African Fig Fly

Appearance

The characteristic black and white 'zebra' stripes of this genus have two different origins. In the simplest form, the white stripes are caused by an absence of the pigment in the cuticle. This mechanism is found in species of the subgenus Anaprionus. The absence of pigmentation also occurs in the species of the subgenus Zaprionus, probably complemented by a separate mechanism. In these species, the white stripes contain many long and bent trichomes (fine outgrowths) that have a groove and contain two cavities, polarizing the light. The black stripes are caused by pigmentation.

Physical characteristics in the Drosophilidae species range widely, but there are some that are typical of this family. All flies possess a minute anal cell in the wing, an incomplete subcostal vein with two breaks in it, and postocellar hairs; three of these quills usually rest on either side of the head.

The species Zaprionus indianus Gupta displays a unique pair of white stripes from the antennae to the end of the thorax on its dorsal side; two black lines of equal width straddle each white line. This species is a yellow color and around 3.5 mm in length.

The Drosophila suzukii is a light yellow to brown color, exhibits large red eyes, and in appearance seems very similar to the common fruit fly (Drosophila melanogaster). [8] Females possess a bulky, toughened, jagged ovipositor, but no combs on their anterior feet like the males of this species. [9] Both males and females display continuous black bands on their abdomen. Males are notable by the darkened section on the tips of each wing. This species averages 2-3mm in size.

The Rhagoletis indifferens, commonly referred to as the western cherry fruit fly is 5mm in size and on its wings exhibits a dark arrangement of bands.

Distribution

Members of this genus can be found in the tropics of most continents. The species of the subgenus Zaprionus are found primarily in Africa, while the species of the subgenus Anaprionus are found in Southeast Asia. Two species, Zaprionus ghesquierei and Zaprionus indianus have expanded their range in recent times. Zaprionus ghesquierei has invaded Hawaiʻi,[ while Zaprionus indianus has expanded its range though the Middle East towards India and more recently crossed the Atlantic Ocean and colonized both South and North America.

Habitat

Zaprionus species are found in a wide array of habitats from semi-deserts to the tropical rain forest. Most species breed on fruits, flowers or decaying tree trunks.

Reproduction

Drosophilids deposit their eggs in flowers, fungi, fruit, sap fluxes, or decomposing vegetation by penetrating the surface and laying the egg(s) within. Characteristics in species differ in the number of eggs a female will oviposit at a time; some species lay just one, while others may lay hundreds. The sites where eggs are oviposited also vary. The international species, Drosophila busckii, has been known to breed from lettuce leaves in Victoria and leaves of pea plants in Japan. The Spotted Wing Drosophila uses her hefty, jagged ovipositor to puncture the skin of fruit and lays the eggs inside. These eggs will hatch and allow the larva to begin feeding on the fruit; this food source enables the maggots to develop. The steady consumption of the fruit causes it to spoil and become damaged, which can provide an opening for infection.

Drosophilidae species are formed of post-mitotic cells, possess a brief life span of one to several weeks varying on the climate temperature [15], and display incrementally ageing Due to the short life cycle of fruit flies, they must rapidly reproduce to sustain their population. A Spotted Wing Drosophila may have between 10-15 generations in the year and 2-3 generations during the cherry season. This species is most active at 68oF; when temperatures surpass 86oF the adult males become sterile and activity is reduced. In a Drosophila culture media of a continuous 25oC, the Zaprionus indianus Gupta lived an average of 82 days for the males and 93 days for the females, with a maximum of 150 days. The females’ average number of offspring was 58, with a highest total being 105. The time span from egg fertilization to a grown adult was 19 days.