Behavioral response of insecticide-resistant mosquitoes against spatial repellent: A modified self-propelled particle model simulation

Abstract

Rapidly increasing pyrethroid insecticide resistance and changes in vector biting and resting behavior pose serious challenges in malaria control. Mosquito repellents, especially spatial repellents, have received much attention from industry. We attempted to simulate interactions between mosquitoes and repellents using a machine learning method, the Self-Propelled Particle (SPP) model, which we modified to include attractiveness/repellency effects. We simulated a random walk scenario and scenarios with insecticide susceptible/resistant mosquitoes against repellent alone and against repellent plus attractant (to mimic a human host). Simulation results indicated that without attractant/repellent, mosquitoes would fly anywhere in the cage at random. With attractant, all mosquitoes were attracted to the source of the odor by the end. With repellent, all insecticide-susceptible mosquitoes eventually moved to the corner of the cage farthest from the repellent release point, whereas, a high proportion of highly resistant mosquitoes might reach the attractant release point (the human) earlier in the simulation. At fixed concentration, a high proportion of mosquitoes could be able to reach the host when the relative repellency efficacy (compare to attractant efficacy) was <1, whereas, no mosquitoes reached the host when the relative repellency efficacy was > 1. This result implies that repellent may not be sufficient against highly physiologically insecticide resistant mosquitoes, since very high concentrations of repellent are neither practically feasible nor cost-effective.

Behavioral responses of pyrethroid resistant and susceptible Anopheles gambiae mosquitoes to insecticide treated bed net

“…Recent studies from western Kenya observed high resistance levels, rates of human blood index and sporozoite rates in the mosquitoes resting indoors compared to the mosquitoes collected resting outdoors [34,52]. The study findings are in agreement with similar studies that have observed reduced hostseeking performance of susceptible mosquitoes in the presence of LLINs unlike the resistant mosquitoes whose behavior was not altered [26,51,53,54].…”

Mosquito Excito-Repellency: Effects on Behavior and the Development of Insecticide Resistance

“…There are two types of behavioral responses to insecticides: irritation, which is defined as an insect leaving an insecticide-treated surface after tarsal contact with it, and repellency, or spatial repellency (deterrence or avoidance), which refers to the function of a compound to influence an avoidance response movement away from a chemical stimulus through actual physical contact with it, thus diverting insects from the treated surface [4][5][6]. However, this behavior and the changes in the vector's resting habits and biting activity represent a challenge in the surveillance and vector control strategies [7].…”