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Sirex noctilio is an invasive forest wasp that affects pines in many parts of the globe and can result in severe economic losses.Current trapping methods for monitoring the pest rely heavily on non‐specific semiochemicals. This lack of specificity can translate into low attraction/capture levels, something that is undesired, especially when the intent is to detect the pest when still at low population densities. In this context, an interesting opportunity arises to increase trap sensitivity by incorporating visual cues.For this, we evaluated potential sources of visual information that, in accordance with the ecology of the species, could elicit an attractive response complementary to the olfactory cues.We measured the reflectance spectra of pine bark, chlorotic needles and woodwasp male abdomens. The spectra were then compared with 120 commercial paint colours to be applied on panel traps.During two flight seasons, field experiments were conducted with the deployment of 155 traps, combining the volatile bait (turpentine) and different coloured traps.We observed a significantly higher number of captures towards traps with pine bark‐like colourations compared with the black control traps.Our results are encouraging, as they suggest the potential of combining visual and chemical information for sustainable pest biomonitoring. [ABSTRACT FROM AUTHOR]

Honey bees (Apis spp.) are important components of ecosystems largely because of their pollination services. Within the last few decades, globalization has exposed honey bees to multiple invasive parasites, resulting in substantial honey bee colony losses, with attendant economic woes for apiculture that relies on western honey bees (Apis mellifera). To defend themselves, honey bees rely on their olfactory systems to detect parasitized nestmates, largely via chemical changes in the latter's cuticular hydrocarbon profiles. We review here how honey bee olfaction enables the detection of parasitized nestmates and how that in turn can drive specific hygienic behaviors. Enhancement of these hygienic responses may be one way to mitigate ongoing colony losses. [ABSTRACT FROM AUTHOR]

Within aquatic ecosystems, chemosensory cues are widely used as publicly available risk assessment information, allowing prey to optimize behavioural decisions. In sexually dimorphic species, males and females often have different responses to local predation threats. According to the ‘distracted male’ hypothesis, reproductively active males should show a reduced response to risk cues compared to conspecific females due to the potentially high costs of lost courtship and mating opportunities among males. Recent evidence supports this hypothesis, showing that adult male guppies (Poecilia reticulata) show a reduced or absent response to chemosensory risk cues. Here, we further test the ‘distracted male’ hypothesis by testing non-reproductive male and female guppies, collected from the Lopinot River (high predation) or the Upper Aripo River (low predation). We found that juvenile male and female guppies exhibited similar response patterns. Consistent with our predictions, both juvenile male and female guppies collected from a high predation site exhibited a similar antipredator response (reduced number of lines crossed) when exposed to conspecific alarm cues or a novel odour (vs. water control). Those collected from a low predation site showed similar responses to conspecific alarm cues and no response to a novel odour or the water control. Combined, our results suggest that unlike adult guppies, non-reproductive male and female guppies make similar behavioural decisions in response to acute predation cues. As predicted by the ‘distracted male’ hypothesis, the previously reported absence of a response to chemosensory risk assessment cues among adult males may be due to a devaluation of risk assessment information in favour of continued mating. [ABSTRACT FROM AUTHOR]

In aquatic systems, many prey animals, including anuran tadpoles, predominantly use chemical cues to assess predation threat. In such systems, an array of chemical cues (e.g., kairomones, alarm, dietary) affects the behavioural responses of the prey tadpoles. The study on the behavioural responses of tadpoles belongs to the family Microhylidae to predators are very less hence the outcome of this study will provide a novel information in the field of behavioural ecology of anuran tadpoles with reference to prey-predator interactions. The behavioural responses of tadpoles of Indian painted frog Uperodon taprobanicus (Microhylidae) to its naturally co-existing predatory tadpoles of the Indian bullfrog Hoplobatrachus tigerinus (Dicroglossidae) were studied in the laboratory. The predator's kairomones (water conditioned by a starved predator) was used to simulate predation threat. The results of the experiment showed that U. taprobanicus tadpoles exhibited strong antipredator behavioural responses, i.e. drastically reduced swimming movements and overall time spent in swimming as well as had a higher burst speed in response to kairomones of predators. Thus, U. taprobanicus tadpoles consider H. tigerinus tadpoles as potential predators. This may be because of long ecological co-existence of U. taprobanicus tadpoles with sympatric carnivorous tadpoles, H. tigerinus may have led to the evolution of antipredator defence strategies in response to kairomones of these predators. In summary, tadpoles of U. taprobanicus perceive predation risk by detecting kairomones emanating from the predator H. tigerinus and showed appropriate antipredator behavioural responses. [ABSTRACT FROM AUTHOR]

Invasive species threaten biodiversity globally. Amphibians are one of the most threatened vertebrate taxa and are particularly sensitive to invasive species, including other amphibians. African clawed frogs (Xenopus laevis) are native to Southern Africa but have subsequently become invasive on multiple continents-including multiple parts of North America-due to releases from the pet and biomedical trades. Despite their prevalence as a global invader, the impact of X. laevis remains understudied. This includes the Pacific Northwest of the USA, which now hosts multiple expanding X. laevis populations. For many amphibians, chemical cues communicate important information, including the presence of predators. Here, we tested the role chemical cues may play in mediating interactions between feral X. laevis and native amphibians in the Pacific Northwest. We tested whether native red-legged frog (Rana aurora) tadpoles display an antipredator response to non-native frog (X. laevis) or native newt (rough-skinned newts, Taricha granulosa) predator chemical stimuli. We found that R. aurora tadpoles exhibited pronounced anti-predator responses when exposed to chemical cues from T. granulosa but did not display anti-predator response to invasive X. laevis chemical cues. We also began experimentally testing whether T. granulosa-which produce a powerful neurotoxin tetrodotoxin (TTX)-may elicit an anti-predator response in X. laevis, that could serve to deter co-occupation. However, our short-duration experiments found that X. laevis were attracted to newt chemical stimuli rather than deterred. Our findings show that X. laevis likely poses a threat to native amphibians, and that these native species may also be particularly vulnerable to this invasive predator, compared to native predators, because toxic native newts may not limit X. laevis invasions. Our research provides some of the first indications that native Pacific Northwest species may be threatened by feral X. laevis and provides a foundation for future experiments testing potential management techniques for X. laevis.

We describe a new and unusual myrmecophilous behaviour displayed by the darkling beetle, Scaurus uncinus (Forster, 1771) (Coleoptera: Tenebrionidae), accessing nests of the harvester ant, Messor barbarus (Linnaeus, 1767) (Hymenoptera: Formicidae), in southeast Spain. The beetles enter the interior of the ant nests using a relatively primitive strategy based only on brute force, which we name "brute force entries". To understand the significance of this behaviour, we have studied the interactions of these two species in the field and in the laboratory during six years. Our observations confirm that specimens of S. uncinus expend a considerable effort to enter the ant nests, despite the ants fiercely attacking them, to the extent that the beetles lose legs and antennae through the process. We describe and discuss this behaviour, and identify hypotheses about its development and significance.

ABSTRACT Intraspecific sexual communication, crucial in reproductive interactions, often involves the interchange of signals like vibrations, visual signals, and chemical compounds like sex chemical cues. Within the arachnids, solifuges (“camel spiders”) are an understudied group in terms of the detection of chemical compounds during mate searching and sexual interactions. In solifugids, the malleoli, chemoreceptor structures located on the ventral side of legs IV, are putative structures capable of capturing chemical signals. Our study focused on chemical male perception of female cues in Titanopuga salinarum (Ammotrechidae), examining associated behavioral modifications and the role of malleoli. We analyzed alterations in the motion pattern (activity pulse) and specific behaviors performed by males in association with female chemical stimuli. Using experimental arenas, we exposed males to female chemical cues stimuli similar to those available at the field. Stimuli comprised females (F) and cuticular extracts (CE), with corresponding controls. Males with intact malleoli (N = 26 with F, N = 20 with CE) were compared to those with malleoli removed (N = 21 with F, N = 17 with CE). We found partial evidence that males detect chemical cues of females deposited on the substrate. We observed no differences in the duration and number of the activity pulses spent in the zones with and without stimuli in any of the groups analyzed. However, the males exhibit significant changes in locomotion patterns in response to female chemical cues, suggesting a behavioral response to these stimuli. This finding suggests that the males of this species detect the female chemical cues and modify their behavior, and can quickly gather the necessary olfactory information where the stimulus is located. In addition, we found a possible condition‐dependent regime for the detection of female cues by males, which would be expected from life‐history characteristics of T. salinarum. Our findings prompt discussion from a sexual selection perspective, suggesting the importance of chemical communication in intraspecific interactions in this elusive but fascinating animal model. [ABSTRACT FROM AUTHOR]

Crowding induces behavioural and lasting morphological and chromatic changes in insects. This study examined how larval rearing density of Propylea dissecta (Mulsant, 1850) affected food choice and development duration, hypothesising that larvae under stress will opt for lower quality food as larval density increases. Larvae were reared at various densities under three crowding treatments: direct physical, indirect physical, and chemical tracks. In each treatment, larvae experienced crowding at densities of 0, 2, 4, 6, 8, 10, and 12 individuals per arena. Fourth stage larvae were provided with food choice of aphids, heterospecific eggs, and conspecific eggs. Significant effect of crowding on total development duration, first consumption time, and first food consumption was observed. Decrease in development duration at densities of 4 and 6 and increase in development duration at low and high densities were observed in direct physical crowding. Indirect physical and chemical crowding yield the shortest development duration at densities of 8, 10, and 12, when compared to low and moderate crowding. First encounter time increased with increasing chemical tracks concentration, while first consumption time decreases with crowding across all groups. First consumed food was also significantly influenced by crowding, suggesting a negative impact on larval food choice. Our results indicate that crowding among larvae leads to a longer development duration and show less selectivity in their food choices. [ABSTRACT FROM AUTHOR]

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Many studies have shown that prey can optimize their defence mechanisms based on cues indicating predator presence and pressure. However, little is known about whether prey can assess the actual threat by considering both predator density and the motivational state of cannibalistic predators, which can be influenced by threats from higher order predators. We conducted laboratory experiments to test the hypothesis that high predator density, combined with chemical cues indicating predator stress (e.g. alarm and disturbance cues), may inhibit prey defences. Using Daphnia and Zygoptera/Anisoptera larvae, we observed that Daphnia’s strong response to low-density predator kairomones was suppressed when exposed to high-density predator kairomones and disturbance cues. Surprisingly, we found no evidence of a suppressive response to alarm cues. Our study is to our knowledge, the first to show that prey uses predator stress cues to avoid unnecessary defences, suggesting a ‘cascade of fear’ in which fear at one trophic level reduces fear at a lower level. Furthermore, it is to our knowledge the first to demonstrate that prey can reduce their anti-predator response in the presence of high densities of cannibalistic predators.

Animals that live in human‐impacted landscapes experience an onslaught of novel stimuli that may interfere with natural communication pathways. During mating, this interference may alter the criteria deployed to assess potential mates as males and females find they must shift their focus and emphasize alternative sensory modalities. The wolf spider, Tigrosa helluo (Araneae, Lycosidae) is common in agricultural fields where commercial formulations of herbicides with glyphosate as the active ingredient are regularly applied. With the development of genetically resistant crops, glyphosate‐based herbicides have become among the most widely used and heavily applied agricultural chemicals in the world. In a laboratory experiment, we explored the effects of this herbicide on male—female interactions during courtship, mating, and sexual cannibalism. We expected that it might impact assessment such that there was a shift in the features that were important to the outcome of mating interactions. When herbicide was present, female body condition, an indication of recent feeding success, became important to mating success. This result was, in part, due to higher rates of sexual cannibalism in parings of males and females with low body condition values. The leg raises and pedipalp waves that males perform in courtship were not affected by herbicide nor were they related to mating success but, across all treatments, they were negatively correlated with lytic activity of females as measured just prior to pairing. This result indicates that males detected this aspect of the female's physiology and that a strong immune response made the female less attractive, possibly because it indicated a current or recent infection. Taken together, these results verify that a common herbicide shifts mating criteria used by an agribiont spider and, separate from the herbicide, the immune status of females affects the reactions of courting males. [ABSTRACT FROM AUTHOR]

Ants use chemical cues known as cuticular hydrocarbons (CHCs) for both intraspecific and interspecific recognition. These compounds serve ants in distinguishing between nestmates and non-nestmates, enabling them to coexist in polydomous colonies characterized by socially connected yet spatially separated nests. Hence, the aim of this study was to investigate the intraspecific aggression level between nestmates and non-nestmates of the bullet ant Paraponera clavata (Fabricius, 1775), analyze and compare their CHCs, and evaluate the occurrence of polydomy in this species. We conducted aggression tests between foragers, both in laboratory and field settings. To identify the chemical profiles, we utilized gas chromatography coupled with mass spectrometry (GC-MS). We marked the foragers found at nest entrances and subsequently recaptured these marked ants to validate workers exchange among nests. Across all nests, a low intraspecific aggression level was observed within the same area. However, a significant difference in aggression correlated to distance between nests. Analysis of the cuticular chemical profile of P. clavata unveiled colony-specific CHCs, both qualitatively and quantitatively. Notably, we observed instances of ants from certain nests entering or exiting different nests. This behavior, in conjunction with the observed low intraspecific aggression despite differences in CHCs suggests polydomy for this species. Polydomy can offer several benefits, including risk spreading, efficient exploitation of resources, potential for colony size increasing and reduced costs associated with foraging and competition. [ABSTRACT FROM AUTHOR]

The ability of anuran larvae to efficiently locate food is essential for their growth and development, but little is known about the sensory modalities they use to find food. We experimentally assessed the role of visual and chemical cues in finding food in tadpoles of the invasive species Lithobates catesbeianus. In the two‐choice experiment, using rectangular containers that offer visual and/or chemical food cues on opposite ends, tadpoles chose the side where the chemical cues of the food were present consistently. The visual cues alone showed an initial transient attraction of tadpoles, which disappeared after a few minutes, suggesting that tadpoles are potentially capable of seeing contrasting objects, at least, at a close range and in clear waters and daylight conditions. We also evaluated the foraging behaviour and the capability of tadpoles to find food in an open field experiment under two different lighting conditions: natural daylight and darkness. Results showed that tadpoles find food faster in dark conditions, confirming that chemical cues alone are sufficient for tadpoles of this species to find food. Moreover, the time spent feeding and the number of tadpoles simultaneously exploiting the food patch were greater in darkness suggesting that environments with low visibility conditions could favour the establishment of L. catesbeianus. Understanding the sensory modalities used by tadpoles of this invasive species to find food could help to understand the potential abilities to expand and establish in novel environments. [ABSTRACT FROM AUTHOR]

Chemical eavesdropping is a critical tool used by organisms to gain information about their environment and mediate interactions with other organisms within it, such as prey gaining information about predators and vice versa. However, most chemical eavesdropping studies focus on information used by prey species, not predators. The goal of this study was to assess whether or not a desert ambush predator, Crotalus ornatus (Eastern Black-tailed Rattlesnake), differentiates among chemical cues from nonnative familiar and novel native prey items when choosing ambush spots. Naive neonate C. ornatus were obtained from wild mothers, born and raised in captivity, and placed in an arena where they were presented with aquatic extracts from the integument from 9 known and suspected prey items, a familiar non-native prey item, and a tap water control. Their reactions to the chemical extracts were recorded under diurnal and nocturnal conditions, and they were given a tongue-flick ambush (TFAM) score based on their predatory behavior towards the chemical cue. Ten naive neonate C. ornatus were put through each of the 11 trials under diurnal and nocturnal conditions, and based on TFAM scores, snakes differentiated among the chemical cues, but there were no detectable differences based on photoperiod. Post hoc pairwise tests revealed that snakes preferred native small mammal and lizard prey. The snakes used in this study had never been exposed to wild prey stimuli in their native ecosystem and had fed exclusively on non-native mammalian prey in captivity, thus their preference for native small mammals and lizards indicates an innate basis for prey preference in C. ornatus. [ABSTRACT FROM AUTHOR]

Cuticular hydrocarbons (CHCs) of Drosophila ananassae (Doleschall) was characterized and identified using gas chromatography and mass spectrometry (GC-MS) analysis. A high % of methyl-branched alkanes were identified in all inversion (2LA, 3LA and 2LA+3LA) and inversion-free strains followed by linear alkanes and alkenes. The present work unfolds the significant patterns of variations in the isomeric forms of methylated alkanes between the inversion and inversion free strains (F-46.6; df-3, p 0.005), and non-significant between the sex (F-2.14; df-1, p 0.2394). But in linear alkanes shows significant variation between the inversion strains (F-30.49; df-3, p 0.009) and between the male and female (F-115.45; df-1, p 0.001) was observed. In particular there is a significant correlation between the chromosomal inversion and synthesis of CHCs in D. ananassae. Unique blend of CHCs in Drosophila performs dual role as desiccation resistance and act as chemical signalling molecule. Linear alkanes are majorly involved in desiccation resistance but in methyl- branched CHCs length variation is a key determinant of desiccation resistance. Presence of longer methyl- branched alkanes and higher desiccation resistance, shorter the carbon chain length act as a signalling molecules. The current study revealed the influence of chromosomal inversion on the cuticular hydrocarbon profile in D. ananassae. [ABSTRACT FROM AUTHOR]

The behavioural responses of predator-naïve (laboratory-born), predator-experienced (laboratory-born but with short-term experience with predators), and wild-caught (with long-term experience with predators in natural settings) tadpoles of Sphaerotheca breviceps to carnivorous predatory tadpoles of Hoplobatrachus tigerinus was studied in the laboratory. The predator's stimulus solution (kairomones) was used to simulate predation threat. All S. breviceps tadpoles (i.e., predatornaïve, predator-experienced and wild-caught) exhibited behavioural antipredator responses, i.e., reduced swimming activity and time spent swimming, and had a higher burst speed in response to water-borne kairomonal cues of predators. Wildcaught tadpoles showed stronger responses than predator-naïve and predator-experienced tadpoles and the latter exhibited stronger responses than predator-naïve tadpoles. Our study thus suggests that antipredator behaviour in these tadpoles is basically innate. Furthermore, the enhanced antipredator behaviour of wild-caught tadpoles indicates that learning is involved. [ABSTRACT FROM AUTHOR]

Invasive species threaten biodiversity globally. Amphibians are one of the most threatened vertebrate taxa and are particularly sensitive to invasive species, including other amphibians. African clawed frogs (Xenopus laevis) are native to Southern Africa but have subsequently become invasive on multiple continents—including multiple parts of North America—due to releases from the pet and biomedical trades. Despite their prevalence as a global invader, the impact of X. laevis remains understudied. This includes the Pacific Northwest of the USA, which now hosts multiple expanding X. laevis populations. For many amphibians, chemical cues communicate important information, including the presence of predators. Here, we tested the role chemical cues may play in mediating interactions between feral X. laevis and native amphibians in the Pacific Northwest. We tested whether native red-legged frog (Rana aurora) tadpoles display an antipredator response to non-native frog (X. laevis) or native newt (rough-skinned newts, Taricha granulosa) predator chemical stimuli. We found that R. aurora tadpoles exhibited pronounced anti-predator responses when exposed to chemical cues from T. granulosa but did not display anti-predator response to invasive X. laevis chemical cues. We also began experimentally testing whether T. granulosa—which produce a powerful neurotoxin tetrodotoxin (TTX)—may elicit an anti-predator response in X. laevis, that could serve to deter co-occupation. However, our short-duration experiments found that X. laevis were attracted to newt chemical stimuli rather than deterred. Our findings show that X. laevis likely poses a threat to native amphibians, and that these native species may also be particularly vulnerable to this invasive predator, compared to native predators, because toxic native newts may not limit X. laevis invasions. Our research provides some of the first indications that native Pacific Northwest species may be threatened by feral X. laevis and provides a foundation for future experiments testing potential management techniques for X. laevis. [ABSTRACT FROM AUTHOR]

Poison frogs of the superfamily Dendrobatoidea have fascinated researchers since the 19th century, which is reflected in multiple studies on their natural history, taxonomy, toxicity, colour pattern diversity, and elaborate territorial, reproductive and parental care behaviours. Broadly speaking, however, the term "poison frogs" may apply as well to other taxa which also possess skin toxins. Hereon, we refer to poison frogs as this extended group involving, besides Dendrobatoidea (Dendrobatidae + Aromobatidae), a few genera in families such as Bufonidae and Mantellidae (among others). Most studies on poison frogs have focused on species considered charismatic due to their bright and flashy colours, limiting possible generalisations of patterns and mechanisms explaining the high morphological, ecological, and behavioural differentiation, but also convergence, among these groups. Furthering our understanding of the evolutionary ecology of poison frogs requires increasing not only the scope and depth of our own questions, but also the number and diversity of study systems. Inspired by the special issue on dendrobatid and aromobatid poison frogs published ten years ago in this same journal, we have put together the present special issue aiming to broaden both the topics and the coverage of poison frog clades. This first part consists of 15 manuscripts covering topics ranging from larval behavioural ecology and parental care to space use and its environmental determinants, along with conservation implications. [ABSTRACT FROM AUTHOR]

Environmentally cued hatching is prevalent, diverse, and crucial to many animals' survival. Fish embryos use a variety of chemical cues to initiate hatching to avoid potential predators, yet the function of chemical cues released from the predatory consumption of heterospecific prey is largely unknown. Zebra cichlids (Metriaclima estherae) are ferocious predators that can feed on medaka (Oryzias latipes), though it is impossible for this to occur in their natural habitat. Zebrafish (Danio rerio) embryos have been employed as experimental subjects due to their sensitivity to a variety of chemical signals. In this study, zebrafish embryos were subjected to three types of chemical signals: predator cues (PCs, released from cichlids), heterospecific cues (HCs, released from medaka), and heterospecific dietary cues (HDCs, released from cichlids that have ingested medaka). As a result, the hatching times of zebrafish embryos were accelerated by 6.8% and 12.6% by PCs and HDCs, respectively. PCs and HDCs cause significantly reduced morphology in zebrafish embryos, including regarding total length, eye length, dorsal fin length, trunk height, caudal fin height, and body cavity, and increase yolk sac height. The PCs and HDCs diminished the larvae's motion at 120 and 144 h post fertilization (hpf), which could be attributed to non-developmental embryogenesis. Overall, the impacts of HDCs on embryonic hatching, developmental morphology, and locomotor were more pronounced in comparison with PCs. Our findings demonstrate that predators' dietary cues, even those released after predation on heterospecific prey, can modify embryogenesis, highlighting the critical functions of chemical signals in predation risk assessment using embryos. [ABSTRACT FROM AUTHOR]

Where orangethroat darters (Etheostoma: Ceasia) and rainbow darters (Etheostoma caeruleum) co‐occur, males prefer conspecific over heterospecific females. The cues males use to identify conspecific females remain unclear. We conducted behavioral trials to ask whether chemical cues function in conspecific recognition. We found that males from three orangethroat darter species preferentially associate with female scent over a control. Our results support the use of olfaction in conspecific identification in the orangethroat clade and contribute to our understanding of signals that may facilitate species recognition and underlie the evolution of behavioral isolation. [ABSTRACT FROM AUTHOR]

Simple Summary: Many animals use olfaction to assess potential partners or rivals. However, in the case of birds, the role of olfaction in assessing potential partners is still scarce. We performed a study to analyse whether Zebra Finch females use olfaction to detect male body condition. We used an olfactory chamber to offer females the scent of two males differing in body condition, and we recorded female choice. Our results show that females can detect the body condition of males, but contrary to what should be expected in a reproductive context, females chose the scent of males with a poorer body condition. Therefore, our results suggest that females performed their choice in a non-reproductive social context, avoiding potential conflict with males with better body condition. The role of chemical communication in the social relationships of birds is receiving growing attention, but our knowledge is still scarce compared to that of other taxa. Previous evidence suggests that chemical cues emitted by birds may carry information about their characteristics, which may be useful in the context of sexual selection. However, experimental studies are needed to investigate the role of bird chemical cues in signalling the quality of potential partners. We performed an experimental study aimed at disentangling whether the female Zebra Finches (Taeniopygia guttata), use chemical cues to assess the body condition of potential partners. We offered focal females (N = 28) the scent of two males differing in body condition (body mass/tarsus length ratio) (N = 28 scent donor males). Our results showed that females can assess the body condition of potential partners using olfaction. However, contrary to what should be expected in a mate choice context, females avoided the scent of males with greater body condition. Our results, therefore, suggest that, despite performing the study during the breeding period, social interactions may be mediating the avoidance of the scent of the male in better condition in this gregarious species, probably to avoid a conspecific competitor with better body condition. [ABSTRACT FROM AUTHOR]

Background: Like many cockroaches, Argentinian wood roaches, Blaptica dubia, prefer darker shelters over lighter shelters. In three experiments, we asked whether chemical cues from other roaches might influence shelter choice, a process known as conspecific or heterospecific cueing, depending on whether the cues come from an individual of the same or a different species, respectively. Methods: Each experiment involved trials with focal B. dubia cockroaches in testing arenas containing plastic shelters of varying levels of darkness, with filter paper under each shelter acting as a carrier for chemical cues. In Experiment 1, we tested female and male B. dubia cockroaches with two shelters matched for darkness but differing in cues (conspecific vs. none). The shelter with no cue contained a blank filter paper as a control. In Experiment 2 (conspecific cueing) and Experiment 3 (heterospecific cueing), we tested B. dubia cockroach choices for lighter or darker shelters with filter papers containing chemical cues of other roaches or no chemical cues. For the conspecific cueing study of Experiment 2, we used chemical cues from other B. dubia cockroaches. In contrast, for the heterospecific cueing study of Experiment 3, we used chemical cues from a different species, the death's head cockroach, Blaberus craniifer. Results: In Experiment 1, B. dubia cockroaches overwhelmingly preferred shelters with conspecific chemical cues over darkness-matched shelters without cues. In Experiments 2 and 3, they strongly preferred darker shelters, especially when chemical cues were present. Additionally, they were more likely to be under the lighter shelter when chemical cues were present there. These results reveal that the public information B. dubia cockroaches gain from chemical cues--including those from other species--can drive shelter choices in this species. [ABSTRACT FROM AUTHOR]

Invasive species threaten biodiversity globally. Amphibians are one of the most threatened vertebrate taxa and are particularly sensitive to invasive species, including other amphibians. African clawed frogs (Xenopus laevis) are native to Southern Africa but have subsequently become invasive on multiple continents—including multiple parts of North America—due to releases from the pet and biomedical trades. Despite their prevalence as a global invader, the impact of X. laevis remains understudied. This includes the Pacific Northwest of the USA, which now hosts multiple expanding X. laevis populations. For many amphibians, chemical cues communicate important information, including the presence of predators. Here, we tested the role chemical cues may play in mediating interactions between feral X. laevis and native amphibians in the Pacific Northwest. We tested whether native red-legged frog (Rana aurora) tadpoles display an antipredator response to non-native frog (X. laevis) or native newt (rough-skinned newts, Taricha granulosa) predator chemical stimuli. We found that R. aurora tadpoles exhibited pronounced anti-predator responses when exposed to chemical cues from T. granulosa but did not display anti-predator response to invasive X. laevis chemical cues. We also began experimentally testing whether T. granulosa—which produce a powerful neurotoxin tetrodotoxin (TTX)—may elicit an anti-predator response in X. laevis, that could serve to deter co-occupation. However, our short-duration experiments found that X. laevis were attracted to newt chemical stimuli rather than deterred. Our findings show that X. laevis likely poses a threat to native amphibians, and that these native species may also be particularly vulnerable to this invasive predator, compared to native predators, because toxic native newts may not limit X. laevis invasions. Our research provides some of the first indications that native Pacific Northwest species may be threatened by feral X. laevis and provides a foundation for future experiments testing potential management techniques for X. laevis.

Phytoplanktonic communities have been moulded from a higher level in the food web by zooplankton predation. Diatoms, which are the major primary producers in present day oceans, have evolved many strategies to thrive in the presence of copepods, their predators. Chemical signals are released in the aquatic environment by microarthropods and elicit morphological, behavioural and/or physiological modifications in diatom cells which allow them to cope with predators. Other than the most studied effects of copepod signals on the release of toxins by diatoms, the role of chemical cues on growth and biology of non-toxic diatoms has been little investigated, although it may broaden our knowledge of co-evolutive physiological mechanisms. To examine the response of diatoms to copepod-derived signals, Phaeodactylum tricornutum, Chaetoceros muelleri and Cylindrotheca fusiformis (Bacillariophyceae) were grown in the presence of copepod cues. Physiological modifications occurred and differed in sign and magnitude between species: i) in P. tricornutum cell density was higher, and dry weight lower, suggesting energy allocation into cell division at the expense of lipid and protein quotas; ii) C. muelleri showed a very homeostatic behaviour; and iii) in C. fusiformis cell density was lower and lipid content higher, showing energy allocation into lipids, which likely act as deterrent to feeders. Copepod cues are here suggested to have ruled diatom species composition in the ocean by affecting species-specific growth performance and the energy allocation into macromolecules. [ABSTRACT FROM AUTHOR]

Various strategies have evolved to protect animals from predators. We explored the activity and predation risk experienced by two species of aphid. Both species will drop from plants when disturbed and face a suite of predators, including wolf spiders, when they reach the ground. We focused on Aphis fabae Scopoli and Aphis nerii Boyer de Fonscolombe (Hemiptera: Aphididae, Aphidini); A. nerii sequesters cardiac glycosides when it feeds on milkweed. We explored the interactions between these aphids and the wolf spider Pardosa milvina Hentz (Araneae: Lycosidae) that is likely a predator they encounter when they are not on their host plants. We hypothesized that there would be differences in the susceptibility of the two species to predation and that the more vulnerable species would react more strongly to substrate‐borne cues deposited by the spider. We predicted that any behavioral reactions that the aphid displayed in response to predator cues would be effective in reducing risk. We documented the activity of each aphid species on chemotactile cues from P. milvina and measured predation rate in arenas with and without those same cues. Aphis fabae altered their activity in the presence of P. milvina cues but A. nerii did not. Likewise, A. fabae was more susceptible to predation by P. milvina when no cues were present, but when cues were present, predatory success was much lower. Aphis nerii, the less desirable prey for this predator, moved less and had a different locomotory pattern than A. fabae in control trials with no spider cues and so we cannot determine whether its chemical protection or activity were more important in reducing predation levels. These results provide insight into the risks faced by aphids when they are off of their host plant and in a barren environment. [ABSTRACT FROM AUTHOR]

Most of the anuran tadpoles spend their early phase of life in aquatic medium. In such system, they respond to a wide variety of stimuli (e.g., tactile, chemical and visual cues) and exhibit appropriate behavioural responses. The ability to detection food and predator was studied in the tadpoles of the bicolored frog, Clinotarsus curtipes in the laboratory by using a rectangular glass test tank with end compartments (stimulus zones) providing exclusively visual and/or chemical food (boiled spinach) or predator (Laccotrephes sp.) cues. A test tadpole, C. curtipes (either starved or fed; Gosner stage 25) was held at the centre of the test tank for 5 min (acclimation) to perceive visual and/or chemical food or predator cues. Then it was released from the centre of the test tank and allowed to associate or stay away from the caged stimulus subjects (food or predator), which were placed at one end of the test tank either in a glass beaker (visual cues) or in a mesh cage wrapped with cheese cloth (chemical cues) for a period of 10 min. The test tadpoles were unable to detect both food and predator through visual cues. They spent almost an equal amount of time in the zone housing food or predator in a glass beaker or opposite zone, which was kept empty. However, they detected both food and predator solely through chemical cues. In tests with chemical food cues, they spent a significantly higher period of time (70.42% of total time) near chemical food cues rather than empty or visual food cues. In contrast, in tests with chemical predator cues, they spent the majority of their time (69.32% of total time) away from the chemical predator cues. The findings thus show that C. curtipes tadpoles detect both food and predator solely through chemical cues rather than visual cues. [ABSTRACT FROM AUTHOR]

Carbon nanofibers, recently recognized pollutants, have been heavily used among the nanomaterials in many industries. Due to the poor suspension-stability, carbon nanofibers tend to sediment at the bottom of waterbodies and hence can be consumed by the bottom-dwellers. The current investigation evaluates the impact of carbon nanofibers at concentrations between 0.1 and 10 mg L−1 on the common bottom dweller spiny loach Lepidocephalichthys thermalis inhabiting Indian rivers. Carbon nanofiber exposure elevated the activities of the hepatic antioxidant enzymes superoxide dismutase, catalase, peroxidase and glutathione S-transferase, as oxidative stress markers. The fish behaviour patterns were examined by testing the effect of carbon nanofibers on predator recognition ability using kairomones, conspecific alarm cues, and dietary cues. The carbon nanofiber-exposed fish showed a loss of predator-recognition abilities. The results collectively demonstrated the carbon nanofiber driven hepatic oxidative damage and impaired predator-recognition ability in L. thermalis. The investigation, first of its kind, highlights the toxic potential of the carbon nanofibers on benthic fishes. [ABSTRACT FROM AUTHOR]

Myxobdella sinanensis Oka, 1925 (Arhynchobdellida, Praobdellidae) is endemic to Japan, and was recently observed attaching to the freshwater Japanese crab, Geothelphusa dehaani White, 1847 (Decapoda, Potamidae), revealing that M. sinanensis is a facultative parasite of G. dehaani. Although they both inhabit headwater streams in Japan, their interactions and behavioral responses have not been investigated before. We hypothesized that G. dehaani reacts to M. sinanensis through (1) chemical cues, and (2) visual cues or physical contact in addition to the chemical cues. Two experiments were conducted in a container in which G. dehaani could hide under a rock on the bottom covered with sediment. The duration of activity outside the rock and distance moved before and after introducing rearing water of M. sinanensis, or live M. sinanensis, was measured. No statistical difference was observed in movement distance, behavior, and time outside the rock in G. dehaani, indicating limited sensitivity to chemical cues. G. dehaani remained beneath the rock for a statistically shorter period after M. sinanensis was introduced into the container, indicating its dependence on visual and/or physical cues. It showed altered behavior by remaining stationary and escaping, confirming importance of visual and contact stimuli to escape the ectoparasite. [ABSTRACT FROM AUTHOR]

Intraspecific sex differences in morphology, physiology, and behavior are widespread among taxa. However, despite their fundamental importance, they have been relatively understudied in the context of risk assessment. For instance, with Trinidadian guppies (Poecilia reticulata), there has been a bias toward the exclusive use of females, as males are thought to be less responsive to acute predation threats. However, there is little empirical evidence supporting this assumption. Moreover, the antipredator behavior of male guppies has been unexplored, perhaps resulting in the over-generalization of female behavior to both sexes in previous studies. Here, we conducted laboratory experiments involving wild-caught and laboratory-reared guppies. In Experiment 1, shoals of either male or female guppies from a high-predation population were tested for their response to alarm cues, novel odor, or a water control. We found that while female shoals exhibited strong antipredator responses to alarm cues and neophobic responses to novel odor, male shoals exhibited only a weak response to alarm cues and no evidence of neophobia. In Experiment 2, we exposed male and female guppies to high- or low-predation risk and then tested individuals for their responses to alarm cues, novel odor, or water control. Regardless of background risk, males did not respond to any stimulus. In contrast, low-risk females exhibited antipredator responses toward alarm cues and those from high background risk displayed neophobia. Our results suggest that females are more cautious when encountering an acute predation risk, highlighting the importance of accounting for both sexes in studies on predation. [ABSTRACT FROM AUTHOR]

Aposematic species combine a conspicuous signal with a secondary defence, the majority of which are studied in the context of a visual signal. While multimodality of the aposematic signal appears to be common in invertebrate species, we know very little about the presence or absence of multimodality in vertebrates. Here, we examine the possibility of multimodality of aposematism in the green‐and‐black poison frog, Dendrobates auratus. Using a non‐visual predator (the cat‐eyed snake, Leptodeira annulata) and extractions of chemicals in frog skins, we test whether there is sufficient non‐visual information for predators to avoid this aposematic species without using visual cues. We found that experienced predators avoid chemicals in this poison frog's skin by olfactory cues alone in trials with live frogs and extracts from captive poison frogs, whereas extracts from wild poison frogs did not lead to avoidance behaviours in predators. Further, in our limited sampling, naïve predators demonstrate no avoidance. This not only indicates that predators can make informed decisions from the frog's odour, but also indicates that avoidance based on olfactory cue is a learned response. [ABSTRACT FROM AUTHOR]

The black soldier fly Hermetia illucens Linnaeus (Diptera: Stratiomyidae; BSF) is gaining interest as an alternative protein ingredient for livestock feed. Larval aggregation behaviour occurs commonly in larvae of various dipteran species. However, the cues initiating aggregation behaviour and its occurrence in subsequent larval instars are still unknown in BSF larvae. Here, we focus on understanding the attraction of larvae to cues left behind in the substrate by conspecific larvae. We developed a dual‐choice test in the dark and examined the preference behaviour of different instars with the use of video recordings. Larval choices were identified based on first substrate contact, cumulative number of substrate contacts, entry of the substrate and number of larvae present in a substrate over time. Our results demonstrate that BSF larvae discriminated between similar substrates with or without cues released by conspecifics, with a strong preference for previously colonised substrates. Our results also showed a difference in behaviour between head‐capsule classes. Substrate contacts occurred more frequently in larvae from a lower head‐capsule class and the number of larvae present in a substrate over time differed between the head‐capsule classes 0.71–0.80 mm and 0.91–1.00 mm. Demonstrating arrestment in response to chemical cues from conspecifics is the first step of understanding aggregation behaviour of BSF larvae and offers opportunities to identify the chemical cues involved. [ABSTRACT FROM AUTHOR]

During social interactions, the behavior of an individual often depends on the sex of its social partner. Many animal societies have males and females that play very different behavioral roles, although they coexist and interact non-sexually. At specific phases of the colony cycle, social wasp females and males are contemporaries within a nest, they often interact, although mating occurs mostly off the nest, therefore providing an opportunity to test sex discrimination in contexts other than classical sexual ones. We performed a lure presentation experiment to test if Mischocyttarus metathoracicus discriminate between conspecifics of the 2 sexes during on-nest social interactions. Female wasps discriminated conspecific sex during experimentally simulated nest intrusions. Visual and chemical cues may account for this sex discrimination. Despite sex discrimination (evidenced by differential inspective behavior from the nest females toward the female and the male lures), female wasps were as aggressive toward lures of both sexes. In the female-dominated hymenopteran societies, males are often subordinate and not aggressive on nest, resulting in females directing less aggression to them compared to other females. Instead, M. metathoracicus males and females are both aggressive toward nestmates, so they might be perceived as similar threat during on-nest social interactions. [ABSTRACT FROM AUTHOR]

Pelagic Sargassum spp. is important in the life histories of many economically and ecologically important associated organisms, which collectively form a symbiotic community with this alga serving as the primary host. Fishes play a vital role in these communities, but it is generally unknown how they locate these floating symbiotic habitats. This study examined the role of natural chemical cues from Sargassum spp. patches and a synthetic chemical dimethylsulfoniopropionate (DMSP) for an associated fish, the planehead filefish (Stephanolepis hispidus), and a control fish species not associated with Sargassum spp., the masked goby (Coryphopterus personatus). Choice trials with a Y-maze (olfactometer) apparatus determined that S. hispidus responded significantly to chemical cues from Sargassum spp. while C. personatus did not. DMSP cues did not result in significant behavioral responses for either fish species. Demonstrating that S. hispidus can respond to chemical cues from Sargassum spp. helps further our understanding of this unique floating algal reef and how fishes might locate it to establish this subcomponent of the holobiont (the collective symbionts in the association). [ABSTRACT FROM AUTHOR]

We tested whether Shoshone pupfish Cyprinodon nevadensis shoshone and Amargosa River pupfish C. n. amargosae respond behaviourally to conspecific chemical alarm cues released when epidermal tissue is damaged by a predator. We found that both subspecies reduced activity and vertical position in the water column in response to alarm cues. We then tested if pupfish can use alarm cue to acquire recognition of a novel predator. We trained pupfish with (1) water + odour of largemouth bass fed a diet of earthworms, (2) alarm cues from skin extract (epidermal alarm cues) + odour of bass fed a diet of earthworms, or (3) water + odour of bass fed a diet of pupfish (dietary alarm cues). Pupfish responded to epidermal alarm cues but not to dietary alarm cues. Pupfish were retested with the odour of bass that were fed an earthworm diet. Pupfish that had previously received epidermal alarm cues reduced vertical position and activity relative to the other two treatments. This is the first demonstration of acquired recognition of a novel predator by a pupfish, the first report of partial predator naiveté, and opens the possibility of predator-recognition training as a tool for management and conservation of endangered desert fishes.

Simple Summary: Natural enemies of major pests such as parasitoids require sugar-rich food for development and reproduction. In agricultural fields, honeydew excreted by aphids is often the predominant sugar source that parasitoids can consume. Moreover, honeydew can constitute a cue used by parasitoid females to find their aphid host. However, in some species, such as the woolly apple aphid (Eriosoma lanigerum), honeydew is coated with a thin layer of wax, which could make its consumption harder and prevent the emission of attractive odors for parasitoids. In the present study, we evaluated the benefits in terms of longevity and host searching that could provide honeydew to the main parasitoid of the woolly apple aphid, Aphelinus mali, and infer parasitoid feeding patterns in apple orchards. Results suggested that A. mali is able to consume honeydew in laboratory and field conditions and to benefit from honeydew, as it increased its longevity when honeydew was provided with water. Although no olfactory preference was observed, honeydew also stimulated oviposition by A. mali. The contribution of honeydew to increase the efficiency of A. mali as a biological control agent is discussed. Many parasitoids need to feed on sugar sources at the adult stage. Although nectar has been proven to be a source of higher nutritional quality compared to honeydew excreted by phloem feeders, the latter can provide the necessary carbohydrates for parasitoids and increase their longevity, fecundity and host searching time. Honeydew is not only a trophic resource for parasitoids, but it can also constitute an olfactory stimulus involved in host searching. In this study, we combined longevity measurements in the laboratory, olfactometry and feeding history inference of individuals caught in the field to test the hypothesis that honeydew excreted by the aphid Eriosoma lanigerum could serve as a trophic resource for its parasitoid Aphelinus mali as well as a kairomone used by the parasitoid to discover its hosts. Results indicate that honeydew increased longevity of A. mali females if water was provided. Water could be necessary to feed on this food source because of its viscosity and its coating by wax. The presence of honeydew allowed longer stinging events by A. mali on E. lanigerum. However, no preference towards honeydew was observed, when given the choice. The role of honeydew excreted by E. lanigerum on A. mali feeding and searching behavior to increase its efficiency as a biological control agent is discussed. [ABSTRACT FROM AUTHOR]

Host immune activation is common under a pathogen invasion. This physiological response can promote changes in the body surface compounds, thus providing chemical cues related to health that might be useful to conspecifics. By recognizing the current immunological status of social partners, individuals can modulate their behavior to minimize the risk of infection. Tegument wounding, an immune elicitor, is a required step for many parasites to become established in a host. By using the neotropical eusocial paper wasp Mischocyttarus metathoracicus as a model organism, we first performed a lure presentation experiment in the field to test if wasps discriminate conspecific immunological status (experimentally manipulated by wounding) during on nest social interactions. Then, we performed gas chromatography–mass spectrometry analyses to test if immunostimulation by wounding alters the wasps' cuticular hydrocarbon profile. We found that wasps reduce the duration of aggressive physical contact when interacting with wounded lures, despite displaying a similar frequency of inspective and aggressive behaviors toward both the wounded and the control lures. Besides, we found a subtle increase in a single cuticular hydrocarbon in the wounded wasps. Thus, wasps recognize conspecific immunological status, likely by chemical cues, and modulate their behavior in order to defend the colony against intruders while minimizing the personal risk of infection. [ABSTRACT FROM AUTHOR]

Larvae of some leaf beetles carry masses of feces covering parts or all of the body, which is called a "fecal shield". In general, the shield is thought to be a defense structure against natural enemies. However, some studies have suggested that defense effectiveness varies depending on the natural enemy. In this study, we used a fecal retention leaf beetle Ophrida xanthospilota (Coleoptera: Chrysomelidae), and 2 local generalist predators (an ant, Camponotus japonicus (Hymenoptera: Formicidae) and a stinkbug, Arma custos [Hemiptera: Pentatomidae]) as a system to test the hypothesis that the fecal shield of O. xanthospilota plays different roles in predation behavior of different predators and can provide multiple chemical communication signals in predator–prey interactions. Prey bioassays showed that the fecal shield of O. xanthospilota larvae repelled the ant C. japonicus while attracting the stinkbug A. custos. The results also strongly demonstrated that hexane extracts of the fecal shield significantly repelled C. japonicus, while dichloromethane (DCM) extracts did not inhibit ant predation. Interestingly, DCM extracts attracted A. custos, but hexane extracts did not. Therefore, we suggest that the fecal shield is a double-edged sword for the larvae of O. xanthospilota. Our results also indicated that the risk–benefit tradeoff of an insect should be estimated at a community level involving multiple enemies (predators and parasites) and herbivores, rather than in a single prey–predator pair. [ABSTRACT FROM AUTHOR]

Temporary wetlands constitute a reservoir of fauna, many of which are endemic species well adapted to the typical dry–flooded cycle. The degradation of organic matter (both autochthonous and allochthonous) is an important process in temporary wetlands. Wetland animals like caddisfly and anuran larvae participate directly and indirectly in litter breakdown. Both groups also experience predation by invertebrates and vertebrates, which could alter the dynamics of litter breakdown. We used mesocosms to experimentally study the roles of caddisfly and tadpoles in leaf litter breakdown in the presence of a caged predator. We investigated how the presence of different types of forager (larvae of the caddisfly Verger vespersus and Batrachyla taeniata tadpoles) impacts leaf litter breakdown and also whether the presence of a caged belostomatid predator affected this process. Additionally, we investigated the behavioral response of B. taeniata tadpoles and V. vespersus larvae to predation risk cues from belostomatids previously fed on tadpoles or caddisflies. Our results indicated that only caddisfly larvae have a significant impact on litter breakdown. Predation risk did not influence the process, caddisfly larvae exposed to a caged predator reached the pupal stage more quickly than larvae that were not thus exposed, and tadpoles significantly reduced their activity in response to predation risk cues. None of the life‐history parameters of B. taeniata were affected by the predator, but tadpoles accelerated their development in warmer water. Our study is the first in South America to analyze the interactions between a common assemblage of tadpoles and caddisfly larvae and their impact on leaf litter breakdown when they experience predation risk. The model used here contributes to our understanding of ecosystem processes such as leaf litter breakdown and the impact of different biotic and abiotic variables when foragers co‐occur in the food webs of temporary aquatic systems. [ABSTRACT FROM AUTHOR]

Prey organisms need to detect predators and respond with adequate antipredator behaviours. To recognize predators, chemosensory cues play a pivotal role, particularly in aquatic ecosystems, where sight may be restricted. However, it is less known whether the ability to use these cues, enabling appropriate antipredator behaviour, varies between subpopulations occupying different habitats with different predation risks. We examined antipredator behaviour of wild‐caught larval fire salamanders (Salamandra salamandra) from two different habitats, ponds and streams. Ponds and streams are inhabited by habitat‐specific predators, such as alpine newts (Ichthyosaura alpestris), which only occur in ponds. We confronted larvae from both habitats with either tap water (control) or tap water that had contained alpine newts (newt treatment) and investigated potential behavioural differences in activity and shelter emergence. In the activity test, pond larvae, but not stream larvae, were significantly less active when faced with chemical cues (potentially kairomones) from newts than those faced with a control stimulus, but stream larvae generally exhibited significantly lower activity than pond larvae. In the shelter‐emergence test, larvae from both habitats spent significantly less time outside a shelter in the newt treatment than in control water. This suggests that larval fire salamanders, independent of their habitat, recognize chemical cues from potential predators and alter their behaviour accordingly. Larvae of both habitats were able to detect and use chemical cues released from potential predators, but they differed slightly in their response to these chemical cues. This finding reflects varying antipredator strategies in response to the habitat‐specific differences. [ABSTRACT FROM AUTHOR]

• Electrospun Nanofibrous Dressings can enhance wound Healing and promote accelerated and scar-free wound healing. • Physical, Compositional, and Chemical Cues influence the healing rate and antiscar healing potential of nanofibrous Electrospun wound dressings. • Physical properties like porosity, mechanical characteristics, alignment, and water vapor transition guide cellular behaviors, foster fibroblast proliferation, enhance migration, and promote vascularization, facilitating rapid wound closure with minimized scarring. • The integration of growth factors, drugs, and herbal extracts in the form of chemical cues addresses chronic wound scenarios but requires precise control of their release mechanisms. Various loading techniques, such as blending and co-axial electrospinning, are explored for tailoring the release profiles of these agents. Wound healing is a complex biological process that, when impaired, can lead to the formation of scars. Electrospun nanofibrous wound dressings have emerged as a promising option for promoting scar-free wound healing. This paper explores the complex role of physical, compositional, and chemical cues, each contributing to the remarkable healing potential of these wound dressings. The physical properties of these dressings, such as porosity and mechanical characteristics, can guide cellular behaviors and promote vascularization, fostering a conducive environment for reduced scarring. Furthermore, the integration of natural polymers that mimic the skin's extracellular matrix, known as compositional cues, adds another layer of complexity to these wound dressings. As chemical cues, therapeutic agents have demonstrated their potential to combat chronic wound scenarios leading to scar formation. However, achieving the desired therapeutic effect hinges on the nature of these agents and their controlled release. Therefore, the paper also delves into various loading techniques for tailoring the release profiles of these bioactive agents. Although electrospun nanofibrous wound dressings are promising as wound dressings, a viable commercial product remains elusive. This gap can be attributed to a lack of comprehensive in vivo studies, particularly in animal models that mimic human wound healing. [ABSTRACT FROM AUTHOR]

Crustose coralline algae (CCA) are strong settlement inducers for two exploited limpets, Patella aspera and Patella ordinaria (Patellogastropoda: Patellidae). This study evaluates CCA-conditioned seawater (CSW) as a settlement inducer for the same species through nine assays aimed at its concentration, preservation, production, and as a settlement enhancer for sub-optimal substrates. Two additional assays tested the affinity of limpet larvae to settle on CCA surfaces. Each limpet species showed specific requirements. Settlement of P. aspera was higher in CCA than in CSW, whereas the settlement of P. ordinaria was similar between CCA and CSW. Inductive properties of CSW were nullified by filtration (2.7 μm) and weakened by dilution, but little affected by different preservation methods up to 48 h (room temperature, refrigerated, and autoclave). CSW can be produced serially from different CCA assemblages and preserved frozen during several days. Each limpet species responded differently to CCA and CSW when combined with diatom biofilms. Specific strategies for post larval production are recommended. P. aspera could use CCA-coated structures as collectors designed for limpet settlers in animal production and recruits in the wild; while P. ordinaria may employ movable plates for settlement induction based on CSW. Settlers would require transport to nursery grounds for grow-out. • Coralline algae surface (CCA) attracted settlers of different limpet species. • CCA-coated structures could serve as spat collectors for limpet farming and research. • CCA-conditioned seawater (CSW) can be mass-produced, sterilized, and stored frozen. • CSW is recommended as settlement inducer for generalist limpet species. [ABSTRACT FROM AUTHOR]

The mahogany shoot borer, Hypsipyla grandella Zeller (Lepidoptera: Pyralidae), is one of the most economically important pests in all American tropical forests because it prevents the establishment of monoculture plantations of the family Meliaceae, such as Spanish cedar, Cedrela odorata L. Various studies have focussed on the bioecological aspects and the chemical and silvicultural control of this pest. However, relatively little is known about the biological interactions between this insect and its host plant. In this study, the shoot borer's behavior and attraction response to cedar host plants was evaluated in field cages. We also identified the volatiles emitted by healthy C. odorata plants that were attractive to H. grandella adults. The attraction to headspace volatiles from cedar plants and a synthetic blend were evaluated in a Y-glass tube olfactometer. We observed that virgin and mated females exhibited low activity at night, frequent movement of the antennae, sporadic flight activity, and short (< 10 s) and long (> 30 s) wing-fanning. Virgin females assumed a calling position, whereas mated females exhibited three periods of oviposition. The results showed that all evaluated categories – virgin females, virgin males, and mated females – were attracted to cedar plants. We identified the following volatile compounds: α-pinene, (E)-β-ocimene, 2-ethyl-1-hexanol, limonene, nonanal, (E)-4,8-dimethyl-1,3,7-nonatriene, α-copaene, β-caryophyllene, and germacrene D. A synthetic blend significantly attracted virgin male and mated female shoot borers. Our results suggested that C. odorata volatiles compounds are responsible for the attraction of H. grandella. [ABSTRACT FROM AUTHOR]

Simple Summary: Tadpoles are known to use their sense of smell to detect the presence of predators, but some studies showed their reliance on vision during social interaction, suggesting that vision might have a role in predatory contexts as well. Here, we investigated how chemical or visual cues of a native predator, or a combination of both, influence the defensive behaviour of green toad tadpoles. We expected tadpoles to reduce their activity when exposed to chemical cues and avoid the area of the experimental arena near to the caged predator when exposed to the visual ones. With both cues, we expected tadpoles to show both responses and with greater intensity. Our results indicate that visual cues alone do not elicit any apparent defensive response, suggesting that tadpoles mainly rely on chemical cues to assess predation risk. The anti-predator behaviour of green toad (Bufotes balearicus) tadpoles was investigated by exposing them to only the visual or chemical cues, or a combination of both, of a native predator, southern hawker Aeshna cyanea. We collected green toad egg strings in the field and tadpoles did not receive any predatory stimulus before the onset of the experiment. To manipulate chemical and visual cues independently, dragonfly larvae were caged inside a transparent plastic container, while chemical cues (odour of tadpole-fed dragonfly larvae) were injected into the surrounding arena. An empty container and water were used, respectively, as controls. The behaviour of individually tested tadpoles was videorecorded for 40 min, of which 20 were before their exposure to stimuli. Five second-distance frames were compared to assess both tadpole activity and position within the arena with respect to the visual stimulus. The tadpole level of activity strongly decreased after exposure to either chemical cues alone or in combination with visual cues, while visual cues alone apparently did not elicit any defensive response. The position of tadpoles inside the arena was not affected by visual cues, suggesting that green toad tadpoles mainly rely on olfactory cues to assess the level of predation risk. [ABSTRACT FROM AUTHOR]

The ability of shoaling fish to recognise and differentiate between potential groupmates may affect their fitness and survival. Fish are capable of social recognition and multiple sensory cues mediate the recognition mechanisms. This has been comprehensively studied for juvenile and adult freshwater species. However, the recognition ability and mechanisms intervening during the larval phase of marine species are yet poorly understood. Fish larvae are capable of discriminating conspecifics from heterospecifics based on chemical and/or visual cues, but whether this recognition occurs at finer scales, such as discerning among conspecifics of different reefs, is yet understudied. Here, we tested the hypothesis that larvae of a marine fish species, the sand smelt (Atherina presbyter Cuvier, 1829), are able to recognise and associate with conspecifics of their natal reef versus conspecifics of a non-natal reef based on three sensory modalities—chemical, visual, and chemical and visual simultaneously. Results do not support our hypothesis, but still provide evidence of group cohesion and indicate large differences in the relative importance of the different senses when associating with conspecifics, with visual cues playing a more important role than chemical cues alone.

In animal communication systems, individuals that detect a cue (i.e. "receivers") are often influenced by characteristics of the cue emitter. For instance, in many species, receivers avoid chemical cues that are released by emitters experiencing disturbance. These chemical "disturbance cues" appear to benefit receivers by warning them about nearby danger, such as a predator's approach. While the active ingredients in disturbance cues have been largely unexplored, by-products of metabolized protein are thought to play a role for some species. If so, the content (quality) and volume (quantity) of the emitter's diet should affect their disturbance cues, thus altering how receivers perceive the cues and respond. Guppies Poecilia reticulata are a species known to discriminate among disturbance cues from different types of donors, but dietary variation has yet to be explored. In this study, we found evidence that diet quality and quantity can affect disturbance cues released by guppy emitters (i.e. experimental "donors"). Receivers discriminated between donor cue treatments, responding more strongly to cues from donors fed a protein-rich bloodworm diet (Experiment 1), as well as an overall larger diet (Experiment 2). We also found that receivers exposed to higher background risk were more sensitive to disturbance cue variation, with the strongest avoidance responses displayed by high-risk receivers toward disturbance cues from donors fed the high-quality diet. Therefore, diet, and perhaps protein specifically, affects either the concentration or composition of disturbance cues released by guppies. Such variation may be important in information signaling in social species like the guppy. [ABSTRACT FROM AUTHOR]

The molecular mechanisms underlying the conspecific cue-mediated larval settlement in Crassostrea gigas is not yet fully understood. In this study, we described and compared the transcriptomes of competent pediveligers (Pedi) and conspecific cue-induced postlarvae (PL). A total of 2383 candidate transcripts were identified: 740 upregulated and 1643 downregulated transcripts, after settlement. Gene Ontology analysis revealed active chitin binding, calcium ion binding, and extracellular region processes in both stages. Results showed that the differential expression trend of six candidate transcripts were consistent between the quantitative real-time PCR and transcriptome data. The differential transcript expression related to shell formation showed closely linked dynamics with a gene regulatory network that may involve the interplay of various hormone receptors, neurotransmitters, and neuropeptide receptors working together in a concerted way in the Pedi and PL stages. Our results highlight the transcriptome dynamics underlying the settlement of oysters on conspecific adult shells and demonstrate the potential use of this cue as an attractant for wild and hatchery-grown oyster larval attachment on artificial substrates. It also suggests the possible involvement of an ecdysone signal pathway that may be linked to a neuroendocrine-biomineralization crosstalk in C. gigas settlement. [ABSTRACT FROM AUTHOR]