Correspondence http/urn:lsid:zoobank.org:pub:C02EA8A6-39E3-4814-9846-613A012E99AC N. P. Krivosheina, M. G. Krivosheina. NEW DATA ON THE BIOLOGY OF HORSEFLIES FROM THE GENERA TABANUS LINNAEUS, 1758 AND HYBOMITRA ENDERLEIN, 1922 (DIPTERA, TABANIDAE) REARED FROM WOOD SUBSTRATES. – Far Eastern Entomologist. 2016. N 322: 11-16. A.N. Severtsov Institute of Ecology and Evolution, 33 Leninsky prospect, Moscow 119071, Russia. E-mail: [email protected] Summary. Data on the development of larvae of the three Tabanidae species, Tabanus pleskei Kröber, 1924, Hybomitra nigella Szilady, 1914 and H. tarandinoides Olsufjev, 1936, in decaying wood substrates are given for the first time. The description of larvae of T. pleskei is added; it differs from larvae of T. bovinus Linnaeus, 1758 in the structure of labrum, man- dibles and position of chaetoid spots on ultimate body segment. Key words: Diptera, Tabanidae, Tabanus pleskei, Hybomitra nigella, H. tarandinoides, larva, morphology, development, wood substrate. Н. П. Кривошеина, М. Г. Кривошеина. Новые данные по биологии личинок слепней родов Tabanus Linnaeus, 1758 и Hybomitra Enderlein, 1922 (Diptera, Tabanidae), выведенных из древесных субстратов // Дальне- восточный энтомолог. 2016. N 322. С. 11-16. Резюме. Впервые приводятся данные по развитию в разлагающихся древесных суб- стратах трех видов слепней: Tabanus pleskei Kröber, 1924, Hybomitra nigella Szilady, 1914 и H. tarandinoides Olsufjev, 1936. Дополнено описание личинки T. pleskei, отли- чающейся от личинки T. bovinus Linnaeus, 1758 строением верхней губы, мандибул и расположением хетоидных пятен на последнем сегменте тела. Gadflies or Tabanidae represent one of the most investigated groups of Diptera. Larvae are known as typical inhabitants of moist soil, aggregations of silt around banks and on bottom of shallow water reservoirs, including salt ones (Olsuf'ev, 1977). The development of Nearctic species in decayed wood is known (Teskey, 1976), for example the species of the genus Leucotabanus Lutz, 1913 are connected with plantations of trees. Larvae of L. annulatus (Say, 1823) were found in fallen decaying tree trunks, stumps and moist wood inside tree holes (Tidwell, 1973), and larvae of L. ambiguus Stone, 1938 were discovered in moist decayed wood dust and were always collected in cooperation with certain termite species (Burger, 1977). Up to the present nothing is known on the Palaearctic species with such biology. Our investigations allowed us to register larvae of three Palaearctic species and rear them from decaying tree trunks for the first time. Present study is based on the larval collection of the Institute of Ecology and Evolution (Moscow). RESULTS Tabanus pleskei Kröber, 1924 MATERIAL EXAMINED. Larvae of T. pleskei were repeatedly collected in the end of May 1967 and 1976 (emerged in the middle of July) in brown wood in roots of Maackia amurensis Rupr. and under the bark of fallen Maackia amurensis and Populus sp. trunks on 11 the territory of Kedrovaya Pad Nature Reserve (Primorskii krai) and Khehtsyrskii Nature Reserve (Khabarovskii krai). DISTRIBUTION. Russia (East Siberia, Far East), Mongolia, China, Korea. Figs. 1–5. Larvae of Tabanus pleskei Kröber, 1924 (1–4) and T. bovinus Linnaeus, 1758 (5). 1 – penultimate and ultimate body segments, lateral view; 2, 3 – abdominal segment III dorsally and ventrally; 4 – ultimate body segment, posterior view; 5 – labrum. (Fig. 5 after Andreeva, 1990). DESCRIPTION. Larva. Body length 35-40 mm, body width 5-7 mm; creamy-white. Head capsule light, weakly sclerotized (Figs 6, 7). Mouthparts are of typical for Brachycera- Orthorrhapha structure. Labrum compressed laterally, its anterior margin is inclined under acute angle to dorsal part of labrum (Fig. 12). Apical projection well developed, blunt and almost rectangular. Dorsal side of labrum with few rare spinules; ventral side of labrum with many apical hairs (Fig. 12). Morphology of mandibles is typical for the representatives of the 12 Figs. 6–13. Larva of Tabanus pleskei Kröber, 1924. 6, 7 – head, dorsal and ventral view; 8 – prothoracic setae; 9 – mandibular-maxillary complex; 10 – antenna; 11 – maxillary palpus; 12 – labrum, lateral view; 13 – structures of chaetoid field on prothorax. 13 genus Tabanus. Distal sclerite of mandible curved at base only, parallel, not pointed and roun- ded apically (Fig. 9); its ventral 1/4 apical margin with many apical dents directed posteriorly. Maxilla with well developed stipes and lacinia. Maxillar palpus elongate, its basal segment 3 times as long as wide (Fig. 11). Massive transverse sclerite carrying long dense diverging hairs is present at base of mandibular-maxillary complex. This structure was considered as cardo of maxilla by some authors (Bischoff, 1925), by the others – as mandibular brush attached to accessory mandibular sclerite (Teskey, 1981). The latter authors consider ventral oval mem- branous plate, protruding beyond mandibles and maxillae posteriorly, as labium (Fig. 7). The position of this structure more likely coincides ventral plate of the head capsule of the larvae of lower Brachycera. Salivary reservoir, typical of Tabanidae larvae, is well developed. Antenna narrow, 4-5 times as long as wide, small, significantly smaller than maxillar palpus (Fig. 10). Larva with smooth thoracic segments without tubercles; abdominal segments with 3 pairs of conical prolegs: 2 lateral and 4 ventral, the latter are converged in pairs; dorsal surface of abdominal segments with 2 flat transverse welts and without prolegs. Chaetoid fields on the anterior part of thoracic segments well developed, concentric, without significant protuberan- ces. Prothoracic field 1/6 as long as the segment; dorsolateral longitudinal furrows begin from it posteriorly but not reaching terminal border of the segment. Thoracic dorsal surface smooth and shining, sometimes with few longitudinal furrows. Abdominal segments with anterior chaetoid fields interrupted medially and with many distinct longitudinal furrows. Ultimate body segment without developed chaetoid spots (Fig. 1), which are typical for larvae of T. bovinus. Anal pad with distinct and well developed pre- and postanal isolated folds (Fig. 1, 4). Length of prolegs of abdominal segments not exceeding their width at base (Figs 2, 3). REMARKS. The period of larval development of Tabanus pleskei in Primorskii krai lasts at least for 3-4 years; larva has 8-10 stages (Soboleva, 1974b). Larvae of this species was briefly described by Soboleva (1970), but was not included in keys published by Andreeva (1990) possibly because of absence of some of important diagnostic characters. Our description of larva allows to clarify these characters. Tabanus pleskei belongs to bovinus species group, represented by few species, the larvae of which have many common features: ultimate body segment with not protruding short siphon; anal pad with distinct and well developed pre- and postanal isolated folds; length of prolegs of abdominal segments not exceeding their width at base; prothorax without lateral chaetoid fields consisting of small hairs, anterior part of prothorax smooth dorsally, shining, with 7-8 rare longitudinal folds. Besides the species is characterized by weak development of dark minute spots, which form longitudinal or inclined rows beginning from anterior chaetoid concentric bands. T. pleskei Kröber, 1924 is supposed to replace widely distributed species T. bovinus Linnaeus, 1758. The areas of these two species are mutually exclusive: the former species is typical to east territories of Palaearctic region; the latter is abundant from Europe and North Africa to western border of East Siberia. The larvae of these species may be distinguished as follow. 1. Dorsolateral side of ultimate body segment with 3-4 chaetoid spots. Apical concentric chaetoid field occupies 1/4 of the length of prothorax. Anterior margin of labrum forms right angle with its dorsal side (Fig. 5). Apical projection of labrum conical, rounded at apex. Dorsal side of labrum with a field of many spinules forming at least 4 rows. Distal sclerite of mandibles dentate at lower apical half ............................................. T. bovinus – Dorsolateral side of ultimate body segment without chaetoid spots. Apical concentric chaetoid field occupies 1/6 of the length of prothorax. Anterior margin of labrum forms acute angle with its dorsal side (Fig. 12). Apical projection of labrum well developed, blunt, rectangular at apex. Dorsal side of labrum with few spinules. Distal sclerite of mandibles dentate at lower apical quarter (Fig. 9) ............................................. T. pleskei 14 Hybomitra nigella Szilady, 1914 MATERIAL EXAMINED. Larvae of H. nigella were found 9.V 1975 (emerged 19.VI 1975) inside fallen trunk of bird-cherry tree Prunus sp. on the territory of Khinganskii Nature Reserve (Amurskaya oblast). DISTRIBUTION. Russian Far East, China. REMARKS. Larvae of H. nigella were registered in swamp hillocks, in coastal soil of rivers, springs and bayous; this species is common in taiga zone and takes the second place after H. taranoides in abundance. Hybomitra tarandinoides Olsufjev, 1936 MATERIAL EXAMINED. Larvae of H. tarandinoides were discovered 18.IV 1967 (emerged 14.V 1967), under the bark of fallen Ulmus trunk covered with moss on the territory of Ussurijskii Nature Reserve (Primorskii krai). DISTRIBUTION. Russia (from Altai and Kemerovskaya oblast to Primorskii krai), Ka- zakhstan, Mongolia, China. REMARKS. The complex of insects in the bark of fallen Ulmus trunk in reserve includes also several larvae of Tipula Linnaeus, 1758 and colonies of Bibio Geoffroy, 1762. CONCLUSION While single specimens of larvae of Tabanus pleskei, Hybomitra nigella and H. tarandi- noides were found in moist soil along river and spring banks and different water loggings on the territory of deciduous valley forests, cedar-deciduous and mountain mixed forests of Primorskii krai (Soboleva, 1974a, b, 1977; Soboleva et al., 1974a, b) but the data on the development of larvae of these species in decaying wood substrates are given here for the first time. REFERENCES Andreeva, R.V. 1990. Determinants of horse fly larvae: Europaean part of the USSR, Caucasus, Middle Asia. Naukova Dumka, Kiev. 171 pp. [In Russian]. Bischoff, W. 1925. Uber die Kopfbildung der Dipterenlarven. III Teil. Die Kopfe der Orthorrhaphen-Brachycera-Larven. Archiv fur Naturgeschichte, A, 90(8): 1–105. Burger, J.F. 1977. The biosystematics of immature Arizona Tabanidae (Diptera, Tabanidae). Transactions of the American Entomological Society, 105: 145–258. Olsuf'ev, N.G. 1977. Horse-flies. Family Tabanidae. Fauna of the USSR. New Series. No. 113, Insects, Diptera, 7(2). Nauka, Leningrad. 434 pp. [In Russian]. Soboleva, R.G. 1970. Description of earlier unknown larvae and pupae of three species of the genus Tabanus (Diptera, Tabanidae) from the Primorje territory. Parazitology, 4(3): 150–160. [In Russian]. Soboleva, R.G. 1974a. Slepni yuga Primorskogo kraya. Nauka, Novosibirsk. 262 pp. [In Russian]. Soboleva, R.G. 1974b. Biology of gadfly Tabanus pleskei Kröb. (Diptera, Tabanidae) in the south of Primorye territory. Proceedings of Institute of Biology and Pedology Far East Science Centre Academy of Sciences of the USSR, 19(122): 87–101. [In Russian]. Soboleva, R.G. 1977. Biologiya slepnei Primorskogo kraya. Nauka, Moscow. 197 pp. [In Russian]. 15 Soboleva, R.G., Bodrova, Yu.D. & Kirpichnikova V.A. 1974a. Hatching sites of gadflies (Diptera, Tabanidae) in the north of Primorye territory. Proceedings of Institute of Biology and Pedology Far East Science Centre Academy of Sciences of the USSR, 19(122): 101–118. [In Russian]. Soboleva, R.G., Kirpichnikova,V.A., Bodrova,U.D. & Sagdieva,A.D. 1974b. Fauna and ecology of gadflies (Diptera, Tabanidae) in cedar broad-leaved forests of Sikhote-Alin state reservation. Proceedings of Institute of Biology and Pedology Far East Science Centre Academy of Sciences of the USSR, 19(122): 58–67. [In Russian]. Teskey, H. J. 1976. Diptera larvae associated with trees in North America. Memoirs of the Entomological Society of Canada, 100: 1–53. Teskey, H.J. 1981. Morphology and terminology – larvae. In: McAlpine et al. (Eds.) Manual of Nearctic Diptera. 1. Research Branch Agriculture Canada. Monograph 27: 65–88. Tidwell, M.A. 1973. The Tabanidae (Diptera) of Luisiana. Tulane Studies in Zoology and Botany, 18: 1–95. 16