomeres (broken), first flagellomere about 3 × longer than wide, 1.2 × longer than second flagellomere.

Mesosoma: 1.7 × longer than high ( Fig. 1D ) and 1.7 × longer than wide ( Fig. 1C ); pronotal collar short, not visible in dorsal view, pronotal furrow wide, smooth; mesoscutum transverse in dorsal view, its median length 0.9 × its width; mesoscutal lobes coriaceous, sparsely pilose along notauli; median mesoscutal lobe without longitudinal furrow; notauli wide, deep and scrobiculate, not meeting, reaching the end of mesoscutum in a longitudinally rugose area; scutellar disc coriaceous slightly rugose anteriorly, prescutellar furrow with six transverse carinae; mesopleuron entirely coriaceous; subalar groove wide and scrobiculate; precoxal sulcus wide, deep, slightly coriaceous, running along 0.75 of mesopleuron; metapleuron entirely rugose—areolate; propodeum strongly rugose—areolate, slightly rugose-coriaceous basally, with two diverging carinae.

Wings: fore wing 2.8 × longer than wide ( Fig. 1F ). Pterostigma 3.4 × as long as wide and 0.8 × as long as R. Vein r 0.7 × as long as 3RSa, 0.2 × as long as 3RSb, and as long as r-m. Vein 2RS interstitial with m-cu, vein RS+Mb absent. Hind wing vein M + CU 0.9 × as long as 1 M, vein m-cu almost straight, slightly curved towards wing base.

Legs: hind coxa with distinct, pointed basoventral tooth, with large, dense pilosity, ventrally coriaceous rugose. Hind femur 3.4 × longer than wide.

Metasoma: first tergite 1.6 × wider than long, longitudinally costate-carinate, with two longitudinal carinae running at the base; transverse basal carina distinct ( Fig. 1E ). Second and basal half of third tergites longitudinally costate-carinate, suture between second and third tergites almost indistinct and straight; apical half of third and remaining tergites finely coriaceous. Ovipositor 0.8 × as long as metasoma.

Variation. Body size 2.9–3.2 mm. Antenna with 27–28 flagellomeres.

Male. Similar to female ( Figs 2A–F ). Body size 2.9–3.1 mm. Darker areas of mesosoma and metasoma extending to anterior part of mesopleuron, most part of propodeum and median areas of all tergites. Antenna with 27–28 flagellomeres. Hind femur swollen, about 2.6–2.7 × longer than wide.

Holotype. Female ( CNIN IBUNAM). Brasil, Minas Gerais, Lavras , UFLA, 21° 13’ 46” S 44° 58’ 58.87” W, ex. Inga vera seeds, 16.I.2020, I2 FR23, T.C.T. Oliveira col.

Paratypes. ( CNIN-IBUNAM). Twelve males, 12 females. Same data as holotype, reared 16.I.2020, 13.I.2021, T.C.T. Oliveira .

Biology. A total of 167 adult specimens of Al. lavraensis were reared from the pod seeds of I. vera . The host seeds were deformed on the nutritious layer outside of the seed, indicating that they had formed galls ( Fig. 3 ). We did not find evidence of parasitoidism in this species since there were no remains of other insects inside the gall chamber. Similar to a previous report by Morales-Silva & Modesto-Zampieron (2017), we found three unidentified species of Eurytoma ( Eurytomidae ) in various seeds where we reared specimens of Al. lavraensis ( Fig. 2 ), although the number of specimens of these Eurytoma species was considerably lower compared with the number of Al. lavraensis reared ( Eurytoma sp. 1 n= 4, Eurytoma sp. 2 n= 5, Eurytoma sp. 3 n= 5, Al. lavraensis n=167, respectively; Fig. 3 ). This indicates strongly that Al. lavraensis is a gall-inducing species on seeds, whereas the species of Eurytoma could be parasitoids, though this has yet to be confirmed. Members of Eurytoma have been previously suggested to be ectoparasitoids of other species of Allorhogas ( Morales-Silva & Modesto-Zampieron 2017; Penteado-Dias & Carvalho 2008; Tuller et al. 2015).

The pods and seeds of I. vera support a wide insect community composed of 47 species, most of which are herbivores and parasitoids interacting with each other ( Oliveira et al. 2023). The seed feeders affect up to 3.5% of the seeds, with Al. lavraensis accounting for 11.8% (n=167) of the herbivorous specimens. We observed a maximum of seven Al. lavraensis specimens forming galls in a single seed with a minimum of one specimen per seed. We found up to six seeds in the same pod with Al. lavraensis galls, but more frequently only one seed was predated by Al. lavraensis in the same fruit. Each pod had between three and 11 seeds each, with a median of seven seeds per fruit.

Etymology. The name of this species refers to the city where its type specimens were collected, Lavras, in Minas Gerais state, southeast Brazil.

Figures

FIGURE 1. Allorhogas lavraensis sp. nov. (Female, holotype): A. Habitus, lateral view; B. Head, frontal view; C. Head and mesosoma, dorsal view; D. Head and mesosoma lateral view; E. metasoma, dorsolateral view; F. fore wing.

FIGURE 2. Allorhogas lavraensis sp. nov. (Male, paratype): A. Habitus, lateral view; B. Head, frontal view; C. Head and mesosoma, dorsal view; D. Head and mesosoma lateral view; E. metasoma, dorsolateral view; F. fore and hind wings.

FIGURE 3. Inga vera seeds with ovoid galls: Galls with Allorhogas lavraensis and Eurytoma sp. in the upper and middle part of the seed, respectively.