Biology subjects

Greppi, C.

Publications and source records attributed to Greppi, C..

3 recordsLinked to original sources

bioRxiv2025

A Signaling Hub in the Mosquito Rectum Coordinates Reproductive Investment After Blood Feeding

After a blood meal, female Aedes aegypti mosquitoes suppress host-seeking while converting ingested nutrients into yolk protein for egg development. Neuropeptide Y-like Receptor 7 (NPYLR7) is required for this behavioral switch, but its physiological role and sites of action were unknown. We identify a specialized, non-neuronal population of npylr7-expressing cells in the rectal pads of the mosquito hindgut. While this tissue is associated with fluid and ion balance, npylr7 mutants maintain fluid regulation but show impaired oocyte provisioning. These cells display neuroendocrine features, including calcium responses to the NPYLR7 ligand RYamide and amino acids, as well as expression of neurotransmitter synthesis and vesicle release machinery. Vesicle recruitment occurs in these cells post-blood meal in wild-type, but not npylr7 mutants. Our findings reveal an unexpected role for NPYLR7 in a rectal cell population senses nutritional cues and communicates with the nervous system to regulate reproductive physiology, paralleling gut-brain circuits in mammals.

neuroscience↗

bioRxiv2024

Circadian modulation of mosquito host-seeking persistence by Pigment-Dispersing Factor impacts daily biting patterns

Daily rhythms in mosquito attraction to humans are thought to drive biting patterns and contribute to disease transmission dynamics. Behavioral rhythms in many insects are controlled by specialized clock cells in the brain that are coordinated by the neuropeptide Pigment-Dispersing Factor (PDF). We show that female Aedes aegypti mosquitoes with genetically disrupted PDF display altered daily behavioral timing with reduced locomotor activity and biting in the morning. Using an automated behavioral tracking system, we also report that mosquitoes exhibit daily modulation of response persistence to the host cue carbon dioxide and loss of PDF alters this pattern. These findings indicate that PDF regulates temporal features of host-seeking behavior that promote biting success at specific times of day and may underlie blood feeding patterns observed in the field.

neuroscience↗

bioRxiv2022

Heat and humidity sensors that alert mosquitoes to nearby human hosts

Mosquito-borne diseases sicken >500,000,000 people annually, killing >500,0001. Mosquito host-seeking is guided by multiple host-associated cues, which combine to drive blood feeding in a manner that remains poorly understood2,3. While heat is a powerful mosquito attractant, recent studies indicate that disruption of heat seeking has little impact on host detection by the malaria vector Anopheles gambiae4, suggesting other cues act alongside heat in the complex sensory environment of a human host. Here we show mosquitoes require Ir93a (an Ionotropic Receptor5) to maintain attraction to a human host and feed on warmed blood. Using Ir93a, we uncover the previously uncharacterized mosquito hygrosensory system, and show Ir93a is required for humidity detection by humidity sensors (hygrosensors) as well as temperature detection by thermosensors, and for attraction to each stimulus. These findings indicate that hygrosensation and thermosensation function in parallel, driving host proximity detection in response to the overlapping heat and humidity gradients humans produce6,7. These host cue sensors appear to have arisen by co-opting existing sensors of physical cues rather than de novo, as Ir93a-dependent thermo- and hygro-sensors support physiological homeostasis in non-blood-feeding insects8-11. While Ir93a is conserved among arthropods, reliance on heat and humidity evolved independently in multiple blood-feeding lineages, suggesting multiple, vector-specific implementations of this common host-seeking strategy.

neuroscience↗