Parasitoids of Fruit-Infesting Tephritidae

For additional information, see the Psyttalia page.

This species was originally described as Opius concolor by Szepligeti (1910). The original description was based on material collected from olives infested with olive fly, Bactrocera oleae, in Tunisia.
Fischer (1987) later included concolor in the Opius subgenus Psyttalia.
Psyttalia was subsequently elevated to generic rank by Wharton (1987). Almost all of the biological literature on this and related species is under the generic name Opius.

See section on relationships.

During the exploration phase of the Oriental fruit fly program, and using the genus name Opius, several of the opiines from Kenya were variously identified as either perproxima or as color varieties of concolor (Clausen et al. 1965). Material from the same localities had been identified as either humilis or perproxima during an earlier sampling program (Bianchi and Krauss, 1936). Difficulty in identification of these three nominal species is still a problem (Kimani-Njogu et al. 2001, Rugman-Jones et al. 2009), and uncertainty over whether or not they are distinct makes it difficult to correctly associate previously published host records. Psyttalia concolor was originally described from Tunisia, P. humilis from Western Cape Province of South Africa, and P. perproxima from Benin, Ghana, and Nigeria in West Africa. In some of the more recent studies, populations from Kenya have been tentatively identified as P. concolor because of reproductive compatibility with populations from Italy (Kimani-Njogu et al. 2001, Wharton et al. 2000). Because the two populations are genetically distinct, however, the name humilis can be used for subsaharan populations and the name concolor for populations from the Mediterranean Region when it is useful to do so, such as in some biological control programs (Rugman-Jones et al. 2009). Laboratory studies need to be expanded to determine reproductive compatibility under field conditions to further address this problem.

Similarly, two decades after the purposeful introduction of P. concolor to Italy to control olive fly, Bactrocera oleae (Rossi), Monastero (1931) described Psyttalia siculus from Sicily as a parasitoid of B. oleae. Considerable debate ensued over whether P. siculus was actually distinct from P. concolor (Monastero, 1934; Delucchi, 1957). Fischer (1963, 1971, 1972) treated P. siculus as a subspecies of P. concolor with slightly longer ovipositor, and retained P. humilis as distinct from P. concolor “because of differences in morphology of developmental stages.”

Three other species from Africa are also difficult to distinguish from Psyttalia concolor: Psyttalia dacicida (Silvestri) reared from Bactrocera oleae in Eritrea, Psyttalia dexter (Silvestri) reared from Dacus longistylus in Senegal, and Psyttalia inconsueta (Silvestri) reared from Carpophthoromyia tritea in southern Nigeria. Almost nothing is known of these three species other than the information provided by Silvestri from his original collections made prior to 1914. Psyttalia lounsburyi (Silvestri) is also similar to concolor and the other species mentioned here but is much darker in coloration. It has been reared from olive fly infesting wild and cultivated olives in South Africa and wild olives in Kenya.

As of 2010, populations originating from Italy (concolor) and from Kenya (referred to as either “cf. concolor” or humilis) have been reared in the laboratory for about a 10 year period in Guatemala, California (where it has been released against olive fly), and Hawaii (Yokoyama et al. 2008).

Due to current taxonomic problems, some caution should be exercised in interpretation of the native distribution, as listed in the section below (see the Psyttalia humilis page).

This page was first constructed some time ago. Recent updates include:
Egypt: seasonal abundance (Abd El_Megid, E. J. and Hammad, A. K. K. 1999).
Virus-like particles in poison-glands: Jacas et al., 1997; Wharton, 1997.

Originally described from material reared from olive fly, Bactrocera oleae, infesting olives in Tunisia. Psyttalia concolor has also been reared from olive fly collected from Olea europaea cuspidata in Kenya (Copeland et al. 2004), from medfly (Ceratitis capitata) in arabica coffee in Kenya (Wharton et al. 2000, Kimani-Njogu et al. 2001, and from medfly in argan (Sapotaceae) trees in Morocco (Balachowski and Mesnil 1935, Debouzie and Mazih 1999). Psyttalia concolor is commonly mass-reared on medfly in the Mediterranean Region because medfly is easier to rear in large quantities than olive fly.

Though normally attacking and developing on third instar larvae, P. concolor successfully parasitized second instar larvae of Ceratitis capitata (Wiedemann), and first and second instar larvae of Bactrocera oleae (Rossi) in laboratory experiments (Canale 1998, Raspi and Canale 2000). See Biological Control section below for more references to the biology of this species.

Psyttalia concolor was introduced to Italy in an effort to control olive fly shortly after its discovery in Tunisia. Its early use in Italy has been well documented (Silvestri, 1922, 1938; Delucchi, 1957), as has its subsequent use in augmentation programs following development of mass rearing techniques using medfly as hosts. As a result of these efforts, there is now a considerable amount of information on the developmental biology of Psyttalia concolor, as well as other facets of its biology related to its utility for biological control of fruit pests (Poutiers and Turnetti, 1921; Canovas, 1940; Bodenheimer, 1951; Féron, 1954; Isaakides, 1955; Biliotti and Delanoue, 1959; Delanoue, 1960, 1961; Arambourg, 1962; Favard, 1964; Stavraki-Paulopoulou, 1966; Genduso, 1967; Genduso, 1969; Liotta, 1969; Cals-Usciati, 1972; Ragusa, 1974; Jimenez-Alvarez, 1977; Delanoue and Pralavorio, 1977; Kapatos et al., 1977; Canard et al, 1979; Cals-Usciati, 1982; Avilla and Albajes, 1983; Avilla and Albajes, 1984; Bigler et al., 1986; Raspi and Loni, 1994; Gonzalez et al., 1996; Loni, 1997; Canale, 1998; Tomassini Barbarossa et al., 1998; Zhang and Raspi, 1999; Raspi and Canale, 2000; Canale and Raspi, 2000; Canale, 2002; Loni, 2002; Loni, 2003; Canale, 2003; Sime et al., 2006).

A listing of P. concolor introductions to the New World for biological control, prior to 1999, is provided below, summarized from Ovruski et al. 2000. More recently, it has been introduced to California (Johnson et al. (2008)).

Puerto Rico—introduced 1935-37 against Anastrepha suspensa, A. obliqua (Muesebeck 1931).
Costa Rica—introduced in 1956 against Ceratitis capitata; specimens recovered (Hernandez 1996, Wharton et al. 1981, Vaughn 1992).
Bolivia—introduced in 1969 against C. capitata, Anastrepha spp.; specimens recovered, established (Altieri et al. 1989, Bascope 1994, Vaughn 1992).
El Salvador—introduced in 1971 against C. capitata (Hentze et al. 1993, Wharton et al. 1981).
Florida, USA—introduced 1977-79 against A. suspensa (Baranowski et al. 1993).