New species of Dacini continue to be discovered and described, and some previously established species names are synonymized as more molecular data become available. A brief taxonomic history of Bactrocera is provided in San Jose et al. (2018)San Jose et al. (2018):
San Jose M, Doorenweerd C, Leblanc L, Barr N, Geib S, Rubinoff D, 2018. Incongruence between molecules and morphology: A seven-gene phylogeny of Dacini fruit flies paves the way for reclassification (Diptera: Tephritidae). Molecular Phylogenetics and Evolution 121: 139–149. https://doi.org/10.1016/j.ympev.2017.12.001 , including an explanation of the confusion surrounding the genus names Bactrocera, Strumeta, Dacus, and Zeugodacus, which have frequently been mixed in the literature. Globally leading taxonomists for Dacini have been Dr. Richard (Dick) Drew and Dr. David Hancock. Dr. Drew published a large revision of Australasian Dacini in 1989 (Drew 1989Drew 1989:
Drew RAI, 1989. The tropical fruit flies (Diptera: Tephritidae: Dacinae) of the Australasian and Oceanian regions. Memoirs of the Queensland Museum 1: 1–521.), which is still a standard work for Australian Dacini. Further momentous publications included a revision of all Asian Dacini with 123 newly described species (Drew and Romig 2013Drew and Romig 2013:
Drew RAI, Romig MC, 2013. Tropical fruit flies of South-East Asia. CABI, 655 pp.) and dichotomous keys to identify them (Drew and Romig 2016Drew and Romig 2016:
Drew RAI, Romig MC, 2016. Keys to the Tropical Fruit Flies of South-East Asia. CABI Publishing, 487 pp.), and the description of 65 new species from New Guinea, which is the global epicenter of Dacini diversity (Drew and Romig 2022Drew and Romig 2022:
Drew RAI, Romig MC, 2022. The fruit fly fauna (Diptera: Tephritideae: Dacinae) of Papua New Guinea, Indonesian Papua, Associated Islands and Bougainville. CABI, Wallingford, 124 pp. https://doi.org/10.1079/9781789249514.0000). Without these excellent revisions spanning across political borders the development of the Adult Bactrocera Fruit Fly ID tool would not have been possible. The African Dacini diversity was treated by Dr. Ian White (White 2006White 2006:
White IM, 2006. Taxonomy of the Dacina (Diptera:Tephritidae) of Africa and the Middle East. Entomological Society of Southern Africa, Hatfield, South Africa, 156 pp.), but molecular work indicates that much of the species delimitations there are in need of revision (e.g., Virgilio et al. 2012Virgilio et al. 2012:
Virgilio M, Jordaens K, Breman FC, Backeljau T, De Meyer M, 2012. Identifying insects with incomplete DNA barcode libraries, African fruit flies (Diptera: Tephritidae) as a test case. PLoS ONE 7. https://doi.org/10.1371/journal.pone.0031581). Hence, these taxa are excluded from the Adult Bactrocera Fruit Fly ID tool. Only five species of Bactrocera are native to Africa, and no Zeugodacus, but Dacus is diverse with at least 193 species (Doorenweerd et al. 2018Doorenweerd et al. 2018:
Doorenweerd C, Leblanc L, Norrbom AS, Jose MS, Rubinoff D, 2018. A global checklist for the 932 fruit fly species in the tribe Dacini (Diptera: Tephritidae). Zookeys 730: 19–56. https://doi.org/10.3897/zookeys.730.21786).
Subgenus is the hierarchical taxonomic level between genus and species and has been applied to the non-African Dacini in the literature. The Dacini species in the Lucid key are indicated with their subgeneric assignment in parentheses between the genus and species name. Although these assignments are somewhat in flux based on ongoing taxonomic research (San Jose et al. 2018San Jose et al. 2018:
San Jose M, Doorenweerd C, Leblanc L, Barr N, Geib S, Rubinoff D, 2018. Incongruence between molecules and morphology: A seven-gene phylogeny of Dacini fruit flies paves the way for reclassification (Diptera: Tephritidae). Molecular Phylogenetics and Evolution 121: 139–149. https://doi.org/10.1016/j.ympev.2017.12.001 ), they are broadly informative for lure attraction and certain morphological characters. For example, most Zeugodacus have a medial yellow stripe on the scutum, except for all members of Zeugodacus subgenus Parazeugodacus, and vice versa, all Bactrocera lack a medial stripe, except for members of Bactrocera subgenus Tetradacus. Members of Bactrocera (Bulladacus) and Bactrocera (Daculus) are not attracted to male lures.
A historic moment in the recognition of the complexity of the tribe was the publication by Dr. Drew and Dr. David Hancock in 1994 where they described a large number of Bactrocera dorsalis look-a-like species found across Southeast Asia (Drew and Hancock 1994aDrew and Hancock 1994a:
Drew RAI, Hancock DL, 1994. The Bactrocera dorsalis complex of fruit flies (Diptera: Tephritidae: Dacinae) in Asia. Bulletin of Entomological Research Supplement Series 2: 1–68.). This publication was received with some skepticism among Tephritidae taxonomists, but subsequent integrative taxonomic work that includes molecular data has proven that the vast majority of species recognized in that work are valid (e.g., Doorenweerd et al. 2024Doorenweerd et al. 2024:
Doorenweerd C, San Jose M, Leblanc L, Barr N, Geib SM, Chung AYC, Dupuis JR, Ekayanti A, Fiegalan E, Hemachandra KS, Hossain MA, Huang C, Hsu Y, Morris KY, Maryani A. Mustapeng A, Niogret J, Pham TH, Thi Nguyen N, Sirisena UGAI, Todd T, Rubinoff D, 2024. Towards a better future for DNA barcoding: Evaluating monophyly- and distance-based species identification using COI gene fragments of Dacini fruit flies. Molecular Ecology Resources 24: e13987. https://doi.org/10.1111/1755-0998.13987, Starkie et al. 2022aStarkie et al. 2022a:
Starkie ML, Cameron SL, Krosch MN, Phillips MJ, Royer JE, Schutze MK, Strutt F, Sweet AD, Zalucki MP, Clarke AR, 2022. A comprehensive phylogeny helps clarify the evolutionary history of host breadth and lure response in the Australian Dacini fruit flies (Diptera: Tephritidae). Molecular Phylogenetics and Evolution 172: 107481. https://doi.org/10.1016/j.ympev.2022.107481 , San Jose et al. 2018San Jose et al. 2018:
San Jose M, Doorenweerd C, Leblanc L, Barr N, Geib S, Rubinoff D, 2018. Incongruence between molecules and morphology: A seven-gene phylogeny of Dacini fruit flies paves the way for reclassification (Diptera: Tephritidae). Molecular Phylogenetics and Evolution 121: 139–149. https://doi.org/10.1016/j.ympev.2017.12.001 , Dupuis et al. 2018Dupuis et al. 2018:
Dupuis JR, Bremer FT, Kauwe A, Jose MS, Leblanc L, Rubinoff D, Geib SM, 2018. HiMAP: Robust phylogenomics from highly multiplexed amplicon sequencing. Molecular Ecology Resources 18: 1000–1019. https://doi.org/10.1111/1755-0998.12783). However, there are some notable exceptions. Several species names have since been synonymized with B. dorsalis based on multiple lines of evidence, such as B. invadens, B. papayae, and B. philippinensis (Schutze et al. 2015Schutze et al. 2015:
Schutze MK, Aketarawong N, Amornsak W, Armstrong KF, Augustinos AA, Barr N, Bo W, Bourtzis K, Boykin LM, CÁCeres C, Cameron SL, Chapman TA, Chinvinijkul S, ChomiC A, Meyer MD, Drosopoulou E, Englezou A, Ekesi S, Gariou-Papalexiou A, Geib SM, Hailstones D, Hasanuzzaman M, Haymer D, Hee AKW, Hendrichs J, Jessup A, Ji Q, Khamis FM, Krosch MN, Leblanc LUC, Mahmood K, Malacrida AR, Mavragani-Tsipidou P, Mwatawala M, Nishida R, Ono H, Reyes J, Rubinoff D, Jose MS, Shelly TE, Srikachar S, Tan KH, Thanaphum S, Haq I, Vijaysegaran S, Wee SL, Yesmin F, Zacharopoulou A, Clarke AR, 2015. Synonymization of key pest species within the Bactrocera dorsalis species complex (Diptera: Tephritidae): taxonomic changes based on a review of 20 years of integrative morphological, molecular, cytogenetic, behavioural and chemoecological data. Systematic Entomology 40: 456–471. https://doi.org/10.1111/syen.12113). Confusingly, these synonymous names have been maintained in some publications since 2015—but not in this tool. The Adult Bactrocera Fruit Fly ID tool follows modern taxonomic insights and delimitation of taxa based on integrative approaches of morphological and molecular data at the genus and species level, as far as available.
Something that makes Dacini fruit flies biologically peculiar is the very strong attraction of the males to certain lure chemicals, which are not pheromones. This attraction is the result of co-evolution between the fruit flies, acting as pollinators, and Bulbophyllum orchids and other plants providing these chemicals in their flowers. After the male flies ingest the chemicals they become toxic to certain predators, and the chemicals are incorporated in the pheromones to increase mating success (Nakahira et al. 2018Nakahira et al. 2018:
Nakahira M, Ono H, Wee SL, Tan KH, Nishida R, 2018. Floral synomone diversification of Bulbophyllum sibling species (Orchidaceae) in attracting fruit fly pollinators. Biochemical Systematics and Ecology 81: 86–95. https://doi.org/10.1016/j.bse.2018.10.002, Wee and Tan, 2001Wee and Tan, 2001:
Wee SL, Tan KH, 2001. Allomonal and hepatotoxic effects following methyl eugenol consumption in Bactrocera papayae male against Gekko monarchus. Journal of Chemical Ecology 27: 953–964., Tan and Nishida 2000Tan and Nishida 2000:
Tan KH, Nishida R, 2000. Mutual reproductive benefits between a wild orchid, Bulbophyllum patens, and Bactrocera fruit flies via a floral synomone. Journal of Chemical Ecology 26: 533–546. https://doi.org/10.1023/A:1005477926244). In the literature these male lure chemicals are referred to under various names, including phenylpropanoids, parapheromones, allomones, kairomones and synomones (Tan and Nishida 2005Tan and Nishida 2005:
Tan KH, Nishida R. 2005. Synomone or kairomone? - Bulbophyllum apertum flower releases raspberry ketone to attract Bactrocera fruit flies. Journal of Chemical Ecology 31: 497–507. https://doi.org/10.1007/s10886-005-2023-8). Although this is obviously not a morphological character, it is included in the Lucid key because the attraction is highly species-specific. Species that are attracted to methyl eugenol are never attracted to cue lure, and vice versa, although some species are (somewhat) attracted to zingerone in addition to being attracted to cue lure or methyl eugenol. Zingerone is chemically speaking intermediate between the two (Tan and Nishida 2007Tan and Nishida 2007:
Tan KH, Nishida R, 2007. Zingerone in the floral synomone of Bulbophyllum baileyi (Orchidaceae) attracts Bactrocera fruit flies during pollination. Biochemical Systematics and Ecology 35: 334–341. https://doi.org/10.1016/j.bse.2007.01.013). However, some species are only attracted to zingerone. Other lures than these main three have not been used extensively in the field, and their attraction records are sparse. Overall, the male lure attraction character should be used with caution because attraction data is lacking for many (non-pest) species and selecting a lure may inadvertently rule out too many candidate species.
Authors: Doorenweerd et al.
Last updated October 2024
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