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Control and elimination of invasive fishes, like carps (Order Cypriniformes), may be possible by using chemical stimuli to congregate them for removal. To this end, we tested behavioral responses of grass (Ctenopharyngodon idella), bighead (Hypophthalmichthys nobilis), and silver carp (H. molitrix) to L‐alanine, L‐arginine, L‐glutamic acid, and L‐aspartic acid. In grass carp, the first three amino acids have been shown to be beneficial for growth, and all four produce a strong olfactory response in this species. This study used pairs of conspecific fish in a video‐recorded, sound‐insulated, clear acrylic, tube‐shaped tank; during trials, an amino acid stimulus was delivered at one end of that tank. Changes in space use, velocity, and acceleration across all amino acids differed significantly among species. Changes in space use by grass carp indicated avoidance of only two amino acids, L‐alanine and L‐aspartic acid. There was no evidence for attraction to amino acids for grass or silver carp. For bighead carp, change in spatial use on exposure to amino acids indicated attraction across the four amino acids. This attraction was enhanced by lowered velocity. Our results suggested that olfactory sensitivity does not directly translate to behavioral responses. Other sensory cues, for example tactile, visual, and/or taste, may mediate the selective foraging of grass carp. Amino acids may serve as a better olfactory attractant for bighead carp compared to grass or silver carp. [ABSTRACT FROM AUTHOR]

Today, smart materials are commonly used in various fields of science and technology, such as medicine, electronics, soft robotics, the chemical industry, the automotive field, and many others. Smart polymeric materials hold good promise for the future due to their endless possibilities. This group of advanced materials can be sensitive to changes or the presence of various chemical, physical, and biological stimuli, e.g., light, temperature, pH, magnetic/electric field, pressure, microorganisms, bacteria, viruses, toxic substances, and many others. This review concerns the newest achievements in the area of smart polymeric materials. The recent advances in the designing of stimuli-responsive polymers are described in this paper. [ABSTRACT FROM AUTHOR]

Melanaphis sacchari is a cosmopolitan pest that causes losses in sorghum crops, so new management methods are needed. In addition, the type of fertilization used influences plant compositions and pest infestation, and allelochemicals are a promising method for the possible management of M. sacchari. In this work, we measured the preference of M. sacchari through chemical stimuli towards sorghum plants grown under greenhouse conditions without fertilization (F0), conventional fertilization (CF), and organic fertilization (OF). Leaves were collected from sorghum plants fertilized with 200 kg N ha−1 using ammonium sulfate and poultry manure. Extracts were obtained using Soxhlet extraction, and the compounds were identified using a gas chromatograph coupled with mass spectrometry (GC-MS). Sorghum extracts were individually tested through bioassays to determine M. sacchari preference. The abundance and number of compounds in sorghum differed depending on the type of fertilization used. M. sacchari showed a preference for the extract from CF sorghum plants (76.66%) over the extract from OF plants (23.34%). Therefore, the type of fertilization can be used as a tactic to prevent higher infestations of M. sacchari. The biological activity of the compounds identified here with M. sacchari should be determined for future pest management strategies using allelochemicals, given that the sugarcane aphid uses chemical signals to locate its host plant. [ABSTRACT FROM AUTHOR]

The pace of biological invasions has increased in recent decades, leading to multiple invasions and the potential dominance of invasive species, destabilizing local ecological networks. This provides opportunities to study new ecological species interactions, including predation. Tropical freshwaters have been particularly concerned by aquatic invasions and we focused here on the Martinique island (Lesser Antilles). We examined the predator–prey relationships involving invasive Thiarid snails (Tarebia granifera and Melanoides tuberculata) and the native Neritina punctulata, both confronted with a newcomer predator, the redclaw crayfish (Cherax quadricarinatus). We conducted several mesocosm experiments to assess the impact of crayfish predation on snail survival and the passive and active antipredator responses of snails. A first experiment indicated snail survival rates between 50% and 80%, depending on crayfish size and sex. Notably, there was a negative correlation between snail survival and male crayfish size and the predation method (shell crushing vs. "body sucking") varied with crayfish size. The second experiment suggested no refuge size for snails, with both very small (<5 mm) and very large (>5 mm) unable to escape predation, regardless of crayfish size (from 77 to 138 mm) or sex. Finally, we investigated the escape behavior of Thiarids regarding three crayfish cues. Melanoides tuberculata tend to bury in the substrate and T. granifera to climb up aquarium walls, what was expected from their shell morphologies, and both responding to crayfish cues within minutes. Overall, C. quadricarinatus proves to be an efficient snail predator with limited escape options for snails, potentially contributing to the decline of certain snail populations in Martinique. This omnivorous predator might impact other native species across different groups, including shrimps and fish. Our study underscores the urgent need for monitoring efforts, solidifying the redclaw crayfish reputation as a dangerous invasive species for freshwater macrobenthic faunas worldwide. [ABSTRACT FROM AUTHOR]

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In ant-aphid interactions, various aphid species offer honeydew to the ant partner and increase their density by ant attendance, whilst others never attend ant species, in which case ants tend to treat them as prey. In this regard, ants should have the ability to distinguish myrmecophile aphid species from non-mutualistic species, so that mutualistic aphids will be accepted as partners rather than prey. Although ant-aphid interactions are now the focus of chemical ecology studies, the role of the different chemical stimuli in determining mutualistic interactions has not been completely clarified. Therefore, we have investigated the cuticular hydrocarbon profile of four myrmecophiles aphid species using GC-MS. We also investigated the behavior of the worker-ants (Lasius niger L., Hymenoptera: Formicidae) to different chemical stimuli derived from aphids. We applied four treatments and found that the behavior of the ant workers varied depending on the source of the different treatments. In particular, the real aphid Aphis pomi and the sugar solution proved to be the most attractive to the ants, while the presence of pure extract of the individuals is enough to disturb the behavior of the ants. We provide evidence that the key stimuli of the tending behavior could be the CHC patterns of the aphids and the CHC profile of the aphids tends to be genus specific. This research will promote further investigations to test the behavior of ant workers towards other species of aphids and treatment combinations. [ABSTRACT FROM AUTHOR]

The use of lanthanide‐based metallogels presents a promising approach for the engineering of stimuli‐responsive gel materials. Stimuli‐responsive luminescent materials based on lanthanides have promising applications in bio‐applications and optical encoding. Synthetic supramolecular metallogels typically become kinetically trapped and usually do not exhibit time‐variable changes in their material properties. However, such supramolecular metallogels can switch between gel to sol when subjected to different external physical and chemical stimuli. This is because weak noncovalent interactions hold together the gel structure and are also influenced by the coordination dynamics of the metal‐ligand bond. This review summarizes recent research progress on stimuli‐responsive supramolecular lanthanide‐based luminescent metallogels. Chemical, physical, and multiple stimuli‐responsiveness of the metallogels are discussed elaborately based on the external stimulus sources. Finally, the latest challenges and opportunities for developing novel metallogels that respond to stimuli are discussed. [ABSTRACT FROM AUTHOR]

Implementation of new activated carboxylic acids is crucial to switch reversibly chemical systems over time in a safer manner. By applying cheap 1,3‐acetonedicarboxylic acid, the pH of aqueous solutions can be decreased before autonomously evolving over time back again to a higher value upon diacid decarboxylation. This decarboxylation can be catalysed by different species such as simple amines or simple metals such as iron and copper salts. This process generates 2 molecules of CO2 and acetone as single waste, considerably decreasing the toxicity associated with such activated acids. The potential of this weak diacid was confirmed by reversibly disrupting a strong gel upon diacid addition and opens the way to the application in complex chemically fuelled systems. [ABSTRACT FROM AUTHOR]

Abstract The pace of biological invasions has increased in recent decades, leading to multiple invasions and the potential dominance of invasive species, destabilizing local ecological networks. This provides opportunities to study new ecological species interactions, including predation. Tropical freshwaters have been particularly concerned by aquatic invasions and we focused here on the Martinique island (Lesser Antilles). We examined the predator–prey relationships involving invasive Thiarid snails (Tarebia granifera and Melanoides tuberculata) and the native Neritina punctulata, both confronted with a newcomer predator, the redclaw crayfish (Cherax quadricarinatus). We conducted several mesocosm experiments to assess the impact of crayfish predation on snail survival and the passive and active antipredator responses of snails. A first experiment indicated snail survival rates between 50% and 80%, depending on crayfish size and sex. Notably, there was a negative correlation between snail survival and male crayfish size and the predation method (shell crushing vs. “body sucking”) varied with crayfish size. The second experiment suggested no refuge size for snails, with both very small (5 mm) unable to escape predation, regardless of crayfish size (from 77 to 138 mm) or sex. Finally, we investigated the escape behavior of Thiarids regarding three crayfish cues. Melanoides tuberculata tend to bury in the substrate and T. granifera to climb up aquarium walls, what was expected from their shell morphologies, and both responding to crayfish cues within minutes. Overall, C. quadricarinatus proves to be an efficient snail predator with limited escape options for snails, potentially contributing to the decline of certain snail populations in Martinique. This omnivorous predator might impact other native species across different groups, including shrimps and fish. Our study underscores the urgent need for monitoring efforts, solidifying the redclaw crayfish reputation as a dangerous invasive species for freshwater macrobenthic faunas worldwide.

Today, smart materials are commonly used in various fields of science and technology, such as medicine, electronics, soft robotics, the chemical industry, the automotive field, and many others. Smart polymeric materials hold good promise for the future due to their endless possibilities. This group of advanced materials can be sensitive to changes or the presence of various chemical, physical, and biological stimuli, e.g., light, temperature, pH, magnetic/electric field, pressure, microorganisms, bacteria, viruses, toxic substances, and many others. This review concerns the newest achievements in the area of smart polymeric materials. The recent advances in the designing of stimuli-responsive polymers are described in this paper.

Melanaphis sacchari is a cosmopolitan pest that causes losses in sorghum crops, so new management methods are needed. In addition, the type of fertilization used influences plant compositions and pest infestation, and allelochemicals are a promising method for the possible management of M. sacchari. In this work, we measured the preference of M. sacchari through chemical stimuli towards sorghum plants grown under greenhouse conditions without fertilization (F0), conventional fertilization (CF), and organic fertilization (OF). Leaves were collected from sorghum plants fertilized with 200 kg N ha−1 using ammonium sulfate and poultry manure. Extracts were obtained using Soxhlet extraction, and the compounds were identified using a gas chromatograph coupled with mass spectrometry (GC-MS). Sorghum extracts were individually tested through bioassays to determine M. sacchari preference. The abundance and number of compounds in sorghum differed depending on the type of fertilization used. M. sacchari showed a preference for the extract from CF sorghum plants (76.66%) over the extract from OF plants (23.34%). Therefore, the type of fertilization can be used as a tactic to prevent higher infestations of M. sacchari. The biological activity of the compounds identified here with M. sacchari should be determined for future pest management strategies using allelochemicals, given that the sugarcane aphid uses chemical signals to locate its host plant.

Olfactometers have been used for more than 100 years and are integral to experimental chemical ecology. Studies utilising olfactometer bioassays form the foundation for understanding the behavioural responses of invertebrates to chemical stimuli under standardised laboratory conditions. Widely used olfactometry apparatuses include two‐arm olfactometers for binary responses through to four‐ and six‐arm arenas to evaluate more complex behaviours. Despite its prevalence in chemical ecology studies, there has never been a review of experimental best practice in olfactometry. This review critically evaluates both olfactometry methods and applications as well as experimental design and analysis. We aim to outline a standard of good practice to improve experimental design and reporting for studies involving olfactometry, thereby establishing a reference guide to build a robust experimental workflow for olfactometry bioassays. [ABSTRACT FROM AUTHOR]

In ant-aphid interactions, various aphid species offer honeydew to the ant partner and increase their density by ant attendance, whilst others never attend ant species, in which case ants tend to treat them as prey. In this regard, ants should have the ability to distinguish myrmecophile aphid species from non-mutualistic species, so that mutualistic aphids will be accepted as partners rather than prey. Although ant-aphid interactions are now the focus of chemical ecology studies, the role of the different chemical stimuli in determining mutualistic interactions has not been completely clarified. Therefore, we have investigated the cuticular hydrocarbon profile of four myrmecophiles aphid species using GC-MS. We also investigated the behavior of the worker-ants (Lasius niger L., Hymenoptera: Formicidae) to different chemical stimuli derived from aphids. We applied four treatments and found that the behavior of the ant workers varied depending on the source of the different treatments. In particular, the real aphid Aphis pomi and the sugar solution proved to be the most attractive to the ants, while the presence of pure extract of the individuals is enough to disturb the behavior of the ants. We provide evidence that the key stimuli of the tending behavior could be the CHC patterns of the aphids and the CHC profile of the aphids tends to be genus specific. This research will promote further investigations to test the behavior of ant workers towards other species of aphids and treatment combinations.

Animal communication depends on signals conveying information to a receiver who must perceive and decode them. Signals involved in territoriality are usually complex stimuli that should be correctly interpreted to avoid unnecessary conflicts. Lacertids use both visual and chemical stimuli in modulating their aggressive response against conspecifics and the rival's size is one of the most important information, affecting the success probability in combat. To assess the actual ability of decoding information about a rival's size based on its chemical stimulus alone, 60 males of Podarcis muralis were tested for three consecutive days in an arena bearing a mirror (to simulate an equal-sized intruder), and the chemical cues (femoral secretions) from an unknown individual of different size. Significant differences were observed in tongue-flicks number, which grew as the size difference between the focal lizard and the secretion donor decreased. This can be interpreted as the need for the lizard to better evaluate the potential competitor's characteristics. The size difference also affected the number of bites against the mirror. They increased when the size of the focal lizard was larger than the donor triggering the aggressive response with a higher probability of winning the contest. This confirms that the focal lizard had correctly decoded the information about the opponent's size by chemical stimulus. Although previous studies have shown that some components of the chemical signals are potentially informative about the signaler's size, this is the first demonstration that male P. muralis is actually able to decode and use such information. [ABSTRACT FROM AUTHOR]

Membrane-bound enzymes play pivotal roles in various cellular processes, making their activity regulation essential for cellular homeostasis and signaling transduction. Given that dysregulation of membrane-bound enzymes involved in various disease, controlling enzyme activity offers valuable avenues for designing targeted therapies and novel pharmaceutical interventions. This review explores chemical stimuli-responsive strategies for modulating the activity of these enzymes, employing diverse stimuli such as small molecules, proteins, nucleic acids, and bifunctional molecules to either inhibit or enhance their catalytic function. We systematically delineate the mechanisms underlying enzyme activity regulation, including substrate binding site blockade, conformational changes, and local concentration of enzymes and substrates. Furthermore, based on some examples, we elucidate the binding modalities between stimuli and enzymes, along with potential modes of regulation, and discuss their potential medical applications and future prospects. This review underscores the significance of understanding and manipulating enzyme activity on the cell membrane for advancing biomedical research and therapeutic development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

The aim of this study was to investigate the effects of gibberellic and salicylic acid on germination improvement and protection of Cassia angustifolia under allelopathic stress of Eucalyptus camaldulensis compounds in laboratory conditions. Treatments consisted of pretreatment with gibberellic acid (125, 250, and 500 ppm) and salicylic acid (100, 200, and 300 mg / l), and 5 concentrations of extracted allelopathic compounds of eucalyptus aerial and terrestrial organs (0, 25, 50, 75, and 100 mg / l). Each treatment had four replications and a factorial experiment in completely randomized design was performed. Results of analysis of variance indicated that the interaction effect of pretreatment and allelopathy on all measured traits was significant (p≤0.01). Means comparison showed that eucalyptus extract has allelopathic inhibitory effects on seed germination and early growth of Cassia angustifolia seedlings such that seed pre-treatment with chemical stimulants improved germination percentage and speed and also early growth of seedlings. Seed pre-treatment with gibberellic acid 500 ppm had the best effect on improvement of germination and early growth of seedlings. Overall, the results showed that Cassia angustifolia's response to seed pre-treatment with gibberellic acid was positive, and the seed pretreatment technique with gibberellic acid 500 ppm before planting decreased significantly the inhibitory effects of eucalyptus allopathic compounds at germination stage.

Invasive species represent one of the greatest threats to freshwater biodiversity. The successful colonisation and establishment of populations of invasive predators in waterbodies may expose the pre‐existing fauna to novel predation strategies to which they are not pre‐adapted. Despite this, there is still a paucity of information on behavioural responses within biological invasion research.Here we present the results of a series of 24‐hr mesocosm experiments that examined the handling times and responses of four Gastropoda species (Radix balthica, Physa fontinalis, Gyraulus albus, Potamopyrgus antipodarum) exposed to physical and chemical cues associated with the invasive crayfish, Pacifastacus leniusculus. We specifically considered four physicochemical treatments: (1) control (no cue); (2) conspecific chemical; (3) crayfish chemical; and (4) physical presence (but confined). In addition, we considered the effect of previous predator experience of the gastropod (predator naïve or aware) and additonally assessed survivourship in encounter trials.Handling time was found to vary significantly between gastropod species with survivorship from predation mirroring handling times observed. P. fontinalis required the greatest handling time (average of 58 s) and had the highest survivorship rate. In marked contrast, P. antipodarum were rapidly consumed, with an average handling time of 6 s and no individuals surviving after 4‐hr in the encounter trials. Handling time varied by gastropod size but also shell morphology.The response to the physical and chemical cues varied between gastropod species. R. balthica and P. fontinalis demonstrated vertical avoidance behaviour most readily whilst P. albus and P. antipodarum displayed active migration only to the physical presence cue. In most instances, the response was immediate with vertical migration (above the reach of the crayfish at 15 cm on the mesocosm wall) evident within an hour.Predation regime was found to exert a significant effect on the avoidance response of the gastropods. This was particularly notable in relation to the crayfish chemical cue and to a lesser extent the injured conspecific chemical cue. Predator‐naïve populations reacted with strong vertical avoidance behaviour in response to the crayfish chemical cue, whilst, in the case of P. fontinalis, predator aware individuals reacted most strongly to the conspecific chemical cue.Our results highlight the multifaceted challenge of understanding predator–prey relationships, particularly in the face of novel invasive species, and provide much‐needed evidence to begin to tackle this complex process. Gaining a better understanding of such interactions is vital in order to underpin management strategies and to enable evolutionary trajectories in invaded ecosystems to be assessed. Previous predator experience in combination with species identity are important attributes in determining predation risk when gastropod populations are exposed to novel predators and their associated predation cues. [ABSTRACT FROM AUTHOR]

Computational models that reveal the structural response of polymer gels to changing, dissolved reactive chemical species would provide useful information about dynamically evolving environments. However, it remains challenging to devise one computational approach that can capture all the interconnected chemical events and responsive structural changes involved in this multi-stage, multi-component process. Here, we augment the dissipative particle dynamics (DPD) method to simulate the reaction of a gel with diffusing, dissolved chemicals to form kinetically stable complexes, which in turn cause concentration-dependent deformation of the gel. Using this model, we also examine how the addition of new chemical stimuli and subsequent reactions cause the gel to exhibit additional concentration-dependent structural changes. Through these DPD simulations, we show that the gel forms multiple latent states (not just the “on/off”) that indicate changes in the chemical composition of the fluidic environment. Hence, the gel can actuate a range of motion within the system, not just movements corresponding to the equilibrated swollen or collapsed states. Moreover, the system can be used as a sensor, since the structure of the layer effectively indicates the presence of chemical stimuli.

Graphical abstract Abstract Nanotechnology-based interventions have gained popularity in the past decade for cancer therapy owing to their ability to overcome several shortcomings encountered in conventional therapy. Among the various nanoparticles that have been explored as drug carriers, mesoporous silica possesses certain desirable properties such as regulated pore size, high surface area, chemical and thermal stability, amenability for surface modification and biocompatibility. These systems have been widely investigated for site-specific delivery of single and multiple therapeutic agents as well as for imaging and theranostic applications. In recent times, the concept of targeted and sustained delivery of the therapeutic agent has transformed into a more attractive and effective approach of triggered drug release thereby ushering in an era of 'on-demand' drug delivery. Mesoporous silica due to its tunable surface functionalities has emerged in the forefront of triggered release systems. Though different types of external stimuli have been extensively investigated to bring about triggered drug release from mesoporous silica, chemo-responsive systems offer more therapeutic effectiveness with minimal collateral damage commonly associated with external stimuli. Chemo-responsiveness is generally achieved by introducing an appropriate gate-keeper molecule at the pore surface that regulates the diffusion of the drug molecules. This review analyzes different strategies that have been attempted to achieve 'on-demand' drug release in mesoporous silica carriers in response to various types of chemical stimuli. Emerging trends in the field of chemo-responsive mesoporous silica are also presented in this review. [ABSTRACT FROM AUTHOR]

Environmental enrichment has proven to be a useful and effective welfare tool in order to evaluate and enhance the well-being of captive animals, but only when it is based on detailed knowledge of each species' natural behaviour. Chemoreception is fundamental to many aspects of reptilian biology; however, sensory enrichment with chemical stimuli has rarely been applied to reptiles. In this study, we evaluate the use of chemosensory enrichment as a method to enhance the welfare of Podarcis liolepis. For seven weeks, we exposed field-caught males to scents from donor conspecific males collected on pieces of filter paper (i.e., "enriched" group, n = 18), and compared their behaviour to that of control males provided with unscented pieces of filter paper (n = 18). We measured the occurrence of normal (e.g., locomotion) and abnormal (escape attempts) behaviours each day for three weeks. In addition, we conducted two exploration tests and a visual barrier test. Compared to controls, enriched lizards showed a consistent long-term decrease (29%-38%) in the occurrence of escape attempts. During exploration tests, enriched lizards spent less time performing escape attempts and devoted more time to perching than controls. As expected, both control and enriched lizards showed a reduction of time in locomotion and an increase in the time spent perching between the first and second exploration test, but these changes were significantly more pronounced for enriched animals. Taken together, our results suggest improved welfare of enriched animals, as they spent less time engaging in abnormal behaviours, more time in normal behaviours, and showed signs of faster habituation to a novel environment. Chemosensory enrichment is a relatively simple enrichment strategy that could potentially be applied to improve the welfare of a wide range of captive lizards, and reptiles at large. [ABSTRACT FROM AUTHOR]

The flow regime around a chemically baited trap is crucial for the trapping process and distribution of bait downstream of traps. We measured the flow field downstream of a trap prototype in flume experiments and mapped the distribution of bait using laser induced fluorescence. The trap produced a downstream wake, where flow recirculated towards the trap, allowing organisms slower than the free stream flow to interact with the trap. The chemical tracer revealed an average gradient with increasing concentrations towards the trap. Finally, we evaluated trap performance in field experiments. Traps with internal light caught on average 3.4 times more zooplankton than traps without light in shortterm deployments (1 h). Trapping efficiency could be manipulated by chemical stimuli; A piece of fish (Salmo salar) inside traps deterred 79% of the zooplankton compared to traps without fish. We conclude that the flow regime around a cylindrical trap may facilitate trapping and that combined stimuli modalities may allow higher selectivity. The effective radius of the trap will depend on the surrounding flow and will likely be small when flow-rate exceeds swimming speed of targeted organisms. Finally, we propose applications for selective traps in aquaculture and pest management. [ABSTRACT FROM AUTHOR]

Augmentative releases of parasitoids may be a useful tool for the area-wide management of tephritid pests. The latter are parasitized by many wasp species, though only a few of them are relevant for augmentative biocontrol purposes. To date, nearly all the actual or potential biocontrol agents for such programs are egg or larval Opiinae parasitoids (Hymenoptera: Braconidae). Here, we review the literature published on their habitat and host location behavior, as well as the factors that modulate this behavior, which is assumed to be sequential; parasitoids forage first for the host habitat and then for the host itself. Parasitoids rely on chemical, visual, and mechanical stimuli, often strongly related to their ecology. Behavioral modulation factors include biotic and abiotic factors including learning, climatic conditions and physiological state of the insect. Finally, conclusions and perspectives for future research are briefly highlighted. A detailed knowledge of this behavior may be very useful for selecting the release sites for both inundative/augmentative releases of mass-reared parasitoids and inoculative releases for classical biocontrol.