Zaprionus tuberculatus (commonly known as the vinegar fly or the pomace fly) is a member of the subgenus and genus Zaprionus, family Drosophilidae, and order Diptera. It is an invasive fruit fly that originated in Africa, but can also be found in Europe and Asia. The fly earned its common name, the "vinegar fly", because researchers frequently captured the species using vinegar traps. Z. tuberculatus was previously considered a strictly tropical fly, but evidence of invasion to nontropical regions such as Turkey has been shown.
This fly typically resides on rotting fruit, and the larvae have been found to develop on 49 species of fruits. The life cycle of the fly depends on the temperature of the environment as males are sterile at or above 30 degrees Celsius. It is reddish-brick colored and contains four longitudinal stripes down its head and body. The courtship behavior includes song singing and complex dance rituals. In regard to other organisms, Z. tuberculatus is considered a secondary pest to fruit and a potential threat to ecosystems it invades. A close relative, Z. indianus is an invasive fly species that infests fig orchards.
Taxonomy
Zaprionus tuberculatus was first discriminated from its close relative Z. sepsoides in the 1970s. Z. tuberculatus has recently classified as a member of the Tuberculatus species subgroup and is a member of the inermis species group. Previously, Z. tuberculatus was classified as a member of the armatus group. The genus Zaprionus if primarily found throughout Africa and contains 59 species, the most common of which being Z. indianus and Z. tuberculatus. The 59 species of the genus Zaprionus are divided into two subgroups: Afrotropical Zaprionus sensu stricto (s.s.), to which Z. tuberculatus belongs, and Anaprionus near Asia and Australia. Within the Zaprionus sensu stricto (s.s.) subgenus are several further subgroups, including the armatus subgroup to which Z. tuberculatus belonged until 2010.
Description
Zaprionus tuberculatus contains four white horizontal stripes across its head and thorax, similar to other members of the Zaprionus subgroup. The males bear hairs on its forelegs. Both male and female flies have a protruding bristle from the forefemur. The frons have a medium-white stripe and the aedeagus is robust and curved and they have a dark-brown colored thorax. Two white, aligned, horizontal lines characterize the mesonotum and metanotum. Z. tuberculatus shares several common features with other members of the genus Zaprionus, including a completely smooth larval cephalopharyngeal.
Reproductive system
Between individual flies, siblings are distinguished by testicular size (TST), for which the mean is 3.2mm. The average seminal recepaical (SR) of a female fly is 3.6mm.
Distribution
Zaprionus tuberculatus, originally from islands near the Indian Ocean and Afrotropical Region, then became invasive and expanded geographically to southern Europe. Within the Afrotropical region, the species has been reported in Mauritius, Réunion, Madagascar, Saint-Helena, Cape Verde, and Seychelles . The species had first been reported in Europe in Italy September, 2013. Z. tuberculatus has also been reported in North Africa, Malta, Cyprus, and the Canary Islands. Z. tuberculatus was trapped in Eastern Europe in Southern Romania between September and October 2014. Z. tuberculatus has been reported in a few other areas of Europe, including Spain, Greece, and Northern Italy. Z. tuberculatus has also been reported in Asian regions, including Israel and southern Turkey.
Habitat
Zaprionus tuberculatus typically reside on rotting fruit and has been captured via the use of vinegar traps, which earned the species its nickname "vinegar fly." The fly does not thrive in strictly tropical environments.
Ecology
Zaprionus tuberculatus is an invasive species, meaning its spread from one geographical region to other may harm to existing ecosystems.
Life cycle
Zaprionus tuberculatus life cycle varies depending on the temperature of the environment. Zaprionus tuberculatus males are sterile at or above 30 degrees Celsius. The mean Z. tuberculatus female life span varies from about 40 days to 60 days, whereas the mean male lifespan varies from about 50 to 200 days when temperature is varied.
Egg
The eggs of Z. tuberculatus have four filaments, with the posterior filaments being elongated more than the anterior filaments and are spatulated. The lengths of these filaments vary within species.