Mediterranean fruit fly, Medfly
Ceratitis capitata, commonly known as the Mediterranean fruit fly or medfly, is a yellow-and-brown fly native to sub-Saharan Africa. It has no near relatives in the Western Hemisphere and is considered to be one of the most destructive fruit pests in the world. There have been occasional medfly infestations in California, Florida, and Texas that require extensive eradication efforts to prevent the fly from establishing itself in the United States.
C. capitata is the most economically important fruit fly species because of both its ability to survive cooler climates more successfully than most other fruit fly species and its ability to inhabit more than 200 tropical fruits and vegetables to which it causes severe destruction and degradation. The practices that are used to eradicate the medfly after its introduction into a new environment can be extremely difficult and expensive, but infestation of C. capitata lowers crop yields and induces costly sorting processes for fresh fruits and vegetables.
The Geographic Distribution Map of C. capitata provides information on the distribution of the Mediterranean fruit fly, C. capitata, throughout the world. The information is mainly based on available Mediterranean fruit fly national surveillance reports. Therefore, the map displays assessments of the presence of this pest at the national level and in some cases at sub-national levels. According to this map, C. capitata is present throughout Africa, South and Central America, the Middle East, and Southern Europe. It has been confirmed to be absent in much of North America, the Indian subcontinent, some parts of South America, and most of Australia. Climate change might have role in modifying the distribution and abundance of C. capitata.
The four stages of the C. capitata life cycle are the egg, larvae, pupae and adult stages. Female medflies oviposit in groups of roughly 10–14 eggs and deposit them just under the skin surface of their host fruit. Once the eggs are deposited below the skin, they hatch in only a few days, emerging as maggots, or larvae. C. capitata flies are known to disperse up to distances of 12 miles in search of host fruit. In the instances where host fruit is plentiful in their current locations, they will not disperse beyond 300 to 700 feet.
The lifespan of the C. capitata is quite short as half of most populations die in under 60 days. However, cool conditions and proper sustenance can enable some flies to live 6 months or up to a year. In lab conditions, under controlled diets of sugar and protein, the life expectancy of females is usually longer than that of males by 1.5 days. On average, the lifespans of flies in captivity are 10 days longer than those of wild flies.
The lifespans of certain species are also affected by periods of food deprivation, which is a key driver of invasion success, adaptation, and biodiversity. Starvation resistance is a plastic trait that varies due to the relation between environmental and genetic factors. Recent studies into the starvation resistance (SR) of C. capitata has found that SR decreases with increasing age and that age-specific patterns are shaped in relation to adult and larval diet. Furthermore, females exhibited higher SR than males, and the greatest influence on SR in C. capitata was due to age and adult diet followed by gender and larval diet.
Among fruit fly species, C. capitata has the largest variety of host-fruits, including over 200 different types of fruits and vegetables. These fruits include but are not limited to akee, star apple, oranges, grapefruit, guava, mango, plum, and pears. C. capitata in the adult and larval stage feed in different ways.
Studies have shown that wild C. capitata flies were found to partake in more head-butting behavior, direct opponent contact, and less likely to cede an occupied leaf to an invader. Furthermore, it was found that sounds that are produced during body vibration constitutes threat behavior. Aggressive sounds are substantially higher in pitch (roughly around 1–3 kHz) while sounds produced during non-aggressive moments such as courtship times tended to be around 0.16–0.35 kHz. Aggressive behaviors can be observed during the courtship ritual. If the approaching fly is discerned to be an intruder male fly, the resident male fly terminates his calling position and lunges towards the intruder, physically pushing the intruder with his head. This interaction lasts until either party loses position or eventually leaves the position. Males can also partake in passive defensive actions which consists of a "face-off" with the intruder male rather than a physical "head-butt". Males in the "face-off" position can last up to 5 minutes until one male eventually turns and leaves the territory.
