US Federal List: no special status
CITES: no special status
Agasicles hygrophila are important as a biological control agent of alligator weed. Alligator weed is an invasive exotic plant to North America, New Zealand, Australia, and several Asian countries. It became an invasive by being transported in the ballast water of ships from South America. It grows in dense mats that crowd out native vegetation and block the passage of light through the water. These mats interfere with the function of the invaded habitat, navigation, recreation, flood control, and rice production.
Agasicles hygrophila is used in the biological control of Alligatorweed because it is the primary consumer of Alligatorweed. In Florida, introduced populations of A. hygrophila were so effective in controlling Alligatorweed that 3 years after its introduction the U.S. Army Corps of Engineers canceled all herbicide sprays of the plant.
Positive Impacts: controls pest population
Agasicles hygrophila feeds on alligator weeed (Alternanthea philoxeroides) almost exclusively, but will occaisonally feed on Polygonaceae, which is a closely related plant family to alligator weed. Adults feed on young foliage, while larvae feed on stems and eat the lower surface of the leaves (they also prefer young leaves).
Plant Foods: leaves; wood, bark, or stems
Primary Diet: herbivore (Folivore , Lignivore)
The alligatorweed flea beetle naturally inhabits southern Brazil and northern Argentina along waterways. It has been introduced to the southern United States.
Biogeographic Regions: nearctic (Introduced ); neotropical (Native )
The alligatorweed flea Beetle is naturally restricted to waterways where the plant Alternanthera philoxeroides (the alligator weed) grows. Agasicles hygrophila require a steady temperature of 20 - 30 degrees Celsius.
Habitat Regions: tropical ; terrestrial ; freshwater
Aquatic Biomes: lakes and ponds; rivers and streams
Other Habitat Features: riparian
Adult beetles are between 4 and 7 mm long, and about 2 mm wide . Head and thorax are shiny and black in color. Adult elytra (forwings) are characterized by black and yellow longitudinal stripes, and they also have greatly enlarged hind femora for jumping. Mature larvae are up to 6 mm long and are black. Eggs are cream colored at deposition and gradually become yellowish (or pale orange-yellow) in color.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Females lay eggs 6 days after emergence. Females may lay up to 1000 eggs, and they deposit the eggs in masses on the undersides of alligatorweed leaves. The eggs are arranged in 2 parallel rows to form a zigzag pattern. Eggs hatch after 4 days (at diurnal temperatures between 20-30°C with sustained high humidity, while the larval stage generally lasts 8 days. Pupation takes place in the hollow stem of the plant.
Range eggs per season: 1000 (high) .
Key Reproductive Features: sexual ; fertilization (Internal ); oviparous
Agasicles hygrophila is a species of leaf beetle known by the common name alligator weed flea beetle. It has been used successfully as an agent of biological pest control against the noxious aquatic plant known as alligator weed (Alternanthera philoxeroides).
This beetle is native to South America but has been imported to areas where alligator weed is a problem. The adult beetle is 5 mm in length and black with yellow stripes on its elytra. The female lays about 1,000 eggs in her six-week lifetime. Millimeter-long eggs are laid in rows on leaves, and the small yellow larvae emerge and eat the leaves. Adults also feed on the leaves. Defoliation of alligator weed mats kills the weed and clears the infested waterway. This beetle is established in much of the southeastern United States, where it lives on alligator weed only.[2]
The beetle has been used as a biological control of alligator weed in New Zealand.[3]
Agasicles hygrophila is a species of leaf beetle known by the common name alligator weed flea beetle. It has been used successfully as an agent of biological pest control against the noxious aquatic plant known as alligator weed (Alternanthera philoxeroides).
This beetle is native to South America but has been imported to areas where alligator weed is a problem. The adult beetle is 5 mm in length and black with yellow stripes on its elytra. The female lays about 1,000 eggs in her six-week lifetime. Millimeter-long eggs are laid in rows on leaves, and the small yellow larvae emerge and eat the leaves. Adults also feed on the leaves. Defoliation of alligator weed mats kills the weed and clears the infested waterway. This beetle is established in much of the southeastern United States, where it lives on alligator weed only.
The beetle has been used as a biological control of alligator weed in New Zealand.
