A flea beetle is any small, jumping beetle of the leaf beetle family (Chrysomelidae) that is part of the tribe Alticini, which is part of the subfamily Galerucinae. Historically the flea beetles were classified as their own subfamily.

Traditionally, the Alticini were separated from other Galerucinae by the presence of jumping hind legs, characterised by enlarged femora containing a spring structure allowing the flea beetles to jump. Recent phylogenetic studies suggest that jumping hind legs evolved multiple times in the Galerucinae, rather than once, and that several genera should be transferred between Alticini and Galerucinae sensu stricto (or Galerucini in some classifications).

Description and ecology 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. The jumping mechanism of flea beetles has been studied extensively. One study looked at several species of flea beetles, including the Altica cirsicola species, and described the jumping mechanism of these beetles to be very efficient. This study even applied the knowledge gained from the flea beetles to create a preliminary design for a bionic leg that can jump. Flea beetles can also walk normally and fly. Many flea beetles are attractively colored; 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 (e.g. of Phyllotreta species) 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 behavior of hiding in the soil.

Relationship with humans Flea beetles may be beneficial or may be pests, depending on the species.

Pest

Many major agricultural crops are attacked by flea beetles, including various cruciferous plants such as mustard and rapeseed. Numerous garden plants are also subject to flea beetle feeding, such as flowers of Gardenia and Rothmannia by Altica species.

Flea beetles execute their most severe attacks during dry weather and are most active on sunny days. The larvae are known to chew roots.

Companion plant

Flea beetles can be deterred by a number of different companion plants, that can be grown intercropped in a garden to benefit neighboring plants. For example, thyme, catnip, and other kinds of mint cover up the scent of nearby plants.

Radishes, on the other hand, can be grown as a trap crop, luring the flea beetles away from more important crops. Since the root isn't harmed by the beetles, they remain useful, themselves.5 Secrets to Vegetable Garden, Companion Planting Revealed

A number of natural predators can be employed to keep flea beetles in check, including two that parasitize it: braconid wasps and tachinid flies. In both cases, the larval stage feeds on the flea beetle, while the adults feed on nectar and pollen; some species are even important pollinators. To encourage braconid wasps and tachinid flies, some types of flowers can be planted between crops: umbels such as caraway, herb fennel, coriander and Ammi majus, and simple open flowers such as California poppies and pot marigolds, as well as yarrows.

Beneficial insect 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 virgata), 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.

Selected genera This genus list is not complete. It is also partially from ITIS and might include genera placed elsewhere in other sources.

Acallepitrix J.Bechyné, 1956 Acrocyum Jacoby, 1885 Afroaltica Biondi & D'Alessandro, 2007 Agasicles Jacoby, 1904 Altica Geoffroy, 1762 Andersonoplatus Linzmeier & Konstantinov, 2018 Anthobiodes Weise, 1887 Aphthona Chevrolat in Dejean, 1836 Aphthonoides Jacoby, 1885 Apteropeda Chevrolat in Dejean, 1836 Argopistes Motschulsky, 1860 Argopus Fischer von Waldheim, 1824 Arrhenocoela Foudras, 1861 Asphaera Duponchel & Chevrolat, 1842 Aulacothorax Boheman, 1858 Batophila Foudras, 1860 Blepharida Chevrolat in Dejean, 1836 Capraita J.Bechyné, 1957 Cerataltica Crotch, 1873 Chaetocnema Stephens, 1831 Cornulactica Bechyné, 1955 Crepidodera Chevrolat in Dejean, 1836 †Crepidocnema Moskeyko et al., 2010 Derocrepis Weise, 1886 Dibolia Latreille, 1829 Disonycha Chevrolat in Dejean, 1836 Distigmoptera Blake, 1943 Dysphenges Horn, 1894 Epitrix Foudras in Mulsant, 1859 Glenidion H.Clark, 1860 Glyptina J.L.LeConte, 1859 Hemiglyptus Horn, 1889 Hemiphrynus Horn, 1889 Hermaeophaga Foudras, 1860 Heyrovskya Madar & Madar, 1968 Hippuriphila Foudras in Mulsant, 1859 Hornaltica Barber, 1941 Kashmirobia Konstantinov & Prathapan, 2006 Kuschelina J.Bechyné, 1951 Lanka Maulik, 1926 Longitarsus Berthold, 1827 Luperaltica Crotch, 1873 Lupraea Jacoby, 1885 Lysathia J.Bechyné, 1957 Lythraria Bedel, 1897 Mantura Stephens, 1831 Margaridisa J.Bechyné, 1958 Minota Kutschera, 1859 Mniophila Stephens, 1831 Mniophilosoma Wollaston, 1854 Monomacra Chevrolat in Dejean, 1836 Neocrepidodera Heikertinger, 1911 Nesaecrepida Blake, 1964 Nisotra Baly, 1864 Ochrosis Foudras, 1861 Oedionychis Latreille, 1829 Omophoita Chevrolat in Dejean, 1836 Orestia Chevrolat in Dejean, 1836 Pachyonychis H.Clark, 1860 Pachyonychus F.E.Melsheimer, 1847 Palaeothona Jacoby, 1885 Parchicola J.Bechyné and B.Springlová de Bechyné, 1975 Phydanis Horn, 1889 Phyllotreta Chevrolat in Dejean, 1836 Podagrica Chevrolat in Dejean, 1836 Pseudodibolia Jacoby, 1891 Pseudolampsis Horn, 1889 Pseudorthygia Csiki in Heikertinger and Csiki, 1940 Psylliodes Berthold, 1827 Sphaeroderma Stephens, 1831 Strabala Chevrolat in Dejean, 1836 Stuckenbergiana Scherer, 1963 Syphrea Baly, 1876 Systena Chevrolat in Dejean, 1836 Trichaltica Harold, 1876 Ugandaltica D'Alessandro & Biondi, 2018

See also List of flea beetle genera

References

External links

Flea beetle description at Kansas State University The Handbook of Palearctic Flea Beetles - identification of Palearctic flea beetle genera, along with morphology, host plant information, and literature references "Flea Beetles" by W.S. Cranshaw, Colorado State University Extension entomologist and professor