Bactrocera (Bactrocera) niogreta Doorenweerd, 2020

Doorenweerd, Camiel, Ekayanti, Arni & Rubinoff, Daniel, 2020, The Dacini fruit fly fauna of Sulawesi fits Lydekker's line but also supports Wallacea as a biogeographic region (Diptera, Tephritidae), ZooKeys 973, pp. 103-122 : 103

Bactrocera (Bactrocera) niogreta Doorenweerd sp. nov. Figures 2-7

Holotype.

Male. Labelled: "Indonesia: Sulawesi: South Sulawesi: Insitu. WGS84 -2.5464 120.7921 16-23.i.2019 Zingerone trap. Leg. Jerome Niogret. DNA sample ms09121". Deposited at the University of Hawaii Insect Museum (UHIM).

Differential diagnosis.

Bactrocera (Bactrocera) niogreta sp. nov. is most similar to B. (Tetradacus) brachycera (Bezzi, 1916), which is known from India, Bhutan, and China ( Drew and Romig 2013). Both species have an incomplete black ‘T’ marking on the abdomen, and a costal band that follows vein R4+5 and expands distally to reach vein M. Bactrocera niogreta can be distinguished by the connection of the yellow presutural marking with the notopleuron, which resembles a yellow curly bracket ‘{‘ in dorsal view. Bactrocera niogreta further has smaller facial spots, not filling the basal ½ of the socket, and in the male genitalia it has a deep emargination of sternum V, which is shallow in B. brachycera . Bactrocera niogreta may in Sulawesi be most easily be confused with B. megaspilus , but the latter has a more angular expansion of the costal band, no medial black markings on the abdomen, no presutural yellow markings and all fulvous legs.

Molecular diagnostics.

The COI sequence of Bactrocera niogreta is, in our database, most similar to Bactrocera fuscitibia , which can morphologically easily be distinguished by not having a clearly expanded costal band. The EF1-alpha sequences are most similar to B. enochra (Drew, 1972), which is morphologically different in not having a wide costal band, and has a wide red band medially across the scutum and three longitudinal black bands along the abdomen. Both COI and EF1-alpha are diagnostic to identify B. niogreta (See BOLD Dataset DOI: http://doi.org/10.5883/DS-DACSU).

Description of adult.

Head (Fig. 3 ). All parts uniformly fulvous to yellow, ocellar triangle slightly darker. Face fulvous with rectangular spot in each antennal furrow. Antennae uniformly fulvous. Thorax (Figs 2 , 4 ). Scutum and pleural areas black with narrow red-brown areas lateral of the yellow postsutural lateral vittae. Yellow markings: postpronotal lobes; notopleura; postsutular lateral vittae broad and parallel sided, reaching intra-alar seta; presutural marking to the lateral vittae that connects to the notopleura and in dorsal view resembles a curly bracket ‘{‘; broad mesopleural stripe, almost reaching posterior level of postpronotal lobe, continuing onto katepisternum as a broad transverse spot, anterior margin slightly convex; katatergite; anatergite. Medial vitta absent. Scutellum yellow except for narrow black basal band. Setae: two scutellar; one prescutellar; one intraalar; one posterior supraalar; one anterior supraalar; one mesopleural; two notopleural; four scapular; all setae well developed and red-brown. Abdomen (Figs 2 , 5 ). Oval to diamond shaped; terga free; pecten present on tergum III; posterior lobe of surstylus short (Fig. 7 ); abdominal sternum V with a deep concavity on posterior margin that reaches the center of the sternum. Tergum I fulvous with apical margin narrowly yellow. Tergum II yellow with anteromedial dark marking. Tergum III mostly dark, with a narrow concave posterior fulvous band. Terga IV and V with a medial longitudinal dark marking. Tergum IV with triangular anterolateral dark markings, tergum V with narrow anterolateral dark markings. Ceromatae (shining spots) contrasting red-brown. Legs (Fig. 4 ). All leg segments fulvous to yellow; tibiae fulvous with apical black spur on mid tibiae; tarsi fulvous to yellow. Wings (Fig. 6 ). Length 6.1 mm, basal costal and costal cells fuscous, increasingly darker distally; microtrichia in outer corner of cell costal only; remainder of wings with a pale fulvous tint except fuscous subcostal (anal) cell; broad fuscous costal band that reaches vein R4+5, gradually darker distally until dark brown and expands to reach vein M; a broad fuscous anal streak ending at apex of A1 + CuA2; dense aggregation of microtrichia around A1 + CuA2; supernumerary lobe not pronounced.

Male lure.

Zingerone.

Host plant.

Unknown.

Etymology.

The species name is an adjective that refers to instigator of the 2016-2019 Dacini surveys in Sulawesi: Jerome Niogret.

Comments.

the morphology of B. niogreta overall most closely resembles B. (Tetradacus) brachycera , the combination of a short posterior lobe of the surstylus in the male genitalia and a deep concavity on sternum V support placement in subgenus Bactrocera . In the Drew and Romig (2016) key to the Southeast Asian fruit flies, B. niogreta characters lead to the Indian species Bactrocera (Bactrocera) andamanensis , couplet 90 on page 140. The key can there be adapted to include that B. niogreta differs from B. andamanensis in having an all-black scutum, broad postsutural yellow lateral vittae, and dark lateral markings on abdominal segment IV, with no dark markings on the legs.

Dacus longicornis form icariiformis

Dacus longicornis Wiedemann is a widespread Southeast Asian species that is a minor pest: the larvae feed on Luffa , Trichosanthes and some other Cucurbitaceae ( Allwood et al. 1999; Drew et al. 1998; Hardy and Adachi 1954). The morphology of D. longicornis is most extensively treated by Drew et al. (1998), where many synonyms were established and the variability of the species was first documented. In particular, this was the first, and only, publication that noted two forms: "There are two forms of D. longicornis , one with and one without a small medial postsutural vitta" (Drew 1998). However, this knowledge was not incorporated in subsequent publications, such as the Drew and Romig (2013) treatment of the Southeast Asian fauna, nor the accompanying Drew and Romig (2016) identification keys. We here provide the first figures of both forms (Figs 8-13 ). The postsutural medial vitta is absent in Bangladesh specimens (Figs 8 , 9 ), but always present in Sulawesi specimens (Figs 10-13 ), although sometimes indistinct (Fig. 10 ). The dark markings on the anterior sides of the abdominal segments are more pronounced in Bangladesh specimens of D. longicornis , and Bangladesh specimens have a dark band across the occiput, connecting the compound eyes. The variable presence or absence of a medial vitta is not known for any other Dacinae species, but with all data considered, we see no reason at present to establish this form as a new species. Both COI and EF1-alpha sequence data reveal some genetic substructure in D. longicornis , but the structure differs between the two markers and does not match with the morphological forms (Figs 14 , 15 ). Drew and Romig (2013) had studied the type material of D. icariiformis Enderlein, from India, and concluded that of the three type specimens -no holotype had been designated- the female was actually D. longicornis and only the two males are now regarded as lectotype and paralectotype. This confusion indicates that it is difficult to distinguish D. longicornis from D. icariiformis , and we here refer to the specimens of D. longicornis with a medial vitta that are genetically indistinguishable as D. longicornis form icariiformis . Because we did not study any type material, we refrain from synonymizing D. icariiformis with D. longicornis . However, we note that there are no diagnostic characters indicated in the literature to distinguish D. longicornis form icariiformis from D. icariiformis .

Sulawesi Bactrocera melastomatos

We collected more than 300 specimens with a uniform morphotype that are tentatively included in the checklist as B. melastomatos (Table 1 , Suppl. material 1: Table S1, Figs 16-19 ). We sequenced COI and EF1-alpha fragments for multiple specimens: they are genetically indistinguishable from specimens morphologically identified as B. rubigina (Wang & Zhao, 1989), B. melastomatos and B. osbeckiae Drew & Hancock, 1994 in both markers (Figs 20 , 21 ). Morphologically, the specimens from Sulawesi are an imperfect fit for all three genetically suggested candidate species. Instead, they are more similar to the sympatric B. usitata Drew & Hancock, 1994 (Figs 16-19 ), but B. usitata has a medial black line across abdominal segments III-V, forming the typical Bactrocera black ‘T’, which is never present in Sulawesi B. melastomatos . The costal band of B. usitata and B. melastomatos , including the Sulawesi specimens, extends to vein R4+5, a character also shared with the southern Vietnam form of B. rubigina ( Drew and Romig 2013). In the Drew & Romig ( Drew and Romig 2016) identification keys, the absence of a black ‘T’ shape on the abdomen will lead to Batrocera latifrons , but that species is not attracted to cue lure, and has parallel yellow lateral postsutural vittae, which are strongly tapering, almost triangular, in Sulawesi B. melastomatos . Because there is no genetic support at present to describe this taxon as a separate species, we interpret the morphology of Sulawesi specimens as regional variation and leave their designation as B. melastomatos until more (genomic) data becomes available. Rearing specimens from host fruit would present important ecological data; the currently recorded hosts for this group are all Melastomataceae or Lauraceae ( Liang et al. 1993; Allwood et al. 1999).

Bactrocera carambolae Drew & Hancock, 1994

We collected two specimens of Bactrocera carambolae , both at the Insitu locality, which represent the first records for Sulawesi (Figs 22-25 ). The morphology of the collected specimens is consistent with the description ( Drew and Hancock 1994). However, because B. carambolae is morphologically very similar to B. dorsalis and they have intermingled mitochondrial DNA ( San Jose et al. 2018b), we confirmed the identification with EF1-alpha DNA sequences. EF1-alpha is diagnostic for this species pair based on five positions (see also Leblanc et al. 2019). Bactrocera carambolae was already known from Java and Borneo ( Vargas et al. 2015), so its presence in Sulawesi could be through natural dispersal, and it may have been missed during previous surveys. Alternatively, it could have been introduced through fruit transport, as it is a pest species on commercial fruit. Its natural distribution includes Vietnam, Laos, Cambodia, Thailand, Malaysia, and Indonesia (Java and Kalimantan), and it was recently reported in Bangladesh ( Leblanc et al. 2019). In addition, it is highly invasive in agricultural areas in the Guianas in South America, where it is the only representative of Dacini .

Dacus pullus ( Hardy 1982)

We record specimen ms09122 as a representative of Dacus pullus (Figs 26-31 ), although the wing markings are somewhat incongruent with the description and illustration of the only known other specimen of this species. The original species description states: "Costal band broad extending through upper half of cell Rs for its entire distance and expanded in apical portion to fill entire wing apex below upper edge of cell 2nd M2" ( Hardy 1982). However, the illustration does not depict an expansion in the apical portion. Drew and Romig (2013) also illustrated the holotype, again not showing a significant apical expansion of the costal band. The costal band of specimen ms09122 is mostly confined by vein R4+5, although there is infuscation of crossvein r-m, and distally expands to cross vein M. We opt to err on the side of caution and interpret this as intraspecific variation, and do not describe this specimen as a separate species, also considering the limited availability of material and the fact that both specimens were collected in Sulawesi.

Figures

Figures 2 - 7. Bactrocera (Bactrocera) niogreta sp. nov. Holotype, ms 09121 2 dorsal view 3 frontal view of the face 4 lateral view 5 posterior view of the abdomen showing the ceromatae 6 dissected wing 7 lateral close-up of the genitalia.

Figures 8 - 13. Two forms of Dacus longicornis 8 D. longicornis collected in Bangladesh, Pabna district, 30 - ix- 3 - x- 2013 Leg. M. A. Hossain 9 D. longicornis collected in Bangladesh, Maulvi Bazar Rainforest resort, Leg. L. Leblanc & M. A. Hossain 10 specimen ms 08424, collected in Sulawesi, with a faint medial postsutural yellow vitta 11 specimen ms 08432, collected in Sulawesi 12 specimen ms 08428, collected in Sulawesi 13 specimen ms 08421, collected in Sulawesi.

Figures 14, 15. Maximum Likelihood trees based on COI (14) and EF 1 - alpha (15) DNA sequence data for Dacus longicornis, with D. pullescens Munro and D. vertebratus Bezzi as outgroups. Branch support values are rapid bootstrap values and approximate-likelihood ratio test values, scale bar indicates substitutions per site. Full details on the samples can be found in BOLD dataset DOI: http: // dx. doi. org / 10.5883 / DS-DACSU.

Figures 16 - 19. Sulawesi Bactrocera melastomatos resemble sympatric Bactrocera usitata 16 specimen ms 09144 B. usitata, dorsal view 17 close up of abdomen of ms 09144 18 specimen ms 08838 B. melastomatos, dorsal view 19 close up of abdomen of ms 08838.

Figures 20, 21. Maximum Likelihood trees based on COI (20) and EF 1 - alpha (21) DNA sequence data for Bactrocera melastomatos and allied species, using B. lombokensis Drew & Hancock and B. digressa Radhakrishnan as outgroup. Branch support values are rapid bootstrap values and approximate-likelihood ratio test values, scale bar indicates substitutions per site. Full details on the samples can be found in BOLD dataset DOI: http: // dx. doi. org / 10.5883 / DS-DACSU.

Figures 22 - 25. The two specimens of Bactrocera carambolae that represent the first records for Sulawesi, photographed in ethanol (wings were removed) 22 dorsal view of specimen ms 08439 23 lateral view of specimens ms 08439 24 dorsal view of specimen ms 10710 25 lateral view of specimen ms 10710. Both specimens have the typical rectangular black mark on the lateral sides of the fourth abdominal segment, but lack the black mark on the fore femur, which can further help to distinguish B. carambolae from B. dorsalis.

Figures 26 - 31. Dacus pullus 26 dorsal view 27 frontal view of the face 28 lateral view 29 posterior view of the abdomen showing the ceromae 30 dissected wing 31 lateral close-up of the genitalia.