Helicoverpa armigera is a typical polyphagous species whose larvae primarily bore in flower buds and fruits of host plants, causing serious damage to many crops. Olfaction plays a key role in host selection, but the molecular basis of olfactory perception in larvae is poorly understood. Herein, we identified a highly expressed odorant receptor, HarmOr54, in larval antennae through qRT-PCR and in situ hybridization experiments. Drosophila T1 neurons expressing HarmOr54 ectopically showed specific responses to (-)-bornyl acetate and 2-ethylhexyl acetate. CRISPR/Cas9-generated homozygous mutant larvae lost avoidance to (-)-bornyl acetate, unlike wild-type larvae, while 2-ethylhexyl acetate showed no behavioral effect. Structural modeling and docking revealed that both ligands bound to the same HarmOr54 pocket, but (-)-bornyl acetate displayed stronger binding affinity. These findings enhance our understanding of the olfactory mechanisms in lepidopteran larvae and provide new insights into pest control strategies targeting the larval stage.

The majority of pheromone receptors (PRs) in the cotton bollworm Helicoverpa armigera have been deorphanized, but the function of HarmOR11, a PR highly expressed in both male and female antennae, has remained controversial. We expressed HarmOR11 in Drosophila T1 neurons and found that the neurons respond to plant volatiles benzyl acetate, methyl phenylacetate, and methyl benzoate. When we knocked out HarmOR11 by CRISPR-Cas9, the type A sensilla on the male antennae lost responsiveness to all the three compounds and the enhancing effect of the three compounds on behavioral responses of males toward the sex pheromone disappeared; the trichoid sensilla on female antennae responsive to all the three compounds, originally accounting for 15.38% on wild-type antennae, were no longer responsive, and female preference for oviposition in proximity to these compounds significantly decreased. The discovery advances understanding of PR function evolution and provides new opportunities for enhancing the attractiveness of pheromone traps.

Myo-inositol, a sugar alcohol produced by most plants, serves as a nutrient and feeding stimulant for many phytophagous insects. Inositol-sensitive taste sensilla have been characterized in many Lepidoptera larvae, but their molecular bases remain unclear. In this study, we determined the gustatory receptors (GRs) for myo-inositol in larva of Helicoverpa armigera, a worldwide crop pest. First, electrophysiological analyses revealed that medial sensilla styloconica strongly responded to myo-inositol and ribose, with weaker responses to xylose, and one GRN inside sensillum may mediate the response to these three chemicals. Based on phylogenetic analysis of sugar GRs of Lepidoptera insects and previous results on Bombyx mori, we then selected two candidate GR, HarmGR13 and HarmGR11. Using CRISPR-Cas9, we generated knockout mutants for two genes. Knocking out HarmGR13 abolished the responses of the sensilla to myo-inositol, ribose, and xylose, while knocking out HarmGR11 showed no changes. Behavioral assays confirmed that larvae of HarmGR13 homozygous mutant lost the feeding preference to myo-inositol which the wild-type larvae had. Further functional analysis with Xenopus oocytes expressing system and two-electrode voltage-clamping demonstrated that myo-inositol and ribose specifically induced concentration-dependent currents in HarmGR13-expressing oocytes. Structural predictions and molecular docking of HarmGR13 revealed three amino acid residues potentially involved in ligand binding. Mutation of these residues resulted in loss of oocyte responses to myo-inositol and ribose. We reveal that HarmGR13 is a receptor that mediates the activity of the cells sensitive to inositol and ribose in larvae, providing new molecular targets for the strategy of regulating the feeding behavior of pests by modifying taste.

Sex pheromone communication is an essential component of mate recognition in moths. In this study, we heterologously expressed male-biased pheromone receptors (PRs) of diamondback moths, Plutella xylostella, in Drosophila OR67d neurons and determined their responses toward sex pheromonal compounds. The neurons expressing PxylOR59, PxylOR13, and PxylOR46 specifically responded to three sex pheromone components, Z11-16:Ald, Z11-16:Ac, and Z11-16:OH, respectively. The most effective ligands of other three PRs, PxylOR47, PxylOR49, and PxylOR73 were Z11-14:Ac, Z9,E12-14:Ac, and Z9,E11-14:Ac, respectively. Interestingly, the last two PRs were also tuned to Z11-14:Ac, which was not present in the pheromone glandular extract of P. xylostella in previous studies. Y-tube olfactometer assays revealed that the sex pheromone blend mixed with Z11-14:Ac at a ratio of 100:0.1 attracted more virgin males compared to the sex pheromone blend. These findings improve our understanding of the olfactory coding mechanisms in this important pest and provide promising potential for enhancing insect capture of pheromone traps.

Foraging and food consumption are fundamental for the survival of animals. In natural environments, wild rodents feed on insects, including moth larvae, and odor-guided evaluation of potential food resources is a critical step in initiating feeding behavior. However, the mechanisms by which rodents seek and feed on insect prey remain poorly understood. Herein, we employed a laboratory-based predator-prey interaction system using mice and cotton bollworm larvae to investigate the neural mechanisms underlying food-seeking and feeding behaviors at both cellular and neural circuit levels. We demonstrate that mice exhibit a strong preference for consuming fed larvae, and this preference is dependent on the main olfactory system. Gas chromatography-mass spectrometry analysis revealed significant differences in the chemical profiles of fed and unfed larvae, with fed larvae containing a higher level of linoleic acid (LA) and a lower level of (Z)-9-tricosene [(Z)-9-TE]. Behavioral assays showed that mice, as well as Brand's voles and brown rats, are attracted to LA but avoid (Z)-9-TE in a two-choice odor preference test. Furthermore, we identified that the dopaminergic pathway from the ventral tegmental area (VTA) to the medial olfactory tubercle (mOT) plays a central role in mediating this preference. Chemogenetic inhibition of this pathway abolished the preference for LA over (Z)-9-TE, while chemogenetic activation reversed this effect. Additionally, fiber photometry recordings and pharmacology revealed that mOT D1 and D2 spiny projection neurons preferentially mediate attraction to LA and avoidance of (Z)-9-TE, respectively. These findings uncover a neurobiological system in rodents that supports insect predation based upon chemosignals.

Sexual dimorphism is a crucial aspect of morphological and behavioral traits in animals. Unlike males, adult female locusts, i.e., Locusta migratoria, have highly extensible abdominal intersegmental membranes (ISMs) that facilitate deep oviposition into the soil, displaying an iconic sexual dimorphism, but the underlying mechanisms remain largely unknown. Here, we reveal that the extremely extensible ISMs in adult females are predominantly controlled by two female-specific proteins, LmAbd-1 and LmAbd-6, ensuring the oviposition behavior. Moreover, we discovered that LmJHBP, a juvenile hormone (JH) binding protein specifically expressed in adult female ISMs, mediates JH signaling to induce LmAbd-1 and LmAbd-6 expression. Importantly, the sex differentiation pathway (i.e., Tra-2 and Dsx) determines the female-specific expression pattern of LmJHBP, and thus those of JH signaling and LmAbd-1 and LmAbd-6 expression. The finding of Tra/Dsx-JHBP axis significantly advanced understanding of sexual dimorphism and the adaptation of oviposition behavior in insects, the evolutionarily successful "segmentation" animals.

High-salt diets (HSD) are known to cause renal injury and hypertension in mice, rats, or even humans. Desert rodents have evolved an ability to adapt to water scarcity and concentrated electrolytes in vegetation over a long evolutionary period. However, how the desert rodent species adapt to salty diets remains rarely studied. In this study, we revealed the different adaptive mechanisms in water-sodium regulation using Mongolian gerbils (Meriones unguiculatus) and C57BL/6J mice fed with HSD (containing 4% and 8% NaCl concentrations) as models. The HSD mice showed concentration-dependent reductions in body mass and solute-free water clearance, and increases in total solute excretion, associated with increased nocturnal blood pressure and daily energy expenditure compared with the control mice. In contrast, the HSD gerbils maintained the same body mass and blood pressure as the control gerbils, and adjusted urine osmolality and food intake to achieve water and sodium balance. Transcriptomic and qPCR analysis revealed differential expression of genes related to water and sodium balance, with downregulation of Slc14a2, Nos1, and Corin, and upregulation of Sgk1, Cyp4a14, and Cyp4a10, and upregulation in antioxidative response genes including Gsta1, Gsta2, Gstm3, and Hmgcs2 in mice. However, a small number of differential genes were observed in Mongolian gerbils, with increased Gjb6 and decreased Aqp4 expression related to water-balance regulation, and increased expression of the fibrosis-suppressing gene Grem2. Our study uncovers the unique renal adaptive mechanisms in desert mammals through upregulation of Gjb6 and downregulation of Aqp4 expression for coping with high-salt and arid environments.

BACKGROUND:Chemosensory detection of sugars is crucial to the feeding and oviposition of herbivorous insects. The fall armyworm Spodoptera frugiperda is an invasive polyphagous insect in China, but its molecular and regulatory basis of sugar perception remains elusive. In this study, we investigated the molecular mechanism for sugar sensation in this species. RESULTS:The phylogenetic analysis found that sugar gustatory receptors (GRs) formed species-specific branches, and Group II sugar GRs are highly conserved, with the highest identity between SfruGR6 and HarmGR6. The oocyte expressing SfruGR6 responded to fucose and sucrose by using the Xenopus oocyte expression system. The larval sensilla styloconica have fucose-sensitive gustatory receptor neurons (GRNs), and the neural firing rates from medial sensilla styloconica towards fucose were higher than that in lateral sensilla styloconica. Fucose acts as a feeding stimulant, while sustained feeding of fucose caused the reduction of larval weight and the survival rate of female adults, but had no effect on the pupa weight and period. Ingestion of fucose alters the composition and abundance of gut microbiota in larvae, resulting in the abundance increase of Exceevirus Xc38, Escherichia coli, Klebsiella pneumoniae, and the decrease of Enterococcus casseliflavus, Microbacterium sp. Be9, Enterococcus faecium, and Enterococcus mundtii. CONCLUSION:These findings reveal that SfruGR6 is a sugar GR tuned to fucose and sucrose, and ingestion of fucose negatively affects growth and survival by regulating gut microbiota in S. frugiperda. This work not only enriches the knowledge of co-evolution between insects and plants, but also provides new insights into pest control strategies. © 2025 Society of Chemical Industry.

Ongoing climate warming, particularly intensifying heatwaves, imposes substantial physiological stress on small mammals. Although heat-induced responses have been extensively studied in laboratory models, little is known about how wild small mammals respond to acute thermal stress. To address this gap, we investigated the physiological responses of Brandt's voles (Lasiopodomys brandtii), a diurnal herbivorous rodent native to typical steppe regions of Inner Mongolia, under acute heat exposure (36 °C). Heat-treated voles showed a 1.4 °C rise in core body temperature and a 37 % reduction in metabolic rate, accompanied by a phase advance in the circadian rhythm and the emergence of an 11.8 h ultradian rhythm. Gene expression profiling revealed upregulation of circadian repressors (Per2 and Cry1) and pro-inflammatory genes (Nfκb or Il1α) in the hypothalamus, liver and brown adipose tissue (BAT), and tissue-specific alterations in thermogenic regulators (Pgc1α). Concurrent with these changes, serum TNF-α levels elevated, IL-6 reduced, and thyroxine (T4) increased, while serum T3 remained stable. Correlation analyses showed that Per2 and Cry1 expression in the liver, but not in the hypothalamus or BAT, were positively associated with serum TNF-α, whereas in the hypothalamus and BAT, clock genes were primarily linked to local inflammatory markers such as Nfκb and Il1α. Network modeling further identified Per2 and Bmal1 as central hub genes across tissues, orchestrating regulatory interactions with both inflammatory and metabolic genes. These findings suggest that heat-induced circadian disruption involves tissue-specific interactions between clock genes and immune-metabolic signals, underscoring the circadian system's key role in coordinating adaptive responses to acute thermal stress.

BACKGROUND:Contact chemoreception plays a crucial role in host-plant recognition and acceptance of herbivorous insects; however, the mechanisms by which peripheral taste inputs regulate insect feeding remain unclear. The aim of this study is to clarify the ecological significance of sugar and bitter gustatory receptors (Grs) in the relationship between Helicoverpa armigera and its hostplants. RESULTS:Blocking the positive input via knocking out Gr10 only leads to an increase in palpating frequency, and decreases in both the feeding time and the amounts of larvae on palatable fruit substrates, thereby prolonging the larval stage. Blocking the positive input via knocking out Gr6 only results in a decreased percentage of the proboscis extension reflex (PER) to sucrose and a reduced sucrose intake of adults, thus weakening their ability to detect nectar and decreasing longevity and fecundity. Blocking the negative inputs via knocking out Gr180 decreases palpating frequency and increases both feeding time and amount on unpalatable leaf substrates, leading to early larval mortality and a loss of aversion in adults to coumarin. CONCLUSION:These results indicate that Gr10 is crucial for larvae and Gr6 for adults in tasting some palatable foods, while Gr180 is important for both larvae and adults in avoiding some unpalatable foods. These findings enhance the understanding of how feeding behavior is controlled by taste neuron input in this polyphagous moth species. © 2025 Society of Chemical Industry.

Pieris butterflies recognize host Brassicaceae plants via sensing glucosinolates, but the molecular mechanism remains unclear. Here, we cloned five gustatory receptor genes highly expressed in larval mouthparts, adult foreleg tarsi, and the proboscis of Pieris rapae and then ectopically expressed each of them in Gr5a neurons of Drosophila and determined responses of the neurons to glucosinolates. Among them, only Gr5a > PrapGr19 neurons respond to gluconapin dose-dependently. Knockdown of PrapGr19 by 52.3% significantly reduces the firing rate of the lateral sensilla styloconica in the fifth instar larvae of P. rapae to gluconapin but has no effect on the responses to sinigrin and sucrose. This leads to the loss of the feeding preference of larvae for gluconapin and Cleome spinosa. All these results indicate PrapGr19 is the receptor mediating P. rapae larvae sensing gluconapin, which provides new knowledge for revealing molecular bases of glucosinolate sensing in Pieris butterflies.

Parasitoids are vital biological control agents in agricultural pest management, with mating and parasitism as their core behaviors essential for reproduction and survival. In recent decades, advanced analytical techniques, such as gas chromatography-electroantennographic detection (GC-EAD), have enabled the identification of key semiochemicals that regulate parasitoid behavior. Notably, studies on Campoletis chlorideae (Hymenoptera: Ichneumonidae) have elucidated the mechanisms of sex pheromone communication, advancing our understanding of pheromonal signaling in parasitoids. Moreover, plant-derived synomones and host-derived kairomones serve as pivotal chemical cues for host location, underpinning tritrophic (plant–pest–parasitoid) interactions. The functional characterization of olfactory receptors tuned to herbivore-induced plant volatiles and kairomones, achieved through ectopic expression systems, has further clarified the molecular mechanism underlying semiochemical-mediated behaviors. Synthetic biology offers promising avenues for manipulating parasitoid behavior by leveraging genetic and metabolic engineering of plants and yeast to release critical synomones and kairomones, thereby improving parasitoid recruitment. This review synthesizes the role of semiochemicals in mediating parasitoid behaviors, evaluates methodologies for behavioral manipulation, and explores the potential and limitations of integrating synthetic biology with semiochemicals to advance sustainable pest management.

Almost all herbivorous insects feed on plants and use sucrose as a feeding stimulant, but the molecular basis of their sucrose reception remains unclear. Helicoverpa armigera as a notorious crop pest worldwide mainly feeds on reproductive organs of many plant species in the larval stage, and its adult draws nectar. In this study, we determined that the sucrose sensory neurons located in the contact chemosensilla on larval maxillary galea were 100–1000 times more sensitive to sucrose than those on adult antennae, tarsi, and proboscis. Using the Xenopus expression system, we discovered that Gr10 highly expressed in the larval sensilla was specifically tuned to sucrose, while Gr6 highly expressed in the adult sensilla responded to fucose, sucrose and fructose. Moreover, using CRISPR/Cas9, we revealed that Gr10 was mainly used by larvae to detect lower sucrose, while Gr6 was primarily used by adults to detect higher sucrose and other saccharides, which results in differences in selectivity and sensitivity between larval and adult sugar sensory neurons. Our results demonstrate the sugar receptors in this moth are evolved to adapt toward the larval and adult foods with different types and amounts of sugar, and fill in a gap in sweet taste of animals.

BACKGROUND Omnivores, including humans, have an inborn tendency to avoid risky or non-nutritious foods. However, relatively little is known how animals perceive and discriminate nutritious foods from risky substances. In this study, we explored the mechanism of feeding selection in Ostrinia furnacalis larvae, one of the most destructive pests to the maize crop. RESULTS We identified a gustatory receptor, Gr43a for feeding regulation in larvae of Ostrinia furnacalis, which highly expresses in the mouthparts of the 1st (the period of just hatching out from eggs) and 5th instar larvae (the period of gluttony). The Gr43a regulates foraging plasticity by discriminating sorbitol - a non-sweet nutritious substance and sucralose - a sweet non-nutritious substance through the labra of mouthparts, while it differentiates fructose/sucrose and sucralose via the sensilla styloconica of mouthparts. Specially, Gr43a responds to fructose and sucrose via the medial and lateral sensilla styloconica in O. furnacalis, respectively. Furthermore, Gr43a is negatively regulated by the neuropeptide F (NPF) system, a homologous mammalian NPY neuropeptide system. CONCLUSION This study reveals a smart feeding strategy for animals to meet both nutritional needs and sweet gratification, and offers an insight into a complex feeding selections dependent on food resources in the surrounding environment. This article is protected by copyright. All rights reserved.

The tobacco cutworm Spodoptera litura is one of the most destructive polyphagous crop pests. Olfaction and taste play a crucial role in its host plant selection and sexual communication, but the expression profile of chemosensory genes remains unclear. In this study, we identified 185 chemosensory genes from 7 organs in S. litura by transcriptome sequencing, of which 72 genes were published for the first time, including 27 odorant receptors (ORs), 26 gustatory receptors (GRs), 1 ionotropic receptor (IR), 16 odorant-binding proteins (OBPs), and 2 chemosensory proteins (CSPs). Phylogenetic analyses revealed that ORs, IRs, OBPs, and sensory neuron membrane proteins (SNMPs) were mainly expressed in antennae and sequence-conserved among Noctuidae species. The most differentially expressed genes (DEGs) between sexes were ORs and OBPs, and no DEGs were found in GRs. GR transcripts were enriched in proboscis, and the expression of sugar receptors was the highest. Carbon dioxide receptors, sugar receptor-SliuGR6, and bitter GRs-SlituGR43 and SlituGR66 had higher sequence identities between Noctuidae species. CSPs were broadly expressed in various organs, and SlituCSP13 was a DEG in adult antennae. The functional analysis in the Drosophila OR67d expression system found that SlituOR50, a receptor highly expressed in female antennae, is selectively tuned to farnesyl acetate. The results provide a solid foundation for understanding the molecular mechanisms by which chemosensory genes operate to elicit behavioral responses in polyphagous insects.

Ambient temperatures have great impacts on thermoregulation of small mammals. Brown adipose tissue (BAT), an obligative thermogenic tissue for small mammals, is localized not only in the interscapular depot (iBAT), but also in supraclavicular, infra/subscapular, cervical, paravertebral, and periaortic depots. The iBAT is known for its cold-induced thermogenesis, however, less has been paid attention to the function of BAT at other sites. Here, we investigated the function of BAT at different sites of the body during cold acclimation in a small rodent species. As expected, Brandt's voles (Lasiopodomys brandtii) consumed more food and reduced the body mass gain when they were exposed to cold. The voles increased resting metabolic rate and maintained a relatively lower body temperature in the cold (36.5 ± 0.27 °C) compared to those in the warm condition (37.1 ± 0.36 °C). During cold acclimation, the uncoupling protein 1 (UCP1) increased in aBAT (axillary), cBAT (anterior cervical), iBAT (interscapular), nBAT (supraclavicular), and sBAT (suprascapular). The levels of proliferating cell nuclear antigen (PCNA), a marker for cell proliferation, were higher in cBAT and iBAT in the cold than in the warm group. The pAMPK/AMPK and pCREB/CREB were increased in cBAT and iBAT during cold acclimation, respectively. These data indicate that these different sites of BAT play the cold-induced thermogenic function for small mammals.

Time-restricted feeding (TRF) has the potential to modulate circadian rhythm and widely studied in humans and laboratory mice. However, less is known about the physiological responses to TRF in wild mammals. Here, we used Mongolian gerbils, Meriones unguiculatus, to explore the effect of 6-week TRF on gene expression related with circadian rhythm and inflammation. The TRF gerbils had higher cumulative food intake than the ad libitum (AL) group, but body mass, feeding frequency/time and metabolic rate did not differ between groups. In the hypothalamus, downregulation of circadian genes Per3, Cry1 and Dbp was detected in the daytime-restricted feeding (DRF) group and Cry1 was downregulated in the nighttime-restricted feeding (NRF) group. In the liver, the expression of Per1/3, Rev-erbα/β and Dbp was lower, and Bmal1 was higher in the DRF than in AL group, while NRF gerbils showed no changes. In the colon, the expression of Bmal1 and Cry1 was higher but Per3, Rev-erbα/β and Dbp were lower in the DRF than in AL group. Further, the expression of inflammation-related genes such as NF-κB, IL-1β, IL-18 and Nlrp3 was lower in the liver of DRF gerbils, and IL-1β was lower both in the hypothalamus and liver of NRF gerbils. Moreover, the genes related with inflammation such as NF-κB, Nlrp3, IL-10/18/1β and Tnf-α were positively or negatively correlated with multiple rhythm-related genes in the central and peripheral organs. In conclusion, TRF, particularly DRF, could modulate rhythm-related genes in the central and peripheral tissues and reduce hepatic expression of inflammation-related genes in gerbils.

Leptin is a hormone that is secreted by adipocytes and may promote energy expenditure by increasing thermogenesis. Our previous studies have shown that thermo-transient receptor potentials (thermo-TRPs) and gut microbiota are associated with thermoregulation in Mongolian gerbils, which are characterized by relative high serum leptin concentrations. Here, we tested whether leptin can stimulate non-shivering thermogenesis (NST) in Mongolian gerbils, and whether thermo-TRPs and gut microbiota are involved in leptin-induced thermogenesis. First, gerbils were given acute leptin treatment (ALT) with different doses. Results showed that ALT significantly increased the body temperature of gerbils and changed the composition of gut microbiota. Moreover, ALT groups showed a trend towards increased expression of uncoupling protein 1 (UCP1) in brown adipose tissue (BAT). Then, we investigated the effect of chronic leptin treatment (CLT) on gerbils. Surprisingly, CLT did not affect gerbils' food intake and body mass, but it significantly increased the body temperature at the end. Further, CLT did not affect the expression of thermogenic markers in BAT, white adipose tissue (WAT) or skeletal muscle. However, CLT increased the expression of leptin receptors and TRPV2 in the small intestine and affected the composition of gut microbiota. Together, our data suggest leptin may increase body temperature by regulating gut microbiota. In conclusion, serum hyperleptin in Mongolian gerbils is beneficial for adapting to cold environments, and TRPV2 and gut microbiota are involved.

Semiochemicals are dominant cues for insects to locate food, mates, predators, and oviposition sites. In the modern genomic era, semiochemicals have been identified not only by the conventional chemical ecology based on bioassay-guided protocols but also by reverse chemical ecology started with deorphanization of olfactory proteins with high olfactory sensitivity and selectivity. The Scarab beetle, Anomala corpulenta , is a polyphagous pest, posing a substantial economic burden to agricultural, horticultural, and forestry industries. Here, we focused on four odorant receptors (ORs) abundantly expressed in the antennae. We heterologously expressed them in Xenopus oocytes and examined their responses to a panel of 22 odorants. Of the ORs, AcorOR29 was specifically tuned to a common floral compound, phenethyl propionate (PEP). Further, gas chromatography coupled with electroantennographic detection showed that PEP elicited a strong electrophysiological response from antennae. Y-tube olfactometer assay and field trap experiment demonstrated that PEP is attractive for both sexes of A. corpulenta across a wide range of concentrations, potentiating PEP in practical applications. Our results show that the reverse chemical ecology approach is effective in identifying semiochemicals for A. corpulenta , which would help to formulate novel strategies to control this pest.