The present study aimed to evaluate the anatomical, histochemical, and phytochemical characteristics of Apeiba tibourbou (Aubl.) leaves, analyzing their possible relationship with herbivory. The anatomical characterization was carried out using histological slides prepared with freehand transverse sections in the middle region of the leaf blade, stained with fuchsin and Astra blue. The presence of secondary metabolites was determined through histochemical analyses using histological sections of the plant material, which were subjected to preestablished histochemical tests. Phytochemical analyses were conducted using alcoholic extracts from the dried and ground plant material, which were subjected to specific tests for group of metabolite of interest. The anatomical description revealed the presence of glandular trichomes and calcium oxalates that could serve a protective function against herbivory. Histochemical and phytochemical analyses of A. tibourbou leaves revealed the presence of phenolic compounds, alkaloids, saponins and sesquiterpene lactones. Based on the results, A. tibourbou may exhibit potential insecticidal activity against herbivorous insects.
Social wasps produce various chemical compounds that play roles in prey capture and colony defense. However, knowledge regarding the variation in the composition of these compounds and the influence of the environment on them remains limited, partly due to challenges related to sampling, analysis, and the complexity of the compounds. Therefore, this study evaluated interspecific variation in the venom composition and the importance of environmental factors on intraspecific variation, and the relationship with the age of Polistinae social wasp workers. To achieve this, colonies of Polistes ferreri, P. lanio and P. versicolor, nesting in different environments were collected and analyzed using Fourier transform infrared-photoacoustic spectroscopy (FTIR-PAS). The absorption spectra of the venom were examined to identify the main absorption peaks, followed by the assessment of the intensities and wavenumber positions of these peaks. We found significant differences between species and among colonies of the same species, based on nesting environment and workers age.
The “pupa ring” formed by the Asian corn borer Ostrinia furnacalis (Guenée) is a fascinating phenomenon discovered during the course of this experiment. The structure consists of approximately 2 to 10 pupae connected by their tails, raising speculation about possible underlying signal communication mechanisms. As a major pest of corn crops, the Asian corn borer has significant agricultural importance. Understanding its behavioral responses to chemical stimuli is crucial for exploring its ecological traits and provides valuable data to support ecological chemical control strategies. In this study, we extracted cuticular volatiles from the larvae and pupae of the Asian corn borer, evaluated their taxis behavior, and investigated the effect of these volatiles on pupa ring formation in fifth instar larvae. The results showed that volatiles from female larvae and pupae were more attractive, and those from female larvae were particularly effective at inducing pupa ring formation. This research seeks to explore the underlying causes of this remarkable behavior and offers plausible hypotheses to explain the formation of the pupa ring.
Leaf metabolites are important drivers of biotic interactions. Leaf metabolic profiles are changing over ontogeny and in response to biotic and abiotic conditions. Additionally, plant species diversity can influence leaf metabolomes. However, it is rarely considered how changes in leaf metabolomes might affect the leaf litter volatiles, which mediate interactions with the decomposer community. We designed an optimized and validated solid-phase microextraction (SPME) method coupled with a gas chromatography-mass spectrometry (GC-MS) analysis to analyze liter volatile organic compound (VOC) emissions. This method was applied to test the hypothesis that sessile oak (Quercus petrea) leaf litter VOC profiles are influenced by surrounding tree diversity. The results showed that plot diversity significantly affected oak litter VOC profiles by increasing the emissions of fatty acids. Tree diversity marginally modulated terpenoid emissions. Particularly, the emission rates of (-)-β-bourbonene and (E)-β-caryophyllene decreased with increasing species diversity. Also, ethanol emissions, likely due to microbial activity, decreased with increasing tree diversity. By detecting diversity- and C: N-related changes in terpenoids, and diversity effects on fatty acids and ethanol emissions of Q. petraea leaf litter, we provide new insights into how biodiversity shapes litter chemistry and potentially restructures decomposer interactions.
Elevated carbon dioxide (eCO2) induces various plant physiological, biochemical and morphological modifications by providing extra carbon and altering tissue nutrient composition and biomass allocation, which can influence ecological processes such as plant-insect interactions. In this study, a literature review was conducted to examine how eCO2 could potentially influence plant-herbivore insect interactions. Studies suggested that eCO2 decreases foliar nitrogen and increases leaf toughness, leaf biomass, and the carbon to-nitrogen ratio in plants. This in turn alters foliar chemistry and can significantly decrease the relative growth rate and consequently pupal or nymphal weight, which could exert an influence on the adult. Hence, the herbivore performance can be decreased. The changes in the plant nutritional quality can also result in compensatory feeding as a result of the reduction of food quality. This consequently leads to an increased defoliation rate, which results in altered leaf chemical composition with enhanced secondary metabolites, including defense compounds and toxins. This increases the risk for larvae in their early instars, whose growth and development are more sensitive to the disruptive effects of toxins, compared to the late-instar larvae. Altogether, these effects may modify the overall abundance of the herbivorous species. An emerging hypothesis is that eCO2 downgrades the nutritional quality more in C3 than in C4 plant species, facilitating herbivorous insect species to escalate their feeding stress on C3 plants by increasing food intake which is considered a behavioral adaptation to compensate for the reduced leaf quality (and protein content) relative to C4 species. However, this hypothesis warrants confirmation and cannot be generalized at present.
In a fire salamander population near Bonn, Germany, fire salamander females use two different habitats for larval deposition, i.e. ponds or streams. As it is known that females can discriminate between sexes and habitat types of the males based on chemical cues, we asked whether larvae show habitat specific differences in their surface chemical fingerprints. We took water samples and captured larvae at two ponds and two streams; we used polydimethylsiloxane and TD-GC-MS to collect and analyze samples of the environmental background (i.e. features that were found in the water) as well as from the surface of the larvae. We found a significantly different composition of chemical features in the environmental background samples. Additionally, we found the larvae to carry habitat type-specific chemical features. These finding allow to speculate that the features on the larval surface, if retained across metamorphosis, may be used for assortative mating in the adults, which should be further investigated.
Current research on microbially induced calcite precipitation (MICP) has primarily focused on bacterial-mediated heavy metals (HMs) immobilization, while the potential of urease-producing fungi remains largely unexplored. In this study, two high-activity urease-producing fungal strains, Aspergillus sydowii and Fusarium oxysporum, were isolated from HM-contaminated soils. Cr(VI) removal was driven by fungal urease hydrolyzing urea to release carbonate ions and elevate the local pH, facilitating CaCO3 precipitation in the presence of Ca2+. Dissolved Cr(VI) was subsequently eliminated through surface adsorption onto fungal hyphae, complexation with extracellular polymers, and co-precipitation within the newly formed carbonate precipitation(Ca10Cr6O24(CO3)), leading to a rapid decrease in Cr(VI) concentration within 48 h. The growth dynamics of these strains under various stress conditions were investigated using the Gompertz model, and the growth parameters were optimized, and characterization via XRD and FTIR confirmed the formation of calcium chromium carbonate oxide, calcite, and vaterite as dominant mineral phases. Both strains demonstrated strong Cr(VI) tolerance, achieving immobilization efficiencies of 81.8
This study explores the seasonal variation of volatile organic compounds (VOCs) emitted from the brood chambers of the escamolera ant, Liometopum apiculatum, and examines their potential association with worker foraging behavior. Brood chamber samples were collected during pre-season, in-season, and post-season phases and analyzed using gas chromatography–mass spectrometry to identify and quantify VOCs. A total of 44 compounds were detected, revealing distinct seasonal differences in composition and abundance. Multivariate analyses, including principal component analysis and partial least squares discriminant analysis, revealed consistent chemical profiles linked to each reproductive phase. In parallel, VOC patterns from live ants were evaluated using an electronic nose, which showed consistent seasonal clustering of odor signatures. Foraging activity on artificial trails was quantified and analyzed with a generalized linear mixed-effects model, revealing significantly higher activity in the post-season when brood VOC richness was highest. Nominal logistic regression identified undecane, tridecane, tetradecane, and phytol as key predictors of foraging patterns. Although these findings are correlational, they suggest a potential ecological role for brood-emitted VOCs in seasonal regulation of foraging. This study highlights the value of integrating chemical and behavioral analyses to better understand the mechanisms of social communication in ants.
The bacterium Azospirillum thiophilum found in a sulfide-bearing spring (described by Lavrinenko et al. Int J Syst Evol Microbiol 60:2832–2837, 2010) is reported to be able to reduce SeVI oxyanions (SeO42–; selenate) in static conditions, representing microaerobic environments that are characteristic of many bacteria of the genus Azospirillum, forming selenium(0) nano-sized spheres (Se0-NSs). Their presence, resulting in a brick-red tint of the sediments of bacterial cells (at SeO42– concentrations from 1 to 15 mM), was confirmed by TEM as nano-sized spheres within the bacterial cell biomass. Raman spectroscopic studies of the cell sediment samples obtained by static cultivation with SeO42– exhibited an intensive Raman line at ca. 248 cm–1 with an increased linewidth, which is characteristic of amorphous elemental selenium(0) in its nano-sized structures. This is the first demonstration of the ability of an Azospirillum species (observed so far for A. thiophilum only) to reduce selenate to selenium(0). Noteworthy is that this process occurs in contact with air, which is accompanied by the formation of Se0-NSs of amorphous nature. Hence this ability of strain A. thiophilum BV-S to detoxify selenate (as the most toxic, well soluble and therefore mobile inorganic selenium chemical species) to non-soluble and non-toxic SeNPs is of clear environmental value.
Rhyssomatus nigerrimus (Coleoptera: Curculionidae) is considered an economically important pest of soybean cultivation in Mexico and is attracted by floral odour of soybean. R. nigerrimus has been observed in some inflorescences of alternative host plants that serve as refuge and food when the soybean plant is not seasonally available. The aim of this study was to determine which volatiles emitted by inflorescences of Hamelia rovirosae and Lantana camara, alternative host plants of the weevil, mediate the attraction of R. nigerrimus. We collected the volatiles from both inflorescences by dynamic aeration and analyzed them with gas chromatography coupled to mass spectrometry, performed behavioral bioassays in a Y-shaped olfactometer, and performed electroantennographic measurements. We identified monoterpenes, sesquiterpenes and fatty acid derivatives (ketones, alcohols) in the two species, with α-pinene, β-caryophyllene and 2-ethyl-1-hexanol being most abundant in H. rovirosae, and α-pinene, β-caryophyllene and α-copaene being most abundant in L. camara. The volatiles from the inflorescences, individual compounds and a blend of synthetic compounds elicited antennal and attraction responses in male and female weevils. Males were attracted by α-copaene, α-pinene, β-caryophyllene and linalool, while females by α-copaene, α-pinene, β-caryophyllene, linalool, (E)-β-ocimene and (Z)-linalool oxide furanoid. Overall, this study identified compounds used by R. nigerrimus to find alternative hosts. They might be useful for the management of this pest species.
The Coffee Berry Borer (CBB) Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae) is an important pest species that has invaded all major coffee-producing areas of the world, causing tremendous economic losses every year. Since its discovery on the island of Jamaica approximately 40 years ago, the beetle has moved from lowland regions with comparably warm and dry climates to higher altitudes with cooler and wetter conditions in the Blue Mountains. Some insects have been shown to react to such environmental variation with changes in their cuticular hydrocarbon (CHC) profiles. To investigate if this is also the case in CBBs, we characterized the CHC profiles of beetles collected from different farms varying in altitude and climate across Jamaica and from one farm in Panama. We found that the CHC profiles of CBBs are mainly composed of straight-chain alkanes and methyl-branched alkanes, and that differences in farm location or rearing conditions (lab or field) may not necessarily result in CHC variation. The coffee berries provide a microclimate which protects the beetles from the conditions outside the coffee berries for the majority of their life cycles, thus potentially buffering this major pest from external environmental selection pressures.
The sustainable management of medicinal and aromatic plants is increasingly important due to the threats posed by overexploitation and climate change. Cultivating medicinal and aromatic plants offers a viable alternative to wild harvesting, ensuring resource conservation while maintaining bioactive compound production. This study characterizes the biochemical properties of wild and cultivated Salvia Rosmarinus Spenn., Thymbra capitata (L.) Cav., and Artemisia herba-alba Asso. to assess their potential for sustainable valorization. Essential oils were extracted via hydrodistillation and analyzed using gas chromatography–mass spectrometry to determine their chemical composition and yield. Additionally, hydro-methanolic extracts were evaluated for total polyphenol and flavonoid content, as well as antioxidant and anti-inflammatory activities. Results showed that cultivation significantly increased essential oil yield in Salvia Rosmarinus Spenn. and Thymbra capitata (L.) Cav. while preserving their major chemical composition. However, some major compounds of each species were more abundant in wild plants than in cultivated ones. Polyphenol and flavonoid content were also higher in cultivated plants than in wild ones. Antioxidant activity, assessed via the DPPH assay and reducing power, remained similar between wild and cultivated specimens; whereas anti-inflammatory activity was slightly lower in cultivated plants. Overall, these findings suggest that cultivation enhances essential oil yield and phenolic compound content without compromising bioactive properties. This supports the use of cultivated medicinal and aromatic plants as a sustainable alternative to wild harvesting, contributing to biodiversity conservation and the economic valorization of forest resources.
This study investigates the herbicidal potential and mechanisms of four volatile terpenoids-1,8-cineole, citral, menthone, and geraniol-against the weeds Amaranthus viridis and Chenopodium murale. All compounds exhibited significant allelopathic effects in a dose-dependent manner. Notably, 1,8-cineole and citral strongly inhibited seed germination, shoot, and root growth, with C. murale showing higher sensitivity than A. viridis. Geraniol had the most potent effects on C. murale with IC50 values of 2.25, 2.27, and 7.10 mg/L for seed germination, shoot growth, and root growth, respectively. Menthone was most effective against A. viridis with IC50 values of 31.50, 27.24, and 19.81 mg/L for germination, shoot growth, and root growth, respectively. Molecular dynamics and Molecular Mechanics Generalized Born Surface Area (MMGBSA) studies confirmed these terpenoids as transport inhibitor response 1 (TIR1) antagonists, suggesting their potential as natural herbicides targeting auxin pathways. Further research is needed to assess their ecological impact and practical application.
Plant volatile organic compounds (VOCs) play crucial roles in mediating plant-environment interactions, including pest attraction and deterrence, as well as attracting pollinators and deterring herbivores. The Mediterranean fruit fly (medfly) is a significant pest in fruit crops, requiring precise monitoring to optimize control measures. Our study investigates the differences in VOC profiles between identified “hot spot” areas within orchards where medfly populations tend to concentrate, and “cold spots,” where infestations are less frequent. Using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC–MS), we found that hot spots exhibited distinct VOC profiles, particularly an increase in compounds such as (E)-2-hexenal, (Z)-2-hexanol, (E,E)-2,4-hexadienal, and (E)-2-hexenyl acetate, which are known medfly attractants. These findings suggest that variations in orchard VOC emissions may provide a means of identifying regions at higher risk of infestation, thereby allowing for targeted pest management strategies. This study offers insights into VOC-mediated pest attraction and highlights the potential for refining monitoring systems based on spatial chemical variations in orchards.
This study investigates the volatile organic compound (VOC) diversity of Anthemis cotula L., an European native species that has adapted to grow as both summer and winter annual in the Kashmir Himalaya, and explores whether differences in VOC profiles between these growth forms could shed light on their potential role in the plant’s invasiveness and prolific spread in the region. This study identifies 167 VOCs, with winter annuals exhibiting significantly greater VOC diversity (143) compared to summer annuals (88), as also confirmed by significantly higher Shannon and Simpson diversity indices in winter annuals (p < 0.0001). Winter annuals produced 79 unique VOCs, while summer annuals had 24, with plants of both growth cycles sharing 64 compounds. Terpenes, particularly sesquiterpenes, and monoterpenes, dominated in both growth cycles, but winter annuals showed higher diversity, including a higher abundance of esters (34 vs. 21). VOC profiles also varied by plant part: flowers were rich in esters, while roots and leaves had more terpenes. Elevation had a moderate impact on VOC composition, with the greatest variability observed at higher elevations (2350 masl). Functional Hill diversity was significantly higher in winter annuals (p < 0.0001), suggesting a broader biosynthetic diversity. Redundancy analysis revealed that VOC distribution in plant parts was influenced by environmental variables, with altitude showing a stronger correlation in roots. Molecular network analysis showed VOC segregation in distinct clusters, highlighting the biosynthetic pathway complexity and intricate relationships between chemical compounds of different organs in both growth forms. These findings provide critical insights into the potential role of VOC diversity in the invasiveness of A. cotula, particularly its winter annuals in the Kashmir Himalayan region with potential implications for its management.
Dung beetles are of great importance in livestock ecosystems. The utilization of macrocyclic lactones to control cattle parasites has a detrimental effect on the community of dung invertebrates. The objective of this study was to evaluate the attraction of Onthophagus hircus to ivermectin-fortified fecal matter (IFM) under laboratory conditions. Dung beetles primarily detect food through olfaction. To assess odor discrimination behavior, a passive hole-board olfactometer (HBO) was designed. The efficacy of the design was tested through the execution of two control experiments, which measured the attraction (both group and individual) of O. hircus to control fecal matter (CFM) or soil (S). The third experiment was conducted to evaluate individual attraction to IFM. The data were analyzed using descriptive statistics and comparative analyses, and the selection rate was estimated. In both the individual and group control experiences, active individuals were significantly attracted to CFM (46
Antiaphrodisiacs are chemical bouquets physically delivered from male to female individuals upon copulation which discourage further mating and reduce sperm competition by rendering the female less attractive. Since antiaphrodisiacs may not offer an honest signal of female receptivity, in polyandrous species they may undergo faster diversification resulting from sexual conflict. The Heliconiini tribe of butterflies includes a polyandrous (free-mating) and a monandrous (pupal-mating) clade, both known to produce diverse antiaphrodisiac mixtures as part of their abdominal blends. Using multivariate phylogenetic comparative methods, we analyzed the genital blends of 36 Heliconiini species to test the hypothesis that blend diversity results from male-male competition in polyandry. We found no evidence for shifts in blend diversification rate corresponding to changes in mating strategy, implying male-male competition may have a weaker effect on pheromone diversification in this group than previously thought. The genital blends of most species are dominated by one of four highly volatile compounds; (E)-β-ocimene, octen-3-one, sulcatone and 4-hydroxycyclopent-2-en-1-one. Based on the function of (E)-β-ocimene as the behaviourally active antiaphrodisiac in H. melpomene, we propose a similar role in other species for the other volatiles. We test this hypothesis by investigating 4-hydroxycyclopent-2-en-1-one occurrence in Heliconius sara. While we detect no sex-based differences on its presence, we find the compound is undetectable when larvae are not fed their preferred host plant, providing an intriguing potential link between host plant and reproductive cues. This in turn shows that captive-bred samples do not always provide realistic results and this awareness is important for future experiments.
Ceratitis capitata, known as Mediterranean fruit fly, represents one of the main problems to the agricultural production, due the ability to infest a wide variety of fruits, which makes it one of the most worrying pests globally. The infestation of host fruits by the insect compromises their quality and appearance, causing losses to their commercialization and consumption. In order to minimize this problem, fruit growers have adopted the indiscriminate use of conventional insecticides that raise environmental and public health concerns, in addition to promoting resistance in insects. Alternatively, semiochemicals have been explored as a management tool, attracting males and females into traps or promoting repellency in exposed fruits. In this context, in silico approaches, as Molecular Docking, Molecular Dynamics and the Virtual Screening procedures, offer opportunities to identify new molecular entities as potential ligands to Odorant Binding Proteins (OBP), that are involved in olfactory communication of C. capitata. In this review, we present a collection of data including the chemistry of olfactory communication of C. capitata and some computational tools that can be used in these studies, emphasizing their impact on the behavior of this and other associated insects. We also address theoretical ADME-Tox parameters as initial evaluation criteria to ensure human safety in the environmental applications, as well as the importance of molecular synergism for the effective management of the medfly.
This study developed a laboratory rearing model for the dung beetle Onthophagus hircus (Billberg 1815) to evaluate the ecotoxicological effects of eprinomectin (EPM) on its survival and reproductive performance. Adult O. hircus were exposed to increasing EPM concentrations (0–50 ppm) in bovine feces. Survival was significantly reduced at 50 ppm EPM. A reproductive performance experiment compared control and 0.05 ppm EPM treatment groups. While adult fecundity was not significantly affected, the EPM treatment resulted in complete failure of progeny development, with no adult emergence. The study demonstrates that environmentally relevant EPM concentrations can negatively impact O. hircus populations through larvicidal effects, even when adult survival and reproduction appear unaffected. This highlights the importance of considering long-term impacts when assessing the environmental risks of antiparasitic drugs on beneficial dung fauna. The laboratory rearing model developed provides a valuable tool for further ecotoxicological research on dung beetles.
Cadmium (Cd) toxicity and drought stress are cumulatively disruptive to physiological processes in plants. Salicylic acid (SA) has modulatory roles in osmotic balance in plants. Proline, can act as a compatible solute in osmotic adjustment, elevate antioxidative defense system, which improve adversity tolerance in plants. However, how SA regulates proline metabolism under Cd and drought stresses to improve plant tolerance remains largely unknown. To uncover the alleviation mechanism of SA on Salix matsudana Koidz. seedings to Cd and drought stresses, the non-enzymatic/enzymatic antioxidants, proline metabolism, and related enzyme genes were assayed in S. matsudana. This was done under application of Cd (50 µmol·L− 1) and polyethylene glycol (PEG) (at concentrations of 5
