Chemical Ecology Research Articles (Page 1)

Citrus rust mite (Phyllocoptruta oleivora Ashmead) (Acari: Eriophyidae) (CRM) is a significant biotic stressor affecting citrus fruit quality by damaging the peel and inducing physiological and chemical alterations. This study explores the dual impact of mite infestation on the pomological traits and peel phytochemistry of Citrus sinensis (orange), with a focus on polymethoxyflavones (PMFs), a class of secondary metabolites associated with plant defense. Oranges with varying levels of visible CRM injury (INJ1 to INJ3) were compared to uninjured controls. Morphological analysis revealed significant reductions in fruit weight, size, peel thickness, and juice content with increasing injury severity, while total soluble solids (TSS) increased moderately. Phytochemical profiling of peel extracts obtained by subcritical water extraction and supercritical CO₂ extraction indicated a notable rise in PMFs content-from 3.8% in control samples to 9.5% in the most severely injured group. These biochemical and morphological changes together represent distinct stress fingerprints associated with CRM. Our results demonstrate that CRM infestation elicits a multifaceted plant response, simultaneously impairing physical fruit traits and activating secondary metabolism. The accumulation of PMFs in damaged peel suggests an induced defense mechanism that may serve as a biochemical marker of herbivore stress. These findings underscore the importance of integrating chemical ecology perspectives into citrus pest management and provide new insights into host-arthropod interactions in perennial crop systems.

The unique mutualism between male euglossine bees and the perfume flowers they pollinate in tropical America is one of the most iconic plant–pollinator associations, with a rich body of research incorporating chemical ecology, speciation, and natural history. Male bees collect species-specific blends of compounds from the environment to subsequently use during courtship display. As bees exhibit rapidly evolving olfactory preferences, divergence in floral scent causing visitation by different sets of bee species is thought to drive speciation of the plants via pollinator isolation. Here, we synthesize our current understanding of this specialized system, reviewing the extensive literature on chemical production and diversity in these plants with implications for speciation, and discuss broader patterns from biogeographic and macroevolutionary studies in the group. We highlight gaps in knowledge and propose promising future avenues of research.

Insects heavily depend on chemical communication to mediate ecological interactions, where specific compounds trigger distinct behavioral responses shaping their life history traits. Odorant-binding proteins (OBPs) are critical targets for identifying behavior-modulating compounds. Here, we employed a reverse chemical ecology approach to identify potential larval attractants of Spodoptera litura. This study first analyzed the tissue distribution and ligand-binding profile of S. litura OBP8 (SlitOBP8) using quantitative real-time PCR and fluorescence-based competitive binding assays, determined that SlitOBP8 was highly expressed in the antennae of larvae, and preliminarily screened 12 ligands. Subsequently, RNA interference (RNAi), site-directed mutagenesis, and behavioral assays were combined to functionally validate candidate odorants eliciting larval attraction. The results indicated that SlitOBP8 played a significant role in the process of larvae recognizing the 2-heptanone. Our findings deepen understanding of olfactory mechanisms underpinning host plant selection by insect herbivores and provide a foundation for novel behavior-based control strategies against S. litura.

Heat waves, brief periods of unusually high temperatures, are increasing in frequency and intensity globally. Such extreme weather events can alter plant chemistry, disrupting species interactions that contribute to pest suppression or increase their performance. Yet, most heat wave studies focus on pairwise interactions, leaving us with a poor understanding of how complex agroecosystems respond to temperature extremes. We addressed this knowledge gap by simulating an experimental heat wave in the field on potato plants (Solanum tuberosum L.) and the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), in the presence or absence of their mutualistic microbial symbionts and another pest, the potato aphid (Macrosiphum euphorbiae (Thomas)). We assessed beetle performance alongside changes in volatile organic compounds (VOCs) and glycoalkaloids from host plants. Beetle performance declined in the absence of their microbial symbionts and under aphid competition, but this effect was reversed under heat wave conditions. These results corresponded with a downregulation in glycoalkaloids, suggesting that potato prioritizes heat stress response over herbivore attack by divesting resources from the production of defensive compounds. The heat wave strongly affected VOCs composition, reducing emissions of multiple compounds while increasing others, but these changes were not directly linked with CPB performance. Overall, our results demonstrate that heat wave effects on crop-pest dynamics are dependent on the agroecological context and mediated by specialized metabolites. Importantly, under dual herbivore pressure, potato crops appear to prioritize coping with heat over defending against pests, underscoring the urgent need for pest management strategies that account for extreme climate events.

Fabre's nineteenth-century observation that smell is central to insect communication spurred entomologists and, later, chemical ecologists, neurobiologists, geneticists, structural biologists, and evolutionary biologists to investigate how insects detect survival-related compounds. Structural biologists resolved the three-dimensional structures of pheromone-binding proteins and odorant receptors (ORs), revealing features that enable specific interactions with semiochemicals. Researchers proposed that ORs evolved from gustatory receptors as insects adapted to terrestrial life and then specialized to detect species-specific sex pheromones. Most insects use both broadly and finely tuned receptors, but migratory locusts rely mainly on finely tuned ones. To test hypotheses, genes were silenced, expressed in empty neurons, or resurrected, leading to receptor de-orphanization and discovery of new semiochemicals through reverse chemical ecology. These receptors and coreceptors are expressed in olfactory receptor neurons (ORNs) within sensilla of the antennae and maxillary palps. Recent evidence suggests ORNs may express multiple receptor types, including odorant, ionotropic, and gustatory receptors.

The forked fungus beetle Bolitotherus cornutus has long served as a model organism for the study of population ecology, behavior, chemical ecology, and natural selection in the wild. Today, it has become one of the best model systems for the understanding of social evolution and group selection. To understand the mechanistic drivers of group selection and its ultimate evolutionary consequences, it is crucial to begin studying these traits at the molecular level. Here, we take the first necessary step towards these goals by producing a chromosome-level genome assembly for this species. Using a combination of PacBio HiFi and Hi-C sequencing technologies, we produce a 196 Mb genome assembly with ten major chromosomal scaffolds as well as an assembled mitochondrial genome. We also provide a carefully curated annotation of 12,459 protein-coding genes. The quality and completeness of these resources present essential tools for future genetic and genomic studies of B. cornutus.

Plant volatile organic compounds (VOCs) are key components in plant-insect interactions, greatly influencing herbivory, pollination and tritrophic interactions. Despite the growing body of research exploring the chemical, ecological and applied aspects of VOCs, a systematic bibliometric synthesis to consolidate existing knowledge and identify emerging trends is still lacking. This review employs bibliometric and thematic analyses on 362 peer-reviewed publications to map the intellectual landscape of VOC research in plant–insect ecology. Data were retrieved through a structured search strategy and screened based on language and publication type. Notable trends include a sharp rise in VOC-related publications after 2013, with major contributions from journals such as Journal of Chemical Ecology and New Phytologist. Leading authors such as M. Dicke and T.C.J. Turlings have helped shape the field's direction, while collaborative networks reveal strong international partnerships, especially among the US, China, Germany and the UK as determined by citation frequency and network centrality metrics. Thematic mapping shows central focus areas on insect responses, plant defences and chemical signalling, with rising interdisciplinary interest in genomics, microbial ecology and climate impacts. Notably, gaps persist in macroevolutionary studies, belowground VOC signalling and field-based validations. This review highlights the evolving research frontiers and encourages deeper integration of VOC research with sustainable agriculture, molecular ecology and environmental resilience. These findings provide a valuable reference for guiding future studies and fostering innovation in plant-insect chemical ecology.

Chemical ecology in marine fungi: diversity and dynamics of pyran-2-ones in a mussel- derived Penicillium restrictum

Role of metabolomics in natural product discovery and chemical ecology

Marine chemical ecology and natural products research in our changing ocean

Reverse chemical ecology to study the defense of the plant host Sextonia rubra and the chemical mediators of its endophyte Fusarium falciforme against phytopathogen Trametes versicolor.

The chemical profiles of the cuticle of adult flies are highly influenced by environmental factors and generational variation, although the extent and mechanisms of these influences are still poorly understood. This research rigorously investigates the influence of rearing environment and generational changes on the cuticular hydrocarbon (CHC) profiles of adult flies collected from the natural environment in Swindon (UK), in June 2019. Gas chromatography-mass spectrometry (GC-MS) was used to analyze the hydrocarbon profiles. Then, chemometric analysis was applied to determine the chemical variation patterns, allowing the samples to be classified according to their chemical fingerprints. Significant differences in hydrocarbon composition were found between laboratory-maintained and field-collected specimens, underscoring the impact of environmental conditions on CHC expression. Additionally, gradual modifications in hydrocarbon content were detected across generations raised in the controlled environment, suggesting the involvement of adaptive physiological or epigenetic mechanisms. These findings contribute valuable insights into cuticle plasticity, highlighting its relevance in forensic entomology, chemical ecology, and insect evolutionary biology. The implications also extend to forensic investigations, where cuticular hydrocarbon profiles (CHCs) demonstrate potential for enhancing postmortem interval (PMI) estimation accuracy and species identification in criminal cases. By demonstrating quantifiable differences in CHC composition across rearing conditions and generations (AUC values ≥0.92 for all comparisons), this study provides a foundation for the broader application of chemical markers in forensic investigations.

Long’s Braya, Braya longii Fernald (Brassicales: Brassicaceae), is an endangered plant in the family Brassicaceae found only on the Limestone Barrens of the Great Northern Peninsula of Newfoundland, Canada. Conservation of this species hinges on management of pests, diseases, and disturbances, which threaten their small populations. In particular, a global agricultural pest, diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), causes significant damage to persistence of B. longii and contributes to possible extinction. This study investigates if there are key volatiles that attract P. xylostella to B. longii, thereby contributing to the pest’s impact on the plant. Headspace collections, GC-MS, and GC-EAD revealed a unique volatile profile for B. longii, with (E)-2-nonenal as a key volatile that elicited strong antennal responses in P. xylostella. Oviposition assays confirmed female preference for E2-nonenal-baited radishes. This finding has implications for P. xylostella pest management, highlights the importance of chemical ecology in both crop protection and endangered species conservation.

Evaluating the olfactory preferences of emerging insect pests is critical to develop monitoring tools and improve early detection and management strategies. Here the chemical ecology and olfactory preferences of the allium leafminer Phytomyza gymnostoma Loew (Diptera: Agromyzidae), an invasive pest in North America affecting allium crops such as leeks and onions, were investigated. Three bioassay methods were assessed under laboratory conditions: wind tunnel, Y-tube olfactometer, and arena bioassay. All bioassays measured the responses of P. gymnostoma adults to odors of host and non-host plants. Two common allium crops, leek and chive, were used as host plants. Results of the wind tunnel bioassays showed a clear preference for host plants compared to non-host plants, with leek being twice as attractive as chive. Leek plants already infested by P. gymnostoma were half as attractive as healthy plants. Olfactometer and arena bioassays failed to show any significant response of adult flies toward host plant volatiles. This study is the first to compare multiple bioassays for behavioral investigations of P. gymnostoma, providing novel insights into the pest's host-finding behavior and highlighting methodological considerations for future work. Overall, these results suggest that both visual and chemical cues play a role in P. gymnostoma's foraging behavior and are a promising first step toward the development of monitoring tools against this invasive pest.

Insects utilize sophisticated olfactory systems to detect chemical cues critical for behaviors such as mating, host selection, and predator avoidance. In lepidopteran moths, sex pheromone communication offers a well-established model in which males detect female-emitted signals over long distances. Central to this process are pheromone-binding proteins (PBPs), which solubilize and transport hydrophobic pheromones through the sensillar lymph to olfactory receptors, enabling precise signal detection. Recent advances in molecular biology, structural biochemistry, and gene-editing technologies such as CRISPR/Cas9 have uncovered nuanced mechanisms underlying PBP function, including ligand-binding specificity, pH-dependent conformational dynamics, and molecular interactions. These discoveries have broad implications, extending beyond chemosensory biology to applications in reverse chemical ecology, biosensing, and environmentally conscious pest control. This review synthesizes insights from in vitro, in silico, and in vivo studies, highlighting the structural and functional diversity of PBPs across species and emphasizing their translational utility as molecular targets for sustainable agriculture and biodiversity conservation.

Molecular mimicry: ecology, evolution, and applications of doppelgänger peptides.

Natural products, specifically secondary metabolites, produced by marine organisms, play crucial roles in their survival and performance. Research on natural products derived from marine organisms, particularly soft corals, has been ongoing for over 30years in Taiwan, resulting in the isolation and identification of over 2000 unique compounds from 100 species of soft corals. These studies have not only uncovered bioactive compounds with potential useful applications but have also provided insights into the chemical evidence for the taxonomy of soft corals as well as the biological functions of these products within soft corals. Following the central dogma of molecular biology, this review notes that, according to the biosynthesis pathways, the types of natural products identified for seven clades of soft corals align with the updated phylogenetic system of soft corals based on DNA sequencing analysis. Thus, these natural products can serve as chemical evidence to support our understanding of soft coral taxonomy. Furthermore, to understand the influences of geographic factors on the production of natural products in soft corals, we compiled data on natural products from species repeatedly collected at different locations around Taiwan. Interestingly, the oxidation levels of briaranes in Briareum stechei and Junceella fragilis, and cembranes in Sclerophytum flexibile and Lobophytum crassum, tended to increase with rising seawater temperatures, while other soft corals also exhibited different metabolite profiles across spatial and temporal scales. Finally, we highlight the challenges and future perspectives in studying natural products from soft corals and propose that recent advancements in techniques, which offer comprehensive tools, such as mass spectral molecular networking, can significantly improve the elucidation of secondary metabolite structures. By addressing these challenges and leveraging new technologies, future research can provide novel insights into the roles that natural products play in marine chemistry. Collectively, this will contribute to a better understanding of marine biodiversity, the chemical dynamics of marine chemical ecology, and potential biotechnological applications.

Pomacea canaliculata, a destructive invasive species, threatens agriculture and ecosystems globally. Environmentally safe control methods like sex pheromones remain unexplored for this snail. Integrating behavioral tests, metabolomics, and field trials, we identified key chemical ecology traits. Male P. canaliculata were strongly attracted to virgin female-conditioned water, specifically its medium ultrafiltrate, but unresponsive to male or mated female samples. Nontargeted metabolomics of 135 up-regulated metabolites in virgin females pinpointed 4-hydroxyphenylacetic acid as a critical attractant. Behavioral assays confirmed its unique efficacy in luring males, while structural analogs failed, indicating specificity. Field trials validated its practical trapping potential, with optimal performance at a concentration of 1 mol/L. This study identifies 4-hydroxyphenylacetic acid as a candidate component of sex pheromone in P. canaliculata, offering a targeted strategy for eco-friendly population control. These findings advance invasive species management by enabling pheromone-based traps, reducing reliance on chemical pesticides and mitigating ecological impacts.

The discovery of odorant-binding proteins (OBPs) at the early nineteen eighties raised a lot of interest being the first biochemical components of the olfactory system to be experimentally studied. About 10 years later, the identification of odorant receptors attracted the attention of scientists, leaving OBPs in the background. A generally accepted role as carriers for odorants and pheromones reduced the interest in these soluble proteins, regarded as accessory elements in the process of olfactory transduction. More recently, however, OBPs have received new attention based on (i) the recognition that some proteins of this family can act directly as nonvolatile pheromones, (ii) the possibility of investigating the structures of pheromones in species extinct or difficult to approach adopting the method of reverse chemical ecology, and (iii) the suitability of OBPs and their artificial mutants as sensing elements in electronic olfaction, as well as in other biotechnological applications. In this review, after summarizing the main structural and functional aspects of OBPs and other soluble carrier proteins both in mammals and in arthropods, we focus on their most recent uses and their potential developments.

Tubastraea coccinea and T. tagusensis, commonly known as sun corals, are two species of stony corals (Scleractinia, Dendrophylliidae) native to the Indo-Pacific region (T. coccinea) and the Galapagos Islands (T. tagusensis), respectively. They are considered highly invasive species, particularly in the Western Atlantic Ocean, due to high adaptability to various ecological conditions and notable resilience. Given their demonstrated invasiveness, it is important to delve into their physiology and the molecular bases supporting their resilience. However, to date, only a few molecular tools are available for the study of these organisms. The primary objective of the present study was the development of an efficient RNA extraction protocol for Tubastraea coccinea and T.a tagusensis samples collected off Ilha Grande Bay, Rio de Janeiro (Brazil). The quantity of isolated RNA was evaluated using NanoDrop, while its purity and quality were determined by evaluating the A260/A280 and A260/230 ratios. Subsequently, based on genes known for T. coccinea, two housekeeping genes and seven stress response-related genes were isolated and characterized, for the first time for both species, using a molecular approach. An interactomic analysis was also conducted, which revealed functional interactions among these genes. This study represents the first report on gene networks in Tubastraea spp., opening new perspectives for understanding the chemical ecology and the cellular mechanisms underlying the invasiveness of these species. The results obtained will be useful for ecological conservation purposes, contributing to the formulation of strategies to limit their further expansion.