Dirrhagofarsus modestus (Fleutiaux, 1923)

Otto, Robert L., 2022, A new species and new records for two other exotic species of Dirrhagofarsus Fleutiaux, 1935 (Coleoptera: Eucnemidae: Melasinae: Dirhagini) in the United States, Insecta Mundi 2022 (932), pp. 1-15 : 8-11

Dirrhagofarsus modestus (Fleutiaux, 1923)

Fig. 21–30

Dirrhagus modestus Fleutiaux 1923: 311–313

Diagnosis. Simple elytral apices ( Fig. 21 ) as viewed laterally will distinguish D. modestus from D. lewisi . Presence of well-developed longitudinal carinae with microcombs on the frons will further distinguish the eucnemid species from D. unicolor . Dirrhagofarsus modestus is very similar to D. brevis new species and D. ernae . When compared with D. brevis new species, D. modestus has longitudinal carinae positioned further away from the compound eyes. The species can be distinguished from D. ernae by the presence of indistinct striae throughout the elytra and variably indicated medio-longitudinal carina on the frons.

Specimens examined. One hundred twenty-eight specimens were available for study: CONNECTICUT: “ CONNECTICUT: New Haven ; Co., 1.2 km NE Morgan ; Point , 41.25376, −72.87708 ; 9m, 15–28 Jun 2018, LFT; K. Bjarnason, BSF# 79688” (1, CMNH); FLORIDA: “ Florida: Suwannee Co .; 6.5 miles W White Springs ; March 29, 2017 at light; Kyle E. Schnepp ” (1, KESC); “ Florida: Suwannee Co .; ~ 7 miles W White Springs ; March 29– April 19, 2017; Lindgren funnel trap; Kyle E. Schnepp ” (1, KESC) ; “ Florida: Suwannee Co.; ~ 7 miles W White Springs; March 29–April 19, 2017; Lindgren funnel trap; Kyle E. Schnepp ” / “ Dirrhagofarsus ; ernae ; Otto; Muona & McClarin; Det. R.L. Otto; 2017” [folded] (1, KESC) ; “ Florida: Suwannee Co .; ~ 7 miles W White Springs ; May 16–June 20, 2017; Lindgren funnel trap; Kyle E. Schnepp ” (1, KESC); GEORGIA: “ Georgia: Long Co .; ~ 10 miles WNW Ludowici ; July 22, 2116 at light; Kyle E. Schnepp ” (1, KESC); “ GEORGIA: Chatham Co .; 4.4km WNW Port Went- ; worth, 32.16031, −81.20731; 5 m, 11–25 Apr 2018, LFT; R. Morgan, BSF# 78446” (1, CMNH); INDIANA: “ Indiana: Montgomery Co .; Shades State Park ; May 21–June 8, 2013; fermenting sugar trap; Kyle E. Schnepp ” (1, KESC); MAINE: “ MAINE: Aroostook Co .; 3.2km N Masardis , 175m ; 46.53279, −68.36319; 25 Jun–10 Jul 2018, LFT; J. Bither, BSF# 81272” (1, CMNH) ; “ MAINE: Aroostook Co.; 3.3 km N Masardis ; 46.53279, -68.36319; 175m, 10–23 Jul 2018 ” / “black cross-vane panel; trap, J. Bither; BSF# 81309” (1, CMNH) ; “ MAINE: Aroostook Co .; 3.2km N Masardis , 175 m ; 46.53279, −68.36319; 23 Jul–7 Aug 2018, LFT; J. Bither, BSF# 81274” (1, CMNH); “ MAINE: Somerset Co .; 7.1km SSE Solon , 181 m ; 44.89562, −69.80982; 3–17 Aug 2018, K.Kimball; M.Smith, LFT, BSF#82015” (1, CMNH); “ MAINE: Aroostook Co.; 3.2 km N Masardis ; 46.53279, −68.36319; 174 m, 4–18 Sep 2019 ” / “black cross-vane; panel trap, J. Bither; BSF# 89419” (1, GERP) ; MASSACHUSETTS: “MASSACHU- SETTS: Essex; Co., 0.9km WSW Salisbury ; 42.839571, −70.870927; 12 m, 31 May–13 Jun 2018; J. Klein, LFT, BSF# 80400” (1, CMNH); “ MASSACHUSETTS: Middle- ; sex Co., 4.8km N Framingham ; Center , 42.339856, −71.428893 ; 78 m, 6–19 Jun 2018; J. Klein, LFT, BSF#80405” (1, GERP); NEW JERSEY: “ NEW JERSEY: Morris Co .; 2km SSE Netcong , 324m ; 40.882025, −74.697199; 29 May–15 Jun 2018; K. Pinto, LFT, BSF#79375” (2, CMNH); NEW YORK: “ NEW YORK: Franklin Co .; 8.2 km E of Hogansburg ; 44.9771, −74.5593, 67 m; 29 Jul–14 Aug 2019, LFT; A. Johnson, BSF# 88001” (1, GERP); OHIO: “ OHIO: Cuyahoga Co .; 4.2km SW Strongsville ; 41.2857, -81.8681, 290m; 26 May–9 Jun 2018, LFT; N. Wright, BSF# 80119” (1, GERP) ; “ OHIO: Seneca County; 2.4km SE Tiffin , 238m; 41.1051, −83.1516; 26 Jun–16 Jul 2018 ” / “cross-vane panel; trap, C. Poe; BSF# 82735” (1, CMNH); RHODE ISLAND: “ RHODE ISLAND: Kent Co .; 3.3 km SSE of Centerville ; 41.66816, −71.51265, 84m; 3–17 Jul 2018, LFT; K. DiVito, BSF# 87905” (1, CMNH); VERMONT: “ VERMONT: Chittenden ; Co., 2.1km NNE Burlington ; 44.494596, −73.208362; 35 m, 13–27 Jul 2018; E. Inoue, LFT, BSF#80825” (1, CMNH); VIR- GINIA: “ VIRGINIA: Fairfax Co .; Turkey Run ; 22.vi–6.vii.2006 ” (1, GWMP); “ VIRGINIA: Fairfax Co .; Turkey Run west; 1–22.v.2008, B. Steury ” (1, GWMP); “ VIRGINIA: Fairfax Co .; Great Falls Swamp ; 19–30.vi.2009; B. Steury ” (1, GWMP); “ VIRGINIA: Fairfax Co .; Little Hunting Creek ; 5–19.v.2017, jar #2” (1, GWMP); “VIR- GINIA: Rockbridge Co .; 1.5km NE Fairfield , 526m ; 37.887858, -79.275894; 31 May–2 Jul 2018, LFT; D. Heltzel, BSF# 79609” (1, CMNH); “ VIRGINIA: Fairfax Co .; Turkey Run ; 18–30.vi.2018 ” (1, GWMP); WEST VIRGINIA: “ WEST VIRGINIA: Raleigh ; Co., 0.8km N Beckley ; 37.78494, −81.19034, 697m; 7 Jun–5 Jul 2016, LFT; R. Hays, BSF# 70752” (1, CMNH) ; WISCONSIN: “WI: Outagamie Co.; along Spencer Road ; N44.25813°; W-088.56426°; EABT100215B; 19 July 2011; Robert L. Otto ” / “Taken from EAB; prism trap baited; with Manuka oil; & Z3-Hexa- 1-ol” (2, GERP) ; “WI: Winnebago Co.; along State Highway 76; N44.24240°; W-088.54046°; EABT100245C; 19 July 2011; Robert L. Otto ” / “Taken from EAB; prism trap baited; with Manuka oil; & Z3-Hexa-1-ol” (2, GERP) ; “WI: Oconto Co.; L. Gipp property; 6 mi. W. Suring ; 17 March 2012; Robert L. Otto ” / “Reared from larvae; in rotten Populus ; stump on 9 May; 2012” (6, GERP) ; “WI: Oconto Co.; L. Gipp property; 6 mi. W. Suring ; 17 March 2012; Robert L. Otto ” / “Reared from larvae; in rotten Populus ; stump on 12 May; 2012” (11, GERP) ; “WI: Oconto Co.; L. Gipp property; 6 mi. W. Suring ; 17 March 2012; Robert L. Otto ” / “Reared from larvae; in rotten Populus ; stump on 16 May; 2012” (1, GERP) ; “WI: Oconto Co.; Chequamegon-; Nicolet N.F.; along S.H. 64; 20 March 2012; Robert L. Otto ” / “Reared from; larvae in rotten; Populus stump; on 1 May 2012 ” (60, GERP) ; “WI: Oconto Co.; Chequamegon-; Nicolet N.F.; along S.H. 64; 20 March 2012; Robert L. Otto ” / “Reared from; larvae in rotten; Populus stump; on 12 May 2012 ” (1, GERP) ; “WI: Oconto Co.; along Bonita Road ; N45.108908°; W−088.451765°; 12–26 June 2012; Robert L. Otto ” / “Taken from elevated; flight intercept trap; baited with manuka oil” (1, GERP) ; “WI: Oconto Co.; along Bonita Road ; N45.108908°; W−088.451765°; 26 June–13 July 2012; Robert L. Otto ” / “Taken from elevated; flight intercept trap; baited with manuka oil” (3, GERP) ; “WI: Oconto Co.; along C.R. NN; N44.859383°; W−087.865933°; 26 June–13 July 2012; Robert L. Otto ” / “Taken from elevated; flight intercept trap; baited with manuka oil” (1, GERP) ; “WI: Dane Co.; Turville Point Preserve ; N43° 03.143′; W−089° 22.156′; 21 October 2012; Robert L. Otto ” / “Reared from larvae; in rotten oak log; on 17 February 2013 ” (5, GERP) ; “ WI: Oconto Co .; along Timberline Rd .; N44° 49.310′ W−088° 9.353′; 11–25 June 2016; Robert L. Otto ; Purple Suzuki- Otto FIT #5” (3, GERP); “WI: Oconto Co .; along County Rd. E ; N44° 47.600′ W−088° 9.495′; 11–25 June 2016; Robert L. Otto ; Purple Suzuki-Otto FIT #8” (1, GERP); “WI: Oconto Co .; along Garrity Rd .; N44° 49.011′ W−088° 8.370′; 25 June–9 July 2016; Robert L. Otto ; Purple Suzuki-Otto FIT #2; baited with Manuka oil” (1, GERP); “WI: Oconto Co .; along Elmlawn Rd .; N44° 47.645′ W−088° 9.198′; 9 July 2016; Robert L. Otto ; on car” (1, GERP); “WI” Oconto Co .; Chequamegon-Nicolet N.F.; along Diamond Roof Road ; N45.33673°, W−88.69745°; 23 June 2021; Robert L. Otto ; handpicked from rotten log” (3, GERP).

Redescription. Male. Length 3.0–4.0 mm. Width, 0.75–1.0 mm. Body subcylindrical, elongate; dorsum uniformly black with infuscate reddish margin of the pronotum; antennae reddish-brown; legs including tarsi reddish-brown; head, pronotum and elytra clothed with short, recumbent yellowish setae ( Fig. 22 ). Head ( Fig. 23 ): subspherical; integument evenly punctate, somewhat dullish, except the vertex; vertex with narrow belt of silver-colored microcombs; frons convex, with variably weak medio-longitudinal carina; pair of longitudinal carinae on frons positioned further away from the compound eyes, well-developed, with silver-colored microcombs;

apical margin of frontoclypeal region rounded, about 2 times wider than base; mandibles stout, bidentate, densely punctate. Antenna: weakly serriform from flagellomeres I–IX, attaining nearly 3/4 the length of the body; flagellomere I longer than II; flagellomeres II–VIII each sub-equal, longer than wide; flagellomere IX longer than VIII. Pronotum: integument somewhat shiny, closely punctate; slightly longer than wide, with moderate, sharp hind angles; lateral sides parallel-sided at basal 3/4, arcuate anteriorly at apical 1/4; disc convex with very shallow median impression; short basal medio-longitudinal carina present; base sinuous; anterolateral pronotal ridge ( Fig. 24 ) somewhat short, about 1⁄6 the length of the pronotum, directed posteroventrally; posterolateral pronotal ridge elongate, extending 3/4 the length of pronotum, slightly sinuous. Scutellar shield: quadrate, sub-triangular, shallowly punctate, setose and distally rounded. Elytra: indistinctly striate throughout; interstices flattened; integument shiny, transversely rugose at basal 1/4 and closely punctate elsewhere; specialized punctures present along lateral sides near elytral apices. Legs: First tarsomere as long as the combined lengths of the remaining four on meso- and metatarsi; tibiae rounded in cross section; metatarsomeres I–III simple; metatarsomere IV excavated, emarginate; metatarsomere V elongate with simple claws. Venter: evenly punctate, with short, recumbent yellowish setae; hypomeron with notosternal antennal grooves; metepisterna parallel-sided; metacoxal plates medially 3.0–6.0 times wider than laterally; last abdominal ventrite apically produced.

Sexual dimorphism. Females ( Fig. 25 ) are similar to males, but can be distinguished by their slightly shorter antennae, about 1/2 the length of the body, and more robust body. Flagellomeres are much stouter than the males, being slightly longer than wide for flagellomeres II–VIII. Females are just as long or longer and as wide as or slightly wider than males; length 3.5–5.5 mm and width 1.0– 1.25 mm.

Aedeagus ( Fig. 26 ): Basal piece longer than wide, spatulate, dorsally open, apically rounded; remaining parts elongate, basally narrow, laterally arcuate, widest medially; parameres very short, apically rounded, simple; secondary lateral lobes present, very short, shorter than parameres; median lobe very short and basally broad, apically pointed, as long as the parameres.

Distribution. This commonly encountered eucnemid species is known from Japan (Honshu and Kyushu), Russia (Far East), South Korea (Gangwond-Do, Gyeonggi-Do, Jeju-Do (Isl.), Jeollanam-Do and Seoul-Si) and the United States ( Seung et al. 2018; Otto, pers obs.). In the United States, D. modestus was taken in Connecticut, Florida, Georgia, Indiana, Maine, Massachusetts, New Jersey, New York, Ohio, Rhode Island, Vermont, Virginia, West Virginia, and Wisconsin.

Biology. In South Korea, larvae were taken from dead, standing Alnus japonica ((Thunberg) Steudel ( Betulaceae )) trees. Many adults were reared from collected larvae as well as taken commonly from light traps ( Seung et al. 2018). Three specimens were taken from cross-vane panel traps in Maine and Ohio. Two specimens were taken from lights. One specimen was taken from a fermenting sugar trap in Indiana. Seventeen specimens were taken from Lindgren funnel traps deployed in states across northeastern and southeastern United States. A large series of eucnemid specimens were reared from rotten Populus (Betulaceae) logs or stumps and oak logs ( Fagaceae ) in Wisconsin. Four specimens were taken from purple prism traps baited with Manuka oil and Z3-Hexa-1-ol in Wisconsin. Five specimens were taken from an elevated flight intercept trap baited with Manuka oil in northeastern Wisconsin. One specimen was handpicked from my car. Five specimens were taken from my home-made flight intercept traps inspired from an image provided by W. Suzuki dubbed “Suzuki-Otto FIT”. A rotten stump and nearby log were examined ( Fig. 27–30 ) on 23-VI-2021 along Diamond Roof Road within the Chequamegon- Nicolet National Forest, Wisconsin (GPS coordinates: N45.33673°, W−88.69745°). Several adults were spotted crawling on the surfaces, especially at the edges around mid-morning. Several adult female beetles were handpicked from a nearby rotten log at this site. So far, the species have been taken largely in the northern mesic forests and southern mesic forests in Wisconsin.

Note. Both Otto et al. (2014) and Seung et al. (2018) used the presence of weak medio-longitudinal carina on the frons to diagnose D. modestus from other species within the group. In examining a number of specimens, I found the character state exhibits a degree of variability among these specimens, making it quite difficult for diagnosing D. modestus from other similarly known small, dark-colored Dirrhagofarsus species, especially D. ernae . Both D. ernae and D. modestus have been found together in a number of localities in Wisconsin which indicate D. modestus may have been present in the United States since the late 1990’s, as long as D. ernae . Unknown larvae of Dirrhagofarsus believed to belong to D. modestus were recovered from a rotten Populus stump approximately 20 miles northwest of Suring, Wisconsin, U.S.A. on 12 March 2012.

Figures

Figures 21–26. Dirrhagofarsus modestus (Fleutiaux). 21) Elytral apices, lateral view. 22) Male, dorsal habitus. 23) Head, frontal view. 24) Pronotum, lateral view. 25) Female, dorsal habitus. 26) Aedeagus, dorsal view. (Scale: 21–26 = 1.0 mm.)

Figures 27–30. Dirrhagofarsus modestus (Fleutiaux) habitat, Chequamegon-Nicolet National Forest, along Diamond Roof Road, Oconto County WI, U.S.A., 23-VI-2021. 27) Rotten stump. 28) Female beetle on stump. 29) Female beetle on nearby fallen log. 30) Nearby fallen log. Images taken by author with Samsung Galaxy S10e smartphone.