Ragwort Flea Beetle

The tiny Ragwort Flea Beetle feeds on Common Ragwort.

Species introduction

At a glance
Latin name: 
Longitarsus jacobaeae
Family: 
Flea or leaf beetles
Family Latin name: 
CHRYSOMELIDAE
Category: 
Insects other
Vernacular names: 

Tansy ragwort flea beetle

Species description

Species description

These insects have enlarged femurs, which is typical of flea beetles, enabling them to be strong jumpers. They can be seen all year round, although they peak in the late spring and summer months. They are widespread in Britain and reasonably common, although very difficult to spot because of their diminutive size.

There are two small insects resembling this small red beetle. One is Sphaeroderma testaceum, and the other is Longitarsus jacobaeae. Both are leaf beetles. The former feeds on thistles and has pale antennae. The latter, the Ragwort Flea Beetle, feeds on Ragwort leaves and has antennae that progressively darken towards the tips. We believe that the individual shown here, photographed by one of our keen-eyed volunteers, is a Ragwort Flea Beetle because it was spotted on a Common Ragwort plant.

Species photographs

Larger photograph(s) (click to magnify)
The tiny Ragwort Flea Beetle feeds on Common Ragwort.

Details

Species family information

Flea beetles, also known as Leaf beetles, cover between 40,000 and 50,000 different species of small beetles which are grouped into numerous sub-families. No single characteristic defines this family of insects. As with other beetles, the life-cycle includes larvae and adults, both of which feed on plant tissue. Many are pests of crops.

Category information

Insects evolved in the Ordovician from a crustacean ancestral lineage as terrestrial invertebrates with six legs (the Hexapoda). This was the time when terrestrial plants first appeared. In the Devonian some insects developed wings and flight, the first animals to do so. An early flying group was the Odonata from the Carboniferous, the damselflies and dragonflies, which have densely-veined wings and long, ten-segmented bodies. They are day-flying carnivores, with an aquatic larval stage, so are commonly seen flying near water. The carnivorous larvae are called nymphs. Odonata species are short-lived, damselflies surviving for 2-4 weeks, dragonflies for up to 2 months.

Some insect groups in the Cretaceous co-evolved with the flowering plants, and they have had a close association ever since. These groups are the Hymenoptera (bees, wasps, and ants), the Lepidoptera (butterflies and moths), the Diptera (flies), and the Coleoptera (beetles). The diversity of beetles is astonishing. Of all the known animal species on the planet, one in five is a beetle!