Landing behaviour of the host seeking malaria vector anopheles coluzzii in response to host associated cues

v ABSTRACT Female mosquitoes of the genus Anopheles transmit the parasites responsible for malaria, one of the most serious vector-borne diseases, which affects one-fifth of the world population. Current malaria prevention relies heavily on vector control interventions, which are most effective and sustainable when based on mosquito behaviour. Although much research has focussed on host-seeking behaviour, less is known about the close-range phase, including landing and post-landing behaviour. Thus, this research aimed to 1) quantify the relative effect that host-associated stimuli have on landing response, 2) quantify the effect that physical target characteristics have on flight behaviour and landing response, and 3) characterise pre- and post-landing behaviour and feeding success in relation to variations of target temperatures. Using behavioural assays, this project firstly quantified the relative role of three host-associated stimuli (thermal, visual, and olfactory) in driving landing and found that they act synergically to increase landing response, that host odour is an essential cue in this phase, and that the landing response is the result of a flexible yet accurate stimuli integration. Secondly, mosquitoes were offered targets with different physical characteristics, and it was found that more mosquitoes landed on the target when at least half of its surface was heated, which suggests a basis for more cost-effective trap designs. Furthermore, more mosquitoes landed on large targets, although small targets caught a greater density of mosquitoes per unit area; however, no effect on landing was observed when targets were oriented vertically or horizontally. Thirdly, it was demonstrated that the surface temperature of a target strongly influenced the feeding success, with mosquitoes being equally successful in feeding on blood at temperatures that ranged from normal human physiological to febrile conditions. Surface temperature also influenced post-landing behaviour, as mosquitoes displayed few foraging events and fed promptly on blood at 36 °C, whilst behaved radically different when presented with blood at 30 °C and 48 °C. Altogether, these results indicate that mosquitoes respond with distinct behaviours depending on the set of cues encountered during host-seeking. The results presented here could be used to improve vector surveillance and control tools by incorporating specific stimuli that are known to elicit specific behavioural responses. Thus, this research aids the cause of reducing the global burden of mosquito-transmitted diseases.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of Greenwich

Year dc:date.issued

2022

Author dc:creator

• Carnaghi, Manuela

• Q Science (General)

Language dc:language

en