Bradysia strenua (Winnertz, 1867)

Broadley, Adam, Kauschke, Ellen & Mohrig, Werner, 2018, Black fungus gnats (Diptera: Sciaridae) found in association with cultivated plants and mushrooms in Australia, with notes on cosmopolitan pest species and biosecurity interceptions, Zootaxa 4415 (2), pp. 201-242 : 229-230

Bradysia strenua (Winnertz, 1867)

( Fig. 16 A–D )

Sciara strenua winnertz, 1867 [winnertz (1867): 100]

= Bradysia watsoni Colless, 1962 syn. n. [ Colless (1962): 955 –957, fig. 1 a–g]

Literature: Edwards (1925): 540; Edwards (1938): 201 (both as Sciara varians ); Laurence (1994): 118; weber et al. (1995): 94–96; Laurence (1996): 87 (all as Bradysia brunnipes ); Mohrig & Menzel (1993): 283–285, fig. 17 a–d; Menzel (1998): 20; Menzel & Mohrig (2000): 142–143.

Material studied. NEW SOUTH WALES: 1 male, November 1978, Armidale, in soil and bulbs, ASCT 00054275, leg. unknown ( ASCU).

TASMANIA ( MACQUARIE ISLAND): 2 males (paratypes), 23 March 1961, Langdon Point, leg. K. Watson, M/61/ In /242, ANIC Database No . 29, 0 0 6589 (PABM) and 0 0 6590 (PWMP). 2 males (paratypes), 19 January 1961, Langdon Point, leg. K. Watson, M/61/In/48, ANIC Database No. 29, 0 0 6592 (ANIC) and 0 0 6593 (PABM). 1 male, 27 October 2009, Australia, TAS, Macquarie Island , Razorback Ridge, M &P004 SCBT, leg. P.

Hudson & M. Potter, Stilbocarpa beating (SAMA). 1 female, 2015, ( Barcode of Life MACQSCI; dx.doi.org/ 10.5883/DS-SCIAMACQ; GenBank accession MG647919 ) 54.49384 158.94148, pitfall trap, Poa foliosa (tussock), leg. M. Houghton ( PABM) .

Comments: Colless (1962) described B. watsoni from Macquarie Island, a subantarctic island located in the southwest Pacific Ocean about half way between New Zealand and Antarctica. In his paper, Colless noted that “the possibility cannot be entirely excluded, that the Macquarie I. species is an immigrant, already described in another country. However, in the literature available to me, I can find no definite evidence that this is so.” The type and a series of paratypes are deposited in the Australian National Insect Collection in Canberra. The male holotype is mounted in a card stub so detailed microscopic examination of it was difficult. However, we were able to select 3 male paratypes from the pinned material and slide mount them in Canada balsam. All 3 paratypes and a male specimen collected from the island in 2009 are identical to the figures given by Colless (1962). In the ASCU material we found one male specimen that was collected in 1978 from "soil and bulbs" in Armidale, New South Wales. This is the first Australian mainland record. All of these specimens are morphologically identical to Bradysia strenua from Europe. We also examined a female specimen collected from a pitfall trap on Macquarie Island in 2015 and found a 99–100% match for B. strenua via sequencing and analysis of the cytochrome oxidase 1 (CO1) gene. The species may have been introduced to Macquarie Island in the 19th or early 20th century, when seal harvesting gangs were exploiting the island. Adults have been recorded on the island throughout the year; most commonly walking or flying under Macquarie Island cabbage ( Stilbocarpa polaris ), but they have also been found in tall grasslands, and on Poa annua , Leptinella plumosa and Pleurophyllium hookeri (van Klinken & Greenslade 2006). In Europe, B. strenua is free living and rather common in open fields. It is seldomly found in forests or caves. The larvae are herbivorous, perhaps mining in leaves, and they have been reared from decaying narcissus bulbs, potatoes, a mole nest, angelica root, and old ragwort stems (Menzel et al. 2006).

Diagnostic remarks. The species is characterised by an elongate gonostylus with a rounded apex, a strong apical tooth and apically rounded tegmen with a small longer than wide area of teeth and short hairs on the inner ventral margin of the gonocoxites (in this latter character it differs from the similar species B. pallipes ).

Economic importance. Not known to mass breed or to be a pest so unlikely to be of economic importance.

Distribution. Holarctic: Canada, Germany, Norway, Poland, Spain, United Kingdom; Australia (new record): New South Wales, Tasmania ( Macquarie Island).

Figures

FIGURE 16. Bradysia strenua (winnertz, 1867). A. Left side of the hypopygium in ventral view. B. Gonostylus. C. 4th flagellomere.D. Scutellum.