Tetralonioidella mimetica M. C. Orr & C. D. Zhu, 2024

Orr, Michael C., Chesters, Douglas, Williams, Paul H., Wood, Thomas J., Zhou, Qingsong, Bossert, Silas, Sless, Trevor, Warrit, Natapot, Rasmont, Pierre, Ghisbain, Guillaume, Boustani, Mira, Luo, A’rong, Feng, Yuan, Niu, Ze-Qing & Zhu, Chao-Dong, 2024, Integrative taxonomy of a new species of a bumble bee-mimicking brood parasitic bee, Tetralonioidella mimetica (Hymenoptera, Apoidea, Apidae), investigated through phylogenomics, Journal of Hymenoptera Research 97, pp. 755-780 : 755-780

Tetralonioidella mimetica M. C. Orr & C. D. Zhu sp. nov.

Tetralonioidella mimetica Orr & Zhu, 2023 : holotype ( IOZ (E) 2148141 ): male: male, holotype: China, Sichuan Province, Wenchuan City, Yingxiu County, 900 m, 1983.8. 3, coll. Zhang Huaicheng. Verbatim: 四川汶川映秀 900 m // 1983, 8.3 张怀成 // IOZ (E) 2148141 . Translation: Sichuan Province, Wenchuan City, Yingxiu, 900 m // 1983.8. 3 Zhang Huaicheng // IOZ (E) 2148141 . Coordinates from Google Earth retroactive georeferencing: 31.05, 103.49.

Diagnosis.

The forewing marginal cell is clearly longer than the distance from its apex to the apex of the forewing, and this character separates it from other melectine genera. Additionally, both sexes are immediately recognizable from nearly all other Melectini by color, specifically the yellow scutellar hair followed by a largely black metasoma tipped with reddened terga and hairs. Among melectines, it may still be confused with Tetralonioidella tricolor , from which both sexes can be distinguished by a transverse black stripe of hair on the scutum, and in males additionally by the unmodified hindleg of T. tricolor compared to the enlarged, flattened hindbasitarsus of the new species.

In the key of Niu et al. (2017), females run to couplet 7 but clearly do not fit the color patterns described. Males key to couplet 19 and their S 8 more closely resembles that of T. tianmuensis , though with a much stronger medial point. Some males with brighter scutal setae color may key instead to Tetralonioidella fukienensis Lieftinck, 1983 . In both cases, pubescence color of T. mimetica clearly distinguishes it from the alternatives.

Description.

Male: pubescence and integumental color: See Figs 2 , 3 . Closely resembling bumble bee coloration, specifically group 134 of Williams (2007). Head black, integument of galea medium brown, mandibles dark brown, labrum medium brown-reddish, and sometimes clypeal edges dark brown. Mesosoma yellow over largely black integument. Legs brown to light brown, slightly lighter than primarily dark brown integument. Metasomal T 1-2 black, sometimes reddened slightly on edge of T 2. T 3 onward increasingly reddish-orange in integument and pubescence, wholly so typically by T 4. Metasomal sterna following terga, though starting at dark brown.

Males smaller, body size 12–13 mm.

Head: Galea only slightly longer than height of eye, shiny throughout, with minute single-sized punctures, tip angularly pointed but sides rounded to tip. Mandible unmodified, with weak but distinct inferior blade running parallel to main blade. Labrum shiny but somewhat craggy, large punctures indistinct from various angles, rim shallowly but obviously, roundly indented medially, with distinct row of hairs along rim though not forming dense brush. Lacking facial maculations. Clypeus strongly protuberant, by about half max eye width. Clypeus shiny medially near rim, tessellate elsewhere, with distinct rounding outward above shiny rim, with irregular but dense pitting throughout. Cheek immediately slanted inward from rear of compound eye. Antennal F 1-2 roughly equal length, slightly longer than subsequent flagellomeres. Ocelli nearly linear, medial ocellus only slightly lower than lateral ocelli. Integumental surface near ocelli shiny, strongly pitted below, slightly tessellate and sparsely, minutely pitted between lateral ocelli and compound eye.

Mesosoma: Intertegular distance (at rear) averaging 3.58 mm based on four specimens (3.5, 3.6, 3.5, 3.7). Wings only very slightly darkened, hairy within cells along fore edge and decreasingly so posteriorly, apical papillae strongly apparent. Scutum, scutellum, metanotum typically obscured by dense, plumose hair. Below, integument densely punctured, interspaces weakly tessellate. Tegula translucent, medium brown, somewhat orange. Scutellar spines large, strongly pointed and directed posteriorly and slightly laterally, still obvious through dense hairs although eclipsed by them. Legs largely unmodified, save for hindleg: tibia in profile increasing in width from unmodified base to tip that is over twice its initial width, vaguely triangular overall, not flattened, broadest apically. Hindbasitarsus similarly narrow proximally, though flattened and broadened to tip like a paddle. Basitibial plate absent.

Metasoma: T 1-2 longer from above, about equal, with T 3 at most roughly 2 / 3 of either. Terga covered in small hairs, largely simple medially but increasingly plumose laterally and apically, largely plumose by T 4. Terga weakly tessellate between punctures, with weak reflections; usually apparent through appressed setae for T 1-2 and often T 3. Tergal rims unmodified, of similar opacity, color to rest. Male T 6 unmodified. Male T 7 in profile gradually thinning to tip with slight abrupt dip medially; without medial longitudinal carina, but covered in dense hairs beyond base; lacking lateral projections or flanges; tip from above bilobed with medial indentation similar in size to each of the lobes, with rounded tip. Male S 6 unmodified and lacking distinctive hair patches, very slightly and gradually shallowed medially along rim. Male S 7 overall initially appearing disconnected medially given weak medial scleritization contrasting with stronger tan integumental color laterally; with distinct lateral corners nearing 90 °, but rounded; with strong subapical hair tufts directed laterally; tip broadly bifid with wide pointed tips, lateral to broad apical, V-shaped emargination. Male S 8 shield-like, laterally gradually declivous in latter half though maintaining overall rounded outline until near tip, there projected forward and narrowing to tip, sharply pointed medially with long hairs arising from below. Male genital capsule with outer corners, where gonocoxite tips curve inward to gonostylus, lacking any flange, instead marked by narrowing toward tip, though again slightly expanded terminally, largely without hairs. Interior projection between gonostylus and penis valves also narrowed to tip, but entirely covered in long, plumose hairs largely obscuring form.

Female: highly similar to males overall, differing as given: Pubescence and integumental color: See Fig. 4 . Head generally slightly darker through, save glossa and labrum. Leg hairs darker, more often black or dark brown, integument similar.

Females slightly larger, in part due to more tapering, elongate metasoma, body size 13–14 mm, largest nearing 16 mm.

Head: labrum more narrowly and abruptly indented medially, forming clearer corners.

Mesosoma: Intertegular distance (at rear) similar, averaging 3.63 mm based on three specimens (3.8, 3.5, 3.6). Legs unmodified, hind tibia only slightly expanded apically, with widest point clearly before tip.

Metasoma: Overall shape roughly similar but tapering to more distinct point terminally. T 1-5 visible from above, T 6 typically only visible for pygidial plate, itself triangular near base, coming to narrow tip with near-parallel sides. Sterna largely unmodified, last visible sterna narrowed and curled upward, elongate, forming support for very long sting.

Distribution.

This species is recorded from Sichuan (four sites), Guangzhou (one site), and Hunan (one site) at elevations of 700 m, 700–900 m, 900 m, 1150–1200 m, 1270 m, and 1300 m (relatively low for Sichuan bumble bees, Williams et al. 2009). Notably, this species has not been found on the Qinghai-Tibetan Plateau or the lower elevations of the Sichuan depression (the latter absence could in part be due to local landscape alteration). This bee might be restricted to mid-elevations as such, below the edge of the nearby Qinghai-Tibetan Plateau, although we cannot yet determine any type of habitat specificity with the little data available.

Phenology.

This bee has been collected from July 24 through August 18.

Bee hosts.

Habropoda mimetica Cockerell, 1927 is the most likely host, based on similarities in known distribution (mid-elevation ringing Sichuan depression and adjacent similar habitat), phenological matching, and elevational similarity. This association was especially evident at the Baishuihe National Nature Reserve in Sichuan, where H. mimetica was exceedingly common, while other species of Habropoda were rarer ( Habropoda omeiensis Wu, 1979 , Habropoda sinensis Alfken, 1937 ). It may be that this species targets multiple hosts, but among these H. mimetica is almost certainly utilized.

Floral visitation.

No floral data are available for this species. Brood parasites are generally considered relatively generalist, given that they need not collect pollen for their offspring, but tracking specific resources may benefit a brood parasite in finding specialized hosts.

Etymology.

The name “ mimetica ” is given to reference its mimicry and also its likely host, Habropoda mimetica . This name derives from the Ancient Greek adjective mimetikos (that which imitates), and is in the feminine singular nominative form.

Material examined.

All are paratypes except for the holotype: IOZ (E) 2148141 : male, holotype: China, Sichuan Province, Wenchuan City, Yingxiu City , 900 m, 1983.8. 3, coll. Zhang Huaicheng ; IOZ (E) 2142171 : male: China, Chongqing City, Wanzhou District, Wangerbao National Nature Reserve , 1300 m, 1993.8. 15, Song Shimei ; IOZ (E) 2148161 : male, genitalia pulled: China, Guizhou Province, Tongren City, Shiqian County, Jinxing village , 700 m, 1988.7. 24, coll. Yang Longlong ; IOZ (E) 2148151 : male: China, Hunan Province, Xiangxi Tujia and Miao Autonomous Prefecture, Yongshun County, Muhe Forest farm , 700–900 m, 1988.8. 8, coll. Yang Longlong ; IOZ (E) 2148081 : female, EU 1 COI voucher: China, Sichuan Province, Baishuihe National Nature Reserve , 31 ° 15 ' 56 " N, 103 ° 50 ' 02 " E. 2018.8. 17, coll. Feng Yuan ; IOZ (E) 2148071 : female: Sichuan province, Chengdu City, Pengzhou City, Xiaoyudong Town, Longcaogou (Baishuihe National Nature Reserve) , 31 ° 13 ' 39 " N, 103 ° 45 ' 05 " E, 1150–1200 m, 2018 - VIII- 18 ; IOZ (E) 2148061 : female: Sichuan Province, Wenchuan City , Yingxiu County, 900 m, 1983.8. 3, coll. Zhang Huaicheng .

Comments.

The new species was originally set aside by Yan-Ru Wu as a member of Eupavlovskia , later identified as a possible Tetralonioidella by MCO and ZN and then hypothesized to be Eupavlovskia again by PR.

Figures

Figure 2. Male external morphology of Tetralonioidella mimetica sp. nov. Imaged from the holotype (IOZ (E) 2148141) A face B dorsal C habitus D labels excluding identification label. Lines represent mm. Images by PR.

Figure 3. Male genitalia of Tetralonioidella mimetica sp. nov. Imaged from IOZ (E) 2148161 A genital capsule (brightened, ~ 80 ×) B S 7 (50 ×) C S 8 (50 ×).

Figure 4. Female external morphology of Tetralonioidella mimetica sp. nov. Imaged from IOZ (E) 2148071 A face B dorsal C habitus D labels excluding ID label. Lines represent mm. Images by PR.