TYT.LThome / Insecta · vabzdžiai / Coleoptera · vabalai / Chrysomelidae · lapgraužiai / Cassida viridis · žaliasis skydinukas

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  • green tortoise beetle
  • Grøn skjoldbille, Stor skjoldbille
  • Grüne Schildkäfer
  • isokilpikuoriainen
  • žaliasis skydinukas
  • muntschildpadtor, groen schildpadtorretje, groene schildkever
  • tarczyk zielony

This is the only member of the subgenus Odontionycha Weise, 1891. A transpalaearctic native distributed from Portugal through North Africa and Asia Minor to Japan, and recently discovered to have been introduced into Canada as early as 1974. Adults occur year-round, overwintering in tussocks and moss etc. and becoming active from April to October or November. Host plants include various species of Mentha (mints) as well as a range of Lamiaceae including Nepeta (cat mint), Lycopus (gypsywort), Stachys spp. (woundworts), Galeopsis spp. (Hemp nettles) and Sativa spp. (clarys). Typical habitats include wetland and marginal environments where the hosts thrive. Adults spend a few weeks feeding upon host foliage and possibly also pollen before mating in April and May and ovipositing from May to July. Between 1 and 10 eggs laid in oöthecae which are stuck to stems or under lower leaves and covered with frass and leaf fragments, they hatch within 6 to 10 days and the larvae initially feed below the leaves, moving to the upper surface as they grow, they pass through 5 instars and development is rapid; they are fully grown within 4 to 6 weeks. The larvae are very distinctive; broadly oval and only weakly convex, greyish-green with darker margins and a row of 16 pale long branched spines along each lateral margin and relatively short and broad urogomphi. This species does not carry the ‘faecal shield’ used by other Cassida species for disguise. Pupation occurs from June to September, fully grown larvae move to stems and petioles and become attached by a secretion before they pupate, and this stage is also brief, generally lasting about a week, and new generation adults eclose from July to October.

7-10 mm; distinct species; elongate-oval with the base of the elytra much wider than the base of the pronotum. Entirely matt green, fading to greyish-yellow in dry preserved specimens, the underside, including the head, is black but for pale abdominal borders. The lags are pale and the antennae are dark with sharply-defined pale basal segments. The extent of the dark underside colouration varies; in ab. nigriceps Fairmaire, 1851 it is extensively pale, and in ab. flaviceps Marseul, 1876 it is entirely pale. In Europe the dorsal surface varies from typical green to dark brown and some specimens have the femora darkened. The pronotum is transverse with rounded posterior angles and a weakly sinuate basal margin which is flattened in front of the scutellum; the punctation is random; rather fine and dense on the disc becoming larger and confluent laterally. Elytra smoothly rounded with wide explanate margins and rounded, projecting shoulders which are distinctly wider than the pronotum. The suture and the lateral margins are strongly bordered, and the punctation random, dense and strong.

Išauga iki 8,5–10 mm dydžio. Kūnas neįprastai plokščias, ovalus. Krūtinės sritis ir antsparniai žali, be žymių, kurios būdingos kitoms Cassida rūšims. Apatinė dalis juoda. Kojos ir palyginti trumpos antenos yra rudos. Savo kūno spalva ir forma puikiai prisitaikę būti sunkiai pastebimais tarp žalių augalų. Šie mimikriniai vabalai sutinkami balandžio–spalio mėn. Lervų kūnas su daug ataugų, apsigynimui nuo priešų ir parazitų paprastai kartu su savimi ant nugaros tampo maišelį su ekskrementais ir išnaromis.

Vabalas žiemoja miškingose vietovėse, sausoje žolėje po medžiais ir krūmais. Prabunda balandžio pabaigoje – gegužės pradžioje, migruoja prie mitybinių augalų. Apkramto lapų kraštus arba išėda skyles, kartais pažeidžia jaunų lapų kotus. Pasimaitinę poruojasi ir pradeda dėti kiaušinėlius. Vaisingumas siekia 150–200 kiaušinėlių. Lervos masiškai pasirodo birželio–liepos mėn. Jos įsitaiso aptinėje lapo dalyje, graužia lapalakščio apatinį sluoksnį, palikdamos epidermį, kuris po to džiūdamas suplyšta. Ant augalų maitinasi 20–30 parų. Prieš tapdama lėliuke, lerva prisitvirtina kūną prie lapo apačios ir kabo žemyn galva. Ši stadija trunka 6–9 paras. Naujos kartos vabalai išlenda birželio pabaigoje – rugpjūčio pradžioje, maitinasi apie 10–15 parų, po to sulenda į žiemavietes. Per metus vystosi viena generacija. Daugiausiai minta notreliniais (Lamiaceae) augalais.