12 Bactrocera Species That Pose a Threat to Florida: B. Carambolae and B

12 Bactrocera Species that Pose a Threat to Florida: B. carambolae and B. invadens Aldo Malavasi,1 David Midgarden2 and Marc De Meyer3 1Medfly Rearing Facility – Moscamed Brasil, Juazeiro, Bahia, Brazil; 2USDA/APHIS, Guatemala City, Guatemala; 3Royal Museum for Central Africa, Tervuren, Belgium 12.1 Introduction point, (e.g., a backyard or garden tree) to adjacent areas and commercial groves. Tephritidae is one of the largest families of 2. High natural ability of dispersion. Some fru- Diptera and contains more than 500 genera and givorous fruit fly species are good flyers and can 4000 species, divided into three subfamilies disperse quickly and in large number when suita- (White and Elson-Harris, 1992; Norrbom et al., ble host trees are not available or are out of sea- 1999). Tephri tidae pests are particularly impor- son. Well-fed adults – males and females – can fly tant because of their ability to invade regions large distances in search of reproductive and ovi- far from their native distribution. Introduced position sites or just for shelter. Experiments populations attack commercial fruit species, using the mark-release-recapture methodology which causes countries imp orting fruit to have shown that either males or females can impose quarantine regulations (McPheron and travel many kilometers when the environment is Steck, 1996). These restrictions can inhibit the inadequate. In addition, being physically strong, sale of produce and the development or expan- the adults can be carried large distances by wind, sion of fruit production in the areas in which the hurricanes and masses of warm air, a fairly com- pest species are established. mon phenomenon in the atmosphere. Because of As their name implies, many members of such events, Japan keeps a trapping network in the family are frugivorous (feed on fruit), and the the southernmost island of its archipelago, close most important pest species have a high capacity to Taiwan. The distance between Taiwan and the to disperse to and colonize new areas. There are Yonaguni Island is 180 km. Japan is a fruit fly- three major characteristics that give Tephritidae free country as it had conducted a large eradica- a status of good potential invasive species: tion program some decades ago and Taiwan remains infested by some species of Bactrocera. 1. A large and rapid rate of population growth. Although the distance is large the Japanese This allows many Tephritid species to increase Ministry of Agriculture, Forestry and Fisheries their population size dramatically in a short trapping system occasionally captures Bactrocera period of time. In addition to the increase in den- adults in the islands close to the strait. sity, one or few gravid females can rapidly infest a 3. High anthropogenic dispersion. In fruit fly large number of hosts, expanding the geographic species, the egg and larval stages are necessarily distribution of the population from a single inside a fresh fruit. It is not always possible to 214 © CAB International 2013. Potential Invasive Pests of Agricultural Crops (ed. J. Peña) Bactrocera Species that Pose a Threat to Florida 215 distinguish when a fruit is infested with eggs or APHIS would carry out 100% of inspections at Los larvae of fruit fly. Some fruits, such as guavas Angeles International Airport for all arriving inter- (Psidium guajava L.), carambolas (Averrhoa caram- national flights for at least 1 day. The result was boa L.) and oranges (Citrus spp.) usually do not that in 24 h of full inspection, 73 fruit fly larvae reveal any external evidence that they are infested were intercepted. Considering this number for one unless in advanced ripe stage. Others, such as full year, it is estimated that more than 25,000 lar- apple Malus × domesticum, peaches Prunus persica vae are brought into California every year. L. and papayas Carica papaya L. show in early stages that they are infested. 12.2 Host Range and Colonization Due to these characteristics, many infested Ability fruits can be carried by people traveling large distances. In some cultures (e.g., Latin America, South-East Asia and sub-Saharan Africa), it is Tephritids can be categorized by the number of quite common for people to carry fresh fruit as an fruit species that they attack. Monophagy refers easy source of food, since it is ready for consump- to attacks on a single fruit species; oligophagy tion at any time. Therefore, fruit infested with refers to attacks on different host plants belong- fruit fly eggs or larvae can travel very large dis- ing to the same plant family; polyphagous flies tances, because the cultural habit of people is infest many fruit species belonging to different associated with the modern transportation sys- families. Polyphagous flies have the potential to tem, allowing a large number of immature insects invade new territory when compared with mono- to move distances that would be impossible by or oligophagous flies. For example, the medfly, natural flight. This was the case for B. carambolae, C. capitata, is now a cosmopolitan species that the carambola fruit fly (CFF) (Fig. 12.1), intro- infests more than 300 host plants (Liquido et al., duced in Suriname in the north of South America 1991). The origin of medfly is sub-Saharan Africa in the early 1970s, and discussed in Section 12.3, and it was probably brought to Europe by naviga- as well as for the introduction of the invasive tors in the 17th or 18th centuries. fruit fly B. invadens into Africa. B. dorsalis, the Oriental fruit fly, and Many outbreaks of fruit flies follow a similar B. cucurbitae, the melon fruit fly, occur in the pattern. Every year, Mediterranean fruit fly or med- Hawai’ian Archipelago and are categorized as fly (Ceratitis capitata) and B. dorsalis, the oriental being polyphagous and oligophagous, respec- fruit fly (OFF) are brought into California, USA, by tively. The record of outbreaks of these two travelers bringing fruits from infested countries. species in California, USA, is around 10:1, giving Either returning US tourists or foreigners bringing a good measure of the relative aggressiveness of their preferred fruits to the USA are the most com- both species. mon sources of fruit fly detections in California. In 1993, it was suggested by a Scientific Advisory Panel of the Medfly Program in California that 12.3 Carambola Fruit Fly, Bactrocera carambolae The carambola fruit fly (CFF) (Fig. 12.1), is a native of Indonesia, Malaysia and Thailand, and was first collected in South America in 1975 in Paramaribo, Suriname. The flies collected were not identified and CFF was not found again until 1981 when specimens were sent to the US Department of Agriculture and identified as Dacus dorsalis, the OFF. Although the OFF is one of the world’s most serious pests, no action was taken at that time. In 1986, the international community realized that the presence of OFF in Fig. 12.1 Bactrocera carambolae adults. Suriname would represent an important threat 216 A. Malavasi et al. to the production and marketing of fruit through- small infestations of several B. dorsalis complex out tropical and subtropical America and the species have been found in Chile and the USA in Caribbean Basin Region. The fly was later found California and Florida, but action by respective to be a separate but closely related species from federal and state authorities prevented perma- the OFF, B. carambolae, the CFF. nent establishment. Unsurprisingly, there are direct ties between For much of the 20th century, the OFF has Suriname and the native area of CFF, as both been held responsible for enormous losses to Suriname and Indonesia are former colonies of fruit and vegetable crops throughout Asia and The Netherlands. Today the country has an esti- South-East Asia (Drew and Hancock, 1994). mated 450,000 inhabitants, 15% of whom are Doubts about the singularity of this species began descending from Indonesian colonizers from Java in the 1950s and 1960s (Hardy, 1969) and Drew in the early 20th century. Suriname maintains and Hancock (1994) have now identified 52 mor- strong ties with The Netherlands and > 90% of phologically and behaviorally similar species in trade and travel is with that country. During the what they term the B. dorsalis complex. Forty of colonial period and even after the independence these species are newly described. CFF is the in 1972, the Dutch KLM was the only airline to member of this complex (Drew, 1989) that has operate flights to and from Suriname. established in South America. When Drew and Hancock reviewed the tephritids in Asia, the OFF in Suriname was identified as a species that occurred in Thailand and 12.3.2 Biology Indonesia and which attacked carambola, and was classified as B. carambolae. Mating By 1998 it was clear (Malavasi et al., 2000) that the route of CFF introduction into South There are two basic strategies that have been America was a traveler from Indonesia flying identified in tephritid mating (Prokopy, 1980; from Djakarta to Amsterdam and then from Shelly and Kaneshiro, 1991): (i) resource guard- Amsterdam to Paramaribo in a 12,000-km jour- ing, where the males stake out territory on a ney. The distance between South-East Asia resource such as a host fruit, and (ii) lekking, a (where CFF occurs naturally), and the north of grouping of males of a species for the purpose of South America, does not allow an introduction by attracting females (Sivinski and Burk, 1989; the regular maritime shipping lines. Drew, 1987). Females are attracted to these leks Lack of funding and coordination among the when they are physiologically prepared for mat- international community allowed the fly to ing. Mating in B. carambolae occurs just before expand its geographic distribution.

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