Aphytis mytilaspidis
Encyclopedia
Aphytis mytilaspidis is a species
of chalcid wasp
in the Aphelinidae
family. The adults feed on scale insects and the larvae are ectoparasites of scales.
family, Chloropulvinaria psidii and Pulvinaria psidii in the Coccidae
family and many armoured scales in the Diaspididae
family. In Serbia this species is an ectoparasitoid of Epidiaspis leperii, an armoured scale insect found on fruit trees.
and then sucking out the juices with its feeding tube. Although Lepidosaphes ulmi
seems to be the preferred host in New Zealand, this wasp has been reported as being the most common parasitoid attacking Quadraspidiotus ostreaeformis.
The adult female lands on a scale and palpates it several times with her antennae working from the centre towards the edge. She then thrusts her ovipostor through the scale and deposits an egg beside the soft body of the scale insect. The larva feeds on this and moults three times before becoming a prepupa. It is protected during this time by the scale and completely consumes the insect. After pupation, the adult wasp emerges through an oval hole in the scale. There are several generations of the wasp each year and it overwinters in the larval stage. The female can lay between thirty and sixty eggs during her lifetime.
Males are unknown in this species and the adults are all females. During reproduction, the eggs remain unfertilised and thus have half the number of chromosomes of a normal cell. It has been shown that diploidy is restored by terminal fusion. After the first stage of meiosis
, the pronucleus
fuses with its sister polar nucleus, thus restoring the correct number of chromosomes.
in 1983 in an attempt to control Melanaspis glomerata on sugar cane but did not become established. In California, this wasp has been used successfully to control fig scale (Lepidosaphes conchiformis). In Mediterranean areas it is used against oystershell scale (Lepidosaphes ulmi) and in many countries against pine needle scale (Phenacaspis pinifoliae) and aspidistra scale (Pinnaspis aspidistrae).
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of chalcid wasp
Chalcid wasp
Chalcid wasps belong to the insect order Hymenoptera, and are one of the largest groups within the order, with some 22,000 known species, and an estimated total diversity of anywhere from 60,000 to more than 500,000 species, meaning the vast majority have yet to be discovered and described.Most of...
in the Aphelinidae
Aphelinidae
Aphelinidae is a moderate-sized family of tiny parasitic wasps, with some 1160 described species in some 35 genera. These minute insects are challenging to study as they deteriorate rapidly after death unless extreme care is taken , making identification of most museum specimens difficult...
family. The adults feed on scale insects and the larvae are ectoparasites of scales.
Distribution
Aphytis mytilaspidis occurs in Europe and much of Asia, in South Africa, North America, Mexico, Argentina and Chile. It was first recorded in New Zealand in 1935.Description
The adult Aphytis mytilaspidis is yellowish-orange and about two millimetres long. It has transparent wings and two compound and three simple black eyes.Host species
Aphytis mytilaspidis parasitises a number of scale insects including Asterolecanium pustulans, Asterolecanium variolosum in the AsterolecaniidaeAsterolecaniidae
Asterolecaniidae is a family of scale insects commonly known as pit scales or asterolecaniids. They typically cause a depression in the host plant's tissues and often cause distortion of the shoots. They are found on a range of hosts but are especially common on oaks, bamboos and a number of...
family, Chloropulvinaria psidii and Pulvinaria psidii in the Coccidae
Coccidae
The Coccidae are a family of scale insects belonging to the superfamily Coccoidea. They are commonly known as soft scales, wax scales or tortoise scales. The females are flat with elongated oval bodies and a smooth integument which may be covered with wax. In some genera they possess legs but in...
family and many armoured scales in the Diaspididae
Diaspididae
Diaspididae is the largest family of scale insects with over 2650 described species in around 400 genera. As with all scale insects, the female produces a waxy protective scale beneath which it feeds on its host plant...
family. In Serbia this species is an ectoparasitoid of Epidiaspis leperii, an armoured scale insect found on fruit trees.
Biology
Aphytis mytilaspidis is a solitary wasp whose life history is closely linked to its host scale insects. The adult female feeds by piercing the scale with its ovipositorOvipositor
The ovipositor is an organ used by some animals for oviposition, i.e., the laying of eggs. It consists of a maximum of three pairs of appendages formed to transmit the egg, to prepare a place for it, and to place it properly...
and then sucking out the juices with its feeding tube. Although Lepidosaphes ulmi
Lepidosaphes ulmi
Lepidosaphes ulmi also known as apple mussel scale or oystershell scale is a scale insect that is a pest of trees and woody plants...
seems to be the preferred host in New Zealand, this wasp has been reported as being the most common parasitoid attacking Quadraspidiotus ostreaeformis.
The adult female lands on a scale and palpates it several times with her antennae working from the centre towards the edge. She then thrusts her ovipostor through the scale and deposits an egg beside the soft body of the scale insect. The larva feeds on this and moults three times before becoming a prepupa. It is protected during this time by the scale and completely consumes the insect. After pupation, the adult wasp emerges through an oval hole in the scale. There are several generations of the wasp each year and it overwinters in the larval stage. The female can lay between thirty and sixty eggs during her lifetime.
Males are unknown in this species and the adults are all females. During reproduction, the eggs remain unfertilised and thus have half the number of chromosomes of a normal cell. It has been shown that diploidy is restored by terminal fusion. After the first stage of meiosis
Meiosis
Meiosis is a special type of cell division necessary for sexual reproduction. The cells produced by meiosis are gametes or spores. The animals' gametes are called sperm and egg cells....
, the pronucleus
Pronucleus
A pronucleus is the nucleus of a sperm or an egg cell during the process of fertilization, after the sperm enters the ovum, but before they fuse. Sperm and egg cells are haploid, meaning they carry half the number of chromosomes...
fuses with its sister polar nucleus, thus restoring the correct number of chromosomes.
Biological control
Aphytis mytilaspidis was introduced into MauritiusMauritius
Mauritius , officially the Republic of Mauritius is an island nation off the southeast coast of the African continent in the southwest Indian Ocean, about east of Madagascar...
in 1983 in an attempt to control Melanaspis glomerata on sugar cane but did not become established. In California, this wasp has been used successfully to control fig scale (Lepidosaphes conchiformis). In Mediterranean areas it is used against oystershell scale (Lepidosaphes ulmi) and in many countries against pine needle scale (Phenacaspis pinifoliae) and aspidistra scale (Pinnaspis aspidistrae).