''Chrysolina quadrigemina'' is a species of

beetle Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...

of the family

Chrysomelidae The beetle family Chrysomelidae, commonly known as leaf beetles, includes over 37,000 (and probably at least 50,000) species in more than 2,500 genera, making it one of the largest and most commonly encountered of all beetle families. Numerous s ...

. The species was described by Christian Wilhelm Ludwig Eduard Suffrian in 1851. It is native to Europe and North Africa. It feeds on ''

Hypericum perforatum ''Hypericum perforatum'', commonly known as St. John's wort (sometimes perforate St. John's wort or common St. John's wort), is a flowering plant in the family Hypericaceae. It is a hairless, Perennial, perennial herb with woody Root, roots, y ...

'' and other members of the genus. This plant is an introduced invasive pest in North America and Australia. The beetle was introduced in these regions as a

biological control Biological control or biocontrol is a method of controlling pests, whether pest animals such as insects and mites, weeds, or pathogens affecting animals or plants by using other organisms. It relies on predation, parasitism, herbivory, or o ...

Description

''Chrysolina quadrigemina'' completes one lifecycle each year. They start with egg laying in the fall laying their eggs on the undersides of leaves of new fall basal growth on its host plant, St. John's Wort (''

''). The larvae feed on the plants at night for around one month before burying themselves in the soil to pupate. In this time they will often completely destroy the fall growth of their host plant. The insects remain in individual pupation chambers over the winter. In late spring the adults emerge to feed heavily on the plants just before or after they begin flowering, approximately April or May in California. They feed until high summer when they enter a period of hibernation (

aestivation Aestivation ( (summer); also spelled estivation in American English) is a state of animal dormancy, similar to hibernation, although taking place in the summer rather than the winter. Aestivation is characterized by inactivity and a lowered m ...

). Usually they find small crevices, hide under stones, or in soil cracks. In the fall they emerge to mate and begin the cycle again.

References

Chrysomelinae Biological pest control beetles Taxa named by Christian Wilhelm Ludwig Eduard Suffrian Beetles described in 1851 {{Chrysomelinae-stub