''Aphytis melinus'' is an internal parasite of the California red scale, ''

Aonidiella aurantii ''Aonidiella aurantii'' or red scale is an armored scale insect and a major Pest (organism), pest of citrus. It is thought to be a native of South China but has been widely dispersed by the agency of man through the movement of infected plant ma ...

'', which is a pest of

citrus ''Citrus'' is a genus of flowering trees and shrubs in the family Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, mandarins, lemons, grapefruits, pomelos, and limes. ''Citrus'' is nativ ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

and elsewhere. This wasp drums its antennae against the

scale insect Scale insects are small insects of the Order (biology), order Hemiptera, suborder Sternorrhyncha. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the infraorder Coccomorpha which is considered a more convenient g ...

to find out if it is healthy, if it is already parasitized, how large it is, etc., to decide how to use this prey. It has four choices (from worst to best): leave the scale to keep searching, feed directly on the scale, use the scale as a host for a male ''A. melinus'', or use the scale for a female ''A. melinus''. If it accepts the scale as a host, the female will lay an egg in the host. When the egg hatches, the

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

l wasp consumes the internal organs of the pest. When finished with its host, the larva enters the

pupa A pupa (; : 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 life cycle, the stages th ...

l, or cocoon, stage. From the pupa emerges the

adult An adult is an animal that has reached full growth. The biological definition of the word means an animal reaching sexual maturity and thus capable of reproduction. In the human context, the term ''adult'' has meanings associated with social an ...

wasp, smaller than the scale it consumed, which goes off in search of more scale insects. This beneficial insect has controlled a key pest in citrus, significantly reducing

pesticide Pesticides are substances that are used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others (see table). The most common of these are herbicides, which account for approximately 50% of all p ...

use on citrus in California.

References

Aphelinidae Insects described in 1959 Biological pest control wasps {{Chalcidoidea-stub