Predator regime influences innate anti-predator behaviour in the freshwater gastropod Lymnaea stagnalis

1. Predation incurs high fitness costs in aquatic organisms either through direct consumption or through avoidance responses that reduce time for activities such as feeding and reproduction. Hence, avoidance responses of aquatic organisms should vary to match closely the predation threat in their environment.
2. The freshwater gastropod Lymnaea stagnalis occurs in a variety of environments which vary in the presence or absence of predatory fish. We used naïve snails reared from six populations of this species experiencing different predator regimes (three co-occurring with molluscivorous fish and three without) to assess whether populations differed in the type and degree of their avoidance behaviours. Innate behavioural responses to four treatments (control, conspecific alarm cues, fish kairomones and fish kairomones paired with alarm cue) were compared in laboratory trials.
3. The primary anti-predator behaviour of L. stagnalis in response to fish kairomones was to crawl out of the water rather than seek refuge under water. This response was strongest when fish kairomones were paired with alarm cues, and varied depending on population origin; snails reared from populations co-occurring with predatory fish showed a stronger response than those raised from populations not experiencing such predators. In addition, populations co-occurring with predatory fish responded to the fish kairomones presented alone.
4. Our findings suggest that the degree of innate anti-predator behaviour shown by L. stagnalis , in terms of both the level of risk to which it responds and the degree of response, varies depending on the predator regime experienced by field populations. Together with previous work on cue association, this demonstrates that this gastropod is able to match its avoidance behaviour very closely to short and long term predation threats within its habitat.     

Interacting Effects of Leg Autotomy and Exposure to Predator Cues on Survival in A Wolf Spider (<Emphasis Type="Italic">Pardosa valens</Emphasis>)

Chemical cues from predators (kairomones) are used by many aquatic and terrestrial animals when deciding on behavioral responses to predation threats. These responses may also be affected by the animal’s physiological state (e.g., nutrition level, parasitism, or prior injury), which could alter normal responses to kairomones. In this study, we examined effects of leg autotomy (the voluntary sacrifice of a leg) on subsequent responses to predator chemical cues in females of the riparian-zone wolf spider Pardosa valens. In a fully-crossed design, spiders with all legs intact or with one leg removed were exposed to one of two cue treatments for 90 min: a control (no predator cue) or one with chemical cues (silk and excreta) from a larger sympatric wolf spider, Rabidosa santrita. We then introduced an R. santrita into each container, and recorded subsequent survival of P. valens. Survivorship was significantly higher for individuals previously exposed to predator cues than for those in the control group; however, autotomy had no effect on survivorship, which was similar for both intact and autotomized spiders in both the predator-cue and control treatments. In addition, although P. valens were more likely to be found off the substrate than on it when the predator was added in each of the four treatment pairings, this initial position did not influence survivorship. These results therefore indicate that P. valens can behaviorally respond to predator kairomones in ways that reduce their risk of predation, but that this response is unaffected by the prior sacrifice of a leg.     

Determining sensitive stages for learning to detect predators in larval bronzed frogs: Importance of alarm cues in learning

Successful survival and reproduction of prey organisms depend on their ability to detect their potential predators accurately and respond effectively with suitable defences. Predator detection can be innate or can be acquired through learning. We studied prey–predator interactions in the larval bronzed frogs (Sylvirana temporalis), which have the innate ability to detect certain predators. We conducted a series of experiments to determine if the larval S. temporalis rely solely on innate predator detection mechanisms or can also learn to use more specific cues such as conspecific alarm cues for the purpose. The results of our study clearly indicate that larval S. temporalis use both innate and learned mechanisms for predator detection. Predator-naïve tadpoles could detect kairomones alone as a potential threat and responded by reducing activity, suggesting an innate predator detection mechanism. Surprisingly, predator-naïve tadpoles failed to detect conspecific alarm cues as a potential threat, but learned to do so through experience. After acquiring the ability to detect conspecific alarm cues, they could associate novel predator cues with conspecific alarm cues. Further, post feeding stages of larval S. temporalis are sensitive for learning to detect conspecific alarm cues to label novel predators.     

Do Experience and Body Size Play a Role in Responses of Larval Ringed Salamanders,Ambystoma annulatum,to Predator Kairomones? Laboratory and Field Assays

Prey may experience ontogenetic changes in vulnerability to some predators, either because of changes in morphology or experience. If prey match their level of antipredator behavior to the level of predatory threat, prey responses to predators should reflect the appropriate level of threat for their stage of development. For larval salamanders, responses to predators may change with body size because larger larvae are less vulnerable to predation by gape‐limited predators or because fleeing responses by large salamanders may be more effective than for smaller salamanders. In a field experiment, small larval ringed salamanders, Ambystoma annulatum, responded to chemical stimuli (‘kairomones’) from predatory newts, Notophthalmus viridescens, with an antipredator response (decreased activity). Laboratory‐reared larvae decreased their activity following exposure to newt kairomones, indicating that larval ringed salamanders do not require experience with newts to recognize them as predators. In both experiments, larvae distinguished between chemical stimuli from newts and stimuli from tadpoles (non‐predators) and a blank control. In a third experiment, field‐caught (experienced) larvae showed a graded response to newt kairomones based on their body size: small larvae tended to decrease their activity while larger larvae showed no change or an increase in activity. This graded response was not observed for neutral stimuli, indicating that it is predator‐specific. Therefore, ringed salamander larvae exhibit threat‐sensitive ontogenetic changes in their response to chemical stimuli from predatory newts.     

Effects of Sibship and the Presence of Multiple Predators on the Behavior of Green Frog (Rana clamitans) Tadpoles

In nature, prey are exposed to multiple predators simultaneously. We examined the effects of the cues of two potential predators, mosquitofish and odonate larvae, individually and in combination on the behavior of green frog (Rana clamitans) tadpoles. In addition to examining the behavioral response of green frog tadpoles to multiple predators, we examined variation in behavior among tadpoles from different egg masses (i.e. different sibships). Sibships differed in activity level and there was a significant predator cue by sibship interaction. Two sibships were relatively more active in the control and odonate predator cue treatments but showed reduced activity in treatments containing mosquitofish cues, whereas the remaining sibships showed consistently low levels of activity in all predator cue treatments, including the control. The use of the vegetated side of the aquarium did not differ between tadpoles exposed to the different predator cues. Sibship had no effect on tadpoles’ use of the vegetated side of the aquarium, and there was no interaction between sibship and predator cue. Our results suggest that green frogs did not respond to simultaneous exposure to multiple predator cues any differently than they did to exposure to individual predator cues. More importantly, our results suggest variation, possibly genetically based, in behavioral responses of tadpoles to predators, and thus selection on these behaviors is possible. Of particular interest is that there was variation in behavioral responses to a non‐native predator (Gambusia affinis), suggesting an evolutionary response to an invasive predator is possible.     

Prey risk assessment depends on conspecific density

In many systems, the number of prey killed by predators increases with prey density. This in turn generates higher levels of the indirect signals that prey use to assess predation risk. A model developed by Peacor (2003) showed that prey that respond to predator cues without accounting for conspecific density will consistently over‐ or under‐estimate risk and therefore invest improperly in anti‐predator defense. We tested this model using Rana temporaria tadpoles as prey and Aeshna cyanea dragonfly larvae as predators. As assumed by the model, prey reduced risky activity with increasing concentrations of predator kairomones and increased activity at high prey density. However, prey did not react to changes in cue or density if the ratio of cue‐to‐density remained constant. Prey therefore monitored their per capita risk, strongly supporting Peacor's model.     

The Sound of Danger: Threat Sensitivity to Predator Vocalizations,Alarm Calls,and Novelty in Gulls

The threat sensitivity hypothesis predicts that organisms will evaluate the relative danger of and respond differentially to varying degrees of predation threat. Doing so allows potential prey to balance the costs and benefits of anti-predator behaviors. Threat sensitivity has undergone limited testing in the auditory modality, and the relative threat level of auditory cues from different sources is difficult to infer across populations when variables such as background risk and experience are not properly controlled. We experimentally exposed a single population of two sympatric gull species to auditory stimuli representing a range of potential threats in order to compare the relative threat of heterospecific alarm calls, conspecific alarms calls, predator vocalizations, and novel auditory cues. Gulls were able to discriminate among a diverse set of threat indicators and respond in a graded manner commensurate with the level of threat. Vocalizations of two potential predators, the human voice and bald eagle call, differed in their threat level compared to each other and to alarm calls. Conspecific alarm calls were more threatening than heterospecfic alarm calls to the larger great black-backed gull, but the smaller herring gull weighed both equally. A novel cue elicited a response intermediate between known threats and a known non-threat in herring gulls, but not great black-backed gulls. Our results show that the relative threat level of auditory cues from different sources is highly species-dependent, and that caution should be exercised when comparing graded and threshold threat sensitive responses.     

Do anuran larvae respond behaviourally to chemical cues from an invasive crayfish predator? A community-wide study

Antipredator behaviour is an important fitness component in most animals. A co-evolutionary history between predator and prey is important for prey to respond adaptively to predation threats. When non-native predator species invade new areas, native prey may not recognise them or may lack effective antipredator defences. However, responses to novel predators can be facilitated by chemical cues from the predators’ diet. The red swamp crayfish Procambarus clarkii is a widespread invasive predator in the Southwest of the Iberian Peninsula, where it preys upon native anuran tadpoles. In a laboratory experiment we studied behavioural antipredator defences (alterations in activity level and spatial avoidance of predator) of nine anurans in response to P. clarkii chemical cues, and compared them with the defences towards a native predator, the larval dragonfly Aeshna sp. To investigate how chemical cues from consumed conspecifics shape the responses, we raised tadpoles with either a tadpole-fed or starved crayfish, or dragonfly larva, or in the absence of a predator. Five species significantly altered their behaviour in the presence of crayfish, and this was largely mediated by chemical cues from consumed conspecifics. In the presence of dragonflies, most species exhibited behavioural defences and often these did not require the presence of cues from predation events. Responding to cues from consumed conspecifics seems to be a critical factor in facilitating certain behavioural responses to novel exotic predators. This finding can be useful for predicting antipredator responses to invasive predators and help directing conservation efforts to the species at highest risk.     

Predator faunas past and present: quantifying the influence of waterborne cues in divergent ecotypes of the isopod Asellus aquaticus

Waterborne chemical cues are an important source of information for many aquatic organisms, in particular when assessing the current risk of predation. The ability to use chemical cues to detect and respond to potential predators before an actual encounter can improve prey chances of survival. We investigated predator recognition and the impact of chemical cues on predator avoidance in the freshwater isopod Asellus aquaticus. This isopod has recently colonised a novel habitat and diverged into two distinct ecotypes, which encounter different predator communities. Using laboratory-based choice experiments, we have quantified behavioural responses to chemical cues from predators typical of the two predator communities (larval dragonflies in the ancestral habitat, perch in the newly colonised habitat) in wild-caught and lab-reared Asellus of the two ecotypes. Individuals with prior experience of predators showed strong predator avoidance to cues from both predator types. Both ecotypes showed similar antipredator responses, but sexes differed in terms of threat-sensitive responses with males avoiding areas containing predator cues to a larger extent than females. Overall, chemical cues from fish elicited stronger predator avoidance than cues from larval dragonflies. Our results indicate that in these isopods, prior exposure to predators is needed to develop antipredator behaviour based on waterborne cues. Furthermore, the results emphasise the need to analyse predator avoidance in relation to waterborne cues in a sex-specific context, because of potential differences between males and females in terms of vulnerability and life history strategies.     

Tadpoles of the bronze frog (Rana temporalis) assess predation risk before evoking antipredator defense behavior

Predation threat-associated behavioral response was studied in Rana temporalis tadpoles to discover the importance of predators’ visual and chemical cues (kairomones and diet-derived metabolites of consumed prey) in evoking antipredator behavior. The caged predators (dragonfly larvae) fed on prey tadpoles or insects (Notonecta spp.) and water conditioned with the predators provided the threat stimuli to the tadpole prey. The predators’ visual cues were ineffective in evoking antipredator behaviors in the tadpole prey. However, exposure to caged tadpole-fed predators or water conditioned with tadpole-fed predators elicited predator avoidance behavior in the tadpoles; they stayed away from the predators, significantly reduced swimming activity (swimming time and distance traveled), and increased burst speed. Interestingly, exposure to water conditioned with starved predators did not elicit any antipredator behavior in the prey. Further, the antipredator responses of predator-experienced tadpoles were significantly greater than those exhibited by predator-na?ve tadpoles. The study shows that R. temporalis tadpoles assess predation threat based exclusively on chemical cues emanating from the predators’ dietary metabolites and that the inclusion of conspecific prey items in the diet of the predators is perceived as a threat. The study also shows that antipredator behavior in these tadpoles is innate and is enhanced during subsequent encounters with the predators.     

Sex‐Specific Response of Pardosa milvina (Araneae: Lycosidae) to Experience with a Chemotactile Predation Cue

Predators frequently leave behind chemical information (i.e., semiochemicals such as pheromones or kairomones) that can be detected by their prey and used to avoid areas where predators are likely present. Prey that have interacted indirectly with predators via chemical information thus may gain insight into their risk of being consumed that naïve individuals lack. Pardosa milvina (Araneae: Lycosidae) is a chemosensitive wolf spider that shows adaptive responses to chemotactile cues deposited by the larger wolf spider Tigrosa helluo. We raised offspring from P. milvina to examine the effect of experience with a predation cue on activity, foraging, and antipredator behavior. Spiders differed in activity and foraging behavior across ontogeny and between sexes, but there was no effect of experience with a predation cue. However, a sex‐specific effect of experience was found in antipredator behavior. Male spiders, but not females, used experience with a predator cue to increase their survival in the presence of a live predator. Specifically, naïve males were attacked sooner than experienced males, indicating that prior exposure to predator cues can modify Pardosa antipredator behavior. Intersexual differences in how spiders respond to experience with a predation cue likely reflect the risk of predation faced by males and females in nature.     

Functional responses of contrasting seed predator guilds to masting in two Mediterranean oak species

The predator satiation hypothesis poses that synchronous and variable seed production during masting events increases seed escape through seed predator satiation. The success of this strategy depends upon the type of consumer functional response, in this case defined as the change in seed consumption rate by a predator as a function of change in seed density. Type II (where the proportion of seed consumed is highest at low levels of seed availability) and type III (where the proportion of seed consumed is highest at some intermediate level of seed availability and then declines towards zero) functional responses describe negative density‐dependence and indicate predator satiation. The type of function response should be contingent upon herbivore traits: type II responses are predicted for dietary specialist predators with low mobility, and type III responses are predicted for highly mobile, dietary generalist predators. Surprisingly, most studies have not evaluated whether functional responses vary among seed predator guilds. Here we describe the functional responses at population and individual tree level of highly mobile generalist (birds and rodents) and less mobile specialist (insects) pre‐dispersal seed predators attacking acorns of two sympatric oaks (Quercus suber and Q. canariensis) over a 10‐year period. Our results showed that in most cases specialist seed predators exhibited the predicted type II functional response at both the individual tree and population level for both oak species. However, generalist seed predators did not exhibit the predicted type III response; instead, they also exhibited a type II response at the individual tree and population level for both oak species. By independently assessing the effects of multiple seed predators associated with the same host tree species, our work highlights the influence of herbivore traits on the outcome of plant–seed predator interactions in masting species, and thus furthers our understanding of the ecological and evolutionary mechanisms underlying masting behaviour.     

Predator Inspection Behaviour in a Characin Fish: an Interaction between Chemical and Visual Information?

Recent evidence suggests that predator inspection behaviour by Ostariophysan prey fishes is regulated by both the chemical and visual cues of potential predators. In laboratory trials, we assessed the relative importance of chemical and visual information during inspection visits by varying both ambient light (visual cues) and predator odour (chemical cues) in a 2 × 2 experimental design. Shoals of glowlight tetras (Hemigrammus erythrozonus) were exposed to a live convict cichlid (Archocentrus nigrofasciatus) predator under low (3 lux) or high (50 lux) light levels and in the presence of the odour of a cichild fed tetras (with an alarm cue) or swordtails (Xiphophorus helleri, with an alarm cue not recognized by tetras). Tetras exhibited threat‐sensitive inspection behaviour (increased latency to inspect, reduced frequency of inspection, smaller inspecting group sizes and increased minimum approach distance) towards a predator paired with a tetra‐fed diet cue, regardless of light levels. Similar threat‐sensitive inspection patterns were observed towards cichlids paired with a swordtail‐fed diet cue only under high light conditions. Our data suggest that chemical cues in the form of prey alarm cues in the diet of the predator, are the primary source of information regarding local predation risk during inspection behaviour, and that visual cues are used when chemical information is unavailable or ambiguous.     

Behavioral plasticity in an invaded system: non-native whelks recognize risk from native crabs

Inducible defenses have the potential to affect both invasion success and the structure of invaded communities. However, little is known about the cues used for risk-recognition that influence the expression of inducible defenses in invasive prey, because they involve a novel threat. In laboratory experiments, we investigated behavioral defenses induced by a native crab on two invasive oyster drills (marine whelks Urosalpinx cinerea and Ocinebrina inornata). Both drills hid more often and reduced their feeding rates when they detected predators consuming conspecific prey. Examination of the responses of U. cinerea to specific cue sources (predator kairomones, conspecific alarm cues) indicated that this species had the strongest responses to cues from injured conspecifics, but that it did recognize the novel crab predator. Our observation of native predator (per se) recognition by an invasive marine prey is novel. In addition, we observed that neither species of drill reduced their defensive behavior to reflect predation risk shared by a group of prey. The lack of density dependence in risk-assessment could cause populations of invasive prey to transmit both quantitatively and qualitatively different community effects over the course of an invasion as abundance changes. Together, these findings demonstrate several ways that the risk-assessment strategies could be important in establishment and post-establishment dynamics of invasive prey.     

Antipredator Behavior of American Bullfrogs (Lithobates catesbeianus) in a Novel Environment

Invasive species capable of recognizing potential predators may have increased establishment rates in novel environments. Individuals may retain historical predator recognition and invoke innate responses in the presence of taxonomically or ecologically similar predators, generalize antipredator responses, or learn to avoid risky species in novel environments. Invasive amphibians in aquatic environments often use chemical cues to assess predation risk and learn to avoid novel predators via direct experience and/or associated chemical cues. Ontogeny may also influence recognition; experience with predators may need to occur at certain developmental stages for individuals to respond correctly. We tested predator recognition in invasive American bullfrog ( Lithobates catesbeianus) tadpoles that varied in experience with fish predators at the population and individual scale. We found that bullfrog tadpoles responded to a historical predator, largemouth bass ( Micropterus salmoides), only if the population was locally sympatric with largemouth bass. Individuals from a population that did not co‐occur with largemouth bass did not increase refuge use in response to either largemouth bass chemical cues alone or chemical cues with diet cues (largemouth bass fed bullfrog tadpoles). To test whether this behavioral response was generalized across fish predators, we exposed tadpoles to rainbow trout ( Oncorhynchus mykiss) and found that tadpoles could not recognize this novel predator regardless of co‐occurrence with other fish species. These results suggest that environment may be more important for predator recognition than evolutionary history for this invasive species, and individuals do not retain predator recognition or generalize across fish predators.     

Captive-born cotton-top tamarins (Saguinus oedipus) respond similarly to vocalizations of predators and sympatric nonpredators

What types of cues do callitrichid primates use to detect and respond to predators? Do they respond to predator‐specific cues or to more general cues? The evidence for these questions remains conflicting. We presented captive‐born and reared cotton‐top tamarins with no previous exposure to predators (or predator cues) with vocalizations from three potential predators of cotton‐top tamarin in the wild (white hawk, jaguar, and tayra) and with vocalizations from sympatric nonpredators (black‐faced antthrush and red howler monkey). Vocalizations from predators and from nonpredator mammals elicited equivalent arousal, fear, and vocal responses. Howler monkey roars produced the strongest responses. The results suggest that predator‐naïve cotton‐top tamarins do not recognize specific predator vocalizations, but may respond to vocal qualities (low‐frequency, noisy sounds) that indicate large body size, threat, or aggression. On the other hand, tamarins responded much more strongly to the higher frequency calls from the hawk than the antthrush, suggesting another mechanism must also be involved. The failure of captive‐reared tamarins to distinguish between vocalizations of predators and nonpredator mammals has important implications for reintroduction studies. Am. J. Primatol. 70:707–710, 2008. © 2008 Wiley‐Liss, Inc.     

Type and nature of cues used by Nucella lapillus to evaluate predation risk

The ability of prey to detect and adequately respond to predation risk influences immediate survival and overall fitness. Chemical cues are commonly used by prey to evaluate risk, and the purpose of this study was to elicit the nature of cues used by prey hunted by generalist predators. Nucella lapillus are common, predatory, intertidal snails that evaluate predatory risk using chemical cues. Using Nucella and a suite of its potential predators as a model system, we explored how (1) predator type, (2) predator diet, and (3) injured conspecifics and heterospecifics influence Nucella behavior. Using laboratory flumes, we determined that Nucella responded only to the invasive green crab (Carcinus maenas), the predator it most frequently encounters. Nucella did not respond to rock crabs (Cancer irroratus) or Jonah crabs (Cancer borealis), which are sympatric predators but do not frequently encounter Nucella because these crabs are primarily subtidal. Predator diet did not affect Nucella responses to risk, although starved predator response was not significantly different from controls. Since green crabs are generalist predators, diet cues do not reflect predation risk, and thus altering behavior as a function of predator diet would not likely benefit Nucella. Nucella did, however, react to injured conspecifics, a strategy that may allow them to recognize threats when predators are difficult to detect. Nucella did not react to injured heterospecifics including mussels (Mytilus edulis) and herbivorous snails Littorina littorea, suggesting that they are responding to chemical cues unique to their species. The nature of cues used by Nucella allows them to minimize costs associated with predator avoidance.     

Juvenile western toads, Bufo boreas, avoid chemical cues of snakes fed juvenile, but not larval, conspecifics

Previous investigations have demonstrated the importance of predator diet in chemically mediated antipredator behaviour. However, there are few data on responses to life-stage-specific predator diets, which could be important for animals like amphibians that undergo metamorphosis and must respond to different suites of predators at different life-history stages. In laboratory choice tests, we investigated the chemically mediated avoidance response of juvenile western toads, Bufo boreas, to four different chemical stimuli: (1) live conspecific juveniles; (2) live earthworms; (3) snakes fed juvenile conspecifics; and (4) snakes fed larval conspecifics (tadpoles). Juvenile toads avoided chemical cues from snakes that had eaten juvenile conspecifics, but did not respond to the other three stimuli, including chemical cues from snakes fed larval conspecifics. In addition, the response to cues from snakes fed juveniles differed significantly from that of snakes fed larvae. To our knowledge, this is the first study to demonstrate the importance of diet in predator avoidance of juvenile anurans and the ability of juvenile toads to distinguish between chemical cues from predators that have consumed larval versus juvenile conspecifics. Copyright 2000 The Association for the Study of Animal Behaviour.     

Cautious cannibals: Behavioral responses of juvenile and adult blue crabs to the odor of injured conspecifics

Blue crabs are cannibalistic, and therefore the scent of injured conspecifics represents both a potential food cue, as well as an indicator of predation risk. We examined the response of blue crabs to conspecific odor alone, as well as in mixtures of attractive cues to determine how animals evaluate and respond to this odor. We explicitly manipulated risk-sensitivity based on either animal size (an indicator of susceptibility to predation) or hunger state (susceptibility to starvation) as ways to evaluate theories of risk-allocation, which suggest that decreases in predation risk, or increases in the risk of starvation, ought to result in diminished responses to sensory cues that signal predator presence or activity. Large and small blue crabs were challenged to locate the source of odor plumes consisting of the scent of injured conspecifics (risk cue), attractive food odors (attractive cue), or their mixture (conflicting cue). Neither large nor small blue crabs tracked aversive cues, but large blue crabs consistently tracked conflicting treatments to their source. Responses to conflicting and aversive treatments also involved diminished movement and reduced tracking speed relative to behaviors displayed in attractive plumes. Thus, even cannibalistic crabs seem to respond more prevalently to the apparent predation risk then to food reward, and risk-sensitive behaviors have a likely cost in terms of reduced food intake. Starved animals were more likely than unstarved animals to track conflicting plumes. Both the ontogenic shift and the response of starved animals support the notion that the cost of risk-aversive behaviors results in this strategy being allocated in proportion to the degree of potential risk. Since risk-aversive responses to chemical cues can produce strong effects in communities, the size-dependent nature of these responses in blue crabs may introduce considerable complexity in interactions between blue crabs, their predators, and their prey.     

Influence of rearing and experimental temperatures on predator avoidance behaviour in a freshwater pulmonate snail

1. Predicted increases in the temperature of freshwaters is likely to affect how prey species respond to predators. We investigated how the predator avoidance behaviour of the freshwater pulmonate snail Lymnaea stagnalis is influenced by the temperature at which it was reared and that at which behavioural trials were carried out. 2. Crawl‐out behaviour of juvenile snails from two populations (high predation risk versus low predation risk) reared at either 15 or 20 °C was assessed in response to predation cues (predatory fish kairomones and conspecific alarm cues) in behavioural trials at both 15 and 20 °C. 3. Trial temperature had a significant effect on the time that snails spent in avoidance, regardless of their population of origin. Crawl‐out behaviour was greater during behavioural trials at 15 °C, but there was no effect of trial temperature on the speed with which animals showed avoidance behaviour. 4. There was no interactive effect of rearing temperature (RT) and trial temperature, but the effect of RT on avoidance behaviour did differ between populations. For an RT of 15 °C, snails from the South Drain (high risk) population showed a more rapid and longer avoidance response than those from the Chilton Moor (low risk) population. In contrast, for snails reared at 20 °C, there was no difference between populations for the duration of the avoidance response and snails from Chilton Moor crawled out faster than those from South Drain. 5. Hence, whilst (predictable) differences relative to natural predation threat in crawl‐out behaviour were apparent at 15 °C, raising the developmental temperature to 20 °C eliminated or, in the case of latency, reversed these differences. This suggests that L. stagnalis populations that cohabit with predatory fish and experience high developmental temperatures may have a reduced ability to respond to fish predation risk.