Search

Anopheles aquasalisis a primary malaria vector in coastal South America that grows in brackish waters of mangroves. Its importance has increased in recent years as it has been established as a model for parasite-vector studies for non-modelPlasmodiumspecies, such asP. yoelli. In this study, we present the complete genome ofAn. aquasalisand offer some insights into evolution and physiology. With a 162Mb and 12,446 coding proteins, theAn. aquasalisgenome is similar in size and gene content as other neotropical anophelines. 1,038 single-copy orthologs are present inAn. aquasalisand all Diptera and it was possible to infer thatAn. aquasalisdiverged fromAn. darlingi(the main malaria vector in inland South America) nearly 14 million years ago (mya). Ion transport and metabolism proteins is one the major gene families inAn. aquasaliswith 660 genes. Amongst these genes, important gene families relevant for osmosis control (e.g., aquaporins, vacuolar-ATPases, Na+/K+-ATPases and carbonic anhydrases) were identified in one-to-one orthologs with other anophelines. Evolutionary analysis suggests that all osmotic regulation genes are under strong purifying selection. We also observed low copy number variation in immunity-related genes (for which all classical pathways were described) and insecticide resistance genes. This is the third genome of a neotropical anopheline published so far. The data provided by this study may offer candidate genes for further studies on parasite-vector interactions and for studies on how brackish water anophelines deals with high fluctuation in water salinity.Significance StatementThe brackish water mosquitoAnopheles aquasalisis a primary malaria vector in coastal South America. Besides its peculiar ecological features (it is one of the few anopheline mosquitoes that survives high fluctuation of water salinity),An. aquasalishas gained relevance in recent years as a model for parasite-vector studies for non-modelPlasmodiumparasites. Still, the physiology and genetics ofAn. aquasalisare poorly understood. Here we present the genome ofAn. aquasaliswith more than 12,000 annotated genes, offering insights in genome evolution, osmoregulation related, immunity, chemosensory and insecticide resistance genes. The data presented here will help to further advance the studies onAn. aquasalisgenetics and physiology to better understand parasite-vector interactions in non-model organisms.

Sexual dimorphism in immune function is prevalent across different species, where males trade their ability to fight pathogens for a practical reproductive function while females favor an extended lifespan. In insects, these differences in immune function reflect an evolutionary life strategy, where females have a presumably more robust immune system than insect males. Here, we evaluate immune functioning in four male and female insect vectors, Aedes aegypti (Diptera, Culicidae), Anopheles aquasalis (Diptera, Culicidae), Lutzomyia longipalpis (Diptera, Psychodidae) and Rhodnius prolixus (Hemiptera, Reduviidae). We show evidence that challenges the concept of immune sexual dimorphism in three of these insect vectors. In the three Diptera species, A. aegypti, A. aquasalis and L. longipalpis that transmit arboviruses, Plasmodium spp. (Haemospororida, Plasmodiidae) and Leishmania spp. (Trypanosomatida, Trypanosomatidae), respectively, unchallenged adult males express higher levels of immune-related genes than adult females and immature developmental stages. The main components of the Toll, IMD, and Jak/STAT pathways and antimicrobial effectors are highly expressed in whole-body males. Additionally, males present lower midgut basal microbiota levels than females. In A. aegypti mosquitoes, the differences in immune gene expression and microbiota levels are established in adult mosquitoes but are not present at the recently emerged adults and pupal stage. Antibiotic treatment does not affect the consistently higher expression of immune genes in males, except defensin, which is reduced significantly after microbiota depletion and restored after re-introduction. Our data suggest that Diptera males have a basal state of activation of the immune system and that activation of a more robust response through systemic immune challenge acutely compromises their survival. The ones who survive clear the infection entirely. Females follow a different strategy where a moderate immune reaction render higher tolerance to infection and survival. In contrast, hematophagous adult males of the Hemiptera vector R. prolixus, which transmits Trypanosoma cruzi, present no differences in immune activation compared to females, suggesting that diet differences between males and females may influence immune sexual dimorphism. These findings expand our understanding of the biology of insect vectors of human pathogens, which can help to direct the development of new strategies to limit vector populations.

The specific aims of this work were to examine the antennal sensilla of Lutzomyia longipalpis (Lutz & Neiva 1912) (Diptera: Psychodidae) adults and to characterize their typology and topography, with special attention to olfactory sensilla. The surfaces of the antennal segments of Lu. longipalpis males and females were studied by scanning electron microscopy (SEM). Lu. longipalpis used in the current study were obtained from a colony originating from Lapinha Cave, Minas Gerais state, Brazil. Microtrichiae and 11 subtypes of sensilla were observed and characterized according to the following categories: five subtypes of trichoid sensilla (short, medium, long blunt-tipped, long pointed-tipped, and apical), two coeloconic sensilla (grooved and praying hands), and campaniform, chaetic, basiconic, and squamiform sensilla. SEM analyses showed few differences between males and females in the typology, topography, and quantity of antennal sensilla described. The current study is the first to identify several categories of antennal sensilla of the genus Lutzomyia and their distribution patterns. The identification of these sensillar types may be important in planning future electrophysiological studies to develop alternative measures of control and monitoring of Lu. longipalpis.

The specific aims of this work were to examine the antennal sensilla of Lutzomyia longipalpis (LutzNeiva 1912) (Diptera: Psychodidae) adults and to characterize their typology and topography, with special attention to olfactory sensilla. The surfaces of the antennal segments of Lu. longipalpis males and females were studied by scanning electron microscopy (SEM). Lu. longipalpis used in the current study were obtained from a colony originating from Lapinha Cave, Minas Gerais state, Brazil. Microtrichiae and 11 subtypes of sensilla were observed and characterized according to the following categories: five subtypes of trichoid sensilla (short, medium, long blunt-tipped, long pointed-tipped, and apical), two coeloconic sensilla (grooved and praying hands), and campaniform, chaetic, basiconic, and squamiform sensilla. SEM analyses showed few differences between males and females in the typology, topography, and quantity of antennal sensilla described. The current study is the first to identify several categories of antennal sensilla of the genus Lutzomyia and their distribution patterns. The identification of these sensillar types may be important in planning future electrophysiological studies to develop alternative measures of control and monitoring of Lu. longipalpis.