title: The Genetic Basis of Host Preference and Resting Behavior in the Major African Malaria Vector, Anopheles arabiensis.
abstract: Malaria transmission is dependent on the propensity of Anopheles mosquitoes to bite humans (anthropophily) instead of other dead end hosts. Recent increases in the usage of Long Lasting Insecticide Treated Nets (LLINs) in Africa have been associated with reductions in highly anthropophilic and endophilic vectors such as Anopheles gambiae s.s., leaving species with a broader host range, such as Anopheles arabiensis, as the most prominent remaining source of transmission in many settings. An. arabiensis appears to be more of a generalist in terms of its host choice and resting behavior, which may be due to phenotypic plasticity and/or segregating allelic variation. To investigate the genetic basis of host choice and resting behavior in An. arabiensis we sequenced the genomes of 23 human-fed and 25 cattle-fed mosquitoes collected both in-doors and out-doors in the Kilombero Valley, Tanzania. We identified a total of 4,820,851 SNPs, which were used to conduct the first genome-wide estimates of "SNP heritability" for host choice and resting behavior in this species. A genetic component was detected for host choice (human vs cow fed; permuted P = 0.002), but there was no evidence of a genetic component for resting behavior (indoors versus outside; permuted P = 0.465). A principal component analysis (PCA) segregated individuals based on genomic variation into three groups which were characterized by differences at the 2Rb and/or 3Ra paracentromeric chromosome inversions. There was a non-random distribution of cattle-fed mosquitoes between the PCA clusters, suggesting that alleles linked to the 2Rb and/or 3Ra inversions may influence host choice. Using a novel inversion genotyping assay, we detected a significant enrichment of the standard arrangement (non-inverted) of 3Ra among cattle-fed mosquitoes (N = 129) versus all non-cattle-fed individuals (N = 234; χ2, p = 0.007). Thus, tracking the frequency of the 3Ra in An. arabiensis populations may be of use to infer selection on host choice behavior within these vector populations; possibly in response to vector control. Controlled host-choice assays are needed to discern whether the observed genetic component has a direct relationship with innate host preference. A better understanding of the genetic basis for host feeding behavior in An. arabiensis may also open avenues for novel vector control strategies based on driving genes for zoophily into wild mosquito populations.
authors.affiliation: Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology/University of California, Davis, Davis, California, United States of America.
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Main
authors.affiliation: Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology/University of California, Davis, Davis, California, United States of America.
authors.forename: Yoosook
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Heather M
authors.initials: HM
authors.lastname: Ferguson
authors.affiliation: Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom.|Environmental Health and Ecological Sciences Group, Ifakara Health Institute, Ifakara, United Republic of Tanzania.
authors.forename: Katharina S
authors.initials: KS
authors.lastname: Kreppel
authors.affiliation: Environmental Health and Ecological Sciences Group, Ifakara Health Institute, Ifakara, United Republic of Tanzania.
authors.forename: Anicet
authors.initials: A
authors.lastname: Kihonda
authors.affiliation: Environmental Health and Ecological Sciences Group, Ifakara Health Institute, Ifakara, United Republic of Tanzania.
authors.forename: Nicodem J
authors.initials: NJ
authors.lastname: Govella
authors.affiliation: Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology/University of California, Davis, Davis, California, United States of America.
authors.forename: Travis C
authors.initials: TC
authors.lastname: Collier
authors.affiliation: Department of Entomology and Nematology, University of California, Davis, Davis, California, United States of America.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Cornel
authors.affiliation: Department of Computer Science, University of California, Los Angeles, Los Angeles, California, United States of America.
authors.forename: Eleazar
authors.initials: E
authors.lastname: Eskin
authors.affiliation: Department of Computer Science, University of California, Los Angeles, Los Angeles, California, United States of America.
authors.forename: Eun Yong
authors.initials: EY
authors.lastname: Kang
authors.affiliation: Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology/University of California, Davis, Davis, California, United States of America.
authors.forename: Catelyn C
authors.initials: CC
authors.lastname: Nieman
authors.affiliation: Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology/University of California, Davis, Davis, California, United States of America.
authors.forename: Allison M
authors.initials: AM
authors.lastname: Weakley
authors.affiliation: Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology/University of California, Davis, Davis, California, United States of America.
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Lanzaro
mesh_terms: D000349:Africa; D000818:Animals; D000852:Anopheles / Q000235:genetics* / Q000469:parasitology; D001522:Behavior, Animal / Q000502:physiology; D002417:Cattle; D005838:Genotype; D054884:Host-Pathogen Interactions / Q000235:genetics*; D006801:Humans; D007303:Insect Vectors / Q000235:genetics* / Q000469:parasitology; D007306:Insecticides / Q000627:therapeutic use; D008288:Malaria / Q000453:epidemiology / Q000235:genetics* / Q000469:parasitology / Q000635:transmission; D009032:Mosquito Control; D020641:Polymorphism, Single Nucleotide
chemical_list: D007306:Insecticides