The Flea beetle

Sep 06, 2009 Features / Columnists, Interesting Creatures in Guyana

Adult flea beetles feed externally on plants

The Flea beetle is a general name applied to the small, jumping beetles of the leaf beetle family (Chrysomelidae). This beetle species is in fact one of the insect species that has been known to attack local plant life such as the Boulanger plant.
They make up the tribe Alticini, which is a part of the subfamily Galerucinae, though they were historically classified as a subfamily in their own right. Though most tribes of the Galerucinae are suspect of rampant paraphyly in the present delimitation, the Alticini seem to form a good clade at least for the most part.
The adults are very small to moderately sized Chrysomelidae (i.e. among beetles in general they are on the smallish side). They are similar to other leaf beetles, but characteristically have the hindleg femora greatly enlarged. These enlarged femora allow for the springing action of these insects when disturbed. Flea beetles can also walk normally and fly. Many flea beetles are attractively coloured; dark, shiny and often metallic colors predominate.
Adult flea beetles feed externally on plants, eating the surface of the leaves, stems and petals. Under heavy feeding the small round holes caused by an individual flea beetle’s feeding may coalesce into larger areas of damage. Some flea beetle larvae are root feeders.
In adverse weather conditions (rain, for example) some flea beetles seek shelter in the soil. Some species, such as Phyllotreta cruciferae and P. striolata, prefer to leave their hideouts only during warm and dry weather. The German name Erdflöhe (literally “earth fleas”) refers to their jumping ability and this behaviour of hiding in the soil.
Flea beetles may be beneficial or may be pests, depending on the species. Many major agricultural crops are attacked by flea beetles, including various cruciferous plants such as mustard (particularly canola in north western North America). Numerous garden plants are also subject to flea beetle feeding, such as flowers of Gardenia and Rothmannia by Altica species.
Other flea beetle species are beneficial, feeding on weeds and similar nuisance plants. A few species have even been introduced to various locations as biological control agents against some weeds. One important example is in the control of Leafy Spurge (Euphorbia esula), an invasive weed in the United States. It has a toxic latex and is generally avoided by herbivores. Flea beetles of the genus Aphthona have been successfully introduced to control this plant.
Beetles are the group of insects with the largest number of known species. Forty percent of all described insect species are beetles (about 350,000 species), and new species are frequently discovered. Estimates put the total number of species, described and undescribed, at between five and eight million. The largest family also belongs to this order, the weevils, or snout beetles, Curculionidae.
Beetles can be found in almost all habitats, but are not known to occur in the sea or in the polar regions. They interact with their ecosystems in several ways. They often feed on plants and fungi, break down animal and plant debris, and eat other invertebrates. Some species are prey of various animals including birds and mammals.
(Source: Wikipedia – The Free Online Encyclopedia)