Bombus defector Skorikov

Williams, Paul H., Huang, Jiaxing, Rasmont, Pierre & An, Jiandong, 2016, Early-diverging bumblebees from across the roof of the world: the high-mountain subgenus Mendacibombus revised from species’ gene coalescents and morphology (Hymenoptera, Apidae), Zootaxa 4204 (1), pp. 1-72 : 47-48

9. Bombus defector Skorikov

( Figs 18, 22 , 32 , 42 , 64 )

[? Bombus mendax Gerstaecker ; Morawitz 1880:340, in part, misidentification.]

< Bombus mendax > subsp. defector Skorikov 1910b:330 , type-locality citation (Cyrillic) ‘[Fergana (Alai range)]’. Lectotype queen by present designation ZISP examined, ( Cyrillic ) ‘[ Alai range]’ (Alai, Kyrgyzstan). Note 1.

< Mendacibombus mendax subsp.> defector ( Skorikov); Skorikov 1914 :124.

Mendacibombus defector ( Skorikov); Skorikov 1923 :149; Skorikov, 1931:fig. 17.

[? Mendacibombus turkestanicus var. Skorikov, 1931:215, published with name incomplete.]

Bombus mendax defector Skorikov ; Reinig 1932b:163.

Bombus defector Skorikov ; Reinig 1934:172.

Bombus (Mendacibombus) defector Skorikov ; Panfilov 1957:237; Panfilov 1962:195; S.- F. Wang 1985:160; Williams, 1991: 15, 42 in part; P.H. Williams 1998: 99 in part.

[ Bombus (Mendacibombus) makarjini Skorikov ; P.H. Williams 2011:27, misidentification. Note 2.]

Note 1 ( defector ). Skorikov’s original description of the taxon defector cites the type locality as Fergana ( Alai range). The ZISP collection studied by Skorikov contains a queen that agrees with the original description and carries the labels: (1) white, printed (Cryrillic) ‘[Ak-Basaga, Alai- / skii khr. 2600‒2700 mt. / Makarin] 29/ 30.v. 09.’; (2) white, printed (Cyrillic) ‘[k. Skorikova]’; (3) red, handwritten ‘ Lectotypus Bombus / mendax subsp. / defector Skor. / design. Podbolotsk. ’ (M. Podbolotskaya, unpublished); (4) green, printed ‘ Mendacibombus / MD# 3524 det. PHW’; (5) red, printed ‘ LECTOTYPE [female] / Bombus mendax ssp. / defector / Skorikov, 1910 / det. PH Williams 2012’; (6) white, printed ‘[female] Bombus / ( Mendacibombus ) / defector / det . PH Williams 2012’. This specimen, which is complete, is regarded as one of Skorikov’s syntypes and is designated here as the lectotype in order to reduce uncertainty in the identity and application of the name.

A second queen collected at Ak-Basaga by Makarin in 1909 (MD#315, NHM, sent by Skorikov as part of an exchange with the NHM in 1934), closely similar in morphology, is designated here as a paralectotype and interpreted as conspecific.

Note 2 ( makarjini ). See note 1 on B. makarjini regarding the paralectotype. Examination of this syntype as the only type seen at the time led to the misidentification of this species in Williams (2011).

Etymology. The species is named from the Latin defector for a deserter or rebel, presumably a reference to its slight difference in colour pattern from other co-occurring related bumblebee taxa from the mountains of Central Asia (the taxon margreiteri is closest to it in Skorikov’s original key).

Taxonomy and variation. The interpretation of this species is based here on DNA, as well as on the form of the female labrum and of the male genitalia. This disagrees with earlier concepts ( Skorikov, 1931), diagnosed originally in terms of the hair colour pattern ( Skorikov, 1910b), because the species appears to be more variable in colour pattern than was originally understood.

All specimens have yellow-banded and none has a white-banded colour pattern. Skorikov (1910b) described females of the taxon defector from the Alai mountains (MD#3524) as having the corbicula framed with black hairs, with the pale bands yellow, and with the hair on the lower side of the thorax and on the ventral side of the metasoma black. Our COI tree shows that similar specimens but with the hair on the lower side of the thorax yellow, and even some with yellow hair on the ventral side of the metasoma, have very short branch lengths between them and typical defector (with the lower side of the thorax black) and these are interpreted as conspecific ( Fig. 13 : the extensively yellow females labeled ‘light’ MD#352, 365, 373, 1246, 1285, 1344, 4024 and females of the darker taxon defector s. str. MD#1251, with the black hair most extensive in the worker ‘dark’ MD#1336). The form of the female labrum is diagnostic ( Fig. 18 ).

Skorikov’s illustration of the male genitalia of ‘ Mendacibombus defector’ ( Skorikov 1931: his fig. 17) is correctly identified. Males usually have the hair of T3‒7 orange at least in part, but occasionally the hair of T3‒7 is entirely black ( Fig. 13 : the black-tailed male labeled ‘blacktail’ MD#1250, 1256 and the lighter taxon defector s. str. MD#1251).

Diagnostic description. Wings nearly clear. Female hair colour pattern: generally black, but with yellow hair in a large patch below the base of the antenna, in a large patch or almost absent on the vertex of the head, in a transverse band anteriorly on the thoracic dorsum and extending laterally and ventrally to half way down the side of the thorax, or more rarely to the midleg base, in a transverse band posteriorly on the thoracic dorsum (scutellum; so the thoracic dorsum between the wing bases has the hair entirely black), on T1‒2, although T2 with a few black hairs intermixed along the posterior margin, orange hair on T3 as a posterior fringe, and throughout on T4‒6, except T6 dominated medially by long black hairs. Hindleg tibia with corbicular fringes usually uniformly black, but sometimes with a few hairs on the corbicular surface and in the adjacent fringes orange, or rarely the fringes predominantly orange with black hairs ( Fig. 21 ) (cf. B. makarjini , B. turkestanicus ). Female morphology: labrum with the basal depression broad, the transverse ridge narrower medially than the basal depression, in the median fifth gradually subsiding and narrowly interrupted by a longitudinal band of many dense medium punctures overflowing across it from the basal depression (cf. B. margreiteri , B. turkestanicus ), lateral tubercles with few punctures ( Fig. 18 ). Clypeus in its central half with many widely spaced medium punctures (cf. B. margreiteri , B. turkestanicus ). Hindleg tibia distal edge with the broad spines (rastellum) not continuing onto the posterior edge (cf. B. margreiteri , B. turkestanicus ). Male morphology: genitalia ( Fig. 32 ) with the volsella distally rounded (finger-shaped) and curled back dorsally but not anteriorly; volsella at its broadest near the midpoint of its length, the dorsal surface just distal to this point without a raised curved ridge just inside the inner margin. Penis-valve inner shoulder located at 0.63× the length of the penis valve from the distal end to the broadest point of the spatha.

Material examined. 77 queens 233 workers 173 males, from China, Kazakhstan, Kyrgyzstan, and Tajikistan ( Fig. 64 : AMNH, IAR, ISEAN, IZB, KUK, NHM, OLL, PW, RMNH, ZISP), with 29 specimens sequenced (interpretable sequences listed in Figs. 11–13 ).

Habitat and distribution. Flower-rich alpine and subalpine grassland, at elevations 936‒(2174)‒ 3108 m a.s.l.. A species of the Tian Shan (including the Bogda Shan) and Alai mountains. Compared to B. turkestanicus , the distribution of B. defector extends further to the east in the Bogda Shan, overlaps broadly in the mid part of the range (the two species often occur together), but extends less far to the south. Bombus defector overlaps with B. margreiteri in the Tian Shan and the two sometimes occur together.

Food plants. Williams (1991, 2011), under the name B. makarjini .

Behaviour. No records (see comments on B. turkestanicus ).

Figures

FIGURE 13. Assigning names to species from an estimate of phylogeny for 130 COI sequences of the subgenus Mendacibombus. Based on a BEAST analysis of the 30 unique haplotypes (Fig. 11), with the remaining sequences interpolated back into the tree with 0 branch lengths from their matching samples (where a sequence matches more than one longer sequence within a species in the Collapse results, it is added after the first matching sequence, with the addition of the two short-sequence yellow unbanded specimens from Pakistan, MD # 4058, 4059). The sequence labels follow the format used in Figs 11, 12. Lineages accepted as species from the GMYC models (Fig. 11) are shown as thick branches, the most recent common ancestors of each species are shown with a black spot, and branches within species are shown as thin branches. Asterisks mark samples used as informal proxies for the type specimens of each of the taxon names (Table 1). The proxy sample for the type specimen for the oldest available name (the valid name) for each species (from Fig. 11) is marked in bold. The interpretations of the species with their valid names are shown in grey to the right.

FIGURES 15 ‒ 23. Morphology of the female (queen) head from the ventral aspect (labrum and mandibles): 15, B. marussinus queen, Pakistan MD # 482; 16, B. avinoviellus queen, India MD # 598; 17, B. turkestanicus queen, Tajikistan MD # 320; 18, B. defector queen, Kyrgyzstan MD # 1080; 19, B. margreiteri queen, Mongolia MD # 319; 20, B. himalayanus queen, India MD # 453. Morphology of the female (queen) left hindleg tibia from the left lateral aspect, dorsal at the top of the image, anterior to the left: 21, B. defector, China MD # 1251; 22, B. margreiteri, Mongolia MD # 319; 23, B. turkestanicus, Kyrgyzstan MD # 324.

FIGURES 24 ‒ 35. Morphology of the male genitalia for species of the subgenus Mendacibombus from the dorsal aspect, anterior to the left of the image, posterior to the right: 24, B. superbus, China MD # 339; 25, B. waltoni, China MD # 216; 26, B. convexus, China MD # 215; 27, B. makarjini, Kazakhstan MD # 1240; 28, B. marussinus, Pakistan MD # 408; 29, B. avinoviellus, India MD # 404; 30, B. himalayanus, India MD # 426; 31, B. turkestanicus, China MD # 351; 32, B. defector, Kyrgyzstan MD # 367; 33, B. margreiteri, China MD # 294; 34, B. handlirschianus, Russia MD # 835; 35, B. mendax, Spain MD # 689.

FIGURES 36 ‒ 55. Morphology of parts of the male genitalia from the dorsal aspect of the left side, anterior to the left of the image, posterior to the right, white bars indicating morphological characters referred to in the key to males: 36, B. waltoni; 37, B. mendax; 38, B. superbus; 39, B. convexus; 40, B. waltoni; 41, B. convexus; 42, B. defector; 43, B. mendax; 44, B. mendax; 45, B. turkestanicus; 46, B. avinoviellus; 47, B. mendax; 48, B. mendax; 49, B. makarjini; 50, B. handlirschianus; 51, B. himalayanus; 52, B. turkestanicus; 53, B. himalayanus; 54, B. himalayanus; 55, B. marussinus.

FIGURES 56 ‒ 67. Maps of the global distributions of species of the subgenus Mendacibombus from the material examined, with grey spots for specimen records and black spots for the samples with COI sequences (each species is unknown from regions outside the map boundaries shown); grey crosses for records of all species of Mendacibombus combined. Relief map with hill shading, Cartesian orthonormal projection, grey lines show borders to national administration according to UN maps, north at the top of the map. Image created in ArcGIS using World _ Shaded _ Relief basemap © 2014 Esri.

FIGURES 11 ‒ 12. Recognising species from an estimate of phylogeny for 30 unique COI haplotypes of the subgenus Mendacibombus by BEAST, using GMYC models and the PTP procedure. From the GMYC models (11), the single threshold T is shown by the vertical grey bar so that the intersecting lineages are interpreted as indicating 12 separate species (black spots at coalescent nodes; outgroups not shown). Values below the nodes of the maximum clade-credibility tree are Bayesian posterior probabilities showing branch support (groups with values <0.8 are considered unreliable) from the BEAST analysis with two billion MCMC generations and a 1 % burn-in. The x - scale axis is calibrated in substitutions per nucleotide site. From the PTP procedure (12), the Bayesian PTP solution with highest support also indicates 12 species. Values above the nodes are PTP Bayesian support values that all daughter haplotypes are parts of a single species; values below the nodes are Bayesian posterior probabilities showing branch support. The scale bar is calibrated in substitutions per nucleotide site. Each unique haplotype is represented by one of the longest available sample sequences, labelled with: the sequence length in number of base pairs, a taxon name or name for an unpublished colour pattern (light / dark / yellow / white / pale), and then a code that consists of a specimen identifier (MD #) from the project database and (after the hyphen) a sample identifier from BOLD or from GenBank, followed with its geographic origin.