Experimental hut resting and entrance behaviour of Anopheles darlingi from Zungarococha, a malaria endemic community in Loreto, Northern Peruvian Amazon.

Background: Anopheles darlingi is a primary malaria vector in the Peruvian Amazon, yet characterization of behavioural traits contributing to human-vector contact is limited. Additionally, studies comparing key behaviours of wild-type to colonized An. darlingi populations are minimal. This study compared resting and entry behaviour between these two types of populations. Specific objectives were to use experimental huts to (1) evaluate and compare indoor resting behaviours of wild-type and colonized An. darlingi populations; (2) quantify An. darlingi house entry rates into interception traps in relation to protected Human Landing collection (HLC).

Methods: The study was conducted in Zungarococha village, Loreto, Peru. Prior to hut evaluations, An. darlingi biting activity and population dynamics were evaluated using HLC outside local homes from June 2014 to May 2015. Indoor resting location (window, door, wall, roof) of wild caught and colonized An. darlingi was evaluated in three experimental huts. Controlled indoor releases were performed for 6 days each month from March to August 2015. Wild An. darlingi hourly house-entry rates were quantified using interception traps affixed to an experimental hut and indoor HLC from May to August 2015. Two collectors were positioned inside huts to generate host-seeking cues during evaluations.

Results: Anopheles darlingi had a bimodal outdoor biting pattern with two peaks at 1800 h and 2200 h. HLC densities were associated with Amazon River levels measured nearby Iquitos city. Colonized An. darlingi preferred to rest in lower parts of the door (29.8%), roof (12.7%), and window (11.8%) which was similar to wild caught An. darlingi which preferred to rest in low door (32.7%), window (14.0%), and roof (13.0%). Wild An. darlingi entry behaviour peaked from 2200 to 2300 h, this was clearly observed when collection densities increased, varying between 2300 and 2400 h at low collection densities. Capture rates from interception traps were lower compared to indoor HLC rates from adjacent experimental huts and local houses.

Conclusions: Results from this study provide useful insights into An. darlingi resting and entry behaviour in a malaria endemic area in the Peruvian Amazon and inform on the use of colonized mosquitos in vector behavioural studies. This information is relevant to malaria epidemiology and will be useful to evaluate new tools for malaria control programmes.