Cryptonevra diadema (Meigen)

Barrie, Christine L. & Wheeler, Terry A., 2015, Assembly of a Phragmites - associated Chloropidae (Diptera) fauna in North America: the Palearctic genus Cryptonevra Lioy in the Nearctic, and the genus Lipara Meigen in Canada, Zootaxa 4012 (1), pp. 198-200 : 198-199

Cryptonevra diadema (Meigen)

One female specimen of Cryptonevra was collected in 2011 in an old field habitat in a suburban park ( CANADA: Quebec: Pointe-Claire, Terra Cotta Natural Park, 45.4516° -73.8103°, 30.vi–07.vii.2011, C. Barrie, yellow pan, old field). Subsequent focused collecting with a sweep net in 2013 near a stand of P. australis at the same site yielded 14 more specimens (Pointe-Claire, Terra Cotta Natural Park, 45.4514°, -73.8099°, 11.vii.2013, C. Barrie, sweep, old field, 3 ♂, 11 ♀). Two female specimens were DNA barcoded (658 bp of the mitochondrial CO 1 gene) at the Canadian Centre for DNA Barcoding (University of Guelph, ON, Canada) (BOLD SampleID: CCDB-21329-B04, CCDB-21329-B05; boldsystems.org). All specimens collected in this study are deposited in the Lyman Entomological Museum, McGill University, Ste-Anne-de-Bellevue, QC, Canada (LEM).

The specimens were identified as Cryptonevra diadema (Meigen) ( Fig. 1 ) based on keys and illustrations in Ismay (1994) and Grochowska (2007). Cryptonevra diadema is a widespread Palearctic species whose larvae are associated with P. australis , as inquilines in Lipara galls ( Ismay 1994, Grochowska 2007). Like Lipara and some species of Calamoncosis , Cryptonevra diadema was likely introduced to North America accidentally.

Cryptonevra diadema is one of the few Nearctic species of the chloropid subfamily Chloropinae with an entirely black thorax and abdomen. Most species of Epichlorops Becker , Cetema Hendel or Thaumatomyia Zenker with a completely black scutum have at least some yellow on the scutellum or thoracic pleurites. In Sabrosky’s (1987) key to Nearctic chloropid genera, C. diadema keys to couplet 55 ( Cetema and Epichlorops ), although the scutum is not as distinctly tuberculate as in those two genera. Cryptonevra diadema can be accommodated in the Nearctic key to genera by the following modifications to couplet 54:

54. Scutum (except sometimes postpronotum and/or notopleuron) black, unstriped; scutal setulae arising from tubercles that are often star-shaped, or at least raised ............................................................................................................ 54a - Scutum usually with distinct black or reddish stripes; if uniformly black (rarely), then scutal setulae arising from fine, inconspicuous, piliferous punctures.................................................................................................................... 56 54a. Apex of first flagellomere angulate; frons black posteriorly, yellow at anterior margin, frontal triangle black, appearing shagreened in posterodorsal view; gena divided into microtomentose yellow upper portion and narrower, shining dark brown lower margin; scutal tubercles present but indistinct ................................................ Cryptonevra Meigen - Apex of first flagellomere rounded; frons yellow, contrasting with shining black frontal triangle; gena microtomentose, yellow; scutal tubercles distinctly star-shaped ................................................................................................... 55

Although C. diadema is the first described species of Cryptonevra recorded in North America, an unidentified Palearctic species of Cryptonevra is undergoing testing for possible release in the southern United States as a potential biological control agent for another invasive grass, giant reed ( Arundo donax L., Poaceae ) ( Dudley & Lambert 2007, Goolsby et al. 2009) and adventive populations of Cryptonevra that may be conspecific with that species have been found in coastal southern California ( Dudley & Lambert 2007).

Figures

FIGURE 1. Cryptonevra diadema (Meigen), female habitus. Total length of specimen = 3.3 mm.