Differences In Anti-predator Behaviour Research Articles

Lack of anti-predator recognition in a marine isopod under the threat of an invasive predatory crab

The prey naïveté hypothesis suggests that the failure of prey to recognize novel predators as a threat is caused by a lack of anti-predator adaptations. We tested this hypothesis in a unique natural setting, where the isopod Idotea balthica encountered the rapidly spreading invasive crab, Rhithropanopeus harrissii. Earlier research had indicated high mortality of the isopods during exposure to R. harrissii. The isopod exerted no co-evolutionary history with any littoral crabs and thus the strong impact could be caused by lack of pre-adaptations towards the new predator species. We tested this hypothesis by studying the anti-predator responses of the isopods with water-born cues of R. harrissii and of the native predatory fish Perca fluviatilis. Compared to control water, the isopods lowered their activity when exposed to the fish cue. Instead crab cue did not induce anti-predator behaviour. We also tested the hypothesis that mortality caused by novel predator, similar to predation by P. fluviatilis, would result in differential selection for the two sexes and contribute to the evolution of personalities. However, we found no differences in anti-predator behaviour nor in mortality between the sexes or personalities of the isopods. The outcomes reveal an interesting evolutionary scenario, where predation by a local predator induce soft selection on prey characteristics, but an invasive species cause hard selection without differentiating between prey individuals. Our study—conducted in the dawn of the population outbreak of R. harrissii—provides an excellent reference point for studies resolving the evolutionary impacts of invasive predators on naïve prey.

Hissing females of great tits (Parus major) have lower breeding success than non‐hissing individuals

AbstractAntipredator strategies vary remarkably between individuals within populations. Parents tend to take greater risks when brood value is increased. Moreover, individuals consistently differ in a whole suite of correlated behaviours that may cause distinctive responses to predators. It is likely that individual differences in antipredator behaviour may co‐vary with proxies for fitness such as reproductive success. We used a 4‐year data from wild great tits (Parus major) to test whether passive and active antipredator strategies (females with no response vs. those giving hissing calls towards a nest predator) during the incubation stage can reflect variation in breeding success. Although clutch size did not depend on hissing behaviour, the number of surviving offspring from eggs and neonates to fledglings was higher for non‐hissing than hissing birds. We conclude that females with distinct antipredator strategies can prioritize different fitness components.

Anti-predator behavior in pure and hybrid red-legged partridges

The purpose of this study was to examine the anti-predator behavior in pure red-legged partridges (Alectoris rufa) and hybrids with chukar partridges (A. rufa × (A. rufa × A. chukar)). A total of 117 birds (66 pure and 51 hybrid partridges; 74 females and 43 males) maintained in outdoor cages were used at a range of 52 to 55 wk of age. Four active fear tests were performed (novel object test, fear of humans test, emergence test, and restraint test) in order to analyze differences between pure and hybrid populations regarding the escape response type (novel object test and fear of humans test), the withdrawal distance (fear of humans test), and the reaction time (emergence test and restraint test). These variables could determine the ability of pure partridges captive to survive when released into the wild for hunting. There were no significant differences in anti-predator behavior in pure and hybrid birds, only one trend was observed in withdrawal distance (P=0.09), being greater in pure than in hybrids partridges. There was a significant difference between sexes in the response type in the novel object test (P=0.05); whereby the females came closer to the object than the males. The results of the present study indicate that active anti-predatory behavior was not associated with the genotype. However, since captivity could reduce the active anti-predator behavior, the results could be different if the wild birds that were tested had been sourced from their natural environment. Both sexes had similar active anti-predator behavior, although the males showing less approach behavior to a novel object that could be related to the sex-dimorphic behavior in natural social structure.

Active anti-predator behaviour of red titi monkeys (Plecturocebus cupreus).

Due to their inconspicuous behaviour and colouration, it has been assumed that titi monkeys' main anti-predator behaviour is passive crypsis and hiding. So far, active predator mobbing has been documented only for black-fronted titi monkeys, Callicebus nigrifrons. Here we report for the first time mobbing behaviour of red titi monkeys, Plecturocebus cupreus (previously Callicebus cupreus), as reaction to an ocelot (Leopardus pardalis) and a Boa constrictor. We also report other active anti-predator behaviours, such as alarm calling and approaching, as reactions to tayras (Eira barbara) and raptors. Our observations provide additional evidence for sex differences in anti-predator behaviour, possibly related to the evolution and maintenance of social monogamy.

Differences in anti-predator behavior and survival rate between hatchery-reared and wild grass carp (Ctenopharyngodon idellus)

Grass carp Ctenopharyngodon idellus , is the primary freshwater species produced in China. Because natural populations have shrunk in the wild, restocking programs using hatchery-reared fish have emerged. Artificial rearing could affect fish anti-predator behavior, thus decreasing their survival in the wild. The impact of artificial rearing on C. idellus 's behavior remains unknown because empirical studies are scarce. In this study, we compared anti-predator behavior and survival rate between hatchery-reared and wild C. idellus . Both hatchery-reared and wild C. idellus displayed clear anti-predator behavior when exposed to visual and odor cues of a predator. However, hatchery-reared C. idellus showed significantly lower aggregation index (reflecting shoaling behavior), inspection rate and spent less time in risky area compared to their wild counterparts. When directly exposed to predators, more hatchery-reared C. idellus were predated. This raises concerns about the efficiency of restocking programs and highlights the need to adjust artificial rearing and stocking conditions of C. idellus to produce fish that are better adapted to natural conditions.

Anti-predator behavior of squid throughout ontogeny

Squid utilize an array of complex anti-predator behaviors, which provide advantages to avoid high predation pressure. Although there are morphological and ecological differences among paralarval, juvenile and adult squid, no studies have examined how anti-predator behavior changes through life history stages in cephalopods. The goal of this study was to (1) document how anti-predator behavior in squid changes throughout ontogeny and (2) measure kinematic variables associated with squid-predator interactions to analyze the behavioral cues that trigger anti-predator responses. Anti-predator responses in squid were studied in a series of predator-prey trials using high-speed videography. All life histories of squid exhibited some escape jetting in response to predators, but paralarvae exhibited far fewer escape responses relative to juveniles and adults, and did not demonstrate posturing or inking behavior. For 65% of the interactions, paralarvae used stereotyped behaviors such as swimming in repetitive circles and spirals, rather than escape jetting, and clear body patterning during predator encounters. Inking responses in juveniles and adults were associated with significantly higher predator approach velocities and closer predator-squid distances when compared with postural responses. Older squid were more likely to demonstrate the banded body pattern, and the ‘pseudomorph’ ink shape was most commonly used. The observed differences in anti-predator behavior throughout ontogeny indicate that paralarvae rely on stereotyped swimming behaviors and translucent coloration to avoid capture, while juvenile and adults use kinematic cues of the predator approach to determine whether posturing, inking and escape jetting, or a combination of the two is the most suitable anti-predator behavior.

To flee or not to flee: characterising differentiated anti-predatory responses of two mangrove crabs

In a previous study, lethal effects of mudskipper (predator) presence were detected in the mangrove brachyuran Paracleistostoma depressum but not Haberma nanum. In addition, these effects were sex specific (male: non-significant; female: significant), suggesting differences in anti-predator behaviour. To validate this, predator avoidance strategies of the two prey species were investigated for the variables ‘species’ and ‘sex’. Ex situ responses of 40 crabs (10 per sex per species) to a mudskipper model were video-recorded. Three stimuli were given in the sequence of (A) upper torso appearance, (B) full body appearance and (C) lunge towards crab. Innate behaviour to any innocuous signal was ruled out by replacing the mudskipper model with a rectangular block. Lastly, predator recognition capabilities in terms of shape and presence of eyes were tested using five models with increasing similarity to the predator model. P. depressum and H. nanum share the same suite of observable anti-predatory behaviours: “freeze”, “sit” or “run”. However, varied strategies were observed. Instead of flight, P. depressum “sit”, and reacted most notably in the last stimulus. In contrast, H. nanum reacted early in the onset of impending threat with “run”, with diminished responses despite the increase in signal strength. Contrary to prediction, the factor ‘sex’ was not statistically significant in either species. Predator recognition capabilities were ascertained in both prey species, as behaviours were different after the predator model was replaced. H. nanum displayed greater sensitivity for threat perception by withholding the flight behaviour when uncertain. This keen sense for threat recognition coupled with its flight strategy may be key to explaining the exclusion of H. nanum from the predator’s diet.

Age matters—Experienced predation risk affects behavior and morphology of juvenile 0+ and 1+ perch

Abstract Empirical field studies have shown relations between predation risk and differences in anti-predator behavior and morphology between and within perch populations. The present study used juvenile 0+ and 1+ perch in an experimental approach to vary the factor predation risk. Predators were able to feed on perch during the experimental period in large outdoor tanks. Perceived predation risk affected the behavior and the morphology of both age classes of perch, with perch being deeper bodied and shyer with increasing intensity of predation. Changes in morphology were somewhat more pronounced in the 0+ age group, while the 1+ age group exhibited significantly stronger changes in behavior, but behaved less conform within groups. Though it remains unanswered if the predator induced these changes by selective predation, or if perch adjusted their behavior and morphology in response to the predator, the results indicate that perceived predation risk can have a fast and strong direct effect on amount and distribution of phenotypes within a prey population. The results further suggest that balance and use of anti-predator strategies on different response levels may be differential over age-classes in European perch.

Defensive Aggregation (Huddling) in Rattus Norvegicus toward Predator Odor: Individual Differences, Social Buffering Effects and Neural Correlates

Aggregation is a defensive strategy employed by many prey species in response to predatory threat. Our group has characterized defensive aggregation (huddling) in Rattus norvegicus in response to a ball of cat fur. In this situation some rats huddle less, and approach the threatening cue more than others (active vs. passive responders). The present study explored whether active responding is a stable phenotype associated with behaviors outside direct predatory encounters. The neural substrates of active and passive responding under predatory threat were explored using c-Fos immunohistochemistry. Finally, we examined whether the presence of conspecifics during predatory threat biases behavior towards active responding. Active and passive responding styles were found to be stable in individual rats across consecutive group exposures to cat fur, and were predicted by anxiety-like behavior in an open-field emergence test. Active responders displayed less conditioned fear in an environment associated with predatory threat, and had higher post-exposure intake of a weak sucrose solution (a test of “anhedonia”). Active responding was associated with: greater cat fur-induced activation of the accessory olfactory bulb, reflecting greater olfactory stimulation in rats actively approaching the fur; lowered activation of somatosensory cortex, reflecting reduced huddling with conspecifics; and reduced activation in the lateral septum. Social exposure to cat fur promoted active responding relative to individual exposure, and lowered c-Fos expression in the dorsomedial periaqueductal grey, medial caudate putamen and lateral habenula. We conclude that individual differences in anti-predator behavior appear stable traits with active responders having a more resilient phenotype. Social exposure to predatory threat has an acute buffering effect, subtly changing the neural and behavioral response towards threat and encouraging active responding. An association between active responding and lower c-Fos expression in the lateral septum is consistent with previous studies that highlight this region as an important neurobiological substrate of defensive aggregation.

Predation selects for low resting metabolic rate and consistent individual differences in anti-predator behavior in a beetle

Significant between-individual variation in resting metabolic rate (RMR) of animals is a widespread phenomenon that may have important implications for our understanding of variation in behavior and animal personality. By using wild caught mealworm beetles, Tenebrio molitor, we examined the relationships among survival rate under predator tests, individual response latency time to become immobile under the risk of predation, duration of immobility time, and RMR. Individuals with higher levels of RMR were bold, and bold individuals were found to be more exposed to the risk of bird predation. We found that RMR was positively correlated with the latency of immobility response and negatively correlated with the total duration of immobility. The correlation between behavioral responses suggests a behavioral syndrome in the anti-predator behavior of T. molitor. The results indicate that energy metabolism may be part of a syndrome that involves behavior and life history traits in animals.

Colonization of novel White Sands habitat is associated with changes in lizard anti-predator behaviour

Colonization of novel habitats is often associated with differences in ecological community composition. For small diurnal animals, differences in predator diversity and abundance can lead to behavioural shifts in the novel habitat. The eastern fence lizard Sceloporus undulatus (Bosc and Daudin, 1801) recently colonized the gypsum dunes of White Sands, a predator-poor community relative to the predator-rich community of the surrounding Chihuahuan dark-soil habitat. We used field experiments to assess S. undulatus anti-predator behaviour in white-sand versus dark-soil habitats, and used laboratory assays to determine whether behavioural differences could be mediated by hormonal regulation. Overall, we found that white-sand lizards were less vigilant but more wary than their dark-soil counterparts; it took them longer to detect a simulated predator, but once detected they were more likely to retreat from their perches than dark-soil lizards. At the proximate level, differences in anti-predator behaviour could not be explained by differences in plasma hormone levels (corticosterone and testosterone); we detected elevated corticosterone for lizards in our stress treatment relative to control treatment, but found no differences between habitats in baseline or acute corticosterone levels. At the evolutionary level, we suggest that differences in anti-predator behaviour may be explained by differences across habitats in predation environment, habituation, and/or the cost of retreating. Our study implicates changes in predator community composition in mediating ecological divergence in behaviour.

Do sex and habitat differences in antipredator behavior of Western Sandpipers Calidris mauri reflect cumulative or compensatory processes?

Individuals manage their risk of predation in different ways in different situations. We studied the use of anti-predator behavior by Western Sandpipers (Calidris mauri) at Bahia Santa Maria, northwestern Mexico, foraging in three habitats that differed in presumed predation danger. Brackish flats are completely open, making them theoretically less dangerous for feeding sandpipers than mangroves and cattail marshes, which have closer visual horizons. Western Sandpipers are sexually dimorphic, with females about 15% longer-billed and 10% heavier than males. We previously showed that male and female sandpipers differed in their habitat choice and relative body mass in ways consistent with differential responses to predation danger (Fernandez and Lank in Condor 108:547–557, 2006). Contrary to expectations, however, females were overrepresented in more dangerous habitats. Here, we examine differential usage across habitats and between the sexes of three anti-predator tactics—flock size, density within flocks, and vigilance rate—that may be used cumulatively to reinforce safety, or as trade-offs that compensate for levels of usage of each. We hypothesized, and found, that ordered differences occur among habitats, and that controlling for other factors, females were more cautious than males. For the most part, the use of these three tactics appeared to be cumulative, rather than compensatory. However, with respect to habitat use, birds appeared to compensate for the higher probability of mortality intrinsic to the use of higher-danger habitats by increasing the use of vigilance, foraging in tighter flocks, and maintaining lighter body weights (females only). Thus, both cumulative and compensatory processes operate among anti-predator tactics to determine the net level of safety and trade-off against other factors.

Inter and intra-population variation in shoaling and boldness in the zebrafish (Danio rerio).

Population differences in anti-predator behaviour have been demonstrated in several species, although less is known about the genetic basis of these traits. To determine the extent of genetic differences in boldness (defined as exploration of a novel object) and shoaling within and between zebrafish (Danio rerio) populations, and to examine the genetic basis of shoaling behaviour in general, we carried out a study that involved laboratory-raised fish derived from four wild-caught populations. Controlling for differences in rearing environment, significant inter-population differences were found in boldness but not shoaling. A larger shoaling experiment was also performed using one of the populations as the basis of a North Carolina type II breeding design (174 fish in total) to estimate heritability of shoaling tendency. A narrow-sense heritability estimate of 0.40 was obtained, with no apparent dominance effects.

Seasonal variation in coyote feeding behaviour and mortality of white-tailed deer and mule deer

Young ungulates are considered especially susceptible to predation in the initial weeks following birth. However, the timing of mortality can vary depending on the availability of alternative prey and the type of predator, and could vary depending on antipredator defenses used by prey. I used coyote (Canis latrans) scats, observations of coyote hunting behaviour, and mortality data for deer to examine seasonal variation in coyote feeding behaviour and mortality of sympatric white-tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus) fawns. Coyotes captured the vast majority of deer they consumed, forming groups that hunted deer from June through March. Coyotes were observed hunting deer most often in winter when ground squirrels were not available, and an inverse correlation between the amount of deer and ground squirrel in coyote scat reflected this relationship (rs = 0.77, P = 0.004). Fawns of both species had poor survival rates in 1994 (1 of 10 tagged whitetails survived to 1 year, none of 22 mule deer survived), improved survival rates in 1995 (33% of 15 whitetails, 25% of 24 mule deer), and most mortality appeared to be due to coyote predation. The season in which fawns of each species were most vulnerable differed. Tagged whitetail fawns had similar mortality rates in early summer, when they were less than 8 weeks old, as they did in winter, when they were 5-9 months old (35 and 37%, respectively, in 1995). In contrast, mule deer fawns had low mortality rates in early summer (4% in 1994, 17% in 1995), but high mortality rates in winter (100% in 1994, 53% in 1995). Changes in fawn:doe ratios and the examination of carcasses similarly indicated that coyotes captured more whitetails in summer and more mule deer in winter. The seasonal variation in mortality rates of the two species cannot be explained by physical prey characteristics, their relative abundance, or extrinsic factors, and may be due instead to species differences in antipredator behaviour.

Trait compensation and cospecialization in a freshwater snail: size, shape and antipredator behaviour

We examined relationships between individual differences in antipredator behaviour and prey morphological characters (size, shape) that influence prey vulnerability. Behavioural responses of Physa gyrina to chemical cues associated with predation by crayfish Orconectes rusticus, were assayed in the laboratory for 6 days over a 13-day period. Snails displayed consistent, individually repeatable responses to the predation cues, including hiding (refuge use) and substratum avoidance (crawling to the water surface or out of the water). We assessed shell morphology using morphometric techniques that isolate geometrically independent components of size and shape variation corresponding to aperture width and apertural obstruction. Previous studies indicate that large size, narrow apertures and obstructed apertures reduce morphological vulnerability to the shell-entry predation tactics used by crayfish. In the present study, small, and thus more vulnerable, prey tended to show stronger antipredator behaviour than large prey (i.e. behavioural compensation for morphological vulnerability). In contrast, behavioural and shape-based defences were positively correlated; snails with narrow apertures showed strong antipredator responses. We refer to this ‘double defence’ against predators as cospecialization. With either compensation or cospecialization, suites of correlated behavioural or morphological traits must be studied in tandem to understand the adaptive value of prey responses to predators.

Inter-specific variation in anti-predator behavior in sympatric species of kangaroo rat

Kangaroo rats, Dipodomys, occupy desert habitats with little cover and thus are under high predation risk from diverse predators. The behavior used to assess predation risk or to escape capture is unknown. We therefore compared anti-predator behavior of two sympatric species of kangaroo rat of different sizes, D. merriami and D. spectabilis. We first examined whether kangaroo rats use olfaction as a first line of defense against snake predation and tested the rats for their responses to scent extracted from two species of snake that live sympatrically with the kangaroo rats, the Mojave rattlesnake (Crotalus scutulatus) and the gopher snake (Pitophis melanoleucus). We also tested for species differences in anti-predator behavior through 15-min interactions between the kangaroo rats and free-moving gopher snakes. We found that D. spectabilis actively approached the scent of both rattlesnakes and gopher snakes more than controls of vegetable oil and evaporated solvent (Fig. 1). In contrast, D. merriami did not differentiate snake odors from controls in the experimental arena, but they sniffed the sand where a free-moving snake had passed more than D. spectabilis. Both species successfully avoided predation in encounters with live snakes. Although total numbers of approaches and withdrawals were similar (Fig. 2), D. spectabilis spent significantly more time within striking distance of the snake than D. merriami. D. spectabilis approached the head of the snake in 93% of its approaches and often engaged in nose to snout contact with the snake. If the snake struck, D. spectabilis jumped directly backward to avoid a strike and footdrummed at a safe distance. In contrast, D. merriami oriented to the snake more than D. spectabilis, but approached the head in only 41% of the approaches and rarely engaged in nose-to-snout contact. The snakes struck, hissed and decreased predatory approaches with D. spectabilis but not with D. merriami (Fig. 3). These results show that kangaroo rats can behaviorally influence the risk of being preyed on by snakes. The two species differ, however, in how they react to snakes. The larger D. spectabilis confronts snakes while the smaller D. merriami monitors snakes from a safe distance and avoids them.

Locomotion and antipredator behaviour in three species of semi-aquatic snakes

For temperate-zone ectotherms, a potential cost of an aquatic lifestyle may be impaired locomotor performance, due to rapid cooling of the body when in cold water. Contrary to the hypothesis that more-aquatic species should be better adapted for locomotion at low temperatures, the decline in swimming performance with temperature was similar for three species of snakes (the northern water snake (Nerodia sipedon), eastern ribbon snake (Thamnophis sauritus) and common garter snake (Thamnophis sirtalis)) that varied in their association with aquatic habitats. The effect of temperature on antipredator behaviour was also similar for the three species; at lower body temperatures, snakes relied more on alternative defensive behaviours. However, antipredator behaviour was used less by water snakes than by garter and ribbon snakes. Except for the smallest individuals, all snakes crawled more slowly than they swam, and the difference in performance was greatest for the largest snakes. When crawling, all three species relied more on alternative defensive behaviours than when swimming. In the field, water snakes fled at greater distances from human "predators" than did garter and ribbon snakes, which tended to rely on crypsis. The greater dependence on flight as the primary antipredator behaviour by water snakes, and on other tactics such as crypsis by garter and ribbon snakes, does not conform to the generalization that a species' antipredator behaviour is related to its characteristic dorsal pigmentation pattern. Species differences in antipredator behaviour appear to be more strongly related to habitat use.

Consistency of individual differences in anti-predator behaviour and colour pattern in the garter snake, Thamnophis ordinoides

Abstract. The importance of individual variation in behaviour as both an ingredient and a consequence of natural selection has only recently received much attention from empirical researchers. The manner in which individual differences change ontogenetically and how such changes may affect an individual's fitness are still largely unknown. This study investigates the development of anti-predator behaviour and colour pattern in the northwestern garter snake, Thamnophis ordinoides, during the first 2 years of life under laboratory conditions and in the wild. Several aspects of escape behaviour were examined, including the maximum sprint speed, the distance crawled until an anti-predator display was performed (stamina), and the tendency to perform stereotypical evasive manoeuvres during flight (reversals). These aspects of escape behaviour and the stripedness of colour pattern showed significant changes during this time, although the specific changes varied between laboratory and field conditions. Many of the developmental changes were associated with growth. Traits generally showed strong positive correlations across ages, both in the laboratory and in the field. Individual differences in anti-predator behaviour and colour pattern in this species of snake appear to be relatively consistent throughout the first 2 years of life. Using neonate trait values to estimate selection during this time will provide accurate representations of the form of selection because the ontogenetic trajectories of individuals are parallel.

Sexual Differences in Antipredator Behavior of Breeding American Avocets and Black-Necked Stilts

Journal Article Sexual Differences in Antipredator Behavior of Breeding American Avocets and Black-Necked Stilts Get access Tex A. Sordahl Tex A. Sordahl Department of Biology, Luther College, Decorah, IA 52101 Search for other works by this author on: Oxford Academic Google Scholar The Condor, Volume 92, Issue 2, 1 May 1990, Pages 530–532, https://doi.org/10.2307/1368255 Published: 01 May 1990 Article history Accepted: 02 January 1989 Received: 18 August 1989 Published: 01 May 1990

Effects of body size, sibship, and tail injury on the susceptibility of tadpoles to dragonfly predation

The effect of tadpole body size, sibship, and tail injury on the survival of treefrog tadpoles (Hyla chrysoscelis) in the presence of dragonfly larvae (Tramea lacerata) was examined in a three-way factorial experiment. Tadpole body size had a dramatic effect on survival; large tadpoles had higher survival than medium-sized or small tadpoles. The presence of tail injury simulating an unsuccessful predation attempt significantly reduced survival. Survival of control tadpoles without tail injury in the presence of a predator was almost twice as high as that of tadpoles with 75% tail loss. Tadpole sibship had no effect on survival and indicated that genetic differences in antipredator behavior or production of alarm substances and allelochemicals, independent of body size, were not apparent. There were no significant interactions between tail injury and body size or tail injury and sibship. These results indicate that increasing body size is an effective mechanism for reducing predation and that injury from an unsuccessful predation attempt reduces subsequent survival by increasing the risk of future predation.