Host suitability index for polyphagous tephritid fruit flies

Authors: Follett, Peter; HAYNES, F - Nsw Department Of Primary Industries; DOMINIAK, B - Nsw Department Of Primary Industries

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/2020
Publication Date: 3/14/2021
Citation: Follett, P.A., Haynes, F.E., Dominiak, B.C. 2021. Host suitability index for polyphagous tephritid fruit flies. Journal of Economic Entomology. 114(3):1021-1034. https://doi.org/10.1093/jee/toab035.
DOI: https://doi.org/10.1093/jee/toab035

Interpretive Summary: A Host Suitability Index (HSI) is proposed to describe host status in tephritid fruit flies. International regulatory standards on host status for tephritid fruit flies categorize a fruit as a natural host, conditional host or non-host, but in reality fruit host status is a spectrum ranging from highly attractive fruit supporting large numbers fruit flies to very poor hosts supporting low numbers. The HSI divides host status into six categories based on log infestation rate (# flies per kg fruit) —non-host (0), very poor (<0.1), poor (0.1-1.0), moderately good (1.0-10.0),good (10-100) and very good (>100), and may be a useful concept in developing systems approaches that rely on poor host status, for determining surveillance and detection protocols for potential incursions, and to guide the appropriate regulatory response during fruit fly outbreaks.

Technical Abstract: Tephritid fruit flies are major economic pests for fruit production and are an impediment to trade. Different host fruits are known to vary in their suitability for fruit flies to complete their life cycle. Currently, international regulatory standards on host status for tephritid fruit flies categorize a fruit as a natural host, conditional host or non-host. In reality, fruit host status is a spectrum ranging from highly attractive fruit supporting large numbers fruit flies to very poor hosts supporting low numbers. Here we propose a Host Suitability Index (HSI) that divides host status into six categories based on log infestation rate (# flies per kg fruit) —non-host (0), very poor (<0.1), poor (0.1-1.0), moderately good (1.0-10.0), good (10-100) and very good (>100). Infestation rate is based on field sampling and cage infestation studies. These adjectives are often used in the literature and are intuitive which will facilitate discussion of host status. We illustrate the concept using 20 host status papers covering five species of polyphagous fruit flies in the Pacific region: Bactrocera tryoni, Bactrocera dorsalis, Bactrocera latifrons, Zeugodacus cucurbitae, and Ceratitis capitata (Diptera:Tephritidae). The HSI may be a useful concept in developing systems approaches that rely on poor host status, for determining surveillance and detection protocols for potential incursions, and to guide the appropriate regulatory response during fruit fly outbreaks.