Bactrocera (Bactrocera) latifrons (Hendel), 1995

Doorenweerd, Camiel & Leblanc, Luc, 2018, Unusual Dark Forms of the Solanum Fruit Fly Bactrocera latifrons (Hendel) in Hawaii (Tephritidae: Dacini), Proceedings of the Hawaiian Entomological Society 50, pp. 17-23 : 18-20

Bactrocera (Bactrocera) latifrons (Hendel)

Chaetodacus latifrons Hendel, 1915: 425

Dacus amoyensis Froggatt, 1909: 36 ; nomen nudum

Dacus parvulus Hendel, 1912: 21 ; designated as synonym by White & Liquido (1995)

Chaetodacus antennalis Shiraki 1933: 56 ; designated as synonym of D. parvulus by Hardy (1973)

Dacus (Strumeta) latifrons (Hendel) Hardy 1968: 113

Bactrocera (Bactrocera) latifrons (Hendel) White & Liquido 1995: 251

Differential diagnosis. In Hawaii, Bactrocera latifrons is most similar to B. dorsalis , but can be distinguished by the absence of a distinct black T shape on the abdomen and the apical expansion of the costal band on the wing. Outside Hawaii, B. latifrons is most similar to B. parvula (Hendel) [known from Taiwan] and B. citima (Hardy) [known from Thailand and China], in having two lateral yellow vittae on the scutum, the absence of a medial vitta, an entirely yellow scutellum, absence of a clear dark T shape on the abdomen, wing with clear cells bc and c, costal band widening at the apex and usually crossing R 2+3. Bactrocera latifrons and B. parvula can be distinguished from B. citima by the mesopleural stripe ending midway between the anterior margin of notopleuron and anterior npl. seta dorsally in B. citima ( Figure 16B ), reaching anterior npl. seta dorsally in B. latifrons and B. parvula ( Figure 16A ). Bactrocera citima can further be distinguished by the needle-shaped ovipositor, which is trifurcate in B. latifrons and B. parvula ( Fig. 17 ). Whereas B. citima convincingly stands out as a distinct species, the distinction between B. latifrons and B. parvula is not as clear. The orange-brown abdomen variants of B. latifrons can readily be distinguished from B. parvula . Darker specimens of B. latifrons with varying dark abdomen patterns can also have femora with black markings, as dots or rings, but these never extend fully around the femur apex as (reported) in B. parvula .

Host plants. There has been some dispute in the literature on the theoretical (i.e. lab reared) and realized host range of B. latifrons . The commonly cited Bactrocera host overview by Allwood et al. (1999) lists 28 host plant species from ten plant families, and McQuate and Liquido (2013) reported 59 plant species from 14 families. The Center for Agriculture and Biosciences International (CABI) website lists Solanum , Capsicum , Physalis , Diplocyclos , Lycopersicon [ Solanaceae ] and Citrullus lanatus [ Cucurbitaceae ] (CABI 2018). The predominant natural hosts are all Solanaceae , including tomatoes and peppers ( White and Elson-Harris 1992, Liquido et al. 1994) and secondarily some Cucurbitaceae ( Mziray et al. 2010) . The UHIM collection holds reared material from the invasive devil’s apple, Solanum linnaeanum , and from ‘wild tomato’.

Lure response. Bactrocera latifrons is not attracted to methyl eugenol or cue lure, which are highly attractive to B. dorsalis and Zeugodacus cucurbitae , respectively. There is a specific lure developed for B. latifrons called ‘latilure’ (alpha-ionol), sometimes used in combination with cade oil, but this is only slightly attractive ( McQuate et al. 2004). Recent studies have discovered ionol analogue compounds that have promise for being more effective ( McQuate et al. 2018). Protein baits can be used to attract females, but rearing the species from infested fruit appears to be, at present, the most effective collecting and surveying method (Liquido et al. 1994, Mziray et al. 2010).

Figures

Figure 16. Lateral views showing the difference in the width of the mesopleural stripe. A. Bactrocera latifrons ex USDA fruit fly lab, Honolulu, Hawaii. B. Holotype of B. citima, Chiangdao, Chiangmai prov., Thailand.

Figure 17. Dorsal view drawing of the aculeus (piercer) of the ovipositor, which is needle shaped (above) in Bactrocera citima and trifurcate (below) in B. latifrons and B. parvula.