''Amitus hesperidum '' is a tiny species of

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The ent ...

wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder ...

. It is a

parasitoid In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...

of the citrus blackfly, ''Aleurocanthus woglumi'', an important 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 ...

trees. It is a native of Asia but has been introduced to many other parts of the world as a means of controlling the citrus blackfly.Nguyen R. (August 2008). Citrus blackfly parasitoid, Amitus hesperidum Silvestri. Featured Creatures. EENY-243.
/ref>

Distribution

This wasp is a native of India, Sri Lanka, Pakistan, Hong Kong, Sichuan, Java and Malaysia. It has been introduced to Guam, Venezuela, Mexico and the United States (Texas, Florida and Hawaii) for the purpose of controlling the citrus blackfly.Silvestri F. 1927. Contribuzione alla conoscenza degli Aleurodidae (Insecta: Hemiptera) viventi su citrus in Extremo Oriente e dei loro parasiti. Boll. Lab. Zool. Portici. 21: 1-60.

Description

Both males and females have a shiny black

thorax The thorax (: thoraces or thoraxes) or chest is a part of the anatomy of mammals and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main di ...

and

abdomen The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...

less than one millimetre long. The antennae have ten segments and in the female, the last three are widened making the antennae club-shaped. The males have longer antennae of a uniform width, curved, with all segments longer than they are wide and covered with short bristly hairs. Both antennae and legs are straw coloured and the hind tarsi have five segments. The wings are shiny and translucent.

Life cycle

Several offspring may develop inside a single host but this species is not

polyembryonic Polyembryony is the phenomenon of two or more embryos developing from a single fertilized egg. Due to the embryos resulting from the same egg, the embryos are identical to one another, but are genetically diverse from the parents. The genetic differ ...

. The

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the ...

s are laid in any of 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 stages of the citrus blackfly but the first

instar An instar (, from the Latin '' īnstar'' 'form, likeness') is a developmental stage of arthropods, such as insects, which occurs between each moult (''ecdysis'') until sexual maturity is reached. Arthropods must shed the exoskeleton in order to ...

is preferred. A female larval host results in the production of two or three adult wasps but parasitism of a male

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 ...

produces only one. Parasitism of a female pupa may result in either a male or a female adult wasp. The time taken for an egg to develop into an adult varies from 45 to 60 days under laboratory conditions at a temperature of 27 °C. The wasps live for three to five days in the field during which time the female can produce up to sixty eggs. This wasp is well synchronized with its host and is capable of controlling dense populations of the pest. However it is not good at searching out scattered individuals and its numbers decrease sharply as its host population is controlled. Other hosts which are also parasitised include ''Aleurocanthus citriperdus'' and ''Aleurocanthus spiniferus''.Smith HD, Maltby HL, Jimenez EJ. 1964. Biological control of the citrus blackfly in Mexico. U.S. Department of Agriculture Technical Bulletin 1311: 1-30.

Use in biological control

''Amitus hesperidum'' was introduced into Mexico in the 1960s in an attempt to control the numbers of citrus blackfly there. Suppression of the pest was so successful that introductions were also made into Florida in 1978 and into Texas in 1983. ''

Encarsia perplexa ''Encarsia perplexa'' is a tiny parasitic wasp, a parasitoid of the citrus blackfly, ''Aleurocanthus woglumi'', which is a global pest of citrus trees. It was originally misidentified as ''Encarsia opulenta'', but was recorded as a new specie ...

'' is another citrus blackfly parasitoid that has been used alongside ''Amitus hesperidum'' to control the pest in both states. ''E. perplexa'' multiplies more slowly but is better at scouting for outlying blackflies and is more effective when populations of potential hosts are lower. In Hawaii, both species were introduced in 1999 after the citrus blackfly was discovered there for the first time the previous year. They rapidly became established and were soon controlling the pest on the island of Oahu. Later releases on other islands in the group have also been an effective means of reducing infestations.State of Hawaii: Department of Agriculture
/ref>

References

{{Taxonbar, from=Q4746951 Platygastridae Insects used as insect pest control agents Biological pest control wasps Insects described in 1927 Taxa named by Filippo Silvestri