Predator Cues Research Articles

Behavioural responses to chemical cues of predators differ between fire salamander larvae from two different habitats

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

Copper mediates life history responses of Daphnia pulex to predation threat

A key challenge for ecological and ecotoxicological risk assessment is to predict the risk of organisms when exposed simultaneously to multiple stressors in sub-lethal concentrations. Here, we assessed whether sub-lethal concentrations of an anthropogenic stressors, the heavy metal copper (Cu), mediates the impacts of a natural ecological threat to species, predation risk, among six distinct Daphnia pulex clones. We investigated the interaction between the two stressors on morphological defenses and on several life-history traits including maturation time, size at maturity, somatic growth rate and survival rates. Combining a life table experiment on a response surface design, we found no evidence that the heavy metal copper mediates the effects of predator cue induced morphological responses in the tested D. pulex clones. However, our data indicate that copper can mediate several key life-history responses to predation risk. For age at maturity, we found also clear evidence that the observed interaction between predation risk and copper varied by whether clones were strong or weak morphological responders. Specific exploration of the relationship between morphological responses and life history traits under predation risk and copper suggest a strong hypothesis for multiple strategies to deal with multiple stressors. While interactions between different stressors make it harder to predict their outcomes, and ultimately assess water quality regulations about the effects of such stressors, our study provides evidence that life history theory can aid in understanding and predicting their impacts.

Of mice and cats: interspecific variation in prey responses to direct and indirect predator cues

Of mice and cats: interspecific variation in prey responses to direct and indirect predator cues

A circuit from the ventral subiculum to anterior hypothalamic nucleus GABAergic neurons essential for anxiety-like behavioral avoidance

Behavioral observations suggest a connection between anxiety and predator defense, but the underlying neural mechanisms remain unclear. Here we examine the role of the anterior hypothalamic nucleus (AHN), a node in the predator defense network, in anxiety-like behaviors. By in vivo recordings in male mice, we find that activity of AHN GABAergic (AHNVgat+) neurons shows individually stable increases when animals approach unfamiliar objects in an open field (OF) or when they explore the open-arm of an elevated plus-maze (EPM). Moreover, object-evoked AHN activity overlap with predator cue responses and correlate with the object and open-arm avoidance. Crucially, exploration-triggered optogenetic inhibition of AHNVgat+ neurons reduces object and open-arm avoidance. Furthermore, retrograde viral tracing identifies the ventral subiculum (vSub) of the hippocampal formation as a significant input to AHNVgat+ neurons in driving avoidance behaviors in anxiogenic situations. Thus, convergent activation of AHNVgat+ neurons serves as a shared mechanism between anxiety and predator defense to promote behavioral avoidance.

Ineffective integration of multiple anti-predator defenses in a rotifer: a low-cost insurance?

Abstract To maximize survival, prey often integrates multiple anti-predator defenses. How the defenses interact to reduce predation risk is, however, poorly known. We used the rotifer Brachionus calyciflorus to investigate how morphological (spines) and behavioral (floating) defenses are integrated against a common predatory rotifer, Asplanchna brightwellii, and if their combined use improves survival. To this end, we assessed the cost of the behavioral defense and the efficiency of both defenses, individually and combined, as well as their mutual dependency. The results show that the behavioral defense is costly in reducing foraging activity, and that the two defenses are used simultaneously, with the presence of the morphological defense enhancing the use of the behavioral defense, as does the pre-exposure to predator cues. However, while the morphological defense reduces predation risk, the behavioral defense does not, thus, adding the costly behavioral defense to the morphological defense does not improve survival. It is likely that the cost of the behavioral defense is low given its reversibility—compared to the cost of misidentifying the predator species—and that this has promoted the adoption of both defenses, as general low-cost insurance rather than as a tailored strategy toward specific predators. Thus, the optimal strategy in the rotifer appears to be to express both morphological and behavioral defenses when confronted with the cues of a potential predator.

Commentary: using prey naïveté to inform ecological management.

Commentary: using prey naïveté to inform ecological management.

Non-consumptive effects of predation risk on prey population regulations: empirical evidence from the invasive spider mite Tetranychus ludeni

Tetranychus ludeni Zacher is an invasive pest from Europe. It infests more than 300 plant species, including many economically important crops such as bean Phaseolus vulgaris L. (Fabales: Fabaceae), eggplant Solanum melongena L. (Solanales: Solanaceae), and many other cucurbitaceous plants. Gotoh et al. (2015) predict that this species could replace T. urticae to become a major crop pest in the world. It is often assumed that the success of biological control using predators is achieved through direct predation. However, it is still largely unknown whether predation risk could contribute to the effectiveness of prey biological control. In the present study we investigated the effects of cues from the predatory mite Phytoseiulus persimilis and killed T. ludeni on life history traits and offspring fitness of T. ludeni, providing novel knowledge for evaluation of the non-consumptive contribution to the biological control of T. ludeni and for future development of new spider mite control methods using these cues. We demonstrated that the cues from the predators and killed prey shortened the longevity by more than 23% and oviposition period by more than 35% and reduced the number of eggs laid by more than 31% in T. ludeni females. These cues also significantly reduced the intrinsic rate of increase and net population growth rate and prolonged the time to double the population size. Furthermore, in response to predator cues females significantly delayed their lifetime production of daughters and laid significantly smaller eggs. Offspring from predator-exposed mothers developed significantly more slowly. Our findings strongly suggest that the non-consumptive mortality caused by cues from both predators and killed prey can significantly reduce prey fitness, suppressing their population and lowering their damage to crops. The earlier prey death caused by these cues could result from the energic costs of natural enemy avoidance (Luong et al. 2017), decrease of foraging rate or food intake (Hermann & Thaler 2014) and increase of oxidative damage (Janssens & Stoks 2013). The present study partially supports previous reports that non-consumptive impacts of predation risk on prey are transgenerational (Tariel et al. 2020). Our study provides critical information for evaluation of biological control effectiveness using predators and paves the way for identification of chemical odors from the predator and killed prey and development of new materials and methods for the control of spider mite pests.

A trapdoor spider, Latouchia typica (Araneae: Halonoproctidae), uses vibrational cues as a trigger for predatory behavior

AbstractSpiders are one of the most dominant predators in terrestrial ecosystems. Although cues triggering predatory behavior in web‐building and wandering spiders are well investigated, studies concerning burrowing species, the most ancestral group of spiders, are relatively limited. To clarify critical cues affecting the predatory behavior in burrowing species, we conducted vibration‐reducing experiments with the trapdoor spider Latouchia typica (Araneae: Halonoproctidae) and nymphs of the speckled cockroach, Nauphoeta cinerea (Blattodea: Blaberidae), as prey. Spiders achieved a high success rate of prey capture even when blinded (with paint on the eyes). However, the use of a rubber mat to reduce vibrations significantly decreased predation success rate. In addition, the presence or absence of the blindfold did not affect the predation rates under the reducing vibration condition. These results indicate that substrate vibrations emitted from prey are critically important to trigger the predatory behavior in L. typica, but visual and chemical stimuli are not used even in the case when vibration cues are unavailable. This is the first study to use vibration‐reducing experiments to experimentally demonstrate the critical cues for predation in trapdoor spiders.

Can native predators be used as a stepping stone to reduce prey naivety to novel predators?

AbstractPredator naivety negatively affects reintroduction success, and this threat is exacerbated when prey encounters predators with which they have had no evolutionary experience. While methods have been developed to inculcate fear into such predator-naïve individuals, none have been uniformly successful. Exposing ontogenetically- and evolutionary-naïve individuals first to native predators may be an effective stepping stone to improved responses to evolutionarily novel predators. We focused on greater bilbies (Macrotis lagotis) and capitalized on a multi-year mammalian recovery experiment whereby western quolls (Dasyurus geoffroii) were reintroduced into parts of a large fenced reserve that contained a population of naïve bilbies. We quantified a suite of anti-predator behaviors and measures of general wariness across quoll-exposed and quoll-naive bilby populations. We then translocated both quoll-exposed and quoll-naïve individuals into a large enclosure that contained feral cats (Felis catus) and monitored several behaviors. We found that bilbies can respond appropriately to quolls but found only limited support that experience with quolls better-prepared bilbies to respond to cats. Both populations of bilbies rapidly modified their behavior in a similar manner after their reintroduction to a novel environment. These results may have emerged due to insufficient prior exposure to quolls, inappropriate behavioral tests, or insufficient predation risk during cat exposure. Alternatively, quolls and cats are only distantly related and may not share sufficient similarities in their predatory cues or behavior to support such a learning transfer. Testing this stepping stone hypothesis with more closely related predator species and under higher predation risk would be informative.

Olfaction and reaction: The role of olfactory and hypothalamic investment in the antipredator responses to chemical alarm cues by northern redbelly dace.

Neuroplasticity enables teleosts to promote or downregulate the growth of their brains regionally. To compensate for the effects of predation pressure, teleosts may alter their brain morphology and behavioral responses to mitigate its impact on individual fitness. High-predation environments often promote specific patterns of brain growth and produce bolder and more proactive populations. Owing to the expense of maintaining neural tissue, relative size indicates the regions most relied upon. In northern redbelly dace Chrosomus eos, as little as 2 weeks of elevated predation pressure, resulted in increased investment in their olfactory bulbs and optic tecta, while the imposition of captivity produced smaller, less symmetric hypothalami. Taken together, these results suggest that an individual could potentially become better able to detect a threat, and simultaneously less inclined to react to it, making the impact of either change in isolation is difficult to discern. Here, we compared interindividual variation in gross brain morphology, risk-taking tactics in a novel arena (shy-bold personality), and responding to olfactory cues (proactive/reactive stress-coping style). We hypothesized that olfactory investment would positively correlate with response intensity to predator cue concentration and respond across a wider range of cue concentrations, while hypothalamus size would correlate with shyness and reactivity. Exposure to heightened risk produced more bold/proactive individuals, with larger olfactory bulbs and smaller hypothalami. However, the direction of the correlation between hypothalamus size and behavior varied by treatment, and olfactory investment only corresponded with response intensity amongst proactive individuals. Our findings illustrate the potential pitfalls of relating gross brain morphology to complex behavior and suggest that stress-coping style is a relevant consideration in future studies.

Predator-induced transgenerational plasticity in animals: a meta-analysis

There is growing evidence that the environment experienced by one generation can influence phenotypes in the next generation via transgenerational plasticity (TGP). One of the best-studied examples of TGP in animals is predator-induced transgenerational plasticity, whereby exposing parents to predation risk triggers changes in offspring phenotypes. Yet, there is a lack of general consensus synthesizing the predator–prey literature with existing theory pertaining to ecology and evolution of TGP. Here, we apply a meta-analysis to the sizable literature on predator-induced TGP (441 effect sizes from 29 species and 49 studies) to explore five hypotheses about the magnitude, form and direction of predator-induced TGP. Hypothesis #1: the strength of predator-induced TGP should vary with the number of predator cues. Hypothesis #2: the strength of predator-induced TGP should vary with reproductive mode. Hypothesis #3: the strength and direction of predator-induced TGP should vary among offspring phenotypic traits because some traits are more plastic than others. Hypothesis #4: the strength of predator-induced TGP should wane over ontogeny. Hypothesis #5: predator-induced TGP should generate adaptive phenotypes that should be more evident when offspring are themselves exposed to risk. We found strong evidence for predator-induced TGP overall, but no evidence that parental predator exposure causes offspring traits to change in a particular direction. Additionally, we found little evidence in support of any of the specific hypotheses. We infer that the failure to find consistent evidence reflects the heterogeneous nature of the phenomena, and the highly diverse experimental designs used to study it. Together, these findings set an agenda for future work in this area.

Impact of food availability and predator cues on meadow vole response to social vs. non-social odorants

Abstract The risk of predation and food deprivation may alter the degree to which animals associate with conspecifics. We examined if food deprivation, the risk of predation, or simultaneous exposure to both altered meadow voles’ preference for odour cues in a way that adheres to the terminal investment, safety in numbers, or avoidance hypotheses. Satiated or food-deprived meadow voles were given the choice to investigate either opposite-sex conspecific bedding, same-sex conspecific bedding, clean bedding, or self-bedding when exposed to mink urine or olive oil. Mink urine and food deprivation did not impact the amount of time meadow voles spent with each type of bedding, but meadow voles did begin investigating more quickly when experiencing either or both stressors. However, food deprivation and mink urine did not have an additive impact on any measured variable. Further research is needed to determine if the terminal investment hypothesis is the hypothesis that best describes the mating behaviour of meadow voles facing one or multiple stressors.

Warming and predation risk only weakly shape size-mediated priority effects in a cannibalistic damselfly

Differences in hatching dates can shape intraspecific interactions through size-mediated priority effects (SMPE), a phenomenon where bigger, early hatched individuals gain advantage over smaller, late hatched ones. However, it remains unclear to what extent and how SMPE are affected by key environmental factors such as warming and predation risk imposed by top predators. We studied effects of warming (low and high temperature) and predation risk (presence and absence of predator cues of perch) on SMPE in life history and physiological traits in the cannibalistic damselfly Ischnura elegans. We induced SMPE in the laboratory by manipulating hatching dates, creating following groups: early and late hatchlings reared in separate containers, and mixed phenology groups where early and late hatchlings shared the same containers. We found strong SMPE for survival and emergence success, with the highest values in early larvae of mixed phenology groups and the lowest values in late larvae of mixed phenology groups. Neither temperature nor predator cues affected SMPE for these two traits. The other life history traits (development rate and mass at emergence) did not show SMPE, but were affected by temperature and predator cues. A tendency for SMPE was found for protein content, in the high temperature treatment. The other physiological traits (phenoloxidase activity and fat content) showed fixed expressions across treatments, indicating decoupling between physiology and life history. The results underline that SMPEs are trait-dependent, and only weakly or not affected by temperature and predation risk.

Function of meerkats' mobbing-like response to secondary predator cues: recruitment not teaching

Early detection of predators greatly improves prey escape and survival chances. By investigating cues predators leave behind, such as fur, urine, faeces or feathers (secondary predator cues), prey may gain vital information about predators in the vicinity. Meerkats, Suricata suricatta , display an unusual mobbing-like response upon encountering secondary predator cues, not reported in any other species. The function of this behaviour is unclear because, unlike mobbing of a live predator, it cannot yield the primary benefit of driving the threat away. Here we examine two potential functions. First, we hypothesized that older group members may exhibit exaggerated mobbing-like responses towards secondary predator cues as a form of teaching to promote learning in naïve pups. Meerkats are known to teach pups hunting skills, but there is no evidence that any nonhuman species teaches across multiple contexts. Mobbing-like responses could also function to facilitate group member recruitment, stimulating information gathering and collective decision making by the group. Using experimental presentations of secondary predator cues in the presence and absence of pups, in combination with 20 years of data on natural encounters with secondary predator cues, we found that older group members' response frequency was lower when pups were present and that response intensity declined as the proportion of pups to total group member number increased. Conversely, the intensity of responses increased when a greater proportion of group members interacted with the cue and varied with predator cue type. The response frequency to natural encounters with secondary predator cues was greater in larger groups, and the distance travelled by the group decreased following an encounter with secondary predator cues. These results suggest that meerkats do not show exaggerated responses to secondary predator cues as a form of teaching. Mobbing-like responses more likely serve to increase recruitment of others to investigate the cue and inform defensive group behaviour. • Meerkats show an unusual mobbing-like response to secondary predator cues (SPCs). • We examined potential functions using cue presentations and long-term observations. • No evidence to support teaching via increased mobbing-like response in pup presence. • Large groups responded to SPCs more often; distance travelled fell after encounters. • Mobbing-like response facilitates recruitment and informs group defensive behaviour.

Effects of a Neonicotinoid Insecticide and Population Density on Behavior and Development of Wood Frogs (Rana sylvatica).

Amphibians have been facing global declines over the last decades from direct and indirect effects of anthropogenic activities. A contributor to declines is waterway contamination from agricultural runoffs of pesticides such as neonicotinoids. Beyond direct and indirect effects of the pesticide, few studies have investigated the possible interactions between neonicotinoids and natural environmental stressors across larval development, which could alter the strength and direction of observed neonicotinoid effects. The present study used a fully crossed design to investigate how a concentration of imidacloprid (a neonicotinoid; 10 µg/L) measured in surface waters interacted with low and high population densities (0.33 and 1 tadpole/L, respectively), an important environmental stressor, to influence behavior and development across metamorphosis in wood frogs (Rana sylvatica), known to breed in agricultural landscapes. Behaviors were measured in the absence and presence of predation cues using open-field tests at three distinct developmental stages, up to the metamorph stage. We found that imidacloprid did not interact with population density or independently affect behaviors in the absence of predation cues. However, individuals raised at high density compared with low density were more active at an early developmental stage but less active at metamorphic climax. Furthermore, both density and imidacloprid independently decreased the natural freezing response of tadpoles to predation cues. Finally, we found that distance traveled in the open-field test was weakly repeatable between aquatic stages but not repeatable across metamorphosis, a pattern that was not affected by treatments. The present study provides novel insights on the ecotoxicology of imidacloprid in the presence of a natural stressor, highlighting the importance of including behavioral assays and natural stressors in studies of amphibian ecotoxicology. Environ Toxicol Chem 2022;41:2968-2980. © 2022 SETAC.

Impact of predator model presentation paradigms on titi monkey alarm sequences

Predator presentation experiments are widely used to investigate animal alarm vocalizations. They usually involve presentations of predator models or playbacks of predator calls, but it remains unclear whether the two paradigms provide similar results, a major limitation when investigating animal syntactic and semantic capacities. Here, we investigate whether visual and acoustic predator cues elicit different vocal reactions in black-fronted titi monkeys (Callicebus nigrifrons). We exposed six groups of wild titi monkeys to visual models or playbacks of vocalizations of raptor or felid. We characterized each group’s vocal reactions using sequence parameters known to reliably encode predatory events in this species. We found that titi monkeys’ vocal reactions varied with the predator species but also with the experimental paradigm: while vocal reactions to raptor vocalizations and models were similar, felid vocalizations elicited heterogeneous, different reactions from that given to felid models. We argue that subjects are not familiar with felid vocalizations, because of a lack of learning opportunities due to the silent behaviour of felids. We discuss the implication of these findings for the semantic capacities of titi monkeys. We finally recommend that playbacks of predator vocalizations should not be used in isolation but in combination with visual model presentations, to allow fine-grained analyses of the communication system of prey species.Significance statementIt is common to present prey species with predator models or predator calls to study their vocal reactions. The two paradigms are often used independently, but it remains unclear whether they provide similar results. Here, we studied the vocal reactions of titi monkeys to calls and models of raptors and felids. We show that titi monkeys seem to recognize the vocalizations of raptors but not those of felids. The study of the vocal reactions emitted when titi monkeys cannot clearly identify the threat allows us to draw accurate hypotheses about the meaning of titi monkeys’ alarm utterances. We argue that playbacks of predator calls should be used in conjunction with model presentations, which can allow us to better investigate the information and the structure of the alarm systems.

Predatory cue use in flush responses of a colonial nesting seabird during polar bear foraging

Nest predation is a primary cause of reproductive failure in birds; thus, predators apply strong selective pressure on nesting behaviour, especially risk assessment behaviours during predator encounters at nests. Prey's risk assessments are not static; rather, dynamic risk assessment theory predicts that prey assess risk in real-time and update it according to changes in cues posed by the predator(s). We used drone videography to film nest-flushing behaviours of common eiders, Somateria mollissima, in response to foraging polar bears, Ursus maritimus, on East Bay Island (Nunavut, Canada). We assessed how cue use influenced flushing behaviour and nest fate in a path analysis using 200 observations of 193 eiders in 2017. Our most supported model found that more direct angles of visual gaze and travel angle by polar bears resulted in conspicuous nest flushes by eiders (β = −0.236 ± 0.059), whereas the presence of herring gulls, Larus argentatus, resulted in more discrete flushes of hens walking from their nests (β = −0.181 ± 0.059). Shorter flush initiation distances between eiders and approaching bears resulted in greater nest predation by polar bears (β = −0.203 ± 0.076). We found no support that an eider's visibility from the nest influenced any component of flushing behaviour. We suggest that during encounters with bears, eiders are capable of assessing risk and making appropriate behavioural decisions to reduce the chances of nest loss. However, as the colony experienced heavy predation by bears in 2017, behavioural responses alone appear to be insufficient to mitigate polar bear predation at the population level.

Effect of the presence of predatory cues and hunger on cannibalistic behaviour of ladybird beetle,Menochilus sexmaculatusFabricius (Coleoptera: Coccinellidae)

AbstractCannibalism and its role in population dynamics, along with various factors influencing the rate of cannibalism, have been widely studied across taxa.The effects of predatory cue concentrations and starvation on cannibalistic tendencies and other life‐history traits in cannibalistic and non‐cannibalistic adults ofMenochilus sexmaculatuswere investigated.Egg cannibalism increased with increasing predatory cue concentration and was maximum in high predatory cue treatment; increased with starvation irrespective of their diet history.Latency to cannibalise eggs was shorter for cannibalistic adults as compared to non‐cannibalistic adults irrespective of their hunger status and concentration of conspecific cues.Non‐cannibalistic females have higher fecundity than cannibalistic females.In conclusion, both cannibalistic and non‐cannibalistic individuals respond differently to intrinsic (hunger) and extrinsic cues (predatory cue concentrations). Cannibalistic individuals cannibalise more than non‐cannibalistic ones at low levels of starvation and predatory cues.Our finding suggests that cannibalistic individuals are better at assessing the risk and removing future competitors, which might favour these individuals over non‐cannibalistic ones in adverse conditions and increased competition.

Multimodal Cues Do Not Improve Predator Recognition in Green Toad Tadpoles.

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

Predator- and killed prey-induced fears bear significant cost to an invasive spider mite: Implications in pest management.

The success of biological control using predators is normally assumed to be achieved through direct predation. Yet it is largely unknown how the predator- and killed prey-induced stress to prey may contribute to biological control effectiveness. Here, we investigate variations in life-history traits and offspring fitness of the spider mite Tetranychus ludeni in response to cues from the predatory mite Phytoseiulus persimilis and killed T. ludeni, providing knowledge for evaluation of the nonconsumptive contribution to the biological control of T. ludeni and for future development of novel spider mite control measures using these cues. Cues from predators and killed prey shortened longevity by 23-25% and oviposition period by 35-40%, and reduced fecundity by 31-37% in T. ludeni females. These cues significantly reduced the intrinsic rate of increase (rm ) and net population growth rate (R0 ), and extended time to double the population size (Dt ). Predator cues significantly delayed lifetime production of daughters. Mothers exposed to predator cues laid significantly smaller eggs and their offspring developed significantly more slowly but these eggs had significantly higher hatch rate. Predator- and killed prey-induced fears significantly lower the fitness of T. ludeni, suggesting that these nonconsumptive effects can contribute to the effectiveness of biological control to a great extent. Our study provides critical information for evaluation of biological control effectiveness using predators and paves the way for identification of chemical odors from the predator and killed prey, and development of new materials and methods for the control of spider mite pests. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.