A well coordinated neuro-olfactory regulation is essential for a successful host seeking and blood feeding behavior of adult female mosquitoes. Although, the crucial role of mosquito tiny brain during host selection/choice is of prime interest but how blood meal uptake modulate brain functions which consequently empower the cognition in mosquitoes remains unclear. Here we report that blood meal induced gut 'metabolic switch' shift brain function from external communication to inter-organ management. An exclusive induction of oxidation reduction associated proteins and enhancement of brain's energy metabolism indicate the active functioning of the brain probably to maintain physiological homeostasis. A spatial and temporal change in the expression pattern of neuro-signaling molecules and other neuro-modulators in the brain designate that a guided neuro-stimulation and endocrine regulation is enough to manage the brain-distant organ communication. Analogous to brain, significant modulation of the neuro-modulator receptor genes in the gut signifies its function as 'Second Brain' during metabolic switch in mosquitoes. Furthermore, quantitative analysis of neuro-transmitters (NTs)revealed that the gut of mosquitoes is one of the potent source of NTs during altered metabolic conditions. Finally, quantitative data on NTs dynamics of naïve and aseptic mosquitoes establish the concept of microbiome-gut-brainaxis communication in adult female mosquitoes.
Graphical abstract:Introduction:Central nervous system i.e. the brain is a privileged organ in shaping animal's behavior from lower to higher taxa of which insect's tiny brain is famous for performing amazingly sophisticated behavior. Thus, insects are either enough smart to squeeze more information from limited number of neurons or they use some different algorithms to process information in their microscopic brain system [1]. In particular to mosquitoes, while navigating towards a vertebrate host for blood feeding the brain engagement of adult female mosquitoes is more complex than any other insect species [2][3][4][5]. A crucial interaction of olfactory derived odorant binding proteins (OBPs) and olfactory receptors (Ors) with the environmental guided chemical cues may have direct impact on mosquito's behavioural properties [6,7]. But how this chemical information influences decision
Results & DiscussionHypothesis: Since, neuro system is a versatile centre of chemical information exchange, we hypothesize a minor change in the innate physiological status may have strong impact on mosquito's day to day life. Importantly blood meal uptake causes a drastic metabolic changes, which we named "gut metabolic switch", engages multiple organs simultaneously. We hypothesize that upon blood feeding mosquitoes' brain functions may shift from external communication to internal management such as (a) initiation of diuresis b) finding a resting site for digestion of blood meal in the midgut; (c) distribution of amino acids, generated through the degradation of protein rich blood meal; ...