Search Results (203)

Plutella xylostella (L.) (Lepidoptera: Plutellidae), the diamondback moth (DBM), is a cosmopolitan pest of brassicas. To validate and compare the performance of yeast-derived sex pheromone components with chemically synthesized ones, we studied the behavioral and electrophysiological responses (EAGs) of male DBM adults. In addition, using gas chromatography coupled with electroantennographic detection (GC-EAD), we examined whether any residual impurities present in yeast-derived pheromone components can be perceived by the insects’ antennae and are thus capable of interfering with normal behavior. Furthermore, we assessed the performance of the yeast-derived pheromones under field conditions through monitoring trials conducted in cabbage crops in Greece. Electrophysiological and behavioral assays revealed equivalent responses from the insects to both the yeast-derived (BIO) and chemically synthesized (CHEM) pheromone blends. Consistent with this, GC-EAD results showed no significant differences in antennal response to minor impurities present in the BIO blend compared to the CHEM blend. Finally, it was demonstrated that the binary pheromone blend—comprising (Z)-11-hexadecenal and (Z)-11-hexadecenyl acetate derived from (Z)-11-hexadecen-1-ol produced by yeast cell-factories—was as efficient and specific for trapping male moths in cabbage fields as the conventional ternary synthetic blend [(Z)-11-hexadecenal and (Z)-11-hexadecenyl acetate and (Z)-11-hexadecen-1-ol]. The yeast-derived mixture contained small amounts of unoxidized (Z)-11-hexadecen-1-ol due to incomplete oxidation. Full article

The brown marmorated stink bug, Halyomorpha halys (Stål), is an invasive pest that increasingly threatens apple production in Europe by causing fruit damage, yield losses, and quality deterioration under commercial orchard conditions. This study investigated seasonal population dynamics, spatial patterns of fruit damage, yield effects, and post-harvest fruit responses of two apple cultivars (‘Cripps Pink’ and ‘Fuji’) in a commercial orchard over two consecutive seasons (2024–2025). Adult and nymphal activity was monitored using pheromone traps, while fruit damage was assessed at harvest across orchard positions and canopy layers. Potential yield losses were estimated based on damage incidence, and selected physicochemical properties of healthy and affected fruits were analysed. Clear cultivar-dependent differences were observed. ‘Fuji’ exhibited typical external feeding damage, with low but consistent damage levels and limited yield losses in both seasons. In contrast, ‘Cripps Pink’ showed substantially higher damage rates and potential yield losses, particularly in 2025; however, classical external feeding damage was not observed. Instead, fruits exposed to H. halys pressure expressed atypical responses, primarily as increased individual fruit mass and size, and atypical skin color patterns, including pronounced striping and uneven pigmentation. Damage in ‘Cripps Pink’ was strongly structured within the orchard, with higher incidence in the upper and middle canopy layers and in areas adjacent to the forest edge, whereas damage in ‘Fuji’ remained low and spatially uniform. Overall, the results demonstrate that the impact of H. halys depends not only on pest pressure but also on cultivar traits and within-orchard spatial heterogeneity. These findings support the development of cultivar-specific and spatially targeted integrated pest management (IPM) strategies that better reflect the uneven distribution and expression of stink bug injury in commercial apple orchards. Full article

Climate change and increasingly restrictive pesticide regulations have created a growing need for new tools to support the integrated pest management (IPM) of the olive fruit fly, Bactrocera oleae, in cultivated areas of the Mediterranean. In this study, the environmental suitability for this phytophagous insect in eastern Sicily was mapped by using geographic information system (GIS) tools and species distribution models (i.e., Random Forest and MaxEnt). The models were trained on presence data of the fly, obtained from a network of pheromone traps and locations where olive trees were present, combined with climatic, topographic and soil predictors for both current conditions and the future climate scenario (2021–2040). Correlation analysis was utilised to select ten predictors from an initial set of 33 soil and climate variables. Model performance was evaluated by using 10-fold cross-validation based on accuracy measures Area Under the Curve (AUC), True Skill Statistic (TSS), and the difference between the training and testing AUC) to minimise overfitting. Both algorithms demonstrated excellent predictive performance, producing convergent suitability maps, with high values concentrated in the foothills and hills of the Iblean–Calatino area and low values along the coastal plains and at higher altitudes, where extreme temperatures and unfavourable soil textures reduce habitat suitability. Response curves highlighted the combined influence of moderate temperature and precipitation seasonality, balanced topsoil texture, and moderate slopes in defining the species’ ecological niche. The proposed framework provides an operational basis for optimising monitoring networks and targeting IPM measures under current and near-future climate conditions. Full article

Effective collective motion hinges on the seamless transfer of local information, yet vision-based mechanisms, while potent for generating rapid consensus, are inherently fragile. Visual links can be severed instantly by occlusions, leading to a phenomenon characterized as “sensory amnesia.” Seeking to fortify this vulnerability, Pheromone-Modulated Body Orientation Change (PM-BOC) is introduced as a dual-channel framework that fuses transient visual cues with a persistent environmental memory. Rather than treating these inputs in isolation, motion salience is quantified via BOC and mapped onto a decaying virtual pheromone field, dynamically modulating interaction weights by coupling instantaneous visual projections with local pheromone concentrations. This strategy effectively constructs a temporal buffer, bridging the informational voids left by blind spots. Validation, spanning from systematic physics simulations to high-fidelity simulations with a swarm of 50 UUVs, reveals that PM-BOC sustains superior cohesion in obstacle-laden environments where baseline visual models falter. Notably, this coupling suppresses high-frequency sensory noise while inducing resilient, scale-free velocity correlations that scale linearly with system size. By reconciling the trade-off between the immediacy of visual responsiveness and the robustness of environmental memory, this study offers a scalable paradigm for engineering resilient swarm systems capable of navigating the uncertainties of perception-limited environments. Full article

The Moroccan locust Dociostaurus maroccanus (Thunberg, 1815) (Orthoptera: Acrididae) is recognized as a serious pest of pastures and crops in many Mediterranean countries. So far, the identification of chemical compounds involved in intraspecific communication has been elusive, with only one male-specific compound, namely (2E,7R,11R)-3,7,11,15-tetramethylhexadec-2-enal (2E,7R,11R-phytal), proposed as candidate sex pheromone component. Previous works reported that males also release the sex-specific long-chain aldehydes tetradecanal and hexadecanal, although no evidence of their role in chemical signaling has been presented so far. Here we additionally report another male-specific compound, viz. pentadecanal, and also report the electroantennographic and behavioral responses of virgin and mated females to these three aldehydes. We first demonstrated that their release is age-dependent, with emission overall peaking at 1–2 weeks after fledging. Solid-phase microextraction analyses from male hind legs suggest that these aldehydes are released from this body part. Overall, the antennae of virgin and mated females exhibited a dose-dependent response to increasing concentrations of each aldehyde, except for the response of virgin females to hexadecanal. Significant differences were observed between virgin and mated females at all doses of hexadecanal, while the mating status did not influence the response to tetradecanal and pentadecanal. Furthermore, the behavioral response of females varied according to their mating status. Specifically, mated females showed a significant preference for tetradecanal and pentadecanal, whereas a slight but non-significant attraction to hexadecanal was observed on virgin females. These findings provide new insights into the sexual communication of the species, although further research is needed to decipher their ecological function, especially on mated females. Full article

The red imported fire ant, Solenopsis invicta Buren, is a eusocial insect that relies on a sophisticated chemical communication system for colony organization and function. Its olfactory system is vital for detecting semiochemicals in the environment. This study utilized single sensillum recording (SSR) to assess the olfactory neuronal responses of female alates and workers from basiconica sensilla exposed to a panel of 62 individual pheromones and general odorants, including terpenes, terpenoids, pyrazines, pyridines, ketones, aldehydes, alcohols, acids, aliphatic and aromatic acetates, benzoates, benzyl esters, and three essential oils. Basiconica sensilla, which contain multiple olfactory receptor neurons (ORNs), exhibited moderate to strong responses to most of the tested compounds, demonstrating a broad sensitivity to all odorants elevated. Comparative analysis of the two castes revealed that ORNs had similar responses to 47 odorants; however, workers showed stronger responses to nine specific compounds, while female alates responded more strongly to six others. These differences underscore the caste-specific olfactory tuning, likely reflecting their distinct roles within the colony. This study presents the first comprehensive mapping of basiconica sensilla responses to general odorants in S. invicta female alates and workers, enhancing our understanding of the S. invicta chemical ecology and potentially contribute to more effective fire ant management strategies. Full article

Recent intensive research on the cypress bark beetle, Phloeosinus aubei was prompted because of its invasion of Central Europe that caused serious damage to scale-leaved conifer ornamental trees. This dynamic also increased the risk of accidental introduction into North America. In contrast to other historically well-studied bark beetles infesting spruce, pine or broad-leaf trees, intense study of the pheromones and host plant kairomones of bark beetles associated with cupressaceous trees has only begun in the past decade. This highly specialized clade is represented by the genus Phloeosinus. The pressing need for semiochemical-baited traps demands the identification of behavior-modifying compounds. This challenge involves unraveling the various stimuli interacting in the complex communication system to reveal the composition of signal bouquets and the absolute configuration of their components capable of evoking behavior responses. In this short overview we describe the recent research results on host-finding and intraspecific chemical communication of P. aubei, with a short outlook on the species of this genus. Full article

In external fertilisation, spawning synchrony is often mediated by pheromones. However, their chemical nature is rarely well-established; this is particularly true for bivalves. This study used an electrophysiological technique—the electro-osphradiogram (EOsG)—to investigate the spawning-inducing pheromone (SIP) in the Pacific oyster (Magallana gigas), a species of economic and environmental relevance. Recording the electrophysiological response of the osphradium to conspecific sperm milt and its fractions, we show that the SIP is multicomponent, likely proteinaceous—with at least one component linked to the spermatozoa and the other components in free solution—and all resistant to freezing. At least three active components are involved: one of about 35 kDa, one between 3 and 10 kDa and one of less than 3 kDa. All three, alone, evoke responses from the osphradium, but all three must probably be present to evoke the full biological response—gamete release—in the receiver. All three are likely polar; none were retained by a range of solid-phase extraction cartridges. We suggest that the EOsG will be useful to isolate and identify the individual components of the oyster SIP. Successful identification of the SIP will represent an important step towards more sustainable and efficient bivalve hatchery practices. Full article

Path planning for autonomous mobile robots in dynamic environments is a critical challenge, particularly when robots must navigate both known and unknown obstacles in real-time. Traditional methods like ant colony optimization (ACO) have shown promise in global path planning but often suffer from slow convergence and the risk of getting trapped in local optima. Similarly, while the dynamic window approach (DWA) excels in real-time obstacle avoidance, it exhibits delayed response and higher failure rates in scenarios with fast-moving obstacles. To address these challenges, this study proposes a hybrid path planning framework, IACO-QDWA, which integrates an improved ACO (IACO) for global path optimization with a Q-learning-enhanced DWA (QDWA) for dynamic obstacle avoidance. IACO improves global path search through goal-oriented initialization and adaptive pheromone updates, while QDWA enhances local decision-making by optimizing the state-action space. The experiments demonstrate that IACO-QDWA achieves a reasonable balance between path quality, obstacle avoidance success rate, and real-time performance. It exhibits stable obstacle avoidance behavior and reliable navigation capabilities in highly dynamic environments. Full article

To systematically investigate how the olfactory system of Bombus terrestris adapts to its social division of labor and reproductive strategies, this study integrated the micromorphology of antennal sensilla and the expression profiles of olfactory receptor (OR) genes from the heads of its three castes (workers, drones, and queens) for a multi-level analysis. Scanning electron microscopy (SEM) revealed that drones possess significantly longer chaetic sensilla (Sch), sensilla trichodea (Str A/B), and sensilla basiconica (Sba A), as well as larger-diameter sensilla coeloconica (Sco) compared to workers and queens, indicating structural and functional specialization for sensitive detection of single key signals (e.g., queen pheromones). In contrast, workers and queens exhibited a more complete composition of sensilla types and a higher sensilla distribution density, suggesting the construction of a perceptual system capable of processing multiple chemical signals simultaneously. RNA-seq combined with qRT-PCR confirmed the significant upregulation of seven OR genes (e.g., BterOR3, BterOR4) in drones, while workers showed upregulation of BterOR3/5/7 accompanied by enrichment of P450 detoxification pathways. Phylogenetic analysis suggested that BterOR5 serves as a conserved co-receptor, and some OR genes may originate from recent duplication events. In summary, distinct differences were observed in the morphological structure and molecular expression of the olfactory system among B. terrestris castes. Drones exhibited structural and gene expression features consistent with specialization in queen pheromone detection, while workers and queens demonstrated sensilla diversity and olfactory receptor expression patterns indicative of a broader response capacity to diverse chemical signals. These findings support the view that the olfactory system has undergone multi-level adaptive evolution driven by social division of labor and reproductive roles. Full article

Wildfires pose a growing global threat, demanding rapid, scalable, and autonomous response strategies. This study proposes HG-MADQN (Heuristic-Guided Multi-Agent Deep Q-Network), a hybrid framework that integrates reinforcement learning with biologically inspired pheromone-based heuristics to achieve adaptive fire detection and suppression using drone swarms. The system models a decentralized swarm operating in a grid-based environment, where each drone combines learned policies with heuristic guidance derived from a dual-pheromone mechanism (a fire-attraction field guiding suppression and a coverage-repulsion field promoting exploration). The proposed hybrid approach ensures efficient coordination, minimizes redundant movements, and maintains continuous area coverage without centralized control. Simulation experiments conducted on dynamic wildfire scenarios demonstrate that HG-MADQN significantly outperforms traditional heuristic, Lévy-Flight, and reinforcement learning (MADQN) algorithms. It achieves faster containment, reduced burned area, and lower resource consumption, while exhibiting strong robustness across multiple swarm sizes and fire configurations. The results confirm that hybridizing learned and heuristic decision models enables a balanced exploration–exploitation trade-off, leading to improved scalability and resilience in cooperative fire suppression missions. Full article

Vehicular ad hoc networks (VANETs) must simultaneously satisfy stringent reliability, latency, and sustainability targets under highly dynamic urban and highway mobility. Existing solutions typically optimise one or two dimensions (link stability, clustering, or energy) but lack an integrated, adaptive mechanism that fuses heterogeneous metrics while remaining lightweight and deployable. This paper introduces a VANET routing protocol named SYMPHONY (Synergistic Hierarchical Metric-Fusion and Predictive Hybrid Optimization for Network Yield) that operates in three coordinated layers: (i) a compact neighbourhood filtering stage that reduces forwarding scope and eliminates transient relays, (ii) a cluster layer that elects resilient cluster heads using fuzzy energy-aware metrics and backup leadership, and (iii) a global inter-cluster optimizer that blends a GA-reseeded swarm metaheuristic with a stability-aware pheromone scheme to produce multi-objective routes. Crucially, SYMPHONY employs an ultra-lightweight online weight-adaptation module (contextual linear bandit) to tune metric fusion weights in response to observed rewards (packet delivery ratio, end-to-end delay, and Green Performance Index). We evaluated the proposed routing protocol SYMPHONY versus strong modern baselines across urban and highway scenarios with varying density and resource constraints. The results demonstrate that SYMPHONY improves packet delivery ratio by up to 12–18%, reduces latency by 20–35%, and increases the Green Performance Index by 22–45% relative to the best baseline, while keeping control overhead and per-node computation within practical bounds. Full article

To address the conflict between real-time performance and optimal resource allocation in large-scale digital array radars, this paper proposes a novel resource scheduling framework that integrates graph-theoretic modeling with an adaptive heuristic strategy. Unlike traditional methods, we formulate the multi-beam scheduling problem as a constrained connected subgraph optimization task. To solve this NP-hard problem, an Improved Ant Colony Optimization (I-ACO) algorithm is designed, incorporating pheromone boundary constraints and elite update strategies to effectively balance exploration and exploitation within complex solution spaces. Furthermore, a load-aware Adaptive Algorithm Switching (AAS) strategy is introduced. This mechanism dynamically transitions between the globally optimized I-ACO and a rapid, utility-guided greedy approach based on real-time system load, effectively resolving the trade-off between solution quality and response speed. Experimental results demonstrate that the proposed method reduces solution costs by up to 23.5% compared to greedy algorithms and increases the scheduling success rate to 99.2% under high-load conditions, while significantly improving long-term system load balancing by 41.5%. Full article

Ostrinia nubilalis (Lepidoptera: Crambidae) and Sesamia nonagrioides (Lepidoptera: Noctuidae) are major maize pests in the central-eastern Mediterranean area, responsible for both quantitative and qualitative yield losses. This study investigated the corn borer species present in central-eastern Italy, the presence and prevalence of O. nubilalis pheromone races, and the within-plant larval distribution. Traps baited with E, Z, or E/Z pheromone lures were used to investigate O. nubilalis pheromone races, while 596 maize plants were sampled at harvest and dissected to determine species composition, relative abundance, and larval distribution across three plant sections (lower and upper stalk and ear). Males were captured in traps baited with each pheromone lure, with no significant differences among catches. Larval sampling revealed the co-occurrence of O. nubilalis and S. nonagrioides, with O. nubilalis being the prevalent species. For both species, larvae were significantly more abundant in the lower plant section, and co-occurrence did not appear to influence their within-plant distribution. Comparing the species-specific larval distribution, a significantly higher proportion of S. nonagrioides occurred in the lower plant section, whereas O. nubilalis was significantly more frequent in the ears. However, the presence of both species in the ears highlights the need to consider both pests in management. These findings highlight the importance of monitoring activities in the area, using traps baited with each pheromone lure for O. nubilalis. Knowledge of the co-occurrence between the two species can be considered fundamental for developing Integrated Pest Management strategies, as it can influence the timing and effectiveness of control methods. Full article

Nematode-trapping fungi act as predators of nematodes in soil ecosystems, forming a typical predator–prey relationship. However, this interaction is frequently influenced by environmental factors such as nutrient state. In this study, we demonstrate that starved nematodes had better chances of escaping A. oligospora predation by inhibiting A. oligospora trap formation. Starved nematodes showed downregulated acyl-CoA oxidase genes (acox-1.2/1.3/1.4) and reduced ascaroside pheromone production (ascr#1/#3/#5/#9), thus diminishing A. oligospora trap induction. In soils with uneven nutrient content, nutrient deficiencies can activate this mechanism locally, thereby reducing predation. When avoidance fails, nematodes rely on canonical innate immune pathways (FSHR-1, ATFS-1, and PMK-1) to improve survival during capture. In response to this predation, nematodes have evolved multiple strategies to defend against these pressures, closely linked to their nutritional status. Together, these findings link local nutrient availability to both fungal predation efficiency and the robustness of nematode defenses in soil ecosystems. Full article