The genome of the stable fly, Stomoxys calcitrans, reveals potential mechanisms underlying reproduction, host interactions, and novel targets for pest control.

The stable fly, Stomoxys calcitrans, is a major blood-feeding pest of livestock that has near worldwide distribution, causing an annual cost of over $2 billion for control and product loss in the USA alone. Control of these flies has been limited to increased sanitary management practices and insecticide application for suppressing larval stages. Few genetic and molecular resources are available to help in developing novel methods for controlling stable flies. This study examines stable fly biology by utilizing a combination of high-quality genome sequencing and RNA-Seq analyses targeting multiple developmental stages and tissues. In conjunction, 1600 genes were manually curated to characterize genetic features related to stable fly reproduction, vector host interactions, host-microbe dynamics, and putative targets for control. Most notable was characterization of genes associated with reproduction and identification of expanded gene families with functional associations to vision, chemosensation, immunity, and metabolic detoxification pathways. The combined sequencing, assembly, and curation of the male stable fly genome followed by RNA-Seq and downstream analyses provide insights necessary to understand the biology of this important pest. These resources and new data will provide the groundwork for expanding the tools available to control stable fly infestations. The close relationship of Stomoxys to other blood-feeding (horn flies and Glossina) and non-blood-feeding flies (house flies, medflies, Drosophila) will facilitate understanding of the evolutionary processes associated with development of blood feeding among the Cyclorrhapha

Multiomic interpretation of fungus-infected ant metabolomes during manipulated summit disease

AbstractCamponotus floridanusants show altered behaviors followed by a fatal summiting phenotype when infected with manipulatingOphiocordyceps camponoti-floridanifungi. Host summiting as a strategy to increase transmission is also observed in parasite taxa beyond fungi, including aquatic and terrestrial helminths and baculoviruses. The drastic phenotypic changes observed likely reflect large physiological changes within host cells that span molecular levels from metabolites to nucleic acids. Nevertheless, the underlying mechanisms have not been fully characterized. To investigate the small molecules underlying summiting behavior, we infectedC. floridanusants withO. camponoti-floridaniand sampled their heads for LC-MS/MS when we observed the characteristic manipulation phenotype. We link this metabolomic data with our previous genomic and transcriptomic data to propose mechanisms that underly manipulated summiting behavior in “zombie ants.” This “multiomic” evidence points toward dysregulation of neurotransmitter levels and neuronal signaling. We propose that these processes are altered during infection and manipulation based on: 1) differential expression of neurotransmitter synthesis and receptor genes, 2) altered abundance of metabolites and neurotransmitters (precursors) with known behavioral effects in ants and other insects, and 3) possible suppression of a connected immunity pathway. We additionally report signals for fungal metabolic activity during manipulation and early evidence for alterations of host processes related to detoxification, anti-stress protectants, and insect hormone metabolism.</jats:p

Analysis of milk gland structure and function in Glossina morsitans: Milk protein production, symbiont populations and fecundity

1-ACL (articles avec comité de lecture)A key process in the tsetse reproductive cycle is the transfer of essential nutrients and bacterial symbionts from mother to intrauterine offspring. The tissue mediating this transfer is the milk gland. This work focuses upon the localization and function of two milk proteins (milk gland protein (GmmMGP) and transferrin (GmmTsf)) and the tsetse endosymbionts (Sodalis and Wigglesworthia), in the context of milk gland physiology. Fluorescent in situ hybridization (FISH) and immunohistochemical analysis confirm that the milk gland secretory cells synthesize and secrete milk gland protein and transferrin. Knockdown of gmmmgp by double stranded RNA (dsRNA) mediated RNA interference results in reduction of tsetse fecundity, demonstrating its functional importance in larval nutrition and development. Bacterial species-specific in situ hybridizations of milk gland sections reveal large numbers of Sodalis and Wigglesworthia within the lumen of the milk gland. Sodalis is also localized within the cytoplasm of the secretory cells. Within the lumen, Wigglesworthia localize close to the channels leading to the milk storage reservoir of the milk gland secretory cells. We discuss the significance of the milk gland in larval nutrition and in transmission of symbiotic bacteria to developing offspring