Diplolepis abei Pujade-Villar & Wang, 2020

Pujade-Villar, Juli, Wang, Yiping, Zhang, Wenli, Mata-Casanova, Noel, Lobato-Vila, Irene, Denes, Avar-Lehel & Laszlo, Zoltan, 2020, A new Diplolepis Geoffroy (Hymenoptera, Cynipidae, Diplolepidini) species from China: a rare example of a rose gall-inducer of economic significance, ZooKeys 904, pp. 131-146 : 131

Diplolepis abei Pujade-Villar & Wang sp. nov. Figs 1 , 2

Type material.

Holotype: ♀ deposited in UB with the following labels: ' Lanzhou ( Gansu Province ), ex Rosa sertata × R. rugosa , (03.ii.2011) 15.iii.2011, col. Sheng Maoling’ (white label); ' Diplolepis abei Pujade-Villar & Wang, desig. JP-V-2017' (red label). Paratypes: 11♀♀ with the same labels as the holotype: 8♀♀ in ZAFU, 3♀♀ in UB .

Diagnosis.

This species is characterized by having the following morphological characters: head smooth to alutaceous, mesoscutum alutaceous with piliferous punctures, scutellum rugose with a more delicate sculpture in the centre of the disk; legs, including coxae, reddish; forewings hyaline but slightly smoky in both the radial and the 3rd cubital cells, never with a dusky cloud around veins; second metasomal tergite short. It differs from the rest of species known from China because veins of its forewings are not infuscate. In addition, the deciduous galls have numerous long stout sharp-pointed spines unlike other known species. Molecular results: the two sequenced individuals represent one haplotype (GeneBank accession number: MN434062). Based on the BI tree the species is part of a polytomous clade with a group consisting of D. fructuum , D. mayri and D. rosae , and with D. spinosissimae (Fig. 5 ). The average p -distance compared to the other species is 9.73% (Table 1 ), with the lowest values shown when compared to D. fructuum (6.38%) and D. spinosissimae (6.39%).

Description. Female. Length. Body length 3.3-3.6 mm (N = 4).

Color (Fig. 2g ). Head and mesosoma uniformly black. Antenna black; pedicel, and sometimes also the scapus, lighter. Tegulae brown. Mandibles reddish, with black tips, maxillary and labial palpi brown. Legs reddish, including coxae; last tarsi (and sometimes the 4th tarsomere) darker. Metasoma reddish; basal and posterior parts and hypopygium, brown. Wings hyaline but slightly smoky in both the radial and the 3rd cubital cells; wing veins distinct, dark brown, never with infuscate clouds.

Head (Fig. 1a, b ). Head trapezoidal in frontal view, transverse, as wide as the mesosoma, shiny, with short sparse white setae, 1.3 times as broad as high in frontal view and 2.1 times as broad as long seen from above. Lower face smooth to alutaceous, with distinct piliferous punctures; median elevated area alutaceous. Clypeus quadrangular, broader than high, smooth to alutaceous, flattened; anterior tentorial pits, epistomal sulcus and clypeo-pleurostomal line, distinct, ventral margin straight. Gena smooth to alutaceous, with piliferous punctures and basally with some weak carinae, not broadened behind the compound eye (not visible in frontal view) and 2.0 times as broad as the cross diameter of the compound eye in lateral view. Malar space smooth to coriaceous, around 0.5 times as long as height of compound eye. Transfacial distance 1.5 times as long as height of compound eye; diameter of antennal toruli 1.4 times as long as the distance between them, and distance between torulus and eye margin 1.2 times longer than torulus diameter. Inner margins of compound eyes divergent. Frons and vertex shiny, alutaceous; occiput dull, coriaceous. POL 0.75 times as long as OOL; OOL 2.0 times longer than the diameter of the lateral ocelli and 6.6 times longer than LOL.

Antenna (Fig. 1c ). 14-segmented, 1.5 times longer than head plus mesosoma; pedicel slightly longer than broad; F1 very long, 4.0 times longer than pedicel and nearly 1.8 times longer than F2; F2 as long as F3; F12 slightly longer than F11; placodeal sensilla present in all the funicular segments, but only apically in F1 and in the anterior half in F2. Antennal formula: 6: 4(x3): 16: 9: 9: 8: 8: 8: 7: 7: 7: 7: 7: 9.

Mesosoma (Fig. 1d-g ). Mesosoma curved and slightly longer than high in lateral view, with short white setae. Pronotum very narrow, coarsely punctured, sparsely haired in the middle and coriaceous with some carinae in the basal part. Scutum wider than long and at least 1.7 times longer than the scutellum, alutaceous, with distinct punctures. Notauli complete, convergent posteriorly; median mesoscutal line very shallow, reaching at least the level of tegulae; parapsidal lines visible but poorly impressed, narrow, shining, reaching tegulae level; anterior parallel lines distinct, smooth, extending to half the length of the scutum. Scutellum as long as wide, with parallel lateral margins, rounded posteriorly, dull, rugose, with a more delicate sculpture in the centre of the disk. Scutellar foveae short, transversal, inconspicuous, rugose, not delimited posteriorly. Mesopleuron smooth and shiny, with a strong transverse dull rugose furrow; mesopleural triangle with numerous delicate wrinkles. Metapleural sulcus reaching the mesopleuron slightly above half of its height; axillula ovate, smooth, distally with some short rugae, without setae; subaxillular bar coriaceous, with very delicate carinae. Dorsellum smooth with some carinae, inferiorly convex. Metanotal trough smooth, shining, with some longitudinal parallel weak wrinkles and without setae; ventral impressed area alutaceous, without delicate longitudinal wrinkles, shining. Propodeum laterally rugose, medially smooth; lateral propodeal carinae anteriorly with three straight carinae and strongly curved outwards in posterior 2/3, delimiting a closed area.

Legs. Tarsal claws simple, without a basal lobe.

Forewing (Fig. 2d ). Radial cell partially closed and margin pigmented, 2.3 times longer than wide, first abscissa of radius nearly straight, 2r with an additional median prolongation into the radial cell. Areolet distinct, large. Rs+M well-marked and reaching basalis in the lower third.

Metasoma (Fig. 1h ). Slightly longer than head plus mesosoma length (1.1 ×); in lateral view, 1.4 times longer than high. Second metasomal tergite short, reaching 1/3 if the metasoma; metasomal tergites 2 to 5 without punctures, subsequent tergites alutaceous. Hypopygium plough-shaped, shiny, smooth and large; prominent part of the ventral spine of the hypopygium very thin, 3.0 times longer than broad, with sparse white setae, apical setae short, not extending behind apex of the spine.

Male: unknown.

Gall (Fig. 2a-c ). Resembles the North American gall Diplolepis bicolor (Harris, 1841), but the new species has more abundant spines and a different coloration. It also resembles D. japonica (Walker, 1874), but the shape and the length of the spines are very different. The galls of the new species are spherical-shaped, appearing as monothalamous or one-celled swellings bearing numerous long, stout and sharp-pointed spines that are longer than the diameter of the galls. Their surface is smooth and glabrous. Galls arise on branches, buds or leaf veins of Rosa sertata Rolfe × R. rugosa Thunb., usually in groups. Young galls are pea green or reddish green and soft, gradually turning greyish green and harder when maturing. The inner cell is large, and the delimiting wall of parenchymatous cells is thick, usually 1.5 mm thick. Mature galls are deciduous.

Host.

The new species was collected on the Chinese Kushui rose, a hybrid of Rosa sertata Rolfe × R. rugosa Thunb. which is cultivated mainly in Gansu Province (China) for its oil. Rosa rugosa also occurs at the collection site (a Kushui rose plantation) but no galls were found on them despite growing only a few meters from Kushui roses supporting large numbers of galls. To the best of our knowledge this may be the first known Diplolepis species that causes significant agricultural loss. In Gansu Province (China) the R. sertata × R. rugosa hybrid is commonly planted for its high yields of flowers and oil. The infected shrubs may suffer up to 70% yield loss according to rose oil farmers ( We et al. 2014). In infected plantations, D. abei is considered a significant pest which reduces rose flower numbers and subsequent rose oil yields.

Biology.

Only females are known (Fig. 2g ). Galls appear in mid-April and larvae occupy the most part of the larval chamber (Fig. 2c, e, f ). Adults emerge in early March of the following year.

Comment.

In Wang et al. (2013) and Guo et al. (2013), the material corresponding to this new species is determined as D. rosae . In Wang et al. (2013) seven males and nine females were cited. The reason why there are more females (12) in the present paper than those mentioned in Wang et al. (2013) is that the sexes were confused in Wang et al. (2013): four of the specimens were considered males, although they were females. The other four specimens of the 16 mentioned in Wang et al. (2013) are lost.

Distribution.

China (Gansu Province).

Etymology.

Named in honour of the Japanese cynipidologist and friend, Prof. Yoshihisa Abe (Biosystematics Laboratory, Graduate School of Social and Cultural Studies, Kyushu University, Fukuoka, Japan).

Figures

Figure 1. Diplolepis abei Pujade-Villar & Wang ♀ sp. nov. a head in frontal view b genae in dorsal view c antenna d mesosoma in lateral view e mesosoma in dorsal view f mesosoma in dorso-lateral view g propodeum h metasoma in lateral view.

Figure 2. Diplolepis abei Pujade-Villar & Wang ♀ sp. nov. a-b galls c dissected gall with last instar larva d forewing e lateral and ventral view of the 3 rd instar larva f lateral and ventral view of the last instar larva g lateral habitus.

Figure 5. Bayesian inference (BI) tree of the Diplolepis species that have available mitochondrial COI sequences. Numbers on the branches represent posterior probabilities (PP).