Diel vertical migration arising in a habitat selection game

Predator and prey react to each other, adjusting their behavior to maximize their fitness and optimizing their food intake while keeping their predation risk as low as possible. In a pelagic environment, prey reduce their predation mortality by adopting a diel vertical migration (DVM) strategy, avoiding their predator during their peak performance by finding refuge in deep layers during daylight hours and feeding at the surface during the night. Due to the duality of the interaction between prey and predator, we used a game theory approach to investigate whether DVM can be a suitable strategy for the predator as well as the prey. We formulated three scenarios in plankton ecology in order to address this question. A novel finding is that mixed strategies emerge as optimal over a range of the parameter space, where part of the predator or prey population adopts a DVM while the rest adopt one or other “sit and wait” strategies.     

Implications of shared predation for space use in two sympatric leporids

Spatial variation in habitat riskiness has a major influence on the predator–prey space race. However, the outcome of this race can be modulated if prey shares enemies with fellow prey (i.e., another prey species). Sharing of natural enemies may result in apparent competition, and its implications for prey space use remain poorly studied. Our objective was to test how prey species spend time among habitats that differ in riskiness, and how shared predation modulates the space use by prey species. We studied a one‐predator, two‐prey system in a coastal dune landscape in the Netherlands with the European hare (Lepus europaeus) and European rabbit (Oryctolagus cuniculus) as sympatric prey species and red fox (Vulpes vulpes) as their main predator. The fine‐scale space use by each species was quantified using camera traps. We quantified residence time as an index of space use. Hares and rabbits spent time differently among habitats that differ in riskiness. Space use by predators and habitat riskiness affected space use by hares more strongly than space use by rabbits. Residence time of hare was shorter in habitats in which the predator was efficient in searching or capturing prey species. However, hares spent more time in edge habitat when foxes were present, even though foxes are considered ambush predators. Shared predation affected the predator–prey space race for hares positively, and more strongly than the predator–prey space race for rabbits, which were not affected. Shared predation reversed the predator–prey space race between foxes and hares, whereas shared predation possibly also released a negative association and promoted a positive association between our two sympatric prey species. Habitat riskiness, species presence, and prey species’ escape mode and foraging mode (i.e., central‐place vs. noncentral‐place forager) affected the prey space race under shared predation.     

Predator versus prey: on aerial hunting and escape strategies in birds

Predator and prey attack-escape performance is likely to bethe outcome of an evolutionary arms race. Predatory birds aretypically larger than their prey, suggesting different flightperformances. We analyze three idealized attack-escape situationsbetween predatory and prey birds: climbing flight escape, horizontalspeeding, and turning and escape by diving. Generally a smallerbird will outclimb a larger predator and hence outclimbing shouldbe a common escape strategy. However, some predators such asthe Eleonora's falcon (Falco elenorae) has a very high rateof climb for its size. Prey species with an equal or highercapacity to climb fast, such as the swift Apus apus, usuallyadopt climbing escape when attacked by Eleonora's falcons.To analyze the outcome of the turning gambit between predatorand prey we use a Howland diagram, where the relative lineartop speeds and minimum turning radii of prey and predator definethe escape and danger zones. Applied to the Eleonora's falconand some potential prey species, this analysis indicates thatthe falcon usually wins against the example prey species; thatis, the prey will be captured. Level maneuvering hunting isthe most common strategy seen in Eleonora's falcons. To avoidcapture via use of this strategy by a predator, the prey shouldbe able to initiate tight turns at high linear speed, whichis facilitated by a low wing loading (weight per unit of wingarea). High diving speed is favored by large size. If close enough to safe cover, a prey might still opt for a verticaldive to escape in spite of lower terminal diving speed thanthat of the predator. On the basis of aerodynamic considerationswe discuss escape flight strategies in birds in relation tomorphological adaptations.     

Diel vertical migration of freshwater fishes – proximate triggers,ultimate causes and research perspectives

1. Diel vertical migrations (DVM) are typical for many cold‐water fish species such as Pacific salmons (Oncorhynchus spp.) and coregonids (Coregonus spp.) inhabiting deep lakes. A comprehensive recent overview of DVM in freshwater fish has not been available, however. 2. The main proximate trigger of DVM in freshwater fish is the diel change in light intensity, with declining illumination at dusk triggering the ascent and the increase at dawn triggering the descent. Additional proximate cues are hydrostatic pressure and water temperature, which may guide fish into particular water layers at night. 3. Ultimate causes of DVM encompass bioenergetics efficiency, feeding opportunities and predator avoidance. None of these factors alone can explain the DVM in all cases. Multi‐factorial hypotheses, such as the ‘antipredation window’ combined with the thermal niche hypothesis, are more likely to explain DVM. It is suggested that planktivorous fish move within a layer sufficiently well illuminated to capture zooplankton, but too dark for predators to feed upon the migrating fish. In complete darkness, fish seek layers with a temperature that optimises bioenergetics efficiency. The strength of each factor may differ from lake to lake, and hence system‐specific individual analyses are needed. 4. Mechanistic details that are still poorly explored are the costs of buoyancy regulation and migration, the critical light thresholds for feeding of planktivorous and piscivorous fish, and predator assessment by (and size‐dependent predation risk of) the prey fish. 5. A comprehensive understanding of the adaptive value of DVM can be attained only if the behaviour of individual fish within migrating populations is explicitly taken into account. Size, condition and reproductive value differ between individuals, suggesting that migrating populations should split into migrants and non‐migrants for whom the balance between mortality risk and growth rate can differ. There is increasing evidence for this type of partial DVM within populations. 6. Whereas patterns of DVM are well documented, the evolution of DVM is still only poorly understood. Because experimental approaches at realistic natural scales remain difficult, a combination of comprehensive data sets with modelling is likely to resolve the relative importance of different proximate and ultimate causes behind DVM in fish.     

Danger Comes from All Fronts: Predator-Dependent Escape Tactics of Túngara Frogs

The escape response of an organism is generally its last line of defense against a predator. Because the effectiveness of an escape varies with the approach behaviour of the predator, it should be advantageous for prey to alter their escape trajectories depending on the mode of predator attack. To test this hypothesis we examined the escape responses of a single prey species, the ground-dwelling túngara frog (Engystomops pustulosus), to disparate predators approaching from different spatial planes: a terrestrial predator (snake) and an aerial predator (bat). Túngara frogs showed consistently distinct escape responses when attacked by terrestrial versus aerial predators. The frogs fled away from the snake models (Median: 131°). In stark contrast, the frogs moved toward the bat models (Median: 27°); effectively undercutting the bat’s flight path. Our results reveal that prey escape trajectories reflect the specificity of their predators’ attacks. This study emphasizes the flexibility of strategies performed by prey to outcompete predators with diverse modes of attack.     

Temperature and prey capture: opposite relationships in two predator taxa

Abstract 1. All other things equal, predator capture rates are expected to depend on encounter rate with prey, prey escape capability (including prey defences), and on predator agility. Ectotherm predators and their prey both respond to increasing temperature by increased activity, i.e. predators increase their search area and prey may enhance their escape capability. This means that, as temperature changes, the ability of a predator to catch prey will decrease, increase, or remain unchanged depending on the relative effect of temperature on predator and prey. Their responses may further be differentially moulded by light conditions depending on whether the predator is diurnally or nocturnally active. It was hypothesised that flying Diptera are vulnerable to carabid beetles only at low temperatures and over the full temperature range for spiders because carabids, in contrast to spiders, are not built to catch swiftly moving prey. 2. The first experiment examined the spontaneous locomotor activity of the predators and of fruit flies at different temperatures (5, 10, 15, 20, 25, and 30 °C) and light conditions (light, dark). A second experiment examined the effect of temperature and light on the predation rate of two carabid beetles (Pterostichus versicolor and Calathus fuscipes) and two spiders (Clubiona phragmitis and Pardosa prativaga) using fruit flies (Drosophila melanogaster) as prey. 3. All four predators and the fruit fly increased their locomotory activity at higher temperatures. Activity of the carabid beetles peaked at intermediate temperatures; spiders and fruit flies were most active at the highest temperatures. Predation rate of the spiders increased with temperature whereas the beetles caught flies only at low temperatures (5 and 10 °C). 4. Diurnal variation in temperature may bring different prey groups within the set of potential prey at different times of the day or at different seasons. The ability of many carabid beetles to forage at low temperatures may have nutritional benefits and increases the diversity of interactions in terrestrial food webs.     

Hydrodynamic mediation of predator-prey interactions: differential patterns of prey susceptibility and predator success explained by variation in water flow

In most shallow water marine systems, fluid movements vary on scales that may influence local community dynamics both directly, through changes in the abundance of species, and indirectly, by modifying important behaviors of organisms. We examined how differences in current speed affect the outcome of predator-prey interactions for two species of marine benthic predators (knobbed whelks, Busycon carica, and blue crabs, Callinectes sapidus) foraging on two common prey species (bay scallops, Argopecten irradians, and hard clams, Mercenaria mercenaria). The predators differ in their foraging strategies and prey in their potential escape responses. Predation by blue crabs, highly mobile predators/scavengers that rely upon chemical odors transported in the water column to locate prey, could be strongly affected by changes in current speed and turbulent mixing because their foraging strategy relies on a high degree of spatial integration of prey odor plumes. Whelks, slow moving, predatory gastropods that often forage with their bodies buried in the sediment, may be less susceptible to flow-induced distortion of prey odor plumes because their sluggish movements result in a high degree of temporal integration of prey odors. Bay scallops, relatively mobile bivalves capable of rapid short-distance swimming burst, and hard clams, sedentary bivalves, have been shown to respond to varying degrees to predator odors that are dispersed in the water column. Flow regime for the predator-prey experiments was manipulated in situ using large channels. Predation by blue crabs on both juvenile hard clams and bay scallops decreased with increases in water flow (0-12 vs. 0-30 cm s⁻¹). Whelk predation on bay scallops increased with increases in water flow, whereas predation by whelks on hard clams did not differ between flow regimes. For blue crabs movement decreased at periods of high water flow. Because blue crabs locate prey through chemolocation of water-borne cues, which are diluted rapidly at higher flows, decreases in foraging may result from the inability to successfully detect prey at enhanced flows. Differences in predation by whelks could not be explained by a similar mechanism. Visual observations of foraging whelks revealed no differences in whelk behavior between the two flow regimes. The pattern of higher whelk predation on scallops at enhanced flow is likely to be related to a flow-inhibiting ability of scallops to detect predator approach. Thus, flow enhancement interferes with three of the predator-prey systems but the effect on predator success depends on whether the predator or prey is most affected.     

Self-organization of collective escape in pigeon flocks

Bird flocks under predation demonstrate complex patterns of collective escape. These patterns may emerge by self-organization from local interactions among group-members. Computational models have been shown to be valuable for identifying what behavioral rules may govern such interactions among individuals during collective motion. However, our knowledge of such rules for collective escape is limited by the lack of quantitative data on bird flocks under predation in the field. In the present study, we analyze the first GPS trajectories of pigeons in airborne flocks attacked by a robotic falcon in order to build a species-specific model of collective escape. We use our model to examine a recently identified distance-dependent pattern of collective behavior: the closer the prey is to the predator, the higher the frequency with which flock members turn away from it. We first extract from the empirical data of pigeon flocks the characteristics of their shape and internal structure (bearing angle and distance to nearest neighbors). Combining these with information on their coordination from the literature, we build an agent-based model adjusted to pigeons’ collective escape. We show that the pattern of turning away from the predator with increased frequency when the predator is closer arises without prey prioritizing escape when the predator is near. Instead, it emerges through self-organization from a behavioral rule to avoid the predator independently of their distance to it. During this self-organization process, we show how flock members increase their consensus over which direction to escape and turn collectively as the predator gets closer. Our results suggest that coordination among flock members, combined with simple escape rules, reduces the cognitive costs of tracking the predator while flocking. Such escape rules that are independent of the distance to the predator can now be investigated in other species. Our study showcases the important role of computational models in the interpretation of empirical findings of collective behavior.     

Effect of plants on the searching efficiency of a generalist predator: the importance of predator-prey spatial association

In most studies of tritrophic interactions, the effect of plants on predators is confounded with changes in prey and predator behaviors after an encounter event. Here, we estimate how the effect of plants on prey distribution (in the absence of the predator) and on predator foraging behavior (in the absence of prey) may influence predation rate of Orius insidiosus (Say) (Heteroptera: Anthocoridae) in 11 plant by prey species combinations. The within-leaf distributions of O. insidiosus and its prey overlapped most on bean plants. The predator's foraging behavior (e.g., walking speed, turning rate) also differed among plant species. Simulations, using the prey distribution data and predator's foraging patterns on leaf surfaces of each plant species, show that, overall, the searching efficiency of O. insidiosus was higher on leaves of bean and corn than of tomato. However, the predator's searching efficiency was not consistent within plant species. Thus, the combined effect of plants directly on the predator and indirectly through the prey influenced the predator's searching efficiency.     

Phenotypic plasticity in anti-intraguild predator strategies: mite larvae adjust their behaviours according to vulnerability and predation risk

Interspecific threat-sensitivity allows prey to maximize the net benefit of antipredator strategies by adjusting the type and intensity of their response to the level of predation risk. This is well documented for classical prey-predator interactions but less so for intraguild predation (IGP). We examined threat-sensitivity in antipredator behaviour of larvae in a predatory mite guild sharing spider mites as prey. The guild consisted of the highly vulnerable intraguild (IG) prey and weak IG predator Phytoseiulus persimilis, the moderately vulnerable IG prey and moderate IG predator Neoseiulus californicus and the little vulnerable IG prey and strong IG predator Amblyseius andersoni. We videotaped the behaviour of the IG prey larvae of the three species in presence of either a low- or a high-risk IG predator female or predator absence and analysed time, distance, path shape and interaction parameters of predators and prey. The least vulnerable IG prey A. andersoni was insensitive to differing IGP risks but the moderately vulnerable IG prey N. californicus and the highly vulnerable IG prey P. persimilis responded in a threat-sensitive manner. Predator presence triggered threat-sensitive behavioural changes in one out of ten measured traits in N. californicus larvae but in four traits in P. persimilis larvae. Low-risk IG predator presence induced a typical escape response in P. persimilis larvae, whereas they reduced their activity in the high-risk IG predator presence. We argue that interspecific threat-sensitivity may promote co-existence of IG predators and IG prey and should be common in predator guilds with long co-evolutionary history.     

Increasing isolation reduces predator:prey species richness ratios in aquatic food webs

The number of species that live in a habitat typically declines as that habitat becomes more isolated. However, the influence of habitat isolation on patterns of food web structure, in particular the ratio of predator to prey species richness, is less well understood. We placed aquatic mesocosms at varying distances from ponds that acted as sources of potential colonists; then we examined how isolation affected the ratio of predator:prey species richness in the communities that assembled. In the final sampling, a total of 21 species (12 prey and 9 predators) of insects, crustaceans, and amphibians had colonized the mesocosms. We found that total species richness, as well as the richness of predators and prey, declined with increasing isolation. However, predator richness declined more rapidly than prey richness with increasing isolation, which lead to decreasing predator:prey ratios. This result conflicts with prior demonstrations of invariant predator:prey ratios in freshwater communities.     

Dynamics between a predator and a prey switching two kinds of escape motions

In nature, animals are classified into two large groups. Those that form the prey and that form the predator. A prey animal runs for its life when chased by a predatory animal. When prey animals escape from the chasing enemy, they generally use two types of evasive motion. Those are a straight-line escape motion and a zigzag-line escape motion. A fleeing prey switches between two types of evasive behavior in a manner depending on the predator's performance.I propose a mathematical model that expresses behaviors between a prey and a predator. This model brings that a straight-line escape motion is a better solution for an escape from a slow and far predator. On the other hand, an evasive motion for a near or fast enemy is a zigzag-line escape motion. This model suggests that animals have the best evasive strategy.     

Eco-evolutionary trophic dynamics: loss of top predators drives trophic evolution and ecology of prey

Ecosystems are being altered on a global scale by the extirpation of top predators. The ecological effects of predator removal have been investigated widely; however, predator removal can also change natural selection acting on prey, resulting in contemporary evolution. Here we tested the role of predator removal on the contemporary evolution of trophic traits in prey. We utilized a historical introduction experiment where Trinidadian guppies (Poecilia reticulata) were relocated from a site with predatory fishes to a site lacking predators. To assess the trophic consequences of predator release, we linked individual morphology (cranial, jaw, and body) to foraging performance. Our results show that predator release caused an increase in guppy density and a "sharpening" of guppy trophic traits, which enhanced food consumption rates. Predator release appears to have shifted natural selection away from predator escape ability and towards resource acquisition ability. Related diet and mesocosm studies suggest that this shift enhances the impact of guppies on lower trophic levels in a fashion nuanced by the omnivorous feeding ecology of the species. We conclude that extirpation of top predators may commonly select for enhanced feeding performance in prey, with important cascading consequences for communities and ecosystems.     

A nonlocal kinetic model for predator–prey interactions

We extend the aggregation model from Fetecau (2011) by adding a field of vision to individuals and by including a second species. The two species, assumed to have a predator–prey relationship, have dynamics governed by nonlocal kinetic equations that include advection and turning. The latter is the main mechanism for aggregation and orientation, which results from interactions among individuals of the same species as well as predator–prey relationships. We illustrate numerically a diverse set of predator–prey behaviors that can be captured by this model. We show that a prey’s escape outcome depends on the social interactions between its group members, the prey’s field of vision and the sophistication of the predator’s hunting strategies.     

Predation on two vole species by a shared predator: antipredatory response and prey preference

In prey communities with shared predators, variation in prey vulnerability is a key factor in shaping community dynamics. Conversely, the hunting efficiency of a predator depends on the prey community structure, preferences of the predator and antipredatory behavioural traits of the prey. We studied experimentally, under seminatural field conditions, the preferences of a predator and the antipredatory responses of prey in a system consisting of two Myodes species of voles, the grey-sided vole (M. rufocanus Sund.) and the bank vole (M. glareolus Schreb.), and their specialist predator, the least weasel (Mustela nivalis nivalis L.). To quantify the preference of the weasels, we developed a new modelling framework that can be used for unbalanced data. The two vole species were hypothesised to have different habitat-dependent vulnerabilities. We created two habitats, open and forest, to provide different escape possibilities for the voles. We found a weak general preference of the weasels for the grey-sided voles over the bank voles, and a somewhat stronger preference specifically in open habitats. The weasels clearly preferred male grey-sided voles over females, whereas in bank voles, there was no difference. The activity of voles changed over time, so that voles increased their movements immediately after weasel introduction, but later adjusted their movements to times of lowered predation risk. Females that were more active had an elevated mortality risk, whereas in the case of males, the result was the opposite. We conclude that, in vulnerability to predation, the species- or habitat-specific characteristics of these prey species are playing a minor role compared to sex-specific characteristics.     

Incorporating Motion into Investigations of mimicry

During the past thirty years, natural selection due to predation has been investigated with regard to prey motion in three areas that are relevant to the evolution of mimicry: (1) anti-apostatic selection, (2) locomotor mimicry, and (3) escape mimicry. Anti-apostatic selection, or selection against the odd individuals, arises when prey are at very high densities or when prey are Müllerian mimics. When prey are at high densities, motion of the prey increases selection against odd individuals. When the prey are Müllerian mimics, motion may also play an important role in strengthening selection against odd individuals. This may explain locomotor mimicry between Müllerian mimics. Locomotor mimicry arises when two distantly-related prey species appear alike in behaviour, and there is a corresponding suite of morphological, physiological, and biomechanical traits that the prey have in common. Locomotor mimicry has been demonstrated in Müllerian mimics. It is also predicted to occur in Batesian mimics but with important limitations due to selection by the predator for the prey to maintain the ability to escape if detected. Locomotor mimicry may also occur between palatable species that are alike as a result of unprofitable prey (or escape) mimicry. Escape mimicry arises when prey are difficult to capture. By frustration learning, the predator associates the colour of the prey with unprofitability. In all three instances, dis-similarity in colour or motion probably increases selection against the odd individual. In addition, the interaction of colour and motion gives rise to greater reliability of the signals to a specialist predator. However for a generalist predator, multiple component signals of the prey lead to errors in signal perception and greater risk of cheating. This revised version was published online in July 2006 with corrections to the Cover Date.     

Dynamic Risk Assessment: Prey Rapidly Adjust Flight Initiation Distance to Changes in Predator Approach Speed

The pre‐eminent model of flight initiation distance assumes that the function relating predation risk to distance between predator and prey is constant. However, the risk–distance function can change dramatically during approaches by predators. Changes in predator behavior during approach and in availability of benefits (e.g. food or potential mates) may alter risks and/or costs during encounters. Thus, prey should be able to respond appropriately to changes in cues to risk, such as predator approach speed. Under the assumption that prey assess risk in real time, it was predicted that flight initiation distance (distance between predator and prey when escape begins) decreases when approach speed increases and increases when approach speed decreases during an encounter. Effects of single, abrupt changes from slower to faster approach or the reverse were studied in a lizard, Anolis lineatopus. Flight initiation distances were determined solely by final approach speed, being nearly identical for: (1) continuously fast approaches and approaches initially at the slower and finally at the faster speed and (2) for continuously slower approaches and approaches initially at faster and finally at slower speed. Escape should be adjusted to match changes in risk and cost caused by changes in predator behavior, ability to escape, and costs of escape as attacks unfold. A recent model by Broom and Ruxton [Behavioural Ecology (2004) vol. 16, pp. 534—540] predicts that cryptic prey should stay motionless until detected, then flee immediately. Our results suggest that current escape models can be applied to prey escape strategies when cues to risk change, by assuming that prey base decisions on the current relationship between risk and distance. Empirical studies are needed to test predictions concerning continuous risk assessment.     

ORGANIZATION OF PREDATOR-PREY COMMUNITIES AS AN EVOLUTIONARY GAME

We consider a simple predator-prey model of coevolution. By allowing coevolution both within and between trophic levels the model breaks the traditional dichotomy between coevolution among competitors and coevolution between a prey and its predator. By allowing the diversity of prey and predator species to emerge as a property of the evolutionarily stable strategies (ESS), the model breaks another constraint of most approaches to coevolution that consider as fixed the number of coevolving species. The number of species comprising the ESS is influenced by a parameter that determines the predator's niche breadth. Depending upon the parameter's value the ESS may contain: 1) one prey and one predator species, 2) two prey and one predator, 3) two prey and two predators, 4) three prey and two predators, 5) three prey and three predators, etc. Evolutionarily, these different ESSs all emerge from the same model. Ecologically, however, these ESSs result in very different patterns of community organization. In some communities the predator species are ecologically keystone in that their removal results in extinctions among the prey species. In others, the removal of a predator species has no significant impact on the prey community. These varied ecological roles for the predator species contrasts sharply with the essential evolutionary role of the predators in promoting prey species diversity. The ghost of predation past in which a predator's insignificant ecological role obscures its essential evolutionary role may be a frequent property of communities of predator and prey.     

Temperature effects on ballistic prey capture by a dragonfly larva

Understanding the effects of temperature on prey–predator interactions is a key issue to predict the response of natural communities to climate change. Higher temperatures are expected to induce an increase in predation rates. However, little is known on how temperature influences close‐range encounter of prey–predator interactions, such as predator's attack velocities. Based on the speed–accuracy trade‐off concept, we hypothesized that the increase in predator attack velocity by increasing temperature reduces the accuracy of the attack, leading to a lower probability of capture. We tested this hypothesis on the dragonfly larvae Anax imperator and the zooplankton prey Daphnia magna. The prey–predator encounters were video‐recorded at high speed, and at three different temperatures. Overall, we found that (1) temperature had a strong effect on predator's attack velocities, (2) prey did not have the opportunity to move and/or escape due to the high velocity of the predator during the attack, and (3) neither velocity nor temperature had significant effects on the capture success. By contrast, the capture success mainly depended on the accuracy of the predator in capturing the prey. We found that (4) some 40% of mistakes were undershooting and some 60% aimed below or above the target. No lateral mistake was observed. These results did not support the speed–accuracy trade‐off hypothesis. Further studies on dragonfly larvae with different morphological labial masks and speeds of attacks, as well as on prey with different escape strategies, would provide new insights into the response to environmental changes in prey–predator interactions.     

The influence of generalist predators in spatially extended predator–prey systems

The presence of generalist predators is known to have important ecological impacts in several fields. They have wide applicability in the field of biological control. However, their role in the spatial distribution of predator and prey populations is still not clear. In this paper, the spatial dynamics of a predator–prey system is investigated by considering two different types of generalist predators. In one case, it is considered that the predator population has an additional food source and can survive in the absence of the prey population. In the other case, the predator population is involved in intraguild predation, i.e., the source of the additional food of the predator coincides with the food source of the prey population and thus both prey and predator populations compete for the same resource. The conditions for linear stability and Turing instability are analyzed for both the cases. In the presence of generalist predators, the system shows different pattern formations and spatiotemporal chaos which has important implications for ecosystem functioning not only in terms of their predictability, but also in influencing species persistence and ecosystem stability in response to abrupt environmental changes. This study establishes the importance of the consideration of spatial dynamics while determining optimal strategies for biological control through generalist predators.