Behaviour of the malaria vector Anopheles arabiensis infected with the endosymbiont Microsporidia MB: host seeking and cuticular hydrocarbons associated with mating

Publication Type

Journal Article

Journal Name

Acta Tropica

Publication Date

6-1-2026

Abstract

The Plasmodium transmission blocking symbiont Microsporidia MB has shown potential for the control of malaria. However, there is limited information about the symbiont's physiological and behavioural impact on the mosquito vector, which is important for determining the potential impact of a Microsporidia MB-based malaria intervention. We asked whether Microsporidia MB infection i) alters the attraction of Anopheles arabiensis to human odours; ii) is associated with variation in the types of blood-meal sources utilised, and iii) changes the cuticular hydrocarbon (CHC) profiles of male mosquitoes known to impact mating behaviour. Blood fed An. arabiensis collected in CDC light traps were analysed by PCR for blood meal sources and Microsporidia MB infection. Another engorged cohort aspirated inside selected houses were allowed to oviposit to generate Microsporidia MB isolines which were used for behavioural assays and in the extraction of cuticular hydrocarbons. In olfactometer assays, Microsporidia MB infected An. arabiensis exhibited no preferential attraction to extract of human over cattle odours. Logistic regression model showed no association between mosquitoes that harboured the endosymbiont and selective feeding on humans over other vertebrate hosts (livestock, bird, and monkey). Chemical analysis revealed differences in the CHC profile between Microsporidia MB infected and non-infected male mosquitoes; however, multicollinearity among the CHC constituents was evident with infection status predicted not to be strongly driven by a specific hydrocarbon, based on random forest models. We conclude that under the experimental conditions tested, the symbiont's presence imposes no cost on mosquito host-seeking behaviour to bite humans but may affect chemical signaling and mating behaviour via changes in cuticular hydrocarbon composition.

Keywords

Blood meal analysis, Cuticular hydrocarbon, Endosymbiont, Host seeking behaviour, Malaria vector, Mating

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