Morphological characterisation of Cephalic Sensilla with respect to mammalian host preferences in mosquitoes from selected areas of Wayanad District, Kerala.

Abstract

Insects are the most diversified group in the history of life. Among the various insect groups, mosquitoes deserve special mention with significant ecological and public health importance. Mosquito-borne diseases are among the world's leading causes of illness and death. According to the World Health Organization, more than 300 million clinical cases of mosquito-borne illnesses report each year. In order to understand the vector dynamics and its disease transmission potentiality, it is indispensable to study certain fitness components related to the vector globally. Therefore, understanding the mosquito diversity and exploiting the proximate mechanisms of host location in mosquitoes will help to reduce their interaction with human hosts and the management of the transmission of infectious diseases. The variety of mosquito species, particularly those that serve as vectors, is extremely high in Kerala. Here, the main mosquito-borne disease vectors that are abundant throughout the state are widely dispersed. Therefore, comprehensive information of the prevalence, distribution and biology of mosquitoes in the state would be useful for managing both present disease outbreaks and potential future outbreaks of diseases that are not now common in the state. The study area selected for the analysis was Mananthavady Taluk of Wayanad district, Kerala which is rich with different types of plantations, forest and urban and rural areas. The present work can be considered as a pioneer study from this area. During the study period (2019-2022), a total of 80 species of mosquitoes belonging to 12 genera in 6 tribes and 2 subfamilies were collected and identified based on taxonomic keys. The 29 mosquito species among the collected specimens are mosquito vectors belonging to five genera namely Aedes, Culex, Anopheles, Mansonia and Armigeres. 21 species of mosquitoes and two genera namely Malaya and Lutzia are new reports to Kerala. The taxonomy of mosquitoes has been enhanced by two new records (Uranotaenia sp.) from the region. 35 mosquito species coming under 7 genera were barcoded using marker genes. The mitochondrial cytochrome oxidase I (CO I) gene sequences obtained were deposited in NCBI GenBank for worldwide accession with respective accession numbers Molecular Phylogeny of Subfamilies Anophelinae and Culicinae were discussed with the construction of Maximum likelihood tree. 44 species (29 vector species and 15 non vector species) of mosquitoes from five genera namely Aedes, Culex, Anopheles, Armigeres and Mansonia were chosen for blood meal analysis, and their host preferences were discussed. Considering that the sensillae are very important for mosquitoes for the host selection, morphological studies based on the sensillae of antennae, maxillary palps and proboscis of 19 blood feeding female mosquitoes and one non blood feeding female mosquitoe (Mal.genurostris) were conducted along with their host preferences. The findings of the study are highly significant for the future references and for designing effective prevention and control strategies to mitigate the public health impact of mosquito-borne diseases.