Chrysolina fastuosa (Scopoli, 1763)

Douglas, Hume B, Smith, Tyler W & Bouchard, Patrice, 2023, Palaearctic leaf beetle Chrysolina fastuosa (Coleoptera, Chrysomelidae, Chrysomelinae) new to North America, Biodiversity Data Journal 11, pp. 103261-103261 : 103261

Chrysolina fastuosa (Scopoli, 1763)

Diagnosis

Chrysolina fastuosa is 5.0-6.0 mm long and can be recognised in Canada and USA as belonging to genus Chrysolina by its elongate apical maxillary palpomere, non-connate tarsal claws and metallic elytral colouration ( Riley et al. 2002). It can be distinguished from other North American Chrysolina by its acute (Fig. 1 , E) ventro-apical projection of protarsomere 5 ( Rheinheimer and Hassler 2018 -misinterpreted as bidentate tarsal claws, Wilcox 1972). The apex of protarsomere 5 is uniformly narrowed in all other species with no projection. It is also distinguished by the non-concave anterior edges of the compound eyes. It has a brighter metallic green colouration than perhaps any native North American Chrysomelinae , blue metallic at the elytral suture and, in many, also a median longitudinal orange metallic area on the basal 2/3 of each elytron. The truncate aedeagal apex (Fig. 3 ) is somewhat like C. inornata (Rogers, 1856), but distinguished by its median projection.

Individuals of C. fastuosa can be distinguished from the similar-looking eumolpine, C. auratus by their non-flared metatibial apices without projections. Chrysochus auratus is also larger (6.5-10.0 mm) and also has a raised bead at the posterior edge of the prothorax that is greater than 2/3 the width of the base of antennomere 2. In C. fastuosa , any visible bead is less than half as wide as the base of antennomere 2. In C. fastuosa , antennomere 3 is longer than antennomere 4, while antennomere 4 is longer in C. auratus .

Distribution

PB collected two specimens of C. fastuosa (Figs 1 , 2 , 3 ) at the following locality in Canada: Nova scotia: Dartmouth, Lawnsdale Drive Park Trail 44.683, -63.570. Both are deposited at the CNCI (2023), with database Specimen ID numbers CNC1989589 and CNC1989590. Forty-seven additional individuals were seen in 43 citizen-science observations from Nova Scotia, Canada and Vermont, USA ( iNaturalist contributors and iNaturalist 2023, Simpson et al. 2023). These photos were each identified by iNaturalist contributors as being of C. fastuosa and were confirmed by HD to match C. fastuosa and no other North American chrysomelid species. We present specimen and photographic evidence of 64 individuals from multiple sites in Nova Scotia Canada and Vermont USA, separated by over 900 km over 11 years. These led us to conclude that at least two populations of C. fastuosa are established in North America. We expect that these are the only two large populations in North America because this is a conspicuous, day-active species that is apparently readily documented by iNaturalist users.

Chrysolina fastuosa is known from the following localities in North America (Fig. 4 ). Canada: Nova Scotia. Antigonish County: 45.623 -61.993. Colchester County: Truro, 45.358 -63.263; Coldstream, 45.070 -63.317; Colchester, 45.225 -63.317; Wittenburg, 45.110 -63.233. Guysborough County, Guysborough, 45.350 -61.406. Halifax County: Brookvale, 45.037 -63.085; Dartmouth, 44.647 -63.536; 44.675 -63.484; 44.705 -63.532; 44.664 -63.544; 44.680 -63.562; 44.695 -63.561; 44.695 -63.561; 44.699 -63.561; Halifax, 44.59 -63.553; 44.796 -62.676; 44.643 -63.598; - 44.667 -63.563; - 44.689 -63.501; - 44.691 -63.422; - 44.800 -63.46; 44.604 -63.517; 44.636 -63.5938; Lawrencetown, 44.669 -63.391; Porters Lake, 44.748 -63.298; Seaforth, 44.663 -63.296; 44.663 -63.296; 44.664 -63.296. Pictou County: Pictou, - 45.450 -62.743; White Hill, 45.488 -62.757; 45.488 -62.758. USA: Vermont. Caledonia County: East Hardwick, 44.468 -72.238. Orange County: Bradford, 44.044 -72.197; 44.044 -72.197; Strafford 43.843 -72.374; 43.841 -72.381; USA 43.873 -72.350; Strafford, 43.875 -72.351; Vershire, 43.940 -72.337; 43.941 -72.337. Washington County: Plainfield, 44.233 -72.374; - 44.286 -72.573. Windsor County: Sharon, 43.785 -72.454.

Notes

The external morphology and male genitalia of the Canadian specimens closely matched taxon concepts of C. fastuosa . Specimens were confirmed as C. fastuosa using Mohr (1966) and Rheinheimer and Hassler (2018) and in comparison with specimens from the Canadian National Collection of Insects Arachnids and Nematodes (CNCI) identified by M. Daccordi (Italy), J.C. Bourdonné (France) and R. de Ruette (Ottawa). As the only member of the subgenus Chrysolina Fastuolina Warchalowski, 1991 ( Kippenberg 2010), C. fastuosa is unlikely to be confused with any other species.

Figures

Figure 1. Morphology of a male of Chrysolina fastuosa from Nova Scotia, Canada. A dorsal habitus. B ventral habitus. C lateral habitus. D anterior view of head. E lateral view of protarsomere showing ventro-apical projection (arrow). Scale bars: 5 mm (A-D); 0.5 mm (D, E). Images, K. Savard, AAFC.

Figure 2. Habiti of a female of Chrysolina fastuosa from Nova Scotia, Canada. A dorsal. B ventral. C lateral. Scale bar: 5 mm. Images, K. Savard, AAFC.

Figure 3. Genitalia of Chrysolina fastuosa from Nova Scotia, Canada. A Male aedeagus, lateral view. B Aedeagus, dorsal view. C Aedeagus, ventral view. D Female spermatheca. E Aedeagus, apex in ventral view. Scale bars: 0.5 mm. Images, K. Savard, AAFC.

Figure 4. Map of vouchered record and citizen-science records of Chrysolina fastuosa from eastern Canada and USA.