Diachasmimorpha mellea (Gahan, 1915)

For additional information, see the Diachasmimorpha page.
Taxonomic History / Nomenclature
In publications prior to about 1988, the species of Diachasmimorpha were placed either in the genus Opius or in the genus Biosteres. Diachasmimorpha mellea was first transferred to Diachasmimorpha by van Achterberg and Maeto 1990.

Biosteres rhagoletis Richmond, 1915 is a synonym (Gahan 1919).

Members of the species group to which D. mellea belongs are generally characterized by weakly developed notauli (more faintly impressed posteriorly than in longicaudata and related species) and a straight ovipositor (sinuate apically in longicaudata and related species). Diachasmimorpha mellea is similar in overall appearance to Diachasma alloeum and has been reared from the same hosts and host plants. However, there is a distinct gap between the mandibles and the clypeus in Diachasma alloeum (when the mandibles are closed).
1. D. mellea body: lateral...
2. D. mellea thorax: do...
3.D. mellea abdomen: lateral
4. D. mellea thorax: lateral...
5. D. mellea thorax: dorsal...
6. D. mellea habitus: lateral...
7.D. mellea face
Native to the Nearctic Region.
Biology / Hosts
Parasitoids of fruit-infesting Rhagoletis Loew and Myoleja Rondani (Wharton and Marsh 1978).

In field experiments in Michigan, Feder observed lower rates of D. mellea parasitism in Rhagoletis pomonella that infested apples than in R. pomonella that infested hawthorne, their ancestral host fruit (Feder 1995). D. mellea females were unable to penetrate to the interior of the apples with their ovipositors, creating an enemy-free space for the fly larvae. Feder’s study confirmed the earlier observations by Porter (1928).

The species is well-studied, with detailed biologies by Lathrop and Newton (1933), and rates of parasitism by authors such as Monteith (1971, 1977).

Biology and Behavior
Univoltine, overwintering as fouth instar larvae in the host puparium. Females search for fly larvae in both attached and unattached fruit (Porter 1928, Feder 1995). Some of the earliest work on this species was published under the name Biosteres rhagoletis (Woods 1915a, Woods 1915b, Lathrop and Nickels 1932), attacking Rhagoletis in blueberries.