What is driving Aedes vigilax peaks in the Karama weekly mosquito trap in Darwin: Tides or rainfall?

Background: The northern salt marsh mosquito Aedes vlgllax (Skuse) is an established vector for Ross River and Barmah Forest viruses and is also an aggressive biter and an appreciable pest species. Many of Darwin's northern suburbs are adjacent to a coastal wetland, which offers a breeding habitat for Aedes vigilax. Medical Entomology (ME) of the NT Department of Health and Families conducts EVS trap surveillance and Integrated mosquito control measures for Aedes vigilax breeding in the wetlands of Darwin. One EVS trap, located In Karama, consistently reports some of the highest numbers of Aedes vigilax in all the swamp trap locations. We sought to identify the most important meteorological variables associated With peaks of >500 Aedes vigiax /trap/night. Improved prediction of peaks will enable early intervention, media warnings and should reduce public distress. Furthermore, early prediction of peaks will assist planning of future mosquito surveys, control efforts, and hence maximise the efficiency of the unit. Methods: we identified the maximum tide and cumulative rainfall during the 9 - 13 day period prior to each EVS collection date. logistic regression models were applied, to determine explanatory variables fitted to weekly peaks of female Aedes vigilax mosquitoes >500 per trap. This was modelled controlling for calendar month, year, meteorological variables and larval control efforts. Results: calendar months 9-11 had significantly more peaks than January, with a trend for significance (p=0.09) in December. Discussion: to maximise the efficiency of adult salt-marsh mosquito control operations in Darwin, larval control should be implemented with increased emphasis after rain events during the build-up months between September and November each year. This study reiterates the importance of applying statistical methods to service provider programs, and thus enabling insights into solutions without the need for additional field experiments. This method of evaluation may have applications for other mosquito surveillance and control programs in other areas.