Tansy Beetle (Chrysolina graminis)
Taxonomy |
Kingdom: | Phylum: | Class: | Order: | Family: | Genus: | Species: |
Animalia |
Arthropoda | Insecta | Coleoptera | Chrysomelidae | Chrysolina | C.graminis |
This is a lovely beetle with striking metallic greenish colouration. Its name in English points to the species' host plant, tansy, which is the source of food for the adults and larvae. Chrysolina graminis measures 7.7 to 11.6mm in length. The beetle occurs in most of Europe, including in Great Britain, and in Asia, as far as China. It is listed as vulnerable in Austria, Denmark, Sweden and Norway, and in Germany it is rare in one district, endangered in another. This beetle was once very widespread in Britain but nowadays it can be found only in York and Cambridgeshire. Formally designated as 'Nationally Rare' and categorised as a 'Species of Principal Importance'. In the Netherlands the is is still quite common.
Adults mate between March and June. Mating sesssion can last over 24 hours during which the beetle hardly moves to another spot. This is and ideal opportunity for the photographer to capture the insect really well. The female lays eggs on the underside of tansy leaves. The elongated eggs are yellowish, 2mm long. The female sometimes destroys eggs of another female by eating them up. Between August and September, the new adult population of the season comes out from hiding to feed before returning underground in October to overwinter.