A New Species of Docosia Winnertz Gnat (Diptera: ) Author(s) :Stephen W. Taber Source: Southwestern Entomologist, 36(4):451-464. 2011. Published By: Society of Southwestern Entomologists DOI: URL: http://www.bioone.org/doi/full/10.3958/059.036.0407

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BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. VOL. 36, NO. 4 SOUTHWESTERN ENTOMOLOGIST DEC. 2011

A New Species of Docosia Winnertz (Diptera: Mycetophilidae)

Stephen W. Taber

Biology Department, Saginaw Valley State University, 7400 Bay Road, University Center, MI 48710

Abstract. A new species of Docosia Winnertz fungus gnat was discovered in western Michigan. Males and females were collected in mid-spring in a Malaise trap in a paper birch-red maple-black cherry woods adjacent to a black ash swamp and cattail marsh. Docosia walpurga Taber resembles Docosia dichroa Loew but male terminalia and female coloration indicate a specific difference instead. A remarkable and yet-unidentified empidid that seems to mimic the fungus gnat was found with the new species.

Introduction

The mycetophilid genus Docosia Winnertz has been long-neglected in the Nearctic region, although in the Palearctic a revival of interest in this and in other fungus gnat genera has been ongoing for the last several decades (Laštovka 1974, .XULQD DQG âHYþtN ). While continuing a study of Staeger during which two new species were discovered, a small orange and black mycetophilid invited identification because of its attractive appearance that suggested wasp mimicry despite its small size. This fly belonging to the genus Docosia Winnertz proved to be a previously unknown species.

Materials and Methods

The type locality of the new Docosia species is a narrow ecotone between mostly deciduous second-growth forest and swamp known as “Oxford Swamp”, with GPS coordinates of 43.41° N, 85.44° W, in Manistee National Forest, 7 km east of Brohman, Newaygo County, MI. Forest trees include paper birch (Betula papyrifera Marshall), red maple (Acer rubrum L.), and black cherry (Prunus serotina Ehrhart), whereas the swamp trees are mostly black ash (Fraxinus nigra Marshall). Nearby is a marsh dominated by common cattail (Typha latifolia L.). The were collected with a large Malaise trap erected in March as soon as melting snow allowed access to the site, and specimens of the new species were retrieved thereafter on 7, 15, and 21 May, and on 4 June 2011. These adults included 173 males and 13 females. The holotype male was mounted dry and intact on a microscope slide and the allotype female was pointed dry on a pin, with additional paratype males and one paratype female also preserved dry in these ways. Other specimens were mounted dry on microscope slides in their entirety as well as both intact and dissected in polyvinyl alcohol (PVA) mounting medium, with and without clearing

451 overnight and sometimes longer in KOH. Cover slips were not used unless male genitalia were isolated on a slide because it often becomes important to reposition material for examination from different angles by applying additional mounting medium and waiting a few minutes for the previous application to reliquefy. A few males were preserved in formalin/alcohol/acetic acid/glycerine (FAAG), many others were frozen for future DNA analysis, and the same was done for a few females. Because no new species of Docosia have been discovered in the Nearctic in almost 75 years according to the list in Nomina Insecta Nearctica (1998), a recent summary of taxonomic activity (/DãWRYNDDQGâHYþtN), and a search through Biological Abstracts records from 2000 to 2011, the description follows examples provided for newly published Palearctic congeners instead (Kurina 2006; Laštovka DQG âHYþtN ; âHYþtN  2010; âHYþtN DQG /DãWRYND ; Kurina and âHYþtN ), while drawing upon the morphological terminology of the standard reference on Nearctic Diptera (Vockeroth 1981), and excluding certain characters that are either not normally used in identification, or are likely variable, or both. Figure references sometimes indicate dissected specimens although these illustrations are consistent with textual descriptions of type material. The photographs shown here were taken with stereoscopic and high-power compound microscopes (Olympus SZ40 Zoom and Olympus BH-2, respectively), equipped with a digital SPOT idea camera with software.

Results

Docosia walpurga Taber new species

Diagnosis. The transparent basket-like subterminal process of the male gonostylus distinguished the new species from all those known to occur in the eastern United States. Male specimens of Docosia walpurga might be confused with those of Docosia dichroa Loew by reliance upon their similar orange and black abdominal coloration. However, the female D. walpurga shares that condition of an abdomen black at the tip and orange elsewhere, and so resembles the male of both species, whereas the female D. dichroa reportedly lacks black on the tip of the abdomen which is thus entirely orange (Loew 1870). Type Material. Holotype. Adult male, Manistee National Forest, 7 km east of Brohman, Newaygo Co., MI, 7 May 2011, S. W. Taber, Saginaw Valley State University Collection, University Center, MI. Allotype. Adult female, 21 May 2011. Paratypes. 10 adult males and 4 adult females, all from the same locality on 15 May 2011. Total number of type specimens = 16. Description. Holotype. Adult male (Fig. 1). Total dried length = 3.3 mm. Head: black, palps orange, although some specimens have palps with mixtures of both black and orange, antennae black. Thorax: black with pale setae and blackish bristles, laterotergite bare; coxae orange, trochanters with several blackish spots, femora orange, tibiae and basitarsi light brownish, remainder of tarsomeres darker, increasing in intensity through 5th tarsomere which is blackish, tarsal claws with each of the two tips bifid, tibial spines yellow-brown, mesotibia and metatibia bearing several small black spines near the base of a longer and paler tibial spine, protibia lacking these smaller, darker structures. Wing (Fig. 2): length 3.7 mm, membrane hyaline, Sc intersects R1 approximately half the distance between h and Rs although commonly extending a little farther than halfway in other specimens,

452 Fig. 1. Male holotype of Docosia walpurga; length = 3.3 mm.

Fig. 2. Wing of male Docosia walpurga; length = 3.4 mm.

453 r-m longer than but not quite twice as long as the faintly-colored Mp (petiole of M), although in some specimens r-m is much longer than that of the holotype, fork of Cu located posteriorly between fork of r-m/Mp and fork of M although often opposite to or even basal to the fork of r-m/Mp in other specimens, C continues past confluence with R4+5 by a distance between 1/4 and 1/3 the distance between that confluence and the terminus of M1; halteres orange. Abdomen: mostly orange but much of segment 6 and all segments posterior to 6 blackish (Fig. 3); tergite 9 strongly

Fig. 3. Terminal abdominal segments of male Docosia walpurga.

rounded in outline, with distinct apical notch (Fig. 4). Genitalia (Figs. 5-9) (illustrations from paratypes to retain holotype intact): posterior of hypopygium with median comb of black spines (Fig. 5); gonostylus tri-partite with a dorsal, median, and ventral lobe (Fig. 6), the dorsal lobe bearing a peculiar, largely transparent basket-shaped structure (Fig. 7), the median lobe a smooth blade, the ventral lobe with a row of black spines, the cercus black and strobilus-shaped with 10 rows of spines (Fig. 8), though in some specimens there appeared to be nine rows instead, aedeagus and parameres as illustrated (Fig. 9), aedeagus/paramere complex 0.32 mm in length, 0.23 mm in width.

454 Fig. 4. Tergite 9 of male Docosia walpurga, dorsal view.

Fig. 5. Hypopygium of Docosia walpurga, posterior view with elements removed.

455 Fig. 6. Two gonostyli of Docosia walpurga; DL = dorsal lobe, ML = median lobe, VL = ventral lobe.

Fig. 7. Dorsal lobe of gonostylus of Docosia walpurga.

456 Fig. 8. Cercus of male Docosia walpurga.

Fig. 9. Docosia walpurga aedeagi in ventral, lateral, and dorsal view (left to right).

457 Female Allotype. Total dried length = 3.7 mm. Coloration, including the darkened tip of the abdomen, and wing (length = 3.9 mm), like that of the male but antennae much shorter. Terminalia evident as paired cerci (as shown for the paratype of Figs. 10, 11). Distribution. The new species is known only from the type locality in Manistee National Forest, 7 km east of Brohman, Newaygo County, MI. Remarks. Docosia walpurga will almost key out to Docosia dichroa using the three existing non-genitalic keys to the eastern U.S. species of this genus (Johannsen 1912, Fisher 1937, Shaw and Fisher 1952). However, remarkable contradictions exist between keys and accompanying text. The first of these keys requires that the abdomen, presumably of both genders, be reddish yellow (Johannsen 1912, p. 299). Yet on the same page, the male D. dichroa is said to have its last two segments and the hypopygium blackish instead, whereas the female abdomen is by implication devoid of blackish coloration. In contrast, the male abdomen of the new species is blackish in this same area but that darker part includes segments 6, 7, 8, and all segments posterior to these rather than the smaller number said to be darkened for D. dichroa. In the original description of D. dichroa (Loew 1870, p. 148), the male abdomen is described as Johannsen described it later and the female abdomen is stated explicitly to be entirely “ochraceo rufum” with no mention of black. It is possible that the D. dichroa male abdomen and that of the new species have almost identical coloration despite the statements of previous authors because without treatment in solution such as KOH, the black terminal segments of the new species might be mistaken for only two instead of three segments anterior to segment 9. This is due to the usually telescoped, contracted condition of these parts of the abdomen. Detailed color photographs of the holotype of D. dichroa were available online as posted by Harvard University although the terminalia had been removed and therefore that coloration could not be seen. As museums continue to post photographs of their type material, problems such as the present one become easier to resolve because loans of the material itself are not always forthcoming. Regarding the female, the apparent coloration difference is not so easily explained as perhaps no difference at all because the discoverer of D. dichroa allowed no black on the female abdomen (Loew 1870), whereas segment 8 and all segments posterior to it are strikingly black in the case of D. walpurga (Figs. 10, 11), much like the appearance of the male. This alone might be sufficient evidence of a specific difference despite the usual appeal to male characters and it is of note that D. dichroa was described from the Washington, DC area rather than from much farther west on the Great Lakes peninsula where D. walpurga was discovered. Yet the strongest evidence that these two flies are different species is found where such evidence is most often sought and relied upon – in the male genitalia. These were illustrated by line drawings for D. dichroa in three sources (Johannsen 1909, Plate 7, Fig. 11; Johannsen 1912, Fig. 108; Fisher 1937 [unpublished dissertation], Plate 19, Figs. 5, 6). These authors disagree in some features to such an extent as to encourage the use and recommendation of photographs like those provided herein instead of the customarily used line drawings. One of the most important features of the male terminalia among mycetophilid flies is the gonostylus which in the case of all illustrations for D. dichroa is markedly longer than that of the new species, is usually drawn as more sinuous, and lacks the peculiar basket-shaped process shown here (Fig. 7). A male feature that both species have in common is a set of small dark spines on the inner

458 Fig. 10. Female paratype of Docosia walpurga with extruding eggs.

Fig. 11. Terminal abdominal segments of female Docosia walpurga.

459 tip of the hind tibia (Shaw and Fisher 1952 for D. dichroa). In the case of D. walpurga the female also bears such spines, and these are borne on the mesotibia in both genders, too. Docosia paradichroa Fisher lacks these spines, at least on the hind tibia, that D. dichroa and D. walpurga possess (Shaw and Fisher 1952, p. 199). It is not clear from the literature if the females of previously described species lack the small dark tibial spines, another unfortunate silence leaving one to infer rightly or wrongly. The wings of dry-measured D. walpurga males and females were always longer than the remainder of the body although the Palearctic literature indicates the ZLQJRIFRQJHQHUVLVRIWHQVKRUWHU .XULQDDQGâHYþtN1; all three new European species). Etymology. The new species appeared in the first week of May at the time of Walpurgis Night. With its orange and black colors of the October sister celebration of Walpurgis Night, and because gnats are on the wing in Goethe’s Walpurgis Night’s Dream of Faust Part I, the specific epithet of walpurga came to mind. Biology. Larvae and pupae remain unknown. The early May appearance of adult D. walpurga followed the March appearance of two other new mycetophilid species, Boletina michigana Taber (Taber 2011), and a second Boletina congener being described at the time of writing. Males of all three species appeared in much greater numbers than females. A disparity of a second kind was noticed because all three species flew into the large Malaise trap on the outside edge of a black ash swamp, but no Docosia walpurga were found in a smaller Malaise trap lying nearby but just inside the swamp, and this despite the large numbers of that species. This suggests a narrower habitat preference than might have been expected by the close proximity of the two traps which lay within 50 m of one another, and perhaps flights of only short distances. One D. walpurga retrieved from the Malaise trap on 21 May died while attempting to oviposit (Figs. 10, 11). A total of 44 eggs was dissected from this female (Fig. 12), averaging 0.43 mm in length and each bearing a polygonal chorionic surface structure (Fig. 13). These eggs ranged from translucent to white and might have hardened to a darker color had they matured. One female empidid fly (Fig. 14) was found in the same collection canister with the ovipositing mycetophilid. Its size and coloration were so similar to that of the female D. walpurga as to suggest some relationship such as aggressive mimicry. Perhaps it is not a coincidence that this potential predator made its appearance with the female mycetophilids and not with the first and earlier appearance of the males. Yet when an attempt was made to determine the species, another remarkable turn was taken. Believing the empidid to belong to genus Rhamphomyia Meigen, a photo was sent to an authority on these dance flies in an effort to identify the species with the one female at hand instead of the male gender that is more readily determined. In reply it was opined that the orange and EODFN FRORU ZDV TXLWH SRVVLEO\ D ³FRORuU PRQVWURVLW\´, that an entirely black color was to be expected instead, that the authority had never before seen such an example among Rhamphomyia specimens, that the female might belong to the Pararhamphomyia basalis-complex, and that it might be impossible to determine the species (Dr. Miroslav Barták, personal communication). Finding this empidid among mycetophilid flies that it so closely resembles in size and in color becomes yet more enigmatic upon consideration that most Rhamphomyia females are not known to take prey as adults (Steyskal and Knutson 1981), being fed by the male

460 Fig. 12. Eggs of Docosia walpurga dissected from female; egg length = 0.43 mm.

Fig. 13. Chorion structure of Docosia walpurga egg, 1,000X oil immersion.

461 Fig. 14. Female empidid fly resembling female Docosia walpurga; length = 4.1 mm.

during mating, as dance flies are well known to do. If the female does not take prey as an adult, then the resemblance to Docosia walpurga cannot be explained by aggressive mimicry unless there are yet unknown males of the same species, perhaps a new species, that share the unexpected orange and black coloration, and that capture the fungus gnat to feed to their mates. Or the remarkable color of the single specimen might be a complete coincidence instead.

Discussion

A perusal of illustrations of all of the available illustrated male terminalia of Nearctic and Palearctic congeners of D. walpurga showed no gonostylus process resembling that of the new species, with the exception of the Palearctic Docosia gilvipes (Walker), which bears a similarity that is far from identity (Zaitsev 1994, Plate 81, Fig. 2; Laštovka and âHYþtN  )LJ E   )RU WKDW VSHFLHV,the subterminal process of the gonostylus is more open and freely ciliate than that of D. walpurga according to line drawings, and the remainder of the gonostylus and the dorsal configuration of the ninth tergite (Laštovka and âHYþtN Fig. 1a) bear even less similarity. Perhaps the subterminal process of the gonostylus of D. gilvipes is among the reasons for a suggestion in the same reference that this species deserves a separate subgenus or genus. If so, then the new Nearctic species might deserve similar consideration. Regarding other male terminalia that might resemble that of the new species in one aspect or another, the European Docosia tibialis /DãWRYNDDQGâHYþtNEHDUV a notch resembling that of the male ninth tergite of D. walpurga (Laštovka and

462 âHYþtN  )LJ H  WKH JRQRVW\OXV RI D VHFRQG (XURSHDQ VSHFLHV Docosia kerkini .XULQDDQGâHYþtNEHDUVDURZRIGDUNWHHWKRUVSLQHVOLNHWKDWRQRQHRIWKH lobes of D. walpurga .XULQDDQGâHYþtN , whereas a third European species, Docosia distina Plassmann, bears rudimentary teeth on one of the lobes of its gonostylus, has a second lobe somewhat similar in shape to one of the lobes of the D. walpurga gonostylus, and bears a similar notch on the ninth tergite, but these and especially other features also demonstrate differences of species magnitude /DãWRYNDDQG âHYþtN)LJ 

Acknowledgment

I thank Dean Deborah Huntley of The College of Science, Engineering & Technology at Saginaw Valley State University for subsidizing the cost of publication and for arranging the purchase of additional lab equipment to store and study the accumulating material encountered in my field studies, and I thank Dr. Miroslav Barták of the Czech University of Agriculture for thoughts on the unidentified empidid fly.

References Cited

Fisher, E. G. 1937. A Comparative Study of the Male Terminalia of the Mycetophilidae of Nearctic America. Unpublished dissertation, Cornell University, Ithaca, NY. Johannsen, O. A. 1909. Diptera. Fam. Mycetophilidae. Genera Insectorum, Fascicle 93: 1-141. Johannsen, O. A. 1912. The fungus gnats of North America. The Mycetophilidae of North America. Part III. Bull. Maine Agric. Exp. Sta. [ser. 2] 196: 249-328 + 5 plates. Kurina, O. 2006. Three new species of Docosia Winnertz (Diptera: Mycetophilidae) from Kazakhstan. Entomol. Fennica 17: 110-117. Kurina, O., and J. ŠHYþtN    7KUHH QHZ VSHFLHV RI Docosia Winnertz from central and southern Europe (Diptera: Mycetophilidae). Zootaxa 2810: 26-36. /DãWRYND30\FHWRSKLOLGDH 'LSWHUD GH0RQJROLH$FWD=RRO$FDG6FLHQW Hung. 20: 93-135. /DãWRYND, P., and JâHYþtN$UHYLHZRIWKH&]HFKDQG6ORYDNVSHFLHVRI Docosia Winnertz (Diptera: Mycetophilidae), with atlas of the male and female terminalia. ýDV6OH]Muz. Opava (A) 55: 1-37. Loew, H. 1870. Diptera Americae septentrionalis indigena. Centuria nona. Berliner Ent. Zeit. 13: 129-186. Nomina Insecta Nearctica. 1998. Ent. Inf. Serv., Rockville, MD [online version]. âHYþtN-Docosia rohaceki sp. n. and other interesting records of fungus JQDWV 'LSWHUD 0\FHWRSKLOLGDH  IURP 3RO¶DQD %LRVphere Reserve (Central Slovakia). ýDV6OH]0X]2SDYD $ 55: 131-134. âHYþtN -    Docosia heikkii, sp. nov., the first Oriental record of Docosia (Diptera: Mycetophilidae). Oriental 44: 91-94. âHYþtN - DQG 3 /DãWRYka. 2008. Two new European species of Docosia (Diptera: Mycetophilidae). Biologia 63: 117-119.

463 Shaw, F. R., and E. G. Fisher. 1952. Fungivoridae (= Mycetophilidae), pp. 177- 231. In Guide to the Insects of Connecticut. Part VI. The Diptera or True Flies. Fifth Fasicle: Midges and Gnats. Connecticut State Geological and Natural History Survey Bull. 80 [a literature cited section follows on 232-237 but this combines references from several articles]. Steyskal, G. C., and L. V. Knutson. 1981. , pp. 607-624. In J. F. McAlpine, B. V. Peterson, G. E. Shewell, H. J. Teskey, J. R. Vockeroth, and D. M. Wood [coords.], Manual of Nearctic Diptera. Volume 1. Research Branch, Agriculture Canada, Biosystematics Research Centre, Ottawa, Ontario. Monograph 27. Taber, S. W. 2011. A new species of Boletina Staeger fungus gnat (Diptera: Mycetophilidae). Southwest. Entomol. 36: 335-349. Vockeroth, J. R. 1981. Mycetophilidae, pp. 223-246. In J. F. McAlpine, B. V. Peterson, G. E. Shewell, H. J. Teskey, J. R. Vockeroth, and D. M. Wood [coords.], Manual of Nearctic Diptera. Volume 1. Research Branch, Agriculture Canada, Biosystematics Research Centre, Ottawa, Ontario. Monograph 27. Zaitzev, A. I. 1994. Fungus gnats of the fauna of Russia and adjacent regions. Part 1. Hayka, Moscow.

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