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Autotomy is a drastic antipredator defense consisting of the voluntary shedding of a body part to escape from the predators. The loss of a body part may impair locomotion, feeding or mating, so animals may face a higher predation risk shortly after autotomy. Thus, until regeneration is completed, prey may adjust their behavior to reduce predation risk, and this could involve secondary costs. We assessed the effect of tail loss on the antipredator behavior of wall lizards (Podarcis muralis), comparing the behavior of tailed and tailless individuals exposed to a predatory snake (Coronella austriaca) scent, under controlled experimental conditions. Tailless lizards spent significantly more time performing behaviors with antipredatory significance (e.g., moving slowly), whereas tailed individuals performed exploratory walking for significantly more time. Moreover, tailless lizards spent more time basking, which probably increases the effectiveness of their cryptic design and decreases detection by predators. Lizards intensified the tongue flick rates when exposed to a pungent control or snake scents, as compared to their response to a neutral control. Besides, both tailed and tailless lizards intensified some aspects of their antipredator behavior (walking slowly and avoiding refuge use) when exposed to snake scent, which indicates discrimination of the smell of predatory snakes. Lizards decreased refuge use when exposed to predator scents, probably because the refuges are evaluated as unsafe due to a high concentration of snake scents. To conclude, our experiments showed that, after losing their tails, wall lizards modify their behavior in a way that likely minimizes predation risk.

Tylonycteris pachypus is a gregarious bat species with tens of individuals in a colony. The mechanisms by which mother bats recognize their pups and adult bats recognize each other are not clear. We hypothesized that such recognition is achieved by chemical discrimination and performed experiments to test the hypothesis. Results showed that mother bats were much more attracted to the scent from their own pups. For adult bats, females were attracted to the scent from both male and female groupmates but had a higher preference to the scent from female than from male groupmates. Male bats were much more attracted to the scent from male groupmates while showed no preference to the scent from female groupmates. Within a group, both female and male bats had no difference in preference to the scent from the same or opposite sex. These results suggest that mother–pup and groupmate recognition of T. pachypus can be achieved by olfactory cues.

Olfactory cues provide detailed information to mammals regarding conspecifics. Bats may identify species, colony membership, and individuals using olfaction. Big brown bats (Eptesicus fuscus (Palisot de Beauvois, 1796)) live in mixed-sex colonies and must differentiate between sexes to locate mates. We hypothesized that odour cues convey information about sex. In experiment 1, adult E. fuscus were recorded exploring a Y-maze that contained general body odours sampled from male or female conspecifics. One group of subjects was habituated to the Y-maze prior to experimental trials, whereas a second group was not. Bat exploration and the proportion of time spent near each scent were used as preference indicators for the body odour of a particular sex. Experiment 2 followed similar procedures except the odour cue tested was urine from either male or female conspecifics and without Y-maze habituation. Results found no evidence that E. fuscus prefer the body odours of a given sex, but females did prefer the odour of male urine. Non-habituated animals in experiment 1 were more likely to explore the Y-maze and approach a stimulus scent compared with habituated bats. These findings have important implications for courtship and mating behaviour in bats, as well for designing future behavioural studies.

Banana plants are affected by various viral diseases, among which the most devastating is the "bunchy top", caused by the Banana bunchy top virus (BBTV) and transmitted by the aphid Pentalonia nigronervosa Coquerel. The effect of BBTV on attraction mechanisms of dessert and plantain banana plants on the vector remains far from elucidated. For that, attractiveness tests were carried out using a two columns olfactometer for apterous aphids, and a flight cage experiment for alate aphids. Volatile Organic Compounds (VOCs) emitted by either healthy or BBTV-infected banana plants were identified using a dynamic extraction system and gas-chromatography mass-spectrometry (GC–MS) analysis. Behavioral results revealed a stronger attraction of aphids towards infected banana plants (independently from the variety), and towards the plantain variety (independently from the infection status). GC–MS results revealed that infected banana plants produced VOCs of the same mixture as healthy banana plants but in much higher quantities. In addition, VOCs produced by dessert and plantain banana plants were different in nature, and plantains produced higher quantities than dessert banana trees. This work opens interesting opportunities for biological control of P. nigronervosa, for example by luring away the aphid from banana plants through manipulation of olfactory cues.

This study examined the effect of perceived predation risk imposed by lynx (Lynx lynx) and wolf (Canis lupus) on red deer (Cervus elaphus) foraging behavior under experimental conditions. We hypothesized that in response to large carnivore scent red deer would increase their vigilance, although reducing the frequency and duration of visits to foraging sites. Consequently, browsing intensity on tree saplings was expected to decrease, whereas a higher proportion of more preferred species was expected to be browsed to compensate for higher foraging costs. We expected stronger responses towards the ambush predator lynx, compared with the cursorial predator wolf. These hypotheses were tested in a cafeteria experiment conducted within three red deer enclosures, each containing four experimental plots with olfactory cues of wolf, lynx, cow, and water as control. On each plot, a camera trap was placed and browsing intensity was measured for one consecutive week, repeated three times. Red deer reduced their visitation duration and browsing intensity on plots with large carnivore scent. Despite red deer showing a clear preference for certain tree species, the presence of large carnivore scent did not change selectivity towards different tree species. Contrary to our hypothesis, we found more pronounced effects of wolf (cursorial) compared with lynx (ambush). This study is the first to experimentally assess the perceived risk effects on the red deer foraging behavior of large carnivores differing in hunting modes. Our findings provide insights into the role of olfactory cues in predator–prey interactions and how they can modify fine-scale herbivore–plant interactions., In this study, we tested whether an ambush (lynx) and a pursuit (wolf) predator influenced behavior and food selection of a large herbivore. We experimentally showed that under perceived predation risk of both lynx and wolf, the large herbivore reduced visitation time, altered visitation duration, and reduced food intake. Differences in behavior and food intake under perceived predation risk of both predators suggests more pronounced risk effects from the pursuit predator.

When animals move along well-established pathways, sensory cues along the path may provide valuable information concerning other individuals that have used the same route. Yet the extent to which animals use pathways as sources of public social information is poorly understood. Here we quantified the responses of wild African savannah elephants, Loxodonta africana, to olfactory information along natural elephant pathways, habitual routes that link predictable critical resources in the environment. By monitoring the behaviour of elephants travelling on pathways in a predominantly male study population, we found that elephants were highly olfactorily responsive to pathway substrate. Lone travellers were more responsive than elephants travelling in groups, suggesting elephants without social companions may be more dependent on olfactory cues on pathways during navigation. Furthermore, by experimentally presenting olfactory cues on pathways we found that male African elephants exhibited focused olfactory responses to urine cues of same-sex conspecifics for at least 48 h from time of deposition, and that urine from adult elephants was more likely to elicit vomeronasal system responses than subadult urine. African elephants may therefore potentially be able to discern the age and maturity of individuals they can expect to encounter in the environment from remote urine cues on pathways. We suggest elephant pathways act as a public information resource, assisting navigating elephants via the depositing of urine and dung by previous travellers on the route. These results could help inform elephant management, which may manipulate olfactory information on pathways in high human–wildlife conflict areas, or could use olfactory urine cues to improve the efficiency of corridors that link protected areas for elephants.

Olfactory cues constitute one of the most important plant-pollinator communication channels. Specific chemical components can be associated with specific pollinator functional groups due to pollinator-mediated selection on flower volatile (FV) emission. Here, we used multivariate analyses of FV data to detect an association between FVs and the worldwide distributed pollinator group of the carpenter bees (Xylocopa spp.). We compiled FVs of 29 plant species: 9 pollinated by carpenter bees, 20 pollinated by other bee pollinator functional groups. We tested whether FV emission differed between these groups. To rule out any phylogenetic bias in our dataset, we tested FV emission for phylogenetic signal. Finally, using field assays, we tested the attractive function of two FVs found to be associated with carpenter bees. We found no significant multivariate difference between the two plant groups FVs. However, seven FVs (five apocarotenoid terpenoids, one long-chain alkane and one benzenoid) were significantly associated with carpenter bee pollination, thus being “predictor” compounds of pollination by this pollinator functional group. From those, β-ionone and (E)-methyl cinnamate presented the highest indicator values and had their behavioural function assessed in field assays. Phylogenetic signal for FVs emission was weak, suggesting that their emission could result from pollinator-mediated selection. In field assays, the apocarotenoid β-ionone attracted carpenter bees, but also bees from other functional groups. The benzenoid (E)-methyl cinnamate did not attract significant numbers of pollinators. Thus, β-ionone functions as a non-specific bee attractant, while apocarotenoid FVs emerge as consistent indicators of pollination by large food-foraging bees among bee-pollinated flowers.

Multimodal signalling reinforces specific messages in communication. In gopher tortoises, similar to other reptilian species, visualization of conspecific and chemical exudates from the skin may serve as a multimodal display advertising information about conspecific species, sex, or individual qualities, but this has not been fully elucidated. For gopher tortoises, one such possible source of chemical cues could be secretions from seasonally enlarged mental glands (MG). Here, we used both sexes of gopher tortoises in a paired choice presentation of MG secretions vs. distilled (DI) water on resin tortoise models to assess visual presence with tortoise-specific secretions. We examined behaviours to treatments to examine if MG secretions are recognizable olfactory cues and if visual cues alone are sufficient to maintain social interactions using a simple visual presentation vs. a complex visual and olfactory presentation. Tortoises of both sexes spent more total time (p

Visual and olfactory mediated cues play a major role in mate selection in different groups of insects. This study aimed to observe if there is any role of mate color (under different wavelengths) and/or cuticular hydrocarbons in mate selection of Aulacophora foveicollis. In this study, visual cues and olfactory cues showed a vital role for male A. foveicollis to find mates. Males preferred (81%) orange (similar body colour) coloured glass model than white (52%) and black (49%) under the visible spectrum; whereas under the UV spectrum white coloured model was more preferred (77%) than orange (60%) and black (48%) coloured. In contrast, unresponsive males were very high though white coloured model was still preferred (36.67%) than orange (24.44%) or black (22.22%) coloured under IR spectrum. It was also observed that body surface waxes can play alone an olfactory cue for male mate selection (attraction was 67%) from short distance. Under the visual spectrum, when both visual and olfactory cues were presented, attraction of males toward all orange (93%), white (74%), and black (71%) coloured glass bead model increased. Even under UV and IR spectra attraction increased when body surface extract of female was applied on the glass models though the preference was more towards white coloured model than orange as previous. Male A. foveicollis showed less preference towards black colour. These works provide evidence that both visuals and olfactory cues can act separately as well as synergistically to find mates for male insects. These findings will be helpful for sustainable pest management program.

Male olfactory cues may guide aggregation on spawning reefs, mate evaluation and synchronized gamete release in lake trout Salvelinus namaycush, but a lack of information on the source and identity of the cues precludes direct tests of their function. Using a two-channel flume, we found ovulated female lake trout increased time spent in the channel treated with spermiated male-conditioned water, urine and bile but not synthesized prostaglandin F2α . We suggest future efforts to characterize male olfactory cues focus on urine and postulate that bile acids contribute to its behavioural activity.

Butterflies and moths have substantially different daily activities; butterflies are diurnal, while moths are largely nocturnal or crepuscular. Diurnal moths are subject to different evolutionary pressures that affect several aspects of their behavior and physiology, particularly sexual communication. In this review, species of diurnal moths and the behaviors and mechanisms of their sexual communication are summarized. Diurnal moths are day–flying insects whose partner–finding strategies include visual, olfactory and auditory signals. Males of diurnal Lepidoptera find mating partners using olfactory cues (e.g., sex pheromones) over relatively long distances, or visual (e.g., compound eyes) and/or auditory cues (e.g., ears) over short distances, or even act in combination with the three types of signals. Pheromone–binding proteins and histamine and visual genes play important roles during the signal conduction of sexual communication in diurnal moths. However, the regulatory mechanisms of acoustic communication in day–flying moths are unclear. Understanding this information may help us to explore the evolution of sexual communication in Lepidoptera and to improve biotechnological control strategies against harmful day–flying moths.

Experience can modify how animals respond to relevant stimuli from their environment, for example, through associative learning. In particular, odour stimuli play a central role in foraging by influencing decision making. Numerous studies have shown that odours can acquire relevance for an animal by becoming associated with food after appetitive experience. Therefore, studying to what extent learning can modulate the behavioural response to olfactory stimuli is essential to improve our understanding about the role of experience in food exploitation in nature. Here, we evaluated whether foraging experience can modulate the response of Vespula germanica, a food generalist and opportunistic eusocial wasp, towards an aversive odour. Through field experiments, we evaluated the response of naive and experienced wasps towards an aversive odour under different scenarios, to also examine how these changes affect foraging decisions. Both naive wasps and wasps that had foraging experience in the absence of the aversive odour were not attracted to the odour alone and avoided meat sources paired with this cue. However, wasps that had foraging experience with the aversive odour showed an opposite behavioural pattern; they preferred meat sources with the aversive odour and were equally attracted to this odour and the meat source. The behavioural repertoire (i.e. approaches, landings and search behaviour) elicited by the aversive odour after experience with it indicates that change in the response was due to associative learning, leading the odour which was initially repellent, to become attractive. Interestingly, the change in the aversive odour's valence occurred after one collecting experience and three to five visits promoted long-term memory of the odour. In conclusion, our results show that spontaneous responses to odours can be modulated by experience and provide new insights about learning and memory abilities of social wasps in relation to olfactory cues.

Olfactory cues play an important role in mammalian biology, but have been challenging to assess in the field. Current methods pose problematic issues with sample storage and transportation, limiting our ability to connect chemical variation in scents with relevant ecological and behavioral contexts. Real‐time, in‐field analysis via portable gas chromatography–mass spectrometry (GC‐MS) has the potential to overcome these issues, but with trade‐offs of reduced sensitivity and compound mass range. We field‐tested the ability of portable GC‐MS to support two representative applications of chemical ecology research with a wild arboreal primate, common marmoset monkeys (Callithrix jacchus). We developed methods to (a) evaluate the chemical composition of marmoset scent marks deposited at feeding sites and (b) characterize the scent profiles of exudates eaten by marmosets. We successfully collected marmoset scent marks across several canopy heights, with the portable GC‐MS detecting known components of marmoset glandular secretions and differentiating these from in‐field controls. Likewise, variation in the chemical profile of scent marks demonstrated a significant correlation with marmoset feeding behavior, indicating these scents’ biological relevance. The portable GC‐MS also delineated species‐specific olfactory signatures of exudates fed on by marmosets. Despite the trade‐offs, portable GC‐MS represents a viable option for characterizing olfactory compounds used by wild mammals, yielding biologically relevant data. While the decision to adopt portable GC‐MS will likely depend on site‐ and project‐specific needs, our ability to conduct two example applications under relatively challenging field conditions bodes well for the versatility of in‐field GC‐MS., Olfactory cues play an important role in mammalian biology, but have been challenging to assess in the field. We field‐tested the ability of portable GC‐MS to support two representative applications of chemical ecology research. Despite trade‐offs, portable GC‐MS represents a viable option for characterizing olfactory compounds used by wild mammals, yielding biologically relevant data.

Danaus chrysippus, a species associated in the region with low migrant numbers, has appeared at a small biotope in Cyprus in each of the five years, 2014–2018. We present the results of monitoring at the site and suggest that detection of plant volatiles, perhaps in combination with the presence of male pheromones, assist migrating D. chrysippus to detect small stands of the host-plant Cynanchum acutum, enabling the establishment of temporary populations on the island. We also refer to the recent appearance in Cyprus of D. c. chrysippus f. 'alcippus'.

The advantages of group living are partially offset by the cognitive challenges associated with maintaining social boundaries. These challenges can give rise to recognition mechanisms that adaptively integrate information across multiple sensory modalities. The valley carpenter bee, Xylocopa varipuncta, nests in dead wood in large aggregations of up to several dozen nests. This study investigates the proximate mechanisms by which returning foragers quickly and reliably identify their own nest entrance within a high-density nesting site. We manipulated long- and short-range visual cues associated with nest entrances, removed chemical cues on the inside of nest entrances and added chemical cues from foreign conspecific bees. By measuring the effect of these manipulations on nest search time and search accuracy, we assessed the importance of visual and olfactory sensory modalities in allowing carpenter bees to locate their nests within aggregations. Our results support the hypothesis that both visual and olfactory cues can facilitate nest localization. Removal of nest olfactory cues did not significantly disrupt homing, suggesting that olfactory information may not be necessary for nest localization when visual information is available. However, the addition of olfactory cues from unfamiliar conspecific bees actually aided nest localization rather than disrupting it, suggesting that bees may use generalized species odour cues for homing. Due to intense nest site competition within aggregations, nest localization may have important social implications for maintenance of high-density nesting.

Domestic dogs, Canis familiaris, are highly responsive to human communicative cues and can utilize gestures, such as pointing, to locate hidden rewards. This ability is thought to be the product of both genetic and behavioural selection, allowing dogs to adapt to life with humans. Dogs' responsiveness to human gestures can also lead to suboptimal choices when dogs readily follow misleading cues despite directly contradicting perceptual information such as odour cues. However, this bias likely reflects pet dogs' enculturation with humans and thus may not be representative of other populations of dogs. We investigated the ability of young dogs in training for explosives detection (N = 77) to locate a hidden reward using olfactory cues when presented in conflict with a deceptive communicative gesture in an object-choice task. We assessed performance at 3, 6 and 11 months of age using both cross-sectional and longitudinal designs. We found that, contrary to previous findings with pet dogs, responsiveness to human pointing decreased with age, whereas the ability to locate the reward by scent increased. Furthermore, a lack of susceptibility to deceptive social cues was predictive of future success as a detection dog. These findings further indicate the influence of ontogenetic effects on canine social cognition and demonstrate potential applications for the identification of suitable detection dogs.

International audience; Finding a mate is a crucial step in sexual reproduction. The mutualism between figs and their pollinators is exploited by many figwasps that develop within their galls and attain sexual maturity simultaneously. Male pollinators carry the specific burden of detecting and opening mating holes in galls containing conspecific females before mating with them. The mating behaviourand antennal sensilla of male pollinators associated with Ficus semicordata was investigated to understand mate recognition. Male Ceratosolen gravelyi located female-containing galls from a distance, but only attempted to chew a mating hole after antennal contact with the gall surface was made. They showed similar responses to females and body extracts but failed to respond to washed female bodies. This behaviour indicates that unidentified chemicals present on the body surfaces of females are sufficient to elicit olfactory attraction and tactile confirmation. Multiporous plate sensilla are candidates for olfactory reception from a distance while basiconic sensilla may be involved in contact chemoreceptor. All of the sensilla are highly localised, on the distal part of the terminal flagellomere, suggesting a response to selection for strong directionality in the complex odour environment of the fig in which messages produced by hundreds of females may confuse precise mate localisation.

The first study showing that birds can smell herbivore-induced plant volatiles was published ten years ago. Since then, only 12 studies have been published, showing contradictory results. This review evaluates the role of birds in relation to the crying for help hypothesis and their use of olfactory cues. In accordance with the methodologies used in previous studies, we herein provide a summary of experimental approaches and describe the advantages and disadvantages of experiments conducted in nature versus aviaries. Moreover, we recommend experimental methodologies which lead to a deeper knowledge of the topic, including reflection on the induction of plant defenses and adaptations of birds. Finally, we propose some interesting questions for future research to direct further studies towards a thorough and accurate description of birds’ roles in tritrophic interactions., The work of AM was supported by the University of South Bohemia Grant Agency (078/2018/P), KS by the Programme for Research and Mobility Support of Young Researchers (MSM200961702), and LA by the Ministry of Economy and Competitiveness (CGL2014-58890-P) and Ramón y Cajal Programme.

We report a comparative analysis of the effect of alpha- and beta- isomers of the dipeptides aspartyl-serine and aspartyl-proline on the ability of honeybees to retain the conditioned food reflex to olfactory cues in their short-term/long-term memory. Stimulatory/inhibitory effects of the alpha-dipeptides on memory processes are confined to the concentration range of 10-6–10-8 M. In contrast, beta-dipeptides exert stimulatory/inhibitory effects on memory not only within the same range but also at ultra-low (pico- and femtomolar) concentrations. At concentrations of 10-9–10-11 M, beta-dipeptides have no effect on the characteristics under study (“silence zone”). Thus, we revealed fundamental differences in the effects of alpha- and beta- dipeptide isomers on the memory regulation.

When people meet a potential partner for the first time, they are confronted with multiple sources of information, encompassing different modalities, that they can use to determine whether this partner is suitable for them or not. While visual attractiveness has widely been studied with regard to partner choice, olfactory and auditory cues have received less attention, even though they might influence the attitudes that people have towards their partner. Therefore, in this study, we employed a combination of pre-date multimodal rating tasks followed by speed-date sessions. This offered a naturalistic setup to study partner choice and disentangle the relative effects of a priori attractiveness ratings of sight, scent and sound on date success. Visual attractiveness ratings showed a strong positive correlation with propensity to meet the partner again, while the effects of olfactory and auditory attractiveness were negligible or not robust. Furthermore, we found no robust sex differences in the importance of the three modalities. Our findings underscore the relative importance of visual attractiveness in initial mate choice, but do not corroborate the idea that static pre-date measures of auditory and olfactory attractiveness can predict first date outcomes.

Kin recognition plays an important role in social behavior and evolution, but the proximate mechanisms by which individuals recognize kin remain poorly understood. In many species, individuals form a "kin template" that they compare with conspecifics' phenotypes to assess phenotypic similarity-and, by association, relatedness. Individuals may form a kin template through self-inspection (i.e., self-referencing) and/or by observing their rearing associates (i.e., family referencing). However, despite much interest, few empirical studies have successfully disentangled self-referencing and family referencing. Here, we employ a novel set of breeding crosses using the Trinidadian guppy (

International audience; Water is vital for mammals. Yet, as ephemeral sources can be difficult to find, it raises the question, how do mammals locate water? Elephants (Loxodonta africana) are waterdependent herbivores that possess exceptional olfactory capabilities, and it has been suggested that they may locate water via smell. However, there is no evidence to support this claim. To explore this, we performed two olfactory choice experiments with semi-tame elephants. In the first, we tested whether elephants could locate water using olfactory cues alone. For this, we used water from two natural dams and a drinking trough utilised by the elephants. Distilled water acted as a control. In the second, we explored whether elephants could detect three key volatile organic compounds (VOCs) commonly associated with water (geosmin, 2-methylisoborneol, and dimethyl sulphide). We found that the elephants could locate water olfactorily, but not the distilled water. Moreover, they were also able to detect the three VOCs associated with water. However, these VOCs were not in the odour profiles of the water sources in our experiments. This suggests that the elephants were either able to detect the unique odour profiles of the different water sources or used other VOCs that they associate with water. Ultimately, our findings indicate that elephants can locate water olfactorily at small spatial scales, but the extent to which they, and other mammals, can detect water over larger scales (e.g. km) remains unclear.

The Mediterranean fruit fly (medfly), Ceratitis capitata, is a worldwide pest of agriculture able to use olfactory cues to locate habitat, food sources, mates and oviposition sites. The sensitivity of medfly olfaction has been exploited to develop olfactory-based attractants that are currently important tools for detection, control and eradication of its populations. Among these is Cera Trap® (BIOIBERICA, S.A.U.), a cost-effective bait. Here we used coupled gas chromatography/electroantennographic detection (GC-EAD) and GC/mass spectrometry (GC-MS) approaches to characterize the medfly antennally-active compounds released by this lure. We identified GC peaks corresponding to chemicals belonging to six different classes including heterocyclic aromatic compounds, aliphatic alcohols, aldehydes, esters, sesquiterpene hydrocarbons, and aromatic alcohols. We tested ten potential candidate volatiles belonging to these classes and predicted to be emitted by the lure and found that they were eliciting electroantennographic responses in medfly adults. These results will help in unravelling the physiological mechanisms of odor perception in both sexes, especially in relation to Cera Trap® attractant activity, which in the field has been shown to be female-specific. These findings and their developments will ultimately expand the toolbox for medfly control in the field.

During mate choice, three-spined stickleback (Gasterosteus aculeatus) females make use of male olfactory cues to determine the suitability of potential mates in a species- and habitat-dependent manner. This signal contains peptides reflecting the individual male’s MHC profile and a so-called male validation factor (MVF) indicating the species identity of the sender. In a two-armed flow channel, we exposed gravid females to male odour. The odours from males that produced only the MVF but no MHC signal yet were used to examine whether the MVF of distant stickleback populations, one from Canada and one from Germany – genetically isolated since approximately 31–59 thousand years – has changed to such a degree that present-day females only react to the MVF produced by males from their population of origin. The fish used in the experiments were bred from in vitro-fertilized eggs in either country; those from Canada were shipped for analysis to the Plön laboratory to minimize experimental variability. Given the choice between the two MVFs, females did not significantly prefer the MVF of males of their own origin over the other. However, compared to water, both types of females preferred their own MVF significantly and the foreign MVF almost significantly, respectively, suggesting that they could smell MVFs from both origins. These results suggest that, despite long-term genetic isolation between Canadian and German populations, the three-spined stickleback male validation factor has remained constant and thus represents an evolutionarily conserved signal.

International audience; Olfactory cues of individuals of the same species or from different species may induce changes in behaviors and physiological reactions in mammals. However, there are few studies on the influence of human odor on animal behavior and welfare, especially those of rodents and farm animals. The present study aimed to investigate whether the odor of a stressed human (in sweat) would modify the behavior of mice and cows. We hypothesized that laboratory and farm animals can perceive human emotions though olfactory cues and that human emotional chemosignals can modify their behavioral reactions and welfare. Two odors of human axillary sweat were collected from engineering students (n = 25, 14 females and 11 males; 21.1 ± 0.7 years old, range: 19-23 years old): a "stress" odor collected after an exam and a "non-stress" odor collected after a standard class. Two experiments were then conducted to test the discrimination of these two odors by male mice (n = 20) under standard conditions and by cows (n = 10) under farm conditions. During the experiments, the behavioral responses of the animals to both odors (through a dispenser for the mice and a bucket for the cows) were observed. The mice produced significantly (p = 0.004) more fecal pellets with the stress odor dispenser than with the non-stress-odor dispenser. The cows spent significantly (p = 0.04) more time smelling the non-stress-odor bucket than control. For both species, the other behaviors observed did not differ significantly between the odors. Mice and cows seemed to perceive and react to stressful human chemosignals. Mice showed physiological reactions that indicated stress in response to the stress odor of humans, while cows showed preference reactions in response to the non-stress odor of humans. This preliminary study showed that laboratory and farm animals, such as male mice and cows, seemed to discriminate certain odors emitted by humans that were likely related to different emotions. Animals may recognize stressful human chemosignals, associate these signals with negative husbandry practices or human-animal relationships, and consequently modify their behavior.

Ants are excellent navigators taking into account multimodal sensory information as they move through the world. To be able to accurately localise the nest at the end of a foraging journey, visual cues, wind direction and also olfactory cues need to be learnt. Learning walks are performed at the start of an ant’s foraging career or when the appearance of the nest surrounding has changed. We investigated here whether the structure of such learning walks in the desert antCataglyphis fortistakes into account wind direction in conjunction with the learning of new visual information. Ants learnt to travel back and forth between their nest and a feeder, and we then introduced a black cylinder near their nest to induce learning walks in regular foragers. By doing this across days with different prevailing wind directions, we were able to probe how ants balance the influence of different sensory modalities. We found that (i) the ants’ outwards headings are influenced by the direction of the wind with their routes deflected in such a way that they will arrive downwind of their nest when homing, (ii) a novel object along the route induces learning walks in experienced ants and (iii) the structure of learning walks is shaped by the wind direction rather than the position of the visual cue.

Background Recognition of stress and mobilization of adequate “fight-or-flight” responses is key for survival and health. Previous studies have shown that exposure of Caenorhabditis elegans to pathogens or toxins simultaneously stimulates cellular stress and detoxification responses and aversive behavior. However, whether a coordinated regulation exists between cytoprotective stress responses and behavioral defenses remains unclear. Results Here, we show that exposure of C. elegans to high concentrations of naturally attractive food-derived odors, benzaldehyde and diacetyl, induces toxicity and food avoidance behavior. Benzaldehyde preconditioning activates systemic cytoprotective stress responses involving DAF-16/FOXO, SKN-1/Nrf2, and Hsp90 in non-neuronal cells, which confer both physiological (increased survival) and behavioral tolerance (reduced food avoidance) to benzaldehyde exposure. Benzaldehyde preconditioning also elicits behavioral cross-tolerance to the structurally similar methyl-salicylate, but not to the structurally unrelated diacetyl. In contrast, diacetyl preconditioning augments diacetyl avoidance, weakens physiological diacetyl tolerance, and does not induce apparent molecular defenses. The inter-tissue connection between cellular and behavioral defenses is mediated by JNK-like stress-activated protein kinases and the neuropeptide Y receptor NPR-1. Reinforcement of the stressful experiences using spaced training forms stable stress-specific memories. Memory retrieval by the olfactory cues leads to avoidance of food contaminated by diacetyl and context-dependent behavioral decision to avoid benzaldehyde only if there is an alternative, food-indicative odor. Conclusions Our study reveals a regulatory link between conserved cytoprotective stress responses and behavioral avoidance, which underlies “fight-or-flight” responses and facilitates self-protection in real and anticipated stresses. These findings imply that variations in the efficiency of physiological protection during past episodes of stress might shape current behavioral decisions. Graphical abstract

Vector control is an important component of the interventions aimed at mosquito-borne disease control. Current and future mosquito control strategies are likely to rely largely on the understanding of the behavior of the vector, by exploiting mosquito biology and behavior, while using cost-effective, carefully timed larvicidal and high-impact, low-volume adulticidal applications. Here we review the knowledge on the ecology of mosquito oviposition behavior with emphasis on the potential role of infochemicals in surveillance and control of mosquito-borne diseases. A search of PubMed, Embase, Web of Science, Global Health Archive, and Google Scholar databases was conducted using the keywords mosquito, infochemical, pheromone, kairomone, allomone, synomone, apneumone, attractant, host-seeking, and oviposition. Articles in English from 1974 to 2019 were reviewed to gain comprehensive understanding of current knowledge on infochemicals in mosquito resource-searching behavior. Oviposition of many mosquito species is mediated by infochemicals that comprise pheromones, kairomones, synomones, allomones, and apneumones. The novel putative infochemicals that mediate oviposition in the mosquito subfamilies Anophelinae and Culicinae were identified. The role of infochemicals in surveillance and control of these and other mosquito tribes is discussed with respect to origin of the chemical cues and how these affect gravid mosquitoes. Oviposition attractants and deterrents can potentially be used for manipulation of mosquito behavior by making protected resources unsuitable for mosquitoes (push) while luring them towards attractive sources (pull). In this review, strategies of targeting breeding sites with environmentally friendly larvicides with the aim to develop appropriate trap-and-kill techniques are discussed.

Animals adjust behaviors to balance changes in predation risk against other vital needs. Animals must therefore collect sensory information and use a complex risk-assessment process that estimates risks and weighs costs and benefits entailed in different reactions. Studying this cognitive process is challenging, especially in nature, because it requires inferring sensory abilities and conscious decisions from behavioral reactions. Our goal was to address this empirical challenge by implementing psychophysical principles to field research that explores considerations used by desert isopods (Hemilepistus reaumuri) to assess the risk of scorpions that hunt exclusively from within their burrows. We introduced various combinations of chemical and physical cues to the vicinity of isopod burrows and recorded their detailed reactions on first encountering the cues. The isopods reacted defensively to scorpion odor but only when accompanied with excavated soil or other odors typically found near scorpion burrows. Isopods also reacted defensively to piles of excavated soil without scorpion olfactory cues, suggesting that isopods take precautions even against physical disturbances that do not necessarily reflect predator activity. Simultaneous presence of different cues provoked graded responses, possibly reflecting an additive increase in risk estimation. We conclude that wild isopods use defensive reactions toward environmental signals only when the integrated perceptual information implies an active scorpion burrow or when they lack data to refute this possibility.

Captive animals may lose the ability to recognize their natural predators, making conservation programs more susceptible to\ud failure if such animals are released into the wild. Collared peccaries are American tayassuids that are vulnerable to local\ud extinction in certain areas, and conservation programs are being conducted. Captive-born peccaries are intended for release into\ud the wild in Minas Gerais state, southeastern Brazil. In this study, we tested the ability of two groups of captive-born collared\ud peccaries to recognize their predators and if they were habituated to humans. Recognition tests were performed using models of\ud predators (canids and felids) and non-predators animals, as well as control objects, such as a plastic chair; a human was also\ud presented to the peccaries, and tested as a separate stimulus. Anti-predator defensive responses such as fleeing and threatening\ud displayswere not observed in response to predator models. Predator detection behaviors both from visual and olfactory cues were displayed, although they were not specifically targeted at predator models. These results indicate that collared peccaries were unable to recognize model predators. Habituation effects, particularly on anti-predator behaviors, were observed both with a 1-h model presentation and across testing days. Behavioral responses to humans did not differ from those to other models. Thus, if these animals were to be released into the wild, they should undergo anti-predator training sessions to enhance their chances of survival.

Expression of 12 olfactory genes was analysed in adult sockeye salmon Oncorhynchus nerka nearing spawning grounds and O. nerka that had strayed from their natal migration route. Variation was found in six of these genes, all of which were olfc olfactory receptors and had lower expression levels in salmon nearing spawning grounds. The results may reflect decreased sensitivity to natal water olfactory cues as these fish are no longer seeking the correct migratory route. The expression of olfactory genes during the olfactory-mediated spawning migration of Pacific salmon Oncorhynchus spp. is largely unexplored and these findings demonstrate a link between migratory behaviours and olfactory plasticity that provides a basis for future molecular research on salmon homing.

As animals move through their environment, they must respond to different levels of predation risk in different habitats. We demonstrate that tadpoles use habitat odors to learn about the overall risk associated with specific habitats. Tadpoles adjusted their antipredator behavior to match the risk experienced in different habitats, becoming neophobic (fearful of novel odors) in high-risk habitats. However, responses were not consistent across habitat types, and tadpoles did not use habitat cues when learning about predators.

The importation and establishment of Coccinella septempunctata L. (Coleoptera: Coccinellidae) in North America purportedly caused the displacement and local extirpation of the native ninespotted lady beetle, Coccinella novemnotata Herbst (Coleoptera: Coccinellidae), across most of its former range, and several reports have shown that C. septempunctata maintains competitive advantages over C. novemnotata. We investigated the role of aphid density on the retention time of these two species on fava bean plants, and the effect of con- versus heterospecific pairings of adult beetles on the foraging behavior of C. novemnotata. We found that aphid density did not affect C. novemnotata's retention time, but did affect the retention time of C. septempunctata, which left plants without aphids significantly faster than C. novemnotata. Additionally, C. septempunctata females left plants significantly faster than their male counterparts, whereas we observed no difference between the two sexes for C. novemnotata. Our test of pairs of beetles showed that C. novemnotata were together on plants more frequently than conspecific pairs of C. septempunctata and heterospecific pairs of beetles, and that all beetles were more likely to be found together on the aphid-infested plant versus the non-infested plant regardless of the pairs' composition. These results show that C. novemnotata spend more time foraging for aphids when aphids are scarce compared with C. septempunctata, and that C. novemnotata is less tolerant of occupying plants inhabited by C. septempunctata versus a conspecific beetle, adding additional mechanisms whereby C. septempunctata could outcompete C. novemnotata in the field.

Summary 1. Olfaction is a central aspect of mammalian communication, providing information about individual attributes such as identity, sex, group membership or genetic quality. Yet, the chemical underpinnings of olfactory cues remain little understood, one of the reasons being the difficulty in obtaining high quality samples for chemical analysis. 2. In the present study we adjusted and evaluated the use of thermal desorption (TD) tubes, commonly used in plant metabolomic and environmental studies, for non-invasive sampling of mammalian body odour. We obtained chemical profiles of meerkat (Suricata suricatta) body odour samples using TD tubes analysed with gas chromatography – mass spectrometry (GC-MS). 3. TD tubes captured a wide range of volatile and semi-volatile organic compounds including compounds likely originating from the target animals. Adjustment of sampling parameters (distance, volume, flow rate, interruption of sampling) to increase the feasibility for a non-invasive application yielded samples of adequate quality. However, to minimize the variability between samples, sampling parameters should be kept constant and samples should be collected when no conspecifics are close-by. 4. The method was sensitive enough to pick up population differences in the chemical profiles of two captive groups of meerkats, demonstrating its applicability to biological questions. With sufficiently habituated animals, the method is applicable non-invasively, allowing short- and long-term studies on a wide range of questions, including e.g. chemical signatures of kinship, diet, individual health or reproductive state. This article is protected by copyright. All rights reserved.

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) were trapped in the field using colored plastic sphere traps coated with insect Tangle-trap. Red and black spheres captured significantly more D. suzukii than white spheres. Translucent deli-cup traps deployed in cherry orchards and baited with yeast, the Alpha Scents lure, or the Scentry lure captured significantly more flies than the Trece lure and Suzukii bait; all attractants had poor selectivity for D. suzukii. No-choice evaluations of attractants conducted in field cages corroborated the cherry orchard field study, though translucent deli-cup traps provisioned with the yeast bait captured significantly more flies than those baited with the Alpha Scents lure. Red sphere traps baited with the Scentry lure captured 3–6× more flies than the deli-cup trap baited with the same lure, and 3–4× more flies than the deli-cup trap baited with yeast bait, demonstrating that a trap integrating both visual and olfactory cues is a superior tool for monitoring D. suzukii. Moreover, this simple sticky, dry trap design requires far less labor and maintenance than does a liquid-based deli-cup trap.

Hygienic behavior is an economically beneficial,heritable trait, which has evolved to limit the impact of honeybee pathogens. Selecting and breeding colonies with high levels of hygienic behavior has become a feasible andenvironmentally friendly strategy to control brood diseases in honeybee colonies worldwide. The identification of genes involved in the expression of this character may not only unravel molecular and biochemical pathways underlyinghygienic behavior, but also serve as a practical approach to select disease resistance biomarkers useful for honeybee breeding programs. In the present work, we evaluated, at genetic level, Apis mellifera stocks selected for hygienic behavior, widely used for commercial apiculture in Argentina. We analyzed the expression profiles of five genes previously identified as candidates associated with hygienic behavior both in QTL and global gene expression studies in honeybees, more precisely, involved in perceptionand processing of olfactory information. We validated the differential expression of these genes as potentially responsible for behavioral differences in our selected stocks. Our results indicate that four of them (octopaminereceptor, smell-impaired, odorant-binding protein 3, and odorant-binding protein 4) were differentially expressed between hygienic and non-hygienic bees within our highly hygienic colonies. The present findings improve our understanding of the molecular mechanisms underlying the differentiation of middle-age worker bees in their genetic propensity to perform hygienic behavior. This progresstowards the genetic characterization of highly hygienic colonies that are commercially used in Argentine apiculture lays the groundwork for future development of targets for marker-assisted selection of disease-resistant honeybee stocks Fil: Scannapieco, Alejandra Carla. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina Fil: Mannino, Maria Constanza. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina Fil: Soto, Gabriela Cynthia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina Fil: Palacio, M. A.. Instituto Nacional de Tecnología Agropecuaria; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina Fil: Cladera, Jorge Luis. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina Fil: Lanzavecchia, Silvia Beatriz. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina

Mammalian maternal care usually comes at a large energetic cost. To maximize their fitness, mothers should preferentially care for their own offspring. However, the majority of studies of mother-offspring recognition have focused on herd- or colony-living species and there is little information on maternal discrimination in more solitary-living species. Olfaction has been found to play a major role in mother-offspring recognition across various taxa. Therefore, our aim was to study this in a species evolved from a solitary-living ancestor, the domestic cat. We asked whether cat mothers distinguish between their own and alien offspring when providing maternal care, and whether cat mothers use olfactory cues in the offspring discrimination process. Results of Experiment 1 showed that cat mothers do not discriminate between own and alien young when retrieving them to the nest. They treated own and alien young similarly with respect to latency and order of retrieval. However, the results of Experiments 2 and 3, where we used an olfactory habituation-discrimination technique, showed that mothers were able to distinguish between the odours of their own and alien kittens. We discuss what ecological and/or behavioural factors might influence a mother's decision when faced with discriminating between own and alien young, and why mothers might not discriminate between them when they are able to do so. Our findings support the view that maternal care alone should not be used as a measure of offspring recognition, and equal maternal care of own and alien young should not be immediately interpreted as an inability to discriminate between them.

Although mongooses are well-known to use odor cues in social communication, whether they also use olfaction in foraging is unknown. In this study, I investigated the olfactory ability of wild meerkats to recognize prey items that vary in frequency in their diet. Meerkats aged from 28 days to 2 years were presented with cotton-buds scented with common prey (larvae), less-common prey (scorpions, crickets), non-prey (dung beetles) or a control (no scent). Biting behavior and time spent sniffing the cotton-bud were recorded. Meerkats bit cotton-buds that smelled of larvae more often than cotton-buds that smelled of non-prey or control. They bit cotton-buds that smelled of crickets or scorpions at an intermediate rate. Meerkats’ age and sex did not affect the response. Hence, meerkats can discriminate the odor of their prey from the odor of non-prey items, and tend to show preference for frequent prey over less-common prey. Furthermore, meerkats may use olfactory cues for short-distance detection of prey, but experiments are needed to determine the specific phases of the foraging process where olfaction is involved.

Leaf variegation, the outcome of various genetic, developmental and physiological factors, is a well-known phenomenon proposed and even shown experimentally to defend plants from herbivory. A visually similar phenomenon that we define as pseudo-variegation is induced in plants by various external biological agents. We propose that pseudo-variegation may defend leaves and other plant organs (and also some of the organisms that induce them) from herbivory by several visual and chemical mechanisms: camouflage, aposematism and by indicating via olfactory cues/signals that the plants are damaged or occupied by herbivores or pathogens. From an evolutionary point of view, because of the common reduced quality as food and in many cases even toxicity for herbivores of leaves expressing pseudo-variegation, as well as because of competition with pathogens and herbivores that arrived earlier, or because of cannibalistic or predatory herbivores, such leaves were probably the defended models that were later mimicked by plants with mutations that caused various variegated phenotypes. Pseudo-variegation types induced by various pathogens and herbivores that actually defend plants from herbivory should be considered the extended phenotypes of both these plants and of the inducers that in this way defend their plant habitat.

Nest-site choice in turtles has a demonstrated impact on their fitness. Previous studies of nest-site choice have focused on environmental factors potentially affecting that choice (e.g., temperature, insolation, soil type, or moisture). Observations of nesting of painted turtles (Chrysemys picta) at the Crescent Lake National Wildlife Refuge in the Nebraska Sandhills suggest that females might use olfactory cues (specifically odors of other nesting females) to choose nest sites. We tested this hypothesis indirectly by using the nearest neighbor (nest) distance algorithm in ArcMap 10.1. Our results for nests in 2012–2014 were mixed, with nesting at some sites, in some years, and by some turtles occurring nonrandomly, in very close proximity to previous nests. Preliminary experimental data from 2015 using urine-treated sites in primary nesting areas also suggested that females showed more interest in those sites than sites moistened with equal amounts of water. These data provide some support for ...

Relatively little is known about the ability of ungulates to visually discriminate vegetation patches while foraging on grasslands despite extensive studies with man-made stimuli presented indoors. This study aimed to assess visual discrimination ability of cattle (Bos taurus) under conditions closer to the actual foraging situation. Twelve Japanese Black cows were afforded four successive opportunities to choose between green and dead forages presented as 25 × 25 cm patches 1, 2, or 3 m ahead while walking through a 25-m-long field area. Apparatuses for presenting the forages as visual stimuli were designed to minimize olfactory cues. The green forage differed from the dead forage in appearance (color and texture) and quality (digestible dry matter and crude protein). Cows preferred the green forage to the dead forage and were able to use the forages as visual cues to discriminate them. The proportion of green forage choices was 0.70–0.72 (different from the chance at P

Animals rely on cues informing about future predation risk when selecting habitats to breed in. Olfactory information may play a fundamental role in the assessment of predation threats, because predators produce characteristic body odours, but the role of odours in habitat selection has seldom been considered. Here, we test whether fear of predation induced by odour cues may affect the settlement pattern of a Mediterranean cavity-dependent community of rodents and non-excavator hole-nesting birds. To test this hypothesis, we experimentally manipulated the perception of predation risk on a scale of patch by applying either odours of a carnivore predator (risky odour treatment), lemon essence (non-risky odour treatment) and a control non-odorous treatment and studied bird and rodent settlement patterns. Nest-box occupation probability differed across treatments so that species in the community settled in more numbers in control than in non-risky and than in risky odour-treated nest boxes. Concerning settlement patterns, control nest boxes were occupied more rapidly than nest boxes with odour information. Birds and rodents settled earlier in control than in risky odour-treated nest boxes, but their settlement pattern did not significantly vary between risky odour and non-risky odour-treated nest boxes. Our findings demonstrate that olfactory cues may be used to assess habitat quality by settling species in this community, but we cannot pinpoint the exact mechanism that has given rise to the pattern of preference by nest boxes.

Gastropod diversity is substantial in marine and freshwater habitats, and many aquatic slugs and snails use olfactory cues to guide their navigation behaviour. Examples include finding prey or avoiding predators based on kairomones, or finding potential mates using pheromones. Here, I review the diversity of navigational behaviours studied across the major aquatic taxa of gastropods. I then synthesize evidence for the different theoretical navigation strategies the animals may use. It is likely that gastropods regularly use either chemotaxis or odour-gated rheotaxis (or both) during olfactory-based navigation. Finally, I collate the patchwork of research conducted on relevant proximate mechanisms that could produce navigation behaviours. Although the tractability of several gastropod species for neurophysiological experimentation has generated some valuable insight into how turning behaviour is triggered by contact chemoreception, there remain many substantial gaps in our understanding for how navigation relative to more distant odour sources is controlled in gastropods. These gaps include little information on the chemoreceptors and mechanoreceptors (for detecting flow) found in the peripheral nervous system and the central (or peripheral) processing circuits that integrate that sensory input. In contrast, past studies do provide information on motor neurons that control the effectors that produce crawling (both forward locomotion and turning). Thus, there is plenty of scope for further research on olfactory-based navigation, exploiting the tractability of gastropods for neuroethology to better understand how the nervous system processes chemosensory input to generate movement towards or away from distant odour sources.

Social insects often use olfactory cues from their environment to coordinate colony tasks. We investigated whether leaf-cutting ants use volatiles as cues to guide the deposition of their copious amounts of colony refuse. In the laboratory, we quantified the relocation of a small pile of colony waste by workers of Atta laevigata towards volatiles offered at each side of the pile as a binary choice, consisting of either waste volatiles, fungus volatiles, or no volatiles. Fungus volatiles alone did not evoke relocation of waste. Waste volatiles alone, by contrast, led to a strong relocation of waste particles towards them. When fungus and waste volatiles were tested against each other, waste particles were also relocated towards waste volatiles, and in a high percentage of assays completely moved away from the source of fungus volatiles as compared to the previous series. We suggest that deposition and accumulation of large amounts of refuse in single external heaps or a few huge underground waste chambers of Atta nests is due to both olfactory preferences and stigmergic responses towards waste volatiles by waste-carrying workers.

Raptors are usually considered to be mainly visually dependent, and the use of other sensory modalities has rarely been studied in these birds. Here, we investigated experimentally which senses (vision and/or olfaction) Turkey vultures (Cathartes aura) and Southern caracaras (Caracara plancus) use to find hidden food. First, two identical stainless-steel perforated balls, one containing a putrefied piece of meat and the other an odorless control, were presented to birds in binary choice experiments. Both species interacted more with the smelling ball than with the control, suggesting that they were attracted by the odor of the hidden meat. In a second experiment, individuals were accustomed to eat in one specifically colored ball (blue or green). In the test phase, the meat was hidden in the opposite color with respect to the one each bird had become accustomed to. Vultures still interacted more with the smelly ball disregarding the color, while caracaras interacted equally with the two balls. The prevalence of olfaction in Turkey vultures may partly explain why they are the first raptors to find carcasses in tropical forests. In contrast, caracaras forage on the ground opportunistically, a strategy where both olfaction and sight may be involved. Our experiments suggest that both species are able to use olfactory cues for foraging. However, olfaction could be the predominant sense in Turkey vultures while olfaction and sight could play an equivalent role in Southern caracaras. Electronic supplementary material The online version of this article (10.1007/s10071-018-1220-0) contains supplementary material, which is available to authorized users.

Behavioural responses to the environment often require the suppression of strong internal predispositions or the overriding of external lures, tasks performed by a cognitive function called inhibitory control. Inhibitory control of nonhuman animals is generally measured with the cylinder task: subjects are presented with food inside a transparent cylinder and must inhibit their tendency to reach the food directly and instead detour round the cylinder to solve the task. However, several studies have raised concerns about the validity of this test to compare different species. Recently, a tiny teleost fish, the guppy, Poecilia reticulata, was tested with the cylinder task and scored higher than many mammals and birds. Before considering that guppies display unpredictably high inhibitory control, it is important to exclude that they were advantaged by some noncognitive factors. In particular, guppies could enjoy three advantages: experience with transparent surfaces (i.e. the walls of maintenance aquaria), experience with detouring round see-through obstacles (vegetation in the maintenance aquaria) and the spread of food odour in the water from the sides of the cylinder. We tested whether these factors affect guppies' performance in the cylinder task by manipulating both their experience with transparent surfaces before the task and the diffusion of food odour cues from the cylinder. Guppies raised in transparent aquaria or with transparent panels placed inside the tank did not show advantages over guppies with no experience with transparent surfaces. Furthermore, the guppies’ performance was not reduced when the cylinder was pierced in the middle, so that both visual and olfactory cues lured them in the same direction. These results seem to exclude methodological explanations for the high inhibitory control score of guppies, and they indicate that even teleost fish can display efficient inhibitory control.