Longitarsus jacobaeae
Encyclopedia
Longitarsus jacobaeae is a species of flea beetle
known as the tansy ragwort flea beetle. It is used as an agent of biological pest control
against the noxious weed known as ragwort (Senecio jacobaea).
The adult beetle is light golden brown in color and between 2 and 4 millimeters long. The female is larger than the male, especially when gravid
. The beetle has enlarged femurs
for its main locomotion method of hopping. The female lays eggs on or near the ragwort, its host plant. The larva
emerges in about two weeks and burrows into the ground to feed on the roots. The larvae and adults are dually responsible for damage to the plant. The adult defoliates plants which are often already weakened by larval damage at the roots. This two-pronged attack is quite successful in preventing ragwort growth and development. The beetles have prevented entire populations of ragwort from reaching flowering stage at several monitored sites.
The beetle is not choosy about the genera in which it feeds from, and recent studies with the beetle have shown "that selection pressure by specialist herbivores is not likely a driving force in evolutionary diversification" of the plants which contain the alkaloids that the beetle dines on.
This beetle is native to Eurasia. It was first introduced to the United States as a ragwort biocontrol agent in 1969 and it is now established in much of the western United States.
The beetle is most effective when used in conjunction with the cinnabar moth
(Tyria jacobaeae), another ragwort biocontrol agent. The beetle is not known to attack other plants. A close relative, Longitarsus ganglbaueri, which also feeds on ragwort, does attack other plant species; it is not used as a biocontrol agent for this reason.
Flea beetle
Flea beetles is a general name applied to the small, jumping beetles of the leaf beetle family . 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...
known as the tansy ragwort flea beetle. It is used as an agent of biological pest control
Biological pest control
Biological control of pests in agriculture is a method of controlling pests that relies on predation, parasitism, herbivory, or other natural mechanisms...
against the noxious weed known as ragwort (Senecio jacobaea).
The adult beetle is light golden brown in color and between 2 and 4 millimeters long. The female is larger than the male, especially when gravid
Gravidity
In medicine, gravidity refers to the number of times a woman has been pregnant, regardless of whether the pregnancies were interrupted or resulted in a live birth....
. The beetle has enlarged femurs
Arthropod leg
The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments are of Latin origin, and may be confused with terms for bones: coxa , trochanter , femur, tibia, tarsus, ischium, metatarsus, carpus, dactylus ,...
for its main locomotion method of hopping. The female lays eggs on or near the ragwort, its host plant. The larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
emerges in about two weeks and burrows into the ground to feed on the roots. The larvae and adults are dually responsible for damage to the plant. The adult defoliates plants which are often already weakened by larval damage at the roots. This two-pronged attack is quite successful in preventing ragwort growth and development. The beetles have prevented entire populations of ragwort from reaching flowering stage at several monitored sites.
The beetle is not choosy about the genera in which it feeds from, and recent studies with the beetle have shown "that selection pressure by specialist herbivores is not likely a driving force in evolutionary diversification" of the plants which contain the alkaloids that the beetle dines on.
This beetle is native to Eurasia. It was first introduced to the United States as a ragwort biocontrol agent in 1969 and it is now established in much of the western United States.
The beetle is most effective when used in conjunction with the cinnabar moth
Cinnabar moth
The Cinnabar moth is a brightly coloured arctiid moth, found in Europe and western and central Asia. It has been introduced into New Zealand, Australia and North America to control poisonous ragwort, which its larvae feed on. The moth is named after the red mineral cinnabar because of the red...
(Tyria jacobaeae), another ragwort biocontrol agent. The beetle is not known to attack other plants. A close relative, Longitarsus ganglbaueri, which also feeds on ragwort, does attack other plant species; it is not used as a biocontrol agent for this reason.