Search Results (28)

Sensory systems allow the detection of external and internal cues essential for adaptive responses. Chemosensation exemplifies this integration, guiding feeding, mating, and toxin avoidance while also influencing physiological regulation. Across taxa, chemical detection relies on diverse receptor families, and emerging evidence reveals that transient receptor potential (TRP) channels—traditionally associated with phototransduction, thermosensation, and mechanotransduction—also mediate chemosensory functions. Studies in Drosophila melanogaster and vertebrates demonstrate that TRPs detect tastants, odorants, and internal chemical states, highlighting their evolutionary conservation and functional versatility. This review synthesizes current insights into the roles of TRP channels across four major domains: taste, smell, internal state, and central circuit modulation. Using D. melanogaster and mammalian systems as comparative frameworks, we highlight how TRP channels function as polymodal sensors, signal amplifiers, and modulators embedded within canonical receptor pathways rather than as standalone chemoreceptors. Recognizing these integrative functions not only expands our understanding of how organisms coordinate behavior with internal states but also points to TRP channels as potential targets for addressing chemosensory disorders and metabolic diseases. This framework highlights key directions for future research into TRP-mediated sensory and homeostatic regulation. Full article

Insect parasitoids are key biological agents within terrestrial ecosystems, offering a promising avenue for controlling insect pests. Hyperparasitoids are a group of insects that lay their eggs in or on the body of parasitoid hosts, which can greatly hamper the effectiveness of parasitoids. To optimize their reproductive success, adult parasitoids/hyperparasitoids must find sufficient food sources and mate partners (when they do not reproduce parthenogenetically) and locate suitable hosts for their offspring. To complete these tasks, parasitoids largely rely on their ability to detect relevant chemical cues (semiochemicals or infochemicals). In the last three decades, the identities of semiochemicals and their ethological significance have been widely characterized, and the possibility of using these chemical cues in insect pest management has received a lot of attention. Insects have evolved a highly sensitive and sophisticated chemosensory system adept at navigating complex and dynamic chemical environments. In this review, we first summarize the semiochemicals used by insect parasitoids, primarily including semiochemicals involved in food location, host foraging, and mate finding, while also addressing semiochemicals employed by hyperparasitoids. Next, we discuss recent progress in elucidating the chemosensory mechanisms underlying parasitoid responses to semiochemicals, with a focus on olfactory and gustatory pathways. Finally, we evaluate the potential applications of semiochemicals in pest management, highlighting the roles of parasitoids and hyperparasitoids. This paper aims to establish a theoretical framework for the effective employment of parasitoids in biological control of insect pests. Full article

Rivomarginella morrisoni is a freshwater snail endemic to Thailand, yet its behavioral ecology remains poorly understood. This study described the feeding behavior of R. morrisoni, focusing on its foraging activity, behavioral patterns, and food detection mechanisms under laboratory conditions using specimens collected from four river basins in central Thailand. Daily monitoring revealed nocturnal emergence, peaking between 21:00 and 22:00 h, with stable rhythms established 72 h post-feeding. Feeding trials revealed a preference for aged shrimp over fresh or decayed ones. Behavioral observations confirmed that food localization in R. morrisoni was mediated by chemical cues. Light–dark tests indicated a slight tendency toward darkness, but no significant phototactic response was observed. These findings suggest that R. morrisoni is a generalist scavenger with chemosensory-driven foraging and nocturnal activity. Its apparent sensitivity to habitat disturbance underscores the relevance of behavioral studies for informing future conservation and captive breeding efforts. Full article

The parasitoid wasp Dolichogenidea gelechiidivoris is a key koinobiont solitary endoparasitoid of the invasive agricultural pest Tuta absoluta. This study investigates both the morphological and molecular foundations of sex-specific olfactory differentiation in this species. Morphological analysis revealed that males possess significantly longer antennae (2880.8 ± 20.36 μm) than females (2137.23 ± 43.47 μm), demonstrating pronounced sexual dimorphism. Scanning electron microscopy identified similar sensilla types on both sexes, but differences existed in the length and diameter of specific sensilla. Transcriptomic analysis of adult antennae uncovered molecular differentiation, identifying 11 odorant-binding proteins (OBPs) and 20 odorant receptors (ORs), with 27 chemosensory genes upregulated in females and 4 enriched in males. Integrating morphological and molecular evidence demonstrates complementary sexual specialization in the olfactory apparatus of D. gelechiidivoris. Linking these findings to the potential functions of different sensilla types, as discussed in the context of prior research, provides crucial insights into the sex-specific use of volatile cues. These findings provide critical insights into the use of volatile signals in this highly relevant species for biological control targeting T. absoluta. Full article

Chemical communication is based on the release of chemical cues, including odorants, tastants and semiochemicals, which can be perceived by animals and trigger physiological and behavioral responses. These compounds exhibit a wide size and properties range, spanning from small volatile molecules to soluble proteins, and are perceived by various chemosensory receptors (CRs). The structure of these receptors is very well conserved across all organisms and within the family to which they belong, the G-protein-coupled receptor (GPCR) family. It is characterized by highly conserved seven-transmembrane (7TM) α-helices. However, the characteristics of these proteins and the methods used to study their structures are limiting factors for resolving their structures. Due to the importance of CRs—especially olfactory and taste receptors, responsible for two of our five basic senses—alternative methods are utilized to overcome these structural challenges. Indeed, in silico structural biology is an expanding field that is very useful for CR structural studies. Since the 1960s, many algorithms have been developed and improved in an attempt to resolve protein structure. We review the current knowledge regarding different vertebrate CRs in this study, with an emphasis on the in silico structural methods employed to improve our understanding of CR structures. Full article

Lampreys are primitive fish that rely significantly on olfactory cues throughout their complex life cycle. The olfactory system of the sea lamprey (Petromyzon marinus) is among the best characterized in vertebrates. In recent decades, tremendous advances have been made by isolating individual compounds from sea lampreys that can replicate natural behavior when artificially applied in the wild. In no other aquatic vertebrate has the olfactory ecology been described in such extensive detail. In the first section, we provide a comprehensive review of olfactory behaviors induced by specific, individual odorants during every major developmental stage of the sea lamprey in behavioral contexts such as feeding, predator avoidance, and reproduction. Moreover, pheromonal inputs have been shown to induce neuroendocrine responses through the hypothalamic-pituitary-gonadal axis, triggering remarkable developmental and physiological effects, such as gametogenesis and increased pheromone release. In the second section of this review, we describe a hypothetical endocrine signaling pathway through which reproductive fitness is increased following pheromone detection. In the final section of this review, we focus on the neuronal circuits that transform olfactory inputs into motor output. We describe specific brain signaling pathways that underlie odor-evoked locomotion. Furthermore, we consider possible modulatory inputs to these pathways that may induce plasticity in olfactory behavior following changes in the external or internal environment. As a whole, this review synthesizes previous and recent progress in understanding the behavioral, endocrine, and neuronal responses of lampreys to chemosensory signals. Full article

The increasing environmental and health concerns associated with synthetic pesticides underscore the need for sustainable alternatives in pest management. This study investigates the chemotactic responses of five nematode species—Heterorhabditis bacteriophora, Steinernema carpocapsae, Steinernema feltiae, Phasmarhabditis papillosa, and Oscheius myriophilus—to three major cannabinoids from Cannabis sativa: Δ⁹-tetrahydrocannabinol (THC), cannabigerol (CBG), and cannabidiol (CBD). Using a standardized chemotaxis assay, we quantified infective juvenile movement and calculated Chemotaxis Index (CI) values across varying cannabinoid concentrations. Our results revealed strong species-specific and dose-dependent responses. THC and CBG elicited significant attractant effects in P. papillosa, S. feltiae, and H. bacteriophora, with CI values ≥ 0.2, indicating their potential as behavioral modulators. In contrast, CBD had weaker or repellent effects, particularly at higher concentrations. O. myriophilus exhibited no consistent response, underscoring species-specific variation in chemosensory sensitivity. These findings demonstrate the potential utility of cannabinoids, especially THC and CBG, as biocompatible cues to enhance the efficacy of nematode-based biological control agents in integrated pest management (IPM). Further field-based studies are recommended to validate these results under realistic agricultural conditions. Full article

Chemosensation and mechanosensation are vital to insects’ survival and behavior, shaping critical physiological processes such as feeding, metabolism, mating, and reproduction. During feeding, insects rely on diverse chemosensory and mechanosensory receptors to distinguish between nutritious and harmful substances, enabling them to select suitable food sources while avoiding toxins. These receptors are distributed across various body parts, allowing insects to detect environmental cues about food quality and adjust their behaviors accordingly. A deeper understanding of insect sensory physiology, especially during feeding, not only enhances our knowledge of insect biology but also offers significant opportunities for practical applications. This review highlights recent advancements in research on feeding-related sensory receptors, covering a wide range of insect species, from the model organism Drosophila melanogaster to agricultural and human pests. Additionally, this review examines the potential of targeting insect sensory receptors for precision pest control. Disrupting behaviors such as feeding and reproduction emerges as a promising strategy for pest management. By interfering with these essential behaviors, we can effectively control pest populations while minimizing environmental impacts and promoting ecological balance. Full article

In numerous animals, one essential chemosensory organ that detects chemical signals is the vomeronasal organ (VNO), which is involved in species-specific behaviors, including social and sexual behaviors. The purpose of this study is to investigate the mechanism underlying the processing of chemosensory cues in semi-aquatic mammals using muskrats as the animal model. Muskrat (Ondatra zibethicus) has a sensitive VNO system that activates seasonal breeding behaviors through receiving specific substances, including pheromones and hormones. Vomeronasal organ receptor type 1 (V1R) and type 2 (V2R) and estrogen receptor α and β (ERα and ERβ) were found in sensory epithelial cells, non-sensory epithelial cells and lamina propria cells of the female muskrats’ VNO. V2R and ERα mRNA levels in the VNO during the breeding period declined sharply, in comparison to those during the non-breeding period, while V1R and ERβ mRNA levels were detected reversely. Additionally, transcriptomic study in the VNO identified that differently expressed genes might be related to estrogen signal and metabolic pathways. These findings suggested that the seasonal structural and functional changes in the VNO of female muskrats with different reproductive status and estrogen was regulated through binding to ERα and ERβ in the female muskrats’ VNO. Full article

Ocean acidification may diminish the response of many marine organisms to chemical cues that can be used to sense nearby food and predators, potentially altering community dynamics. We used a Y-maze choice experiment to investigate the impact of ocean acidification on the ability of mud snails (Ilyanassa obsoleta) to sense food cues in seawater. Mud snails have a well-adapted chemosensory system and play an important role in estuarine ecosystem functioning. Our results showed substantially diminished foraging success for the mud snail under acidified conditions, as snails typically moved towards the food cue in controls (pH 8.1) and away from it in acidified treatments (pH 7.6). These results, coupled with previous work, clearly demonstrate the magnitude at which ocean acidification may impair foraging efficiency, potentially resulting in severe alterations in future ecosystem dynamics. Full article

Chemical communication is very important in herbivorous insects, with many species being important agricultural pests. They often use olfactory cues to find their host plants at a distance and evaluate their suitability upon contact with non-volatile cues. Responses to such cues are modulated through interactions between various stimuli of biotic and abiotic origin. In addition, the response to the same stimulus can vary as a function of, for example, previous experience, age, mating state, sex, and morph. Here we summarize recent advances in the understanding of plant localization and recognition in herbivorous insects with a focus on the interplay between long- and short-range signals in a complex environment. We then describe recent findings illustrating different types of plasticity in insect plant choice behavior and the underlying neuronal mechanisms at different levels of the chemosensory pathway. In the context of strong efforts to replace synthetic insecticides with alternative pest control methods, understanding combined effects between long- and close-range chemical cues in herbivore–plant interactions and their complex environment in host choice are crucial to develop effective plant protection methods. Furthermore, plasticity of behavioral and neuronal responses to chemical cues needs to be taken into account to develop effective sustainable pest insect control through behavioral manipulation. Full article

The insect odorant binding proteins (OBPs) and chemosensory proteins (CSPs) are involved in the perception and discrimination of insects to host odor cues. Nephotettix cincticeps, one of the destructive pests of rice plants, not only directly damages hosts by sucking, but also indirectly transmits plant viruses in the field. Previous study found that two rice volatiles ((E)-β-caryophyllene and 2-heptanol) induced by rice dwarf virus (RDV) mediated the olfactory behavior of N. cincticeps, which may promote virus dispersal. However, the OBPs and CSPs in N. cincticeps are still unknown. In this study, to identify the OBP and CSP genes in N. cincticeps, transcriptomic analyses were performed. In total, 46,623 unigenes were obtained. Twenty putative OBP and 13 CSP genes were discovered and identified. Phylogenetic analyses revealed that five putative OBPs belonged to the plus-C OBP family, and the other classic OBPs and CSPs were distributed among other orthologous groups. A total of 12 OBP and 10 CSP genes were detected, and nine OBP and three CSP genes were highly expressed in N. cincticeps antennae compared with other tissues. This study, for the first time, provides a valuable resource to well understand the molecular mechanism of N. cincticeps in the perception and discrimination of the two volatiles induced by RDV infection. Full article

Living organisms deeply rely on the acquisition of chemical signals in any aspect of their life, from searching for food, mating and defending themselves from stressors. Copepods, the most abundant and ubiquitous metazoans on Earth, possess diversified and highly specified chemoreceptive structures along their body. The detection of chemical stimuli activates specific pathways, although this process has so far been analyzed only on a relatively limited number of species. Here, in silico mining of 18 publicly available transcriptomes is performed to delve into the copepod chemosensory genes, improving current knowledge on the diversity of this multigene family and on possible physiological mechanisms involved in the detection and analysis of chemical cues. Our study identifies the presence of ionotropic receptors, chemosensory proteins and gustatory receptors in copepods belonging to the Calanoida, Cyclopoida and Harpacticoida orders. We also confirm the absence in these copepods of odorant receptors and odorant-binding proteins agreeing with their insect specificity. Copepods have evolved several mechanisms to survive in the harsh marine environment such as producing proteins to respond to external stimulii. Overall, the results of our study open new possibilities for the use of the chemosensory genes as biomarkers in chemical ecology studies on copepods and possibly also in other marine holozooplankters. Full article

The pine wood nematode (PWN) Bursaphelenchus xylophilus has caused disastrous losses of pine forests in many countries, and the success of PWN depends strongly on interactions with its insect vectors. Monochamus saltuarius is a newly recorded vector in Northeast China. Feeding (i.e., immature) and egg-laying (i.e., mature) Monochamus spp. target different host plants, and olfactory cues play important roles regarding host choice. Whether infestation with PWN affects olfactory mechanisms in M. saltuarius related to feeding and oviposition is of interest as this may affect the spread of nematodes to new healthy hosts. However, little is known about molecular mechanisms of the olfactory system of M. saltuarius. We identified chemosensory-related genes in adult M. saltuarius and examined the influence of B. xylophilus on the respective expression patterns. Fifty-three odorant-binding proteins (OBPs), 15 chemosensory proteins, 15 olfactory receptors (ORs), 10 gustatory receptors, 22 ionotropic receptors (IRs), and two sensory neuron membrane proteins were identified, and sex bias among non-infested beetles was mainly found with respect to expression of OBPs. Interestingly, OBPs and ORs were markedly down-regulated in male M. saltuarius infested with B. xylophilus, which may reduce olfactory sensitivity of male M. saltuarius and affect the spreading of B. xylophilus to new hosts. Our results will help understand the interactions between B. xylophilus and M. saltuarius, which may lead to the identification of new control targets in the olfactory system of M. saltuarius. Full article

From a unicellular bacterium to a more complex human, smell and taste form an integral part of the basic sensory system. In fruit flies Drosophila melanogaster, the behavioral responses to odorants and tastants are simple, though quite sensitive, and robust. They explain the organization and elementary functioning of the chemosensory system. Molecular and functional analyses of the receptors and other critical molecules involved in olfaction and gustation are not yet completely understood. Hence, a better understanding of chemosensory cue-dependent fruit flies, playing a major role in deciphering the host-seeking behavior of pathogen transmitting insect vectors (mosquitoes, sandflies, ticks) and crop pests (Drosophila suzukii, Queensland fruit fly), is needed. Using D. melanogaster as a model organism, the knowledge gained may be implemented to design new means of controlling insects as well as in analyzing current batches of insect and pest repellents. In this review, the complete mechanisms of olfactory and gustatory perception, along with their implementation in controlling the global threat of disease-transmitting insect vectors and crop-damaging pests, are explained in fruit flies. Full article