August 2015 - Leaf Beetles

Green Dock Leaf Beetle larvae, South Park, Bowthorpe

Rosemary Leaf Beetle at the UEA

Leaf Beetles on Ragwort flowers, Bawburgh

 

Everywhere I go I see different species of Leaf Beetle which is hardly surprising as they belong to an extremely large group of beetles in the family Chrysomelidae which comprise over 35,000 species world-wide.

In May I saw many larvae of the Green Dock Leaf Beetle in South Park, Bowthorpe; dock leaves had been decimated by their ravenous appetites, as can be seen from the photo.  The larvae are about 8mm long whilst the adult beetles are smaller (males 4mm, females slightly larger at 7mm) and are green with a glorious golden sheen. The female adult beetles have distended abdomens in the mating season which often displaces their wing cases. These beetles hardly ever fly, and over winter in the soil around their food plant. This species of beetle is common and can be found anywhere where there is dock.

Flea Leaf Beetles are commonly seen by the River Yare from late spring. These are interesting small creatures (about 4mm long) which jump when touched, hence their name. They have extra muscles on their hind legs, which also helps in their identification. The ones at the UEA are a magnificent blue-green metallic colour, but again they are veracious feeders. The adult beetles hibernate around the roots of plants.

Rosemary Leaf Beetles are also to be found by the River Yare at the UEA.  These 6-7mm long metallic beetles are striped purple-green. The adults mate and lay eggs in late summer, and these hatch into greyish-white larvae with darker stripes running down their bodies. Both larvae and  adults feed from autumn through to spring in mild weather. The larvae, which when fully grown are about 8mm long, pupate in the soil, and the adult beetles emerge in early summer, although feeding does not really start in earnest until later on in the year. The adult beetles tend to be long lived and so generations may overlap each other, and the adults may be found at any time of year.  

Never before have I seen such numbers of a tiny (about 2mm long) black shiny leaf beetle which are feeding on flowers everywhere you look (our garden has a plague of them!). They seem particularly fond of yellow or sweet smelling flowers. Has anyone else noticed these particular flower-eating Leaf Beetles? Does anyone know their name?

 

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lingibson@bawburghvillage.co.uk