Trissolcus japonicus (Ashmead)

Talamas, Elijah J., Buffington, Matthew L. & Hoelmer, Kim, 2017, Revision of Palearctic Trissolcus Ashmead (Hymenoptera, Scelionidae), Journal of Hymenoptera Research 56, pp. 3-185 : 32

Trissolcus japonicus (Ashmead) Figures 6 , 10 , 84-87 , 88-89

Trissolcus dobashii Buhl syn. n.; http://bioguid.osu.edu/xbiod_concepts/223373; Morphbank24

Trissolcus cercus Kozlov & Lê syn. n.; http://bioguid.osu.edu/xbiod_concepts/3199; Morphbank25

Trissolcus mirus Kononova syn. n.; http://bioguid.osu.edu/xbiod_concepts/354848

Trissolcus pontus Kozlov & Lê syn. n.; http://bioguid.osu.edu/xbiod_concepts/3292; Morphbank26

Dissolcus japonicus Ashmead, 1904: 73 (original description); Kieffer, 1926: 124, 125 (description, keyed).

Trissolcus japonicus (Ashmead): Masner & Muesebeck, 1968: 72 (type information, generic transfer); Hirashima & Yamagishi, 1981: 153 (description, synonymy); Ryu & Hirashima, 1984: 37, 43 (description, keyed); Talamas, Buffington & Hoelmer, 2013: 114 (description, synonymy, type information).

Trissolcus cercus Kozlov & Lê syn. n., 1976: 659, 666 (original description, keyed); Kozlov & Lê, 1977: 504 (keyed); Kozlov, 1978: 632 (description); Kozlov & Kononova, 1983: 89 (description).

Trissolcus pontus Kozlov & Lê syn. n., 1976: 659, 664 (original description, keyed); Kozlov & Lê, 1977: 504 (keyed); Kozlov, 1978: 632 (description); Kozlov & Kononova, 1983: 88 (description); Kononova, 1995: 93 (keyed).

Trissolcus dobashii Buhl syn. n., 1996: 128 (original description).

Trissolcus halyomorphae Yang: Qiu, Yang & Tao, 2007: 62 (unavailable: nomen nudum); Yang, Yao, Qiu & Li, 2009: 40 (original description); Talamas, Buffington & Hoelmer, 2013: 114 (junior synonym of Trissolcus japonicus (Ashmead)).

Trissolcus mirus Kononova syn. n., 2014: 749 (original description, diagnosis).

Description.

Female body length: 1.16-1.85 mm (n=21). Male body length: 1.15-1.51 mm (n=20). Body color: head, mesosoma, and metasoma black.

Head. Color of radicle: orange; yellow. Length of radicle: less than width of clypeus. Color of A1-A6 in female: yellow to brown. Color of A7-A11 in female: dark brown to black. Number of basiconic sensilla on A6: 0. Number of basiconic sensilla on A7: 2. Facial striae: absent. Number of clypeal setae: 4. Microsculpture on gena directly above mandibular condyle: present. Shape of ventral gena in lateral view: narrow. Genal carina: absent. Malar striae: absent. Sculpture of malar sulcus: antero-posteriorly striate; faintly rugulose. Orbital furrow: expanding in size ventrally, strongly so at intersection with malar sulcus. Macrosculpture of frons between antennal scrobe and anterior ocellus: absent; weakly transversely strigose. Preocellar pit: absent. Setation of lateral frons: moderately dense. Punctation of lateral frons: sparse. Sculpture directly ventral to preocellar pit: dorsoventrally fluted. Macrosculpture of lateral frons: absent. OOL: lateral ocellus and eye without continuous scleritic separation. Hyperoccipital carina: complete. Macrosculpture of posterior vertex: absent. Microsculpture on posterior vertex along occipital carina: present. Anterior margin of occipital carina: coarsely crenulate.

Mesosoma. Epomial carina: present. Macrosculpture of lateral pronotum directly anterior to netrion: striate, striae formed by elongation of cells of netrion sulcus. Netrion sulcus: complete. Pronotal suprahumeral sulcus in posterior half of pronotum: clearly indicated by cells. Location of pronotal suprahumeral sulcus: percurrent. Number of episternal foveae: 4 or more. Course of episternal foveae ventrally: abutting postacetabular sulcus. Course of episternal foveae dorsally: extending to mesopleural pit. Subacropleural sulcus: present. Speculum: transversely strigose; weakly transversely wrinkled. Mesopleural pit: extending ventrally into dorsoventral furrow parallel to mesopleural carina. Mesopleural carina: well defined anteriorly, poorly defined to absent posteriorly. Sculpture of femoral depression: smooth. Patch of striae at posteroventral end of femoral depression: present, striae perpendicular to long axis of femoral depression. Setal patch at posteroventral end of femoral depression: present. Microsculpture of anteroventral mesopleuron: present dorsally. Macrosculpture of anteroventral mesopleuron: absent. Postacetabular sulcus: formed by large cells. Mesopleural epicoxal sulcus: formed by large cells. Setation of posteroventral metapleuron: absent. Sculpture of dorsal metapleural area: smooth in anterodorsal corner, coarsely rugose posteriorly; rugose. Posterodorsal metapleural sulcus: poorly defined to absent. Paracoxal sulcus in ventral half of metapleuron: indistinguishable from sculpture to absent; indicated by a line of elongate cells. Anteroventral extension of metapleuron: extending to base of mesocoxa. Metapleural epicoxal sulcus: absent or indistinguishable from sculpture; present as coarse rugae. Mesoscutal humeral sulcus: indicated by a line of cells. Median mesoscutal carina: absent. Macrosculpture of mesoscutum: absent; weakly rugulose anteriorly, otherwise absent. Pattern of mesoscutal microsculpture: uniform throughout; effaced posteriorly. Mesoscutal suprahumeral sulcus: comprised of cells. Length of mesoscutal suprahumeral sulcus: about half the length of anterolateral edge of mesoscutum. Parapsidal line: present. Notaulus: extending at least 1/3 length of mesoscutum. Median protuberance on anterior margin of mesoscutellum: absent; present. Protruberance on anterior margin of mesoscutellum directly posterior to notaulus: present. Shape of dorsal margin of anterior lobe of axillar crescent: round. Sculpture of anterior lobe of axillar crescent: dorsoventrally strigose. Area bounded by axillar crescent: striate. Macrosculpture of mesoscutellum: absent. Microsculpture on mesoscutellum: present throughout; present laterally, absent medially. Median mesoscutellar carina: absent. Setation of posterior scutellar sulcus: present. Form of metascutellum: multiple rows of cells. Metanotal trough: foveate, foveae occupying more than half of metanotal height. Metapostnotum: invaginated near lateral edge of metascutellum. Color of legs: coxae dark brown to black, femora and tibia yellow to dark brown, trochanters and tarsi yellow to pale brown. Anteromedial portion of metasomal depression: punctate or crenulate.

Metasoma. Longitudinal striae on T1 posterior to basal costae: present. Number of sublateral setae (on one side): 0; 1. Setation of laterotergite 1: absent. Longitudinal striation of T2: present throughout anterior half of tergite; present in anterior two-thirds of tergite. Setation of T2: present throughout posterolateral corner. Setation of laterotergite 2: present. Posteriorly directed setae on medial S1: present. Striation of S2: present laterally and in anterior half of median third. Setation of S2: present throughout area not covered by laterotergite.

Diagnosis.

Trissolcus japonicus is very similar to T. plautiae and T. kozlovi . Trissolcus japonicus can be separated from T. plautiae by the sculpture directly below the median ocellus: in T. japonicus this area is covered with microsculpture and often a dorsoventral furrow is present. In T. plautiae this area is entirely smooth and without microsculpture. Matsou et al. (2013) used the presence of a sublateral setae to separate T. japonicus from T. plautiae . However, in our experience with specimens reared in quarantine, sublateral setae are not uncommon in T. japonicus . Our preliminary analysis of molecular data is based on DNA extracted non-destructively from specimens of T. japonicus collected in China, Japan, and South Korea, and specimens of T. plautiae from China and Japan. In the specimens used for this analysis, and in the specimens used for monographic work, we found that the pattern of sculpture below the anterior ocellus is stable in both species. It is on this basis that we use this character to separate T. plautiae and T. japonicus , which is consistent with the findings of Matsuo et al. (2013).

Trissolcus japonicus and T. kozlovi can be separated by the sculpture of the frons directly above the antennal scrobe and sculpture of the mesoscutum between the notauli. The sculpture of the frons above the antennal scrobe in T. kozlovi is irregular whereas in T. japonicus , this area of the frons is either smooth or with weakly developed transverse lines of sculpture. The posteromedial mesoscutum in T. kozlovi is obliquely striate, with the lines of sculpture extending anterolaterally from the midline. In T. japonicus there is no macrosculpture in the posterior half of the mesoscutum.

The characters used to separate T. japonicus and T. kozlovi are based on examination of a small number of specimens of the latter species, and they are so similar that we considered that they may actually represent variation within a single species. However, because we are still able to consistently separate them based on morphology, we consider it best to continue to treat them as separate species. Analysis of the DNA sequence and biology of T. kozlovi should be a priority in the future, particularly because as BSMB spreads eastward in Europe its distribution is likely to overlap with that of T. kozlovi .

Link to distribution map.

http://hol.osu.edu/map-large.html?id=3249

Material examined.

Holotype, female, T. dobashii : JAPAN: Fukuoka Pref., woodland / vegetation consisting mainly of bamboo, Mount Aburayama , 10.I.1996, sweeping, P. N. Buhl, zmuc00021257 (deposited in ZMUC) . Holotype, female, T. cercus : RUSSIA: Astrakhan’ Reg., Astrakhan Nature Reserve, 20-VII, M. Y. Asse, ZMAS 0145 (deposited in ZIN) . Holotype, female, T. pontus : RUSSIA: Primor’ye Terr., Ussuriyskiy (Suputinskiy) Nature Reserve , 2.VIII.1961, Kovalev, ZMAS 0144 (deposited in ZIN) . Holotype, female, Dissolcus japonicus : JAPAN: Kanagawa Pref., Ashigarashimo Dist., Hakone Town, no date, Koebele , USNMENT00831865 (deposited in USNM) . Paratypes: CHINA: 2 females, USNMENT00872401, 00872402 (USNM) . Other material: (185 females, 97 males) CHINA: 109 females, 73 males, USNMENT00916340-00916346, 00916462-00916464 (BMNH); USNMENT00979190-00979198, 00979200-00979221 (CNCI); OSUC 75616 (OSUC); UCRC ENT 142613, 142653, 142678, 142682, 142724, 142738, 142750, 143837, 143886, 143900 (UCRC); USNMENT00675704, 00675738-00675739, 00675741-00675743, 00675746-00675749, 00675986, 00675988-00675989, 00764964, 00764984, 00916255, 00916710-00916787, 00916796, 00916801-00916813, 00916815, 00916895-00916899, 00916900-00916903, 00916918-00916930 (USNM). JAPAN: 16 females, 9 males, OSUC542354, 542373, 542549, USNMENT00896137, 00896139-00896340 (CNCI); UCRC ENT 158378 (UCRC); USNMENT00675709-00675713, 00675715-00675716, 00675755, 00675770, 00872125-00872133 (USNM). RUSSIA: 3 females, USNMENT00979287 (CNCI); UCRC ENT 297007, 297010 (UCRC). SOUTH KOREA: 18 females, 11 males, USNMENT00896014, 00896026, 00896033-00896036, 00896038-00896042, 00896117, 00896120, 00979251, 00979254 (CNCI); USNMENT00675705-00675708, 00675718-00675720, 00675723-00675729 (USNM). TAIWAN: 2 females, UCRC ENT 112211, 296942 (UCRC). UNITED STATES: 37 females, 4 males, USNMENT01109017-01109019 (CNCI); USNMENT01059357, 01059359-01059402, 01059404-01059407, 01059409-01059412, 01059414-01059417, 01059420-01059422, 01059424-01059427, 01059430, 01081080, 01109016, 01109020-01109026, 01109132, 01109134, 01109419, 01109562 (USNM) .

Comments.

Trissolcus cercus , which we here treat as a junior synonym, was collected in western Russia, far from the distribution of what we otherwise know to be the native range of T. japonicus . In the late 1960s, Podisus maculiventris , which is a known host of Trissolcus japonicus , was introduced into Eastern Europe in the late 1960's as a biological control agent (Schaefer & Panizzi 2000). The eggs associated with the holotype of T. cercus are included on the pin, and their morphology is consistent with that of eggs of P. maculiventris . The presence of T. japonicus in Eastern Europe may be the result of an adventive population of T. japonicus that followed the introduction of P. maculiventris , and then declined along with the stink bug population.

Figures

Figure 6. Trissolcus japonicus, female (USNMENT 00896000), head, mesosoma, metasoma, ventral view. Scale bar in millimeters.

Figure 7 - 12. 7 T. mitsukurii, female (USNMENT 00675722), axillar crescent, lateral view 8 T. tumidus, female (USNMENT 00979425), axillar crescent, lateral view 9 T. flavipes, holotype of T. circus, female (ZMAS 0143), axillar crescent, lateral view 10 T. japonicus, female (USNMENT 00675989), axillar crescent, lateral view. 11 T. saakowi, female (USNMENT 00977544) axillar crescent, lateral view 12 T. nycteridaner, female (USNMENT 00896178), axillar crescent, lateral view. Scale bars in millimeters.

Figures 84 - 87. 84 Trissolcus cercus (= T. japonicus), female holotype (ZMAS 0145), head, anterior view 85 Trissolcus japonicus, female holotype (USNMENT 00831865), head, anterior view 86 Trissolcus pontus (= T. japonicus), female holotype (ZMAS 0144), head, anterior view 87 Trissolcus dobashii (= T. japonicus), female holotype (zmuc 00021257), head, anterior view. Scale bars in millimeters.

Figures 88 - 89. Trissolcus japonicus 88 female (USNMENT 00979297), head, mesosoma, metasoma, lateral view 89 female (USNMENT 00675989), head, mesosoma, metasoma, dorsal view. Scale bars in millimeters.