Estimating the dispersal of the malaria vector Anopheles farauti through a natural ecosystem in north Queensland, Australia using mark release and recapture experiments

Anopheles farauti (Laveran, 1902) is a major malaria vector in the Southwest Pacific region that is showing behavioural resistance to indoor insecticide-based vector control. This study utilised fluorescent dust-based mark release recapture (MRR) experiments to quantify the dispersal characteristics of An. farauti through a non-village natural ecosystem in tropical north Queensland, Australia. Good quality adult mosquitoes were collected from the field using a Fan Box Traps (FBT), with initial parity dissections of this material showing a daily survival rate of 0.68 during the wet season and 0.75 during the dry season. We then performed 51 separate mosquito MRR releases (19,889 marked An. farauti) during the wet and dry seasons between 2015 and 2017. Mosquito recaptures utilised three collection systems: human landing catches (HLC), FBTs and a bespoke mosquito catch barrier system (MCB). Most of the 308 (1.55%) marked An. farauti were recaptured by the MCB (78%), while the rest (22%) were recaptured by either our CO2 baited FBT and HLC. The longest flight distance was 3.51 km and An. farauti was estimated to travel approximately 73 m per day with HLCs collecting approximately 14 times more mosquitoes than the CO2 baited FBT. This data provides novel insights into the movement and survival of An. farauti in a natural ecosystem, suggesting longer flight distances than documented and different survival rates between the wet and dry seasons. These parameters will be important for modelling pathogen transmission dynamics, potential mosquito gene drive spread, and contribute to future malaria control strategies in the Southwest Pacific.