Flea beetles | |
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Phyllotreta vittula with characteristic feeding damage to Brassicaceae leaf | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Coleoptera |
Infraorder: | Cucujiformia |
Family: | Chrysomelidae |
Subfamily: | Galerucinae |
Tribe: | Alticini Newman, 1834 [1] |
Genera | |
Many, see text |
The flea beetle is a small, jumping beetle of the leaf beetle family (Chrysomelidae), that makes up 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). [2] [3]
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. [4] 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. [4] This study even applied the knowledge gained from the flea beetles to create a preliminary design for a bionic leg that can jump. [4] 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.
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 and rapeseed (particularly canola in northwestern North America). 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. [5]
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. [6]
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. [7]
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. [8]
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.
This genus list is not complete. It is also partially from ITIS and might include genera placed elsewhere in other sources.
The Galerucinae are a large subfamily of the leaf beetles (Chrysomelidae), containing about 15,000 species in more than 1000 genera, of which about 500 genera and about 8000 species make up the flea beetle tribe Alticini.
Catherine N. Duckett is the Associate Dean of the School of Science at Monmouth University. Formerly she worked as Associate Director of the Office for the Promotion of Women in Science, Engineering and Mathematics, and the Program Manager of the Ocean Biogeographic Information System at Rutgers University, as well as a former Associate professor of Biology at University of Puerto Rico at Rio Piedras. She is also a prominent systematic entomologist, specializing in the phylogeny of flea beetles, and an adjunct professor at Rutgers.
Altica is a large genus of flea beetles in the subfamily Galerucinae, with about 300 species, distributed nearly worldwide. The genus is best represented in the Neotropical realm, well represented in the Nearctic and Palearctic, but occurs also in the Afrotropic, Indomalaya, and Australasia. The species are similar to each other, small metallic blue-green-bronze beetles, often distinguished from each other only by the aedeagus. The species of Altica, both as larvae and as adults, are phytophagous, feeding on plant foliage of various food plant taxa, specific for each Altica species. Onagraceae and Rosaceae are the dominant host plant families for Holarctic species. The adult Altica beetles are able to jump away when approached.
Phyllotreta undulata, known generally as the small striped flea beetle or turnip flea beetle, is a species of flea beetle in the family Chrysomelidae. It is found in Australia, Europe and Northern Asia, North America, and Oceania.
Eumolpini is a tribe of leaf beetles in the subfamily Eumolpinae. It is the largest tribe in the subfamily, with approximately 170 genera found worldwide. Members of the tribe almost always have a longitudinal median groove on the pygidium, which possibly helps to keep the elytra locked at rest. They also generally have a subglabrous body, as well as appendiculate pretarsal claws.
Luperini is a tribe of skeletonizing leaf beetles in the family Chrysomelidae. There are more than 30 genera and 500 described species in Luperini.
Acallepitrix is a genus of flea beetles in the family Chrysomelidae. There are more than 20 described species in Acallepitrix. They are found in the Neotropics, Central America, and North America.
Aulacothorax is a genus of leaf beetles in the family Chrysomelidae. There are currently 51 described species in Aulacothorax found worldwide, 40 of which are found in the Indomalayan realm. Historically considered a problematic member of the tribe Alticini, the genus is now classified in its own tribe, Serraticollini.
Asphaera is a genus of flea beetles in the family Chrysomelidae, containing some 130 species, found in North America, Central America, and the Neotropics.
Phyllotreta liebecki is a species of flea beetle in the family Chrysomelidae. It is found in North America.
Blepharida is a genus of leaf beetles of the subfamily Galerucinae. They have co-evolved with plants in the genus Bursera, which they feed on. The plants have developed a sticky, poisonous resin that sprays out when the leaves are bitten into, and the beetles have evolved to cut through the veins of the leaves to disable this mechanism first. There are currently 73 known species in Blepharida, which are found in the Nearctic, Neotropical, Afrotropical and southern Palearctic realms.
Coelomera is a genus of beetles belonging to the family Chrysomelidae.
Podontia is a genus of flea beetles in the family Chrysomelidae. They belong in the Blepharida-group of flea beetles.
Macrohaltica is a genus of flea beetles in the family Chrysomelidae. There are about 20 described species in Macrohaltica, found in Central and South America.
Cacoscelis is a genus of flea beetles in the family Chrysomelidae, found in southern North America, Central America, and South America.
Walterianella is a genus of flea beetles in the family Chrysomelidae. There are more than 40 described species in Walterianella. They are found in Central and South America.
Nisotra is a genus of flea beetles in the family Chrysomelidae. They are found in Africa, Asia, and Australia. There are around 90 described species in Nisotra, including about 70 in Sub-Saharan Africa and Madagascar. Many of these species are agricultural pests.
Stuckenbergiana is a genus of flea beetles belonging to the family Chrysomelidae. There is a single described species, Stuckenbergiana glabrata, which is found in South Africa.