SUMMARY During the lifespans of most animals, reproductive maturity and mating activity are highly coordinated. In Drosophila melanogaster, for instance, male fertility increases with age and older males are known to have a copulation advantage over young ones. The molecular and neural basis of this age-related disparity in mating behavior is unknown. Here we show that the Or47b odorant receptor is required for the copulation advantage of older males. Notably, the sensitivity of Or47b neurons to a stimulatory pheromone, palmitoleic acid, is low in young males but high in older ones, which accounts for older males’ higher courtship intensity. Mechanistically, this age-related sensitization of Or47b neurons requires a reproductive hormone, juvenile hormone, as well as its binding protein Methoprene-tolerant in Or47b neurons. Together, our study identifies a direct neural substrate for juvenile hormone that permits coordination of courtship activity with reproductive maturity to maximize male reproductive fitness.
Mechanisms by which G-protein-coupled odorant receptors transduce information in insects still need elucidation. We show that mutations in the Drosophila gene for G q ␣ (dgq) significantly reduce both the amplitude of the field potentials recorded from the whole antenna in responses to odorants as well as the frequency of evoked responses of individual sensory neurons. This requirement for G q ␣ is for adult function and not during antennal development. Conversely, brief expression of a dominant-active form of G q ␣ in adults leads to enhanced odor responses. To understand signaling downstream of G q ␣ in olfactory sensory neurons, genetic interactions of dgq were tested with mutants in genes known to affect phospholipid signaling. dgq mutant phenotypes were further enhanced by mutants in a PLC (phospholipase C) gene, plc21C. Interestingly although, the olfactory phenotype of mutant alleles of diacylglycerol kinase (rdgA) was rescued by dgq mutant alleles. Our results suggest that G q ␣-mediated olfactory transduction in Drosophila requires a phospholipid second messenger the levels of which are regulated by a cycle of phosphatidylinositol 1,4-bisphosphate breakdown and regeneration.
Sensory perception modulates health and aging across taxa. Understanding the nature of relevant cues and the mechanisms underlying their action may lead to novel interventions that improve the length and quality of life. We found that in the vinegar fly, Drosophila melanogaster , exposure to dead conspecifics in the environment induced cues that were aversive to other flies, modulated physiology, and impaired longevity. The effects of exposure to dead conspecifics on aversiveness and lifespan required visual and olfactory function in the exposed flies. Furthermore, the sight of dead flies was sufficient to produce aversive cues and to induce changes in the head metabolome. Genetic and pharmacologic attenuation of serotonergic signaling eliminated the effects of exposure on aversiveness and lifespan. Our results indicate that Drosophila have an ability to perceive dead conspecifics in their environment and suggest conserved mechanistic links between neural state, health, and aging; the roots of which might be unearthed using invertebrate model systems.
Olfactory responses of Drosophila undergo pronounced changes after eclosion. The flies develop attraction to odors to which they are exposed and aversion to other odors. Behavioral adaptation is correlated with changes in the firing pattern of olfactory receptor neurons (ORNs). In this article, we present an information-theoretic analysis of the firing pattern of ORNs. Flies reared in a synthetic odorless medium were transferred after eclosion to three different media: (i) a synthetic medium relatively devoid of odor cues, (ii) synthetic medium infused with a single odorant, and (iii) complex cornmeal medium rich in odors. Recordings were made from an identified sensillum (type II), and the Jensen-Shannon divergence (D JS ) was used to assess quantitatively the differences between ensemble spike responses to different odors. Analysis shows that prolonged exposure to ethyl acetate and several related esters increases sensitivity to these esters but does not improve the ability of the fly to distinguish between them. Flies exposed to cornmeal display varied sensitivity to these odorants and at the same time develop greater capacity to distinguish between odors. Deprivation of odor experience on an odorless synthetic medium leads to a loss of both sensitivity and acuity. Rich olfactory experience thus helps to shape the ORNs response and enhances its discriminative power. The experiments presented here demonstrate an experience-dependent adaptation at the level of the receptor neuron.imaginal conditioning | sensory adaptation | odor imprinting | JensenShannon divergence | chemo receptor tuning O lfaction in the fruit fly, Drosophila melanogaster, is crucial for a variety of behaviors, including associative learning (1, 2), courtship (3), foraging (4), and flight (5, 6). Odorants are detected by approximately 1,300 olfactory receptor neurons (ORNs), which are housed in sensilla on the third antennal segment and individually express one of approximately 50 functional odor receptors in adults (7-9). All ORNs expressing the same olfactory receptor project to one of approximately 50 glomeruli in the antennal lobe, where they synapse with a set of projection neurons (PNs) (10, 11). The activity of ORNs, either excitation or inhibition, provides behaviorally relevant information about odorants such as their identity, concentration, and source. The information transduced by an ORN is processed in the antennal lobe (12, 13) and sent via PNs to the mushroom bodies, which are believed to be centers for olfactory learning and memory (14, 15).Experience-dependent modifiability (i.e., plasticity) of olfactory representation at the level of the central nervous system is well known (2,16,17). Relatively little attention has been paid to long-term changes in sensory neuron activity resulting from odor experiences. It was previously shown that exposure of newly born imago to a particular set of odorants alters their responses to these odors (18,19). The flies develop an attraction to the chemicals to which they are exposed and an av...
Chemotactic responses of Drosophila to certain esters and alcohols are experience dependent. When the flies are exposed after eclosion to these chemicals, the odorants become strongly attractive. We show that behavioral conditioning is accompanied by an increase in the electrophysiological responses of single neurons in sensilla basiconica. Sensitization involves odorants that act on a common olfactory receptor. The possible mechanism of imaginal conditioning and its ecological and evolutionary significance are discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.