Bactrocera kraussi and B. halfordiae

Taxonomy

Valid name: Bactrocera (Bactrocera) kraussi (Hardy, 1951)
Preferred common name: Krauss' fruit fly
Synonyms:
   Dacus kraussi (original combination in Hardy, 1951)
   Strumeta kraussi (subsequent combination in May, 1953)

Valid name: Bactrocera (Bactrocera) halfordiae (Tryon, 1927)
Preferred common name: saffronheart fruit fly
Synonyms:
   Chaetodacus halfordiae (original combination in Tryon, 1927)
   Dacus halfordiae (subsequent combination in Hardy, 1951)
   Strumeta halfordiae (subsequent combination in May, 1963)
Chaetodacus gurneyi Perkins, 1934 (junior synonym)

Morphology-based identification

Bactrocera kraussi is morphologically similar to B. rufescens, B. halfordiae, B. russeola, and B. fagraea (the 'fagraea' species complex in 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.
). Spot characters for B. kraussi and B. halfordiae are the lack of a medial stripe on the abdomen and dark mark on the scutellum. Drew (1989)Drew (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.
notes that B. kraussi is most closely related to B. halfordiae, with which it is narrowly allopatric.

Molecular identification

Bactrocera kraussi in Doorenweerd et al. (2024)Doorenweerd 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
were misidentified B. rufofuscula. COI reference sequence can be used to identify B. kraussi and B. halfordiae, they are close sister species (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
).

Distribution

Bactrocera kraussi is restricted to the rainforests on the eastern coast of north Queensland and the Torres Strait Islands, and B. halfordiae can be found further south along the East Coast of Australia (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.
).

Further information

Bactrocera kraussi is reported as a "category B" polyphagous pest in Australia 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 B pest is there defined as "polyphagous fruit pests or destructive specialists more restricted in distribution, but at elevated risk of spreading to new locations". Bactrocera kraussi has been reared from 106 different hosts, including citrus, banana, mango, and guava (Hancock et al. 2000Hancock et al. 2000:
Hancock DL, Hamacek EL, Lloyd AC, Elson-Harris MM, 2000. The distribution and host plants of fruit flies (Diptera: Tephritidae) in Australia. Information Series (Q19906). Queensland Department of Primary Industries, 75pp.
).

Bactrocera halfordiae is reported as a "category C" oligophagous fruit pest in Australia 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 C pest is there defined as "relatively minor oligophagous or specialist fruit or cucurbit pests". According to Drew et al. (1982)Drew et al. (1982):
Drew, RAI, Hooper, GHS, Bateman, MA, 1982. Economic Fruit Flies of the South Pacific Region. Queensland Dept. of Primary Industries, Brisbane. Pages 29-31.
it is an occasional pest of citrus, loquat, and some myrtaceous fruits.

 Scientific illustration of  B. halfordiae .
Scientific illustration of B. halfordiae.
 Photo plate of  B. halfordiae .
Photo plate of B. halfordiae.
 Photo plate of  B. kraussi .
Photo plate of B. kraussi.