Dietary L-3,4-dihydroxyphenylalanine (L-DOPA) augments cuticular melanization in Anopheles mosquitos while reducing their lifespan and malaria parasite burden

L-3,4-dihydroxyphenylalanine (L-DOPA) is widespread in the environment including mosquito habitats where it could serve as a component of their diet. Given its role as a precursor for melanin synthesis we investigated the effect of dietary L-DOPA on mosquito physiology and immunity to P. falciparum and C. neoformans infection. Dietary L-DOPA was incorporated into mosquito melanin and had profound transcriptional effects that were associated with enhanced immunity, increased pigmentation and reduced lifespan. Increased melanization resulted in enhanced capacity to absorb electromagnetic radiation that affected insect thermal regulation. Bacteria in the mosquito microbiome were sources of dopamine, which is a substrate for melanization. Our results illustrate how an environmentally abundant amino acid can affect mosquito physiology and suggest its potential usefulness as an environmentally friendly vector control agent.