Synonyms and other taxonomic changes
Disonycha pensylvanica (Illiger)
Orig. Comb: Haltica pensylvanica Illiger, 1807
Det. M. A. Quinn, 2010
The three species of the D. pensylvanica - group are not always safely identified - last hope is male genitalia, in some cases.
Common features: Head completely, or for the most part, black; pronotum reddish, usually with central dark spot (+ lateral spots casually); elytra always with pure black & white stripe pattern, black stripes wider than white ones.
Following characteristics work in most cases:
- head, legs, antennae always black, also underside, except last ventral segment of abdomen;
(dorsal segments red, however!);
- elytra indistinctly punctured, clearly costate in females;
- elytral sutural and sublateral black stripes united at tip;
- pronotum with one central macula, which may become enlarged to cover most of pronotum;
- 5-6.5 mm body length.
. . . . full combination not found; especially, elytral sutural and sublateral black stripes usually shortly interrupted at tip by reddish zone:
- head usually red around antennal sockets;
- legs may have red femora;
- all ventral segments of abdomen with red margin;
- elytra clearly punctured, not costate in females;
- pronotum with a central macula and two smaller lateral spots (may fuse, but not disappear);
- 5.8-8 mm body length.
- head usually red anteriour of antennal base;
- legs usually with red femora, also tibiae can be partly red;
(dark varieties with legs all dark occur)
- abdomen usually completely red;
- elytra finely punctured, +/- costate in females;
- pronotum with 0 -5 spots (may fuse);
- 5.6-6.8 mm body length.
Canada: PQ,ON; eastern US w to Il/AL and LA,TX / s to C. Amer. (2)
For the most part found near aquatic habitats (1)
mostly: May-Aug (BG data)
Normal hosts are Polygonum
spp. including smartweed (Polygonaceae) (3)(4)