Significant role of symbiotic bacteria in the blood digestion and reproduction of Dermanyssus gallinae mites

Abstract

Endosymbiotic bacteria exert profound effects on the fitness of their arthropod hosts. Dermanyssus gallinae, the poultry red mite, is a blood-feeding ectoparasite that feeds solely on the blood of its avian hosts. A relatively comprehensive understanding of its microbial community structures across developmental stages based on 16S rRNA sequencing is available. Yet, their functional integration within the host's physiology remains elusive. This study endeavors to illuminate the role of symbiotic bacteria in the biology of D. gallinae mites. 16S rRNA amplicon sequencing and fluorescence in situ hybridization revealed a prominent midgut-confinement bacterial microbiota with considerable diversity, out of which Kocuria and Bartonella A acted as the predominant bacterial genera inhabiting D. gallinae. The relative abundance of Bartonella A exhibited rapid increments subsequent to blood-sucking, reflecting the bacteria's adaptation to grow in blood or indicating its pivotal role in the mites' post-engorgement life activities. Some of the isolated bacterial strains from D. gallinae display hemolytic activity on blood agar, which could potentially contribute to the blood digestion process in mites. To corroborate this in vivo, antibiotic-mediated clearance was exploited to generate dysbiosed cohorts of D. gallinae mites, lacking some of the key bacterial species. Phenotypic scoring of dysbiosed D. gallinae mites revealed that this cohort resulted in delayed blood digestion and diminished reproductive capacity. Whole genome sequencing revealed that Bartonella A, identified as a new species within the genus Bartonella, displays the characteristics of an obligate symbiont. These findings underscore the significance of microbiota in poultry red mites and suggest microbiota-targeted strategies for controlling mite populations in poultry farms.