Attractive Odor Research Articles

Tachykinin-1-expressing parasubthalamic nucleus neurons are necessary for odorant-induced appetite suppression.

Odorants play a critical role in regulating feeding behavior by signaling potential threats or food sources in the environment. However, the neural mechanisms by which odorants affect feeding are not well understood. Tachykinin-1-expressing neurons in the parasubthalamic nucleus (PSTNTac1 neurons) are critical for reducing food intake in response to internal appetite-suppressing hormones, gastric distension, and external cues that signal danger. Therefore, we tested the hypothesis that activity in these neurons is modulated by exposure to aversive, attractive, and neutral odorants. Using fiber photometry in mice, we found that PSTNTac1 neurons increase activity in response to the aversive predator odorants 2-methyl-2-thiazoline (2MT) and 2,5-dihydro-2,4,5-trimethylthiazoline (TMT), but not to neutral or attractive odorants. This activation correlates with a reduction in food intake and an increase in the latency to initiate feeding. Furthermore, chemogenetic inhibition of PSTNTac1 neurons blocks the suppression of feeding caused by 2MT and TMT. These findings highlight the specificity of PSTNTac1 neurons in processing aversive olfactory signals and their critical role in integrating external threat cues with internal signals that regulate appetite.

Differential Coding of Fruit, Leaf, and Microbial Odours in the Brains of Drosophila suzukii and Drosophila melanogaster.

Drosophila suzukii severely damages the production of berry and stone fruits in large parts of the world. Unlike D. melanogaster, which reproduces on overripe and fermenting fruits on the ground, D. suzukii prefers to lay its eggs in ripening fruits still on the plants. Flies locate fruit hosts by their odorant volatiles, which are detected and encoded by a highly specialised olfactory system before being translated into behaviour. The exact information-processing pathway is not yet fully understood, especially the evaluation of odour attractiveness. It is also unclear what differentiates the brains of D. suzukii and D. melanogaster to cause the crucial difference in host selection. We hypothesised that the basis for different behaviours is already formed at the level of the antennal lobe of D. suzukii and D. melanogaster by different neuronal responses to volatiles associated with ripe and fermenting fruit. We thus investigated by 3D in vivo two-photon calcium imaging how both species encoded odours from ripe fruits, leaves, fermented fruits, bacteria, and their mixtures in the antennal lobe. We then assessed their behavioural responses to mixtures of ripe and fermenting odours. The neural responses reflect species-dependent shifts in the odour code. In addition to this, morphological differences were also observed. However, this was not directly reflected in different behavioural responses to the odours tested.

Enhancing the Trapping of Melon Fruit Fly, Zeugodacus cucurbitae Coquilette through Synergizing the Odour and Visual Cues

The melon fruit fly (Zeugodacus cucurbitae Coquillett) poses a significant threat to cucurbit crops with substantial yield losses and challenging sustainable vegetable production. This study systematically investigated efficient color-based visual cues for attracting melon flies and explored the synergistic effects of these visual cues in conjunction with odour cues. This study was conducted in Agricultural College and Research Institute, TNAU, Madurai during 2024. Our studies included investigations on preferred colour by melon fly through olfactometer & insect cage bioassays in no choice & multiple choice conditions. The additive effect of the preferred colour when combined with the fruit fly attractive odour cue was investigated under field conditions. For both male and female melon fruit flies, yellow colour (RBG coordinates - 255:255:0) consistently emerged as the most efficient visual cue followed by white (255:255:255) and red (255:0:0). Field trials also confirmed the attractiveness of yellow colour as it outperformed other colours. The visual cue, yellow colour and odour cue (synthetic blend of four fruit fly EAG active synthetic compounds in a known ratio) were combined and found to be synergistic as this fusing captured significantly more flies than the either cues alone. These results highlighted the yellow colour as the most attractive visual cue for melon flies and combining effective of visual cues with established odour attractant to greatly enhance the trapping efficiency. This integrated approach offers a promising strategy for the management of melon fly and reduction of reliance on chemical pesticides contributing to more sustainable pest control in cucurbit production. The findings have significant implications for pest management strategies, especially in regions facing melon fly infestations that threaten crop yields and export potential.

The AWC OFF neuron is important for attraction to 1-butanol in Caenorhabditis elegans.

C. elegans uses chemosensation to recognize a variety of odors, many of which are released by bacteria, the major food source of C. elegans . Specific amphid sensory neurons are known to detect different odorants. Here we show that the AWC OFF neuron detects the attractive odorant 1-butanol. Because few odorants that are specifically recognized by the AWC OFF neuron have been identified, we hope that the identification of this additional odorant will facilitate studies of the role of the AWC OFF neuron in odor detection and discrimination.

Direct and delayed effect of the plant Cleome amblyocarpa Barratte & Murb (Capparidaceae) on the two species of (Blattodea) Blattella germanica (Linnaeus, 1767) and Shelfordella lateralis (Walker, 1868)

Finding substantial substitution of chemical pesticides to control cockroaches, which were proved to have a link with multiple health issues, has become the major target of many researchers. In fact, subjecting this pest to the effects of toxic plants extracts is considered ideal to primarily avoid jeopardizing human health. This study is divided into two objectives. The first of which is to confirm the toxicity of the ethanoic extract from the Cleome arabica plant on two species of urban cockroaches; which are Bllattella germanica and Bllatta lateralis, while the second is to verify the effect of the attractive odor of the extract on the feeding behavior of the two already mentioned species. Therefore, the findings demonstrated that, on the one hand, the extract causes a mortality rate of 60% of B. germanica after 30 days of treatment at a high concentration of (3g/l). On the other hand, mortality rate in B. lateralis does not exceed 6.7%. Further, findings exhibited that the proportion of B. germanica attracted by the smell of the plant soaked in hexane at a specified time (15, 30 and 60 minutes) was estimated at 40%, whereas that of B. lateralis exceeded 60%. The results of this work suggest the presence of toxic substances in the studied extract which may lead to the development of bio-insecticides based on Cleome arabica to be used in the pesticide market.

Inhibitory control of locomotor statistics in walking Drosophila.

In order to forage for food, many animals regulate not only specific limb movements but the statistics of locomotor behavior over time, switching between long-range dispersal and localized search depending on resource availability. How pre-motor circuits regulate such locomotor statistics is not clear. Here we analyze and model locomotor statistics in walking Drosophila , and their modulation by attractive food odor. Odor evokes three motor regimes in flies: baseline walking, upwind running during odor, and search behavior following odor loss. During search behavior, we find that flies adopt higher angular velocities and slower ground speeds, and tend to turn for longer periods of time in one direction. We further find that flies spontaneously adopt periods of different mean ground speed, and that these changes in state influence the length of odor-evoked runs. We next developed a simple model of neural locomotor control that suggests that contralateral inhibition plays a key role in regulating the statistical features of locomotion. As the fly connectome predicts decussating inhibitory neurons in the lateral accessory lobe (LAL), a pre-motor structure, we gained genetic access to a subset of these neurons and tested their effects on behavior. We identified one population of neurons whose activation induces all three signature of search and that bi-directionally regulates angular velocity at odor offset. We identified a second group of neurons, including a single LAL neuron pair, that bi-directionally regulate ground speed. Together, our work develops a biologically plausible computational architecture that captures the statistical features of fly locomotion across behavioral states and identifies potential neural substrates of these computations.

The Orbitofrontal Cortex Is Required for Learned Modulation of Innate Olfactory Behavior.

Animals have evolved innate responses to cues including social, food, and predator odors. In the natural environment, animals are faced with choices that involve balancing risk and reward where innate significance may be at odds with internal need. The ability to update the value of a cue through learning is essential for navigating changing and uncertain environments. However, the mechanisms involved in this modulation are not well defined in mammals. We have established a new olfactory assay that challenges a thirsty mouse to choose an aversive odor over an attractive odor in foraging for water, thus overriding their innate behavioral response to odor. Innately, mice prefer the attractive odor port over the aversive odor port. However, decreasing the probability of water at the attractive port leads mice to prefer the aversive port, reflecting a learned override of the innate response to the odors. The orbitofrontal cortex (OFC) is a fourth-order olfactory brain area, involved in flexible value association, with behaviorally relevant outputs throughout the limbic system. We performed optogenetic and chemogenetic silencing experiments that demonstrate the OFC is necessary for this learned modulation of innate aversion to odor. Further, we characterized odor evoked c-fos expression in learned and control mice and found significant suppression of activity in the bed nucleus of the stria terminalis, lateral septum, and central and medial amygdala. These findings reveal that the OFC is necessary for the learned override of innate behavior and may signal to limbic structures to modulate innate response to odor.

Binary mixtures of Vanderbilt University allosteric agonist thermolysis components act as volatile spatial repellents for malaria vector mosquitoes.

The development of economically viable and environmentally neutral tools to control insects that consume or damage over 20% of global agriculture or vector human and animal disease represents one of the most important challenges of the 21st century. The suite of chemical-based strategies currently employed to control insect populations rely primarily on insecticides, which are subject to rapid resistance and often have harmful off-target environmental and health-related impacts, and, to a lesser degree, repellents, which typically rely on masking attractive odors. The discovery and characterization of Vanderbilt University allosteric agonists (VUAAs), a family of small-molecule agonists that target the highly conserved, insect-specific odorant receptor coreceptor (Orco), raise the potential for the development of a novel repellent paradigm for vector/pest management. VUAAs have the potential to target nearly all insect olfactory sensory neurons, leading to highly aversive behavioral responses, but importantly have limited volatility, thereby reducing their utility as spatial repellents. We have characterized VUAA thermolysis components and identified a suite of volatiles (VUAA-based active ingredients, VUAIs) that act specifically in novel binary combinations as robust and long-lasting spatial repellents against Anopheline mosquitoes. In mobility-based behavioral experiments, VUAIs act synergistically as effective spatial repellents and outperform parent VUAA compounds against host-seeking Anopheline mosquitoes. VUAIs are volatile alternatives to Vanderbilt University allosteric agonists (VUAAs) that have the potential for use as spatial repellents in disease vector and agricultural pest control. The repellency observed is odorant receptor coreceptor (Orco)-dependent, supporting the hypothesis that VUAIs and VUAAs similarly target an allosteric Orco recognition site. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Binding characteristics and structural dynamics of two general odorant-binding proteins with plant volatiles in the olfactory recognition of Glyphodes pyloalis

Glyphodes pyloalis Walker (Lepidoptera: Pyralidae) is the most destructive pest, causing severe damage to mulberry production in China's sericulture industry. The insecticide application in mulberry orchards poses a significant risk of poisoning to Bombyx mori. Shifting from insecticides to odor attractants is a beneficial alternative, but not much data is available on the olfactory system of G. pyloalis. We identified 114 chemosensory genes from the antennal transcriptome database of G. pyloalis, with 18 odorant-binding protein (OBP) and 17 chemosensory protein (CSP) genes significantly expressed in the antennae. Ligand-binding assays for two antennae-biased expressed general odorant-binding proteins (GOBPs) showed high binding affinities of GOBP1 to hexadecanal, β-ionone, and 2-ethylhexyl acrylate, while GOBP2 exhibited binding to 4-tert-octylphenol, benzyl benzoate, β-ionone, and farnesol. Computational simulations indicated that van der Waal forces predominantly contributed to the binding free energy in the binding processes of complexes. Among them, Phe12 of GOBP1 and Phe19 of GOBP2 were demonstrated to play crucial roles in their bindings to plant volatiles using site-directed mutagenesis experiments. Moreover, hexadecanal and β-ionone attracted G. pyloalis male moths in the behavioral assays, while none of the candidate plant volatiles significantly affected female moths. Our findings provide a comprehensive understanding of the molecular mechanisms underlying olfactory recognition in G. pyloalis, setting the groundwork for novel mulberry pests control strategies based on insect olfaction.

Morphological characterization and distribution of antennal sensilla of Spodoptera frugiperda (Lepidoptera: Noctuidae) using scanning electron microscopy.

The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a globally significant agricultural pest, causing severe damage to corn production in China. Chemical odor-based trapping is a major approach for FAW control, making it essential to understand the FAW antennal sensillum types to enhance development of effective chemical odor attractants. In this study, we comprehensively examined the antennal sensilla types of FAW, identifying eight types and two subtypes, including Böhm's bristles, sensilla trichoidea, sensilla chaetica (I and II), sensilla coeloconica, sensilla styloconica, sensilla squamiformia (I and II), sensilla auricillica, and sensilla basiconica. Sensilla chaetica II, and sensilla squamiformia II are reported for the first time for FAW in this study. Detailed low-voltage field emission scanning electron microscope (LVSEM) images and descriptions are provided for each sensillum type. This study provides the morphological information to aid in conducting antennal sensillum neurophysiological tests on FAW. RESEARCH HIGHLIGHTS: The types of sensilla of fall armyworm were examined, identifying eight types and two subtypes, including Böhm's bristles, sensilla trichoidea, sensilla chaetica (I and II), sensilla coeloconica, sensilla styloconica, sensilla squamiformia (I and II), sensilla auricillica, and sensilla basiconica. Detailed low-voltage field emission scanning electron microscope images and descriptions were provided for each sensillum type.

Multimodal interactions in Stomoxys navigation reveal synergy between olfaction and vision

Stomoxys flies exhibit an attraction toward objects that offer no rewards, such as traps and targets devoid of blood or nectar incentives. This behavior provides an opportunity to develop effective tools for vector control and monitoring. However, for these systems to be sustainable and eco-friendly, the visual cues used must be specific to target vector(s). In this study, we modified the existing blue Vavoua trap, which was originally designed to attract biting flies, to create a deceptive host attraction system specifically biased toward attracting Stomoxys. Our research revealed that Stomoxys flies are attracted to various colors, with red proving to be the most attractive and selective color for Stomoxys compared to the other colors tested. Interestingly, our investigation of the cattle–Stomoxys interaction demonstrated that Stomoxys flies do not prefer a specific livestock fur color phenotype, despite variation in the spectrum. To create a realistic sensory impression of the trap in the Stomoxys nervous system, we incorporated olfactory cues from livestock host odors that significantly increased trap catches. The optimized novel polymer bead dispenser is capable of effectively releasing the attractive odor carvone + p-cresol, with strong plume strands and longevity. Overall, red trap baited with polymer bead dispenser is environmentally preferred.

Volatile chemical cues emitted by an agricultural companion plant (Cnidium monnieri) attract predatory lacewings (Chrysoperla sinica)

Plant volatiles play an important role in the recruitment of arthropod natural enemies and are widely used in foraging by many species. Therefore, identification of plants that release useful volatile organic compounds (VOCs) for influencing natural enemies and for the control of pests can be helpful in conservation biological control. Cnidium monnieri (L.) can convene many predatory enemies (lady beetles, hoverflies, lacewings) as a functional plant. The Chrysoperla sinica (Tjeder) is a dominant generalist predator, and can control the population of various pests in agricultural fields. However, how C. monnier recruits C. sinica and the chemical association between them is unknown. In this study, we tested the attractiveness of odor released by flowers and leaves of C. monnieri to C. sinica in Y-tube olfactometer. Next, we conducted solid phase microextraction (SPME), gas chromatography-mass spectrometry (GC–MS), and electrophysiological studies (EAG) to analyze the compounds and identified the volatile components which have effects on C. sinica. We also used a Y-tube olfactometer to verify the effectiveness of the volatile components on C. sinica under laboratory conditions. In olfactometer trials, C. sinica adults preferred flowers compared with leaves and fresh air. In GC–MS and electroantennography trials, seventy-six volatiles extracted from C. monnieri, twelve antenna-active components in three different concentrations (0.1 μg/mL, 1 μg/mL, 10 μg/mL) were detected for electroantennography. In the last behavioral identification assays, four synthetic compounds (10 μg/mL) had significant attractiveness of adult C. sinica antenna (i.e., γ-terpinene, trans-β-Ocimene, nerolidol, (Z)-3-Hexen-1-ol). These studies suggest that there is a chemical association between natural enemies C. sinica and the functional plant C. monnieri. This study provides a basis that can facilitate the production and application of attracting natural enemy and development and application of enhancing attractants.

To attract a moth: Wind tunnel and field testing of plant odor and light stimuli and their combination for Ostrinia nubilalis

AbstractThe European corn borer, Ostrinia nubilalis (Hubner), relies on multimodal sensory information to find food, mates, mating and ovipositional grounds. Successful phytosanitary monitoring demands for the bait for the field traps to obtain the most reliable representation of pest abundance. Attraction to light and blend of key components of host plant odor, was tested both in the laboratory and field conditions. Ultraviolet light, which was the most effective in the wind tunnel experiments, was further tested in the field alone and in combination with bisexual lure. Bisexual lure, being attractive in the lab, as well as in the field, did not improve responses to ultraviolet in both experimental designs. All three baits attracted significantly more females than males in the field. Wind tunnel experiments revealed that ultraviolet elicited the shortest response latencies either alone or paired with the odor bait. The lack of synergistic effect between attractive light and odor stimuli is an important issue for pest monitoring. The possible reasons for the observed lack of synergy are the hierarchy of behavioral responses to different stimuli or the intensities of both stimuli are critically important for attractivity of combined stimulus and differ from separately presented ones.

Transgenic line for characterizing GABA-receptor expression to study the neural basis of olfaction in the yellow-fever mosquito.

The mosquito Aedes aegypti is an important vector of diseases including dengue, Zika, chikungunya, and yellow fever. Olfaction is a critical modality for mosquitoes enabling them to locate hosts, sources of nectar, and sites for oviposition. GABA is an essential neurotransmitter in olfactory processing in the insect brain, including the primary olfactory center, the antennal lobe. Previous work with Ae. aegypti has suggested that antennal lobe inhibition via GABA may be involved in the processing of odors. However, little is known about GABA receptor expression in the mosquito brain, or how they may be involved in odor attraction. In this context, generating mutants that target the mosquito's olfactory responses, and particularly the GABAergic system, is essential to achieve a better understanding of these diverse processes and olfactory coding in these disease vectors. Here we demonstrate the potential of a transgenic line using the QF2 transcription factor, GABA-B1QF2-ECFP, as a new neurogenetic tool to investigate the neural basis of olfaction in Ae. aegypti. Our results show that the gene insertion has a moderate impact on mosquito fitness. Moreover, the line presented here was crossed with a QUAS reporter line expressing the green fluorescent protein and used to determine the location of the metabotropic GABA-B1 receptor expression. We find high receptor expression in the antennal lobes, especially the cell bodies surrounding the antennal lobes. In the mushroom bodies, receptor expression was high in the Kenyon cells, but had low expression in the mushroom body lobes. Behavioral experiments testing the fruit odor attractants showed that the mutants lost their behavioral attraction. Together, these results show that the GABA-B1QF2-ECFP line provides a new tool to characterize GABAergic systems in the mosquito nervous system.

Dietary E. coli promotes age-dependent chemotaxis decline in C. elegans

An animal’s ability to sense odors declines during aging, and its olfactory drive is tuned by internal states such as satiety. However, whether internal states modulate an age-dependent decline in odor sensation is unknown. To address this issue, we utilized the nematode Caenorhabditis elegans and compared their chemotaxis abilities toward attractive odorants when aged under different dietary conditions. Feeding with the standard laboratory diet, Escherichia coli attenuated the chemotaxis ability toward diacetyl, isoamyl alcohol, and benzaldehyde when aged. On the other hand, feeding with either the lactic acid bacteria Lactobacillus reuteri or food deprivation selectively maintained the chemotaxis ability toward diacetyl. Our results suggest that ingestion of E. coli causes age-dependent chemotaxis decline. The changes in the chemotaxis behavior are attributed to the different expressions of diacetyl receptor odr-10, and the chemotaxis behavior of aged animals under food deprivation is shown to be dependent on daf-16. Our study demonstrates the molecular mechanism of how diet shapes the trajectory of age-dependent decline in chemosensory behaviors.

Age-related differences in perception and coding of attractive odorants in mice

Hedonic perception deeply changes with aging, significantly impacting health and quality of life in elderly. In young adult mice, an odor hedonic signature is represented along the antero-posterior axis of olfactory bulb, and transferred to the olfactory tubercle and ventral tegmental area, promoting approach behavior. Here, we show that while the perception of unattractive odorants was unchanged in older mice (22 months), the appreciation of some but not all attractive odorants declined. Neural activity in the olfactory bulb and tubercle of older mice was consistently altered when attraction to pleasant odorants was impaired while maintained when the odorants kept their attractivity. Finally, in a self-stimulation paradigm, optogenetic stimulation of the olfactory bulb remained rewarding in older mice even without ventral tegmental area’s response to the stimulation. Aging degrades behavioral and neural responses to some pleasant odorants but rewarding properties of olfactory bulb stimulation persisted, providing new insights into developing novel olfactory training strategies to elicit motivation even when the dopaminergic system is altered as observed in normal and/or neurodegenerative aging.

Descending control and regulation of spontaneous flight turns in Drosophila

The clumped distribution of resources in the world has influenced the pattern of foraging behavior since the origins of locomotion, selecting for a common search motif in which straight movements through resource-poor regions alternate with zig-zag exploration in resource-rich domains. For example, during local search, flying flies spontaneously execute rapid flight turns, called body saccades, but suppress these maneuvers during long-distance dispersal or when surging upstream toward an attractive odor. Here, we describe the key cellular components of a neural network in flies that generate spontaneous turns as well as a specialized pair of neurons that inhibits the network and suppresses turning. Using 2-photon imaging, optogenetic activation, and genetic ablation, we show that only four descending neurons appear sufficient to generate the descending commands to execute flight saccades. The network is organized into two functional units-one for right turns and one for left-with each unit consisting of an excitatory (DNae014) and an inhibitory (DNb01) neuron that project to the flight motor neuropil within the ventral nerve cord. Using resources from recently published connectomes of the fly, we identified a pair of large, distinct interneurons (VES041) that form inhibitory connections to all four saccade command neurons and created specific genetic driver lines for this cell. As predicted by its connectivity, activation of VES041 strongly suppresses saccades, suggesting that it promotes straight flight to regulate the transition between local search and long-distance dispersal. These results thus identify the key elements of a network that may play a crucial role in foraging ecology.

The conserved RNA-binding protein Imp is required for the specification and function of olfactory navigation circuitry in Drosophila

Complex behaviors depend on the precise developmental specification of neuronal circuits, but the relationship between genetic programs for neural development, circuit structure, and behavioral output is often unclear. The central complex (CX) is a conserved sensory-motor integration center in insects, which governs many higher-order behaviors and largely derives from a small number of type II neural stem cells (NSCs). Here, we show that Imp, a conserved IGF-II mRNA-binding protein expressed in type II NSCs, plays a role in specifying essential components of CX olfactory navigation circuitry. We show the following: (1) that multiple components of olfactory navigation circuitry arise from type II NSCs. (2) Manipulating Imp expression in type II NSCs alters the number and morphology of many of these circuit elements, with the most potent effects on neurons targeting the ventral layers of the fan-shaped body (FB). (3) Imp regulates the specification of Tachykinin-expressing ventral FB input neurons. (4) Imp is required in type II NSCs for establishing proper morphology of the CX neuropil structures. (5) Loss of Imp in type II NSCs abolishes upwind orientation to attractive odor while leaving locomotion and odor-evoked regulation of movement intact. Taken together, our findings establish that a temporally expressed gene can regulate the expression of a complex behavior by developmentally regulating the specification of multiple circuit components and provides a first step toward a developmental dissection of the CX and its roles in behavior.

Precise sensorimotor control impacts reproductive fitness of C. elegans in 3D environments.

The ability of animals to sense and navigate towards relevant cues in complex and elaborate habitats is paramount for their survival and reproductive success. The nematode Caenorhabditis elegans uses a simple and elegant sensorimotor program to track odors in its environments. Whether this allows the worm to effectively navigate a complex environment and increase its evolutionary success has not been tested yet. We designed an assay to test whether C. elegans can track odors in a complex 3D environment. We then used a previously established 3D cultivation system to test whether defect in tracking odors to find food in a complex environment affected their brood size. We found that wild-type worms can accurately migrate toward a variety of odors in 3D. However, mutants of the muscarinic acetylcholine receptor GAR-3 which have a sensorimotor integration defect that results in a subtle navigational defect steering towards attractive odors, display decreased chemotaxis to the odor butanone not seen in the traditional 2D assay. We also show that the decreased ability to locate appetitive stimuli in 3D leads to reduced brood size not observed in the standard 2D culture conditions. Our study shows that mutations in genes previously overlooked in 2D conditions can have a significant impact in the natural habitat, and highlights the importance of considering the evolutionary selective pressures that have shaped the behavior, as well as the underlying genes and neural circuits.

The health perception of urban green spaces and its emotional impact on young adults: an empirical study from three cities in China.

Exposure to green space can bring many benefits to physical and mental health, but in China, the attractiveness of green space to youth groups seems to be not significant. The question of how to encourage young people to go out of the house to better perceive green space, enjoy nature, and promote physical and mental health is on our minds. This study combines young people's green space perception, green space use, and purpose of visit to explore its impact on the emotional health of youth groups, combined with the PANAS psychological data scale, an online questionnaire survey of 426 residents (18-35 years old) in three Chinese cities, and was used to construct a multiple regression model and AMOS structural equations. The results of the study showed that, firstly, environmental attractiveness, environmental odor, and number of facilities were the key factors influencing adolescents' landscape perception evaluation, while activity space, environmental odor, and environmental attractiveness had a greater impact on adolescents' emotional well-being. Second, among adolescents' visit purposes, socializing and fitness were more likely to help them generate positive emotions while resting and viewing activities were effective in helping them alleviate negative emotions. In addition, in terms of usage, residents who took public transportation as well as those who arrived on foot were the most emotionally healthy. The findings of this paper provide insights for public policymakers, urban planners, and landscape architects to better encourage youth participation in green spaces when they are installed.