Bactrocera zonata and B. correcta

Taxonomy

Valid name: Bactrocera (Bactrocera) correcta (Bezzi, 1916)
Preferred common name: guava fruit fly
Synonyms:
   Chaetodacus correctus (original combination in Bezzi, 1916)
   Strumeta correctus (subsequent combination in Perkins, 1938)
   Dacus correctus (subsequent combination in Narayanan and Batra, 1960)
Dacus dutti Kapoor, 1971 (junior synonym)
Strumeta paratuberculatus Philip, 1950 (junior synonym)
Dacus bangaloriensis Agarwal and Kapoor, 1983 (junior synonym)

Valid name: Bactrocera (Bactrocera) zonata (Saunders, 1842)
Preferred common name: peach fruit fly
Synonyms:
   Dasyneura zonatus (original combination in Saunders, 1842)
   Dacus zonatus (subsequent combination in Bezzi, 1909)
   Chaetodacus zonatus (subsequent combination in Bezzi, 1916)
   Strumeta zonata (subsequent combination in Perkins, 1937)
Rivellia persicae Bigot, 1890 (junior synonym)
   Dacus persicae (subsequent combination in Bezzi, 1909)
Dacus ferrugineus var. mangiferae Cotes, 1893 (junior synonym)
   Bactrocera ferruginea var. mangiferae (subsequent combination in Bezzi, 1913)

Morphology-based identification

Bactrocera zonata and B. correcta can be identified reliably using morphological characters. The spot character for the pair is the interrupted costal band on the wing. Between the two, B. zonata has an almost completely red scutum, whereas B. correcta has variable black patterns. The overall dark appearance and wing pattern of B. correcta may cause confusion with B. tuberculata, but the latter has all black tergites 3–5.

Molecular identification

Both Bactrocera correcta and B. zonata can be identified using COI sequence data (Doorenweerd et al. 2019Doorenweerd et al. 2019:
Doorenweerd C, Jose MS, Barr N, Leblanc L, Rubinoff D, 2019. Highly variable COI haplotype diversity between three species of invasive pest fruit fly reflects remarkably incongruent demographic histories. Scientific Reports 10: 742007. https://doi.org/10.1038/s41598-020-63973-x). Several non-sequencing methods for more rapid assays have been developed as well, including a fragment-length based COI PCR and real-time PCR (Jiang et al. 2013, Jiang et al. 2016Jiang et al. 2016:
Jiang F, Fu W, Clarke AR, Schutze MK, Susanto A, Zhu SF, Li ZH, 2016. A high-throughput detection method for invasive fruit fly (Diptera: Tephritidae) species based on microfluidic dynamic array. Molecular Ecology Resources 16: 1378–1388. https://doi.org/10.1111/1755-0998.12542) and a CRISPR based method (Li et al. 2024Li et al. 2024:
Li W, Cai B, Chen R, Cui J, Wang H, Li Z, 2024. Application of recombinase polymerase amplification with CRISPR /Cas12a and multienzyme isothermal rapid amplification with lateral flow dipstick assay for Bactrocera correcta. Pest Management Science 80: 3317–3325 https://doi.org/10.1002/ps.8035 ).

Distribution

This species pair is partly allopatric, with an area in Southeast Asia from India to Vietnam where both appear, but Bactrocera zonata is always more common on the western side of this distribution, and B. correcta is more common the eastern side. Bactrocera zonata has invaded the Middle East and northern Africa.

Further information

Bactrocera correcta and B. zonata are listed as "category A" polyphagous pests in Vargas et al. (2015)Vargas et al. (2015):
Vargas RI, Pinero JC, Leblanc L, 2015. An overview of pest species of Bactrocera fruit flies (Diptera: Tephritidae) and the integration of biopesticides with other biological approaches for their management with a focus on the pacific region. Insects 6: 297–318. https://doi.org/10.3390/insects6020297. A category A pest is defined as "widespread invasive polyphagous generalists or highly destructive specialists that have become established outside of their native range".