Descriptive anatomy of the fruit fly Phortica variegata Fallén, 1823 (Diptera: Drosophilidae)

Some fruit flies of the genus Phortica feed on lachrymal fluid of mammals and can transmit the eyeworm Thelazia callipaeda . Phortica variegata is a confirmed vector of the eyeworm in Europe, which primarily infects dogs, foxes and other mammals, including humans. There is a lack of anatomical data on P. variegata . We have addressed this knowledge gap by subjecting ten uninfected laboratory-reared specimens (six males and four females) to µCT scanning, using the data to generate three-dimensional models of one male and one female specimen. We also subjected the same male and female specimens to histological sectioning and dissected two further specimens. We describe the anatomy of the internal organs of P. variegata and compare it with that of Drosophila melanogaster . The digestive tracts are highly similar but the reproductive tracts of both male and female P. variegata have notable differences from those of D. melanogaster . In addition, the thoracic and abdominal ganglion are separate structures. The data on the anatomy of P. variegata provide a baseline for future experimental infection studies and will allow us to study the life cycle of T. callipaeda by locating its developmental stages inside the arthropod vector.