Modelling winter survival, mating and trapping of Queensland fruit fly in Auckland, New Zealand

In February 2015, an established population of the Queensland fruit fly (Qfly, Bactrocera tryoni) was detected in Grey Lynn, Auckland. The ensuing biosecurity response was apparently successful, with no detections of Qfly after March and eradication formally declared in December. During the programme key questions were whether Qfly might successfully overwinter in Auckland, and how trap efficacy and mating behaviour would be affected by winter conditions. These were addressed using published Qfly models that had been developed and parameterised in its native range. A model for cold acclimatisation suggested that Auckland winters would not be sufficiently cold to cause significant mortality of adult Qflies, but other models suggested mating would be relatively rare from June to October. Two models for relative trap efficacy suggested that traps would be relatively ineffective until late spring (October-November). The results are discussed with reference to geospatial projections of New Zealand’s climate suitability for Qfly.