Gymnoclytia sp

Gymnoclytia sp. female
Tachinid Fly

Family: Tachinidae
Subfamily: Phasiinae
Length: typically about 4 mm

Unlike flies in the related genus Gymnosoma, flies in Gymnoclytia have a pair of crossed bristles at the apex of the scutellum. Also in contrast to Gymnoclytia , in Gymnoclytia the pedicel and first antennal segment are short.

One interesting trait of Gymnoclytia flies is that the females, shown on this page, are covered with gray pubescence, while in male Gymnoclytia the pubescence is golden. Both males and females have very distinct sutures between the terga.

Gymnoclytia are parasites of Stink Bugs. Apparently both larval and adult Pentatomids are parasitized by flies in the genus Gymnoclytia. Some Gymnoclytia spp. also parasitize Lepidoptera larvae, both Noctuid moth caterpillars and Pierid butterfly caterpillars.

Of the six Nearctic species of Gymnoclytia, five have ranges that include or may include West Virginia: G. dubia, G. immaculata, G. minuta, G. occidua,and G. uniclolor. Only G. occidentalis is a strictly western species, ranging from British Columbia to New Mexico (O’Hara and Woods, 2004).

Gymnoclytia sp. male
Tachinid Fly

Family: Tachinidae
Subfamily: Phasiinae
Length: typically about 4 mm

One key trait of the genus Gymnoclytia is a pair of crossed bristles at the apex of the scutellum. Also look for unusually distinct tergal sutures.

In this genus males have an abdomen that is usually golden tomentose, while in female Gymnoclytia spp. the abdomen is gray tomentose.

Gymnosoma sp.
Tachinid Fly

Family: Tachinidae
Subfamily: Phasiinae
Length: typically 5 to 7 mm

Flies in the genus Gymnosoma lay their eggs in Hemipteran hosts (True Bugs), on both nymphs and adults. Eggs are large and disk-shaped, and are attached to the host insect’s integument. When development of the embryo is completed, the hatchling burrows into the host.

D.M. Wood, in his treatment of the Tachinidae in McAlpine (1987), noted that all genera in the subfamily Phasiinae save one, lay unincubated eggs on Hemiptera. He added, “This is virtually the sole justification of the taxon.” Morphologically the Phasiinae genera are quite different from each other. (By “unincubated” eggs, Wood was drawing a distinction with other Tachinids where the eggs undergo development within the female fly’s body.)

Gymnosoma flies lack bristles at the apex of the scutellum, in contrast to the closely related genus Gymnocyltia, where there is a pair of apical bristles that cross each other.

In most species of Gymnosoma the abdomen is reddish orange with black markings. On the abdomen the short hairs extend from a raised base giving the abdomen a rough, though shiny, appearance. The pedicel and first antennal segment are elongate.