Longitarsus lewisii Baly, 1874

Pentinsaari, Mikko, Anderson, Robert, Borowiec, Lech, Bouchard, Patrice, Brunke, Adam, Douglas, Hume, Smith, Andrew B. T. & Hebert, Paul D. N., 2019, DNA barcodes reveal 63 overlooked species of Canadian beetles (Insecta, Coleoptera), ZooKeys 894, pp. 53-150 : 53

Longitarsus lewisii Baly, 1874 Figure 42

Distribution.

Native to the Palaearctic region. Widespread in Europe, recorded throughout Eurasia to China and the Russian Far East ( Döberl 2010). Adventive in the Nearctic region (Ontario, Canada).

Canadian records.

Ontario: Cornwall, 19-Sep-2016 to 30-Sep-2016 (5 exx, CBG).

Diagnostic information

(based on Warchalowski 1996 and Rutanen and Martikainen 2014). Body length 1.7-2.3 mm. Habitus as in Fig. 42A, B , convex in dorsal view, sides of elytra rounded. Head brown, pronotum and elytra yellow-brown, elytral suture usually narrowly dark at least near midlength, legs pale, metafemora darker. Ventral side red-brown to black. Pronotum ca. 1.5 times wider than long, finely punctate. Elytra densely and finely punctate, punctures slightly larger around scutellum. Male with a narrow longitudinal impression at the middle of the last ventrite, ending in a small, sharply delimited round pit. Last ventrite of females unmodified or with a very weak impression. Penis in lateral view strongly bent towards dorsum at the apex ( Fig. 42C, D ).

Bionomic notes.

This species feeds on Plantago species, especially P. major L. ( Koch 1992, Rutanen and Martikainen 2014). In Finland, it is most often collected in dry, barren habitats ( Rutanen and Martikainen 2014). The Canadian specimens were collected with a Malaise trap in a suburban residential area.

Comments.

Longitarsus lewisii is closely related to L. pratensis (Panzer, 1794), another adventive species from the Palaearctic region ( Warchalowski 1996, Rutanen and Martikainen 2014). Longitarsus lewisii is more rounded and convex, and on average slightly larger than L. pratensis (1.7-2.3 mm vs. 1.4-2.1 mm) ( Warchalowski 1996). The elytral suture is not darkened in L. pratensis , and the hind femora are paler. However, color is variable in this species group, and the male genitalia and the modifications of the last ventrite are the best distinguishing characters. In males of L. pratensis , the impression of the last ventrite is broad, circular and less sharply delimited than in males of L. lewisii . The penis of L. pratensis is shorter than that of L. lewisii , and less strongly bent. Females of L. pratensis have an elongate-oval, shallow medial impression on the last ventrite. The preferred host plant of L. pratensis is Plantago lanceolata L., but both species use several species of Plantago ( Koch 1992; Döberl 1994; Rutanen and Martikainen 2014).

Figures

Figure 42. Longitarsus lewisii Baly A male habitus, L. Borowiec B female habitus, L. Borowiec C aedeagus, ventral view D aedeagus, lateral view. Scale bars: 1.0 mm (A, B), 0.5 mm (C, D).