''Exapion ulicis'' (formerly ''Apion ulicis'') is a species of straight-snouted weevil known by the general common name Gorse Seed Weevil. It is used as an agent of

biological pest control Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also invo ...

against

Common Gorse ''Ulex europaeus'', the gorse, common gorse, furze or whin, is a species of flowering plant in the family Fabaceae, native to the British Isles and Western Europe. Description Growing to tall, it is an evergreen shrub. The young stems are g ...

(''Ulex europaeus''), which is classified as a

noxious weed A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is injurious to agricultural or horticultural crops, natural habitats or ecosystems, or humans or liv ...

in some countries. The adult weevil is light gray in color with a long snout half as long as its body. It is 2 to 3 millimeters long in total. The adult feeds on gorse by digging into the soft tissue of the stem and spines with its snout, creating characteristic round holes as evidence. The

larva A larva (; plural larvae ) 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. The ...

does more damage, however. It emerges from its egg inside the gorse seed pod and feeds on the seeds for six to eight weeks. The larva then

pupa A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their ...

tes for about two months. This weevil is native to western Europe. It was first introduced to

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

in 1931 and to

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

as an agent of gorse control in the 1950s. It is currently established in gorse populations in the western United States and in

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

. Destruction of seeds may reduce the spread of gorse, which is the main method of biological control by this weevil. It does not eliminate existing stands of the plant, since the adults do not do enough damage to destroy or significantly weaken whole plants.

References

* Coombs, E. M., et al., Eds. (2004). ''Biological Control of Invasive Plants in the United States''. Corvallis: Oregon State University Press, 179.

External links

hear.org Photo gallery
Brentidae Insects used for control of invasive plants Biological pest control beetles Beetles of New Zealand Beetles described in 1771 {{Brentidae-stub