scholarly journals Predator olfactory cues generate a foraging–predation trade-off through prey apprehension

2016 ◽  
Vol 3 (2) ◽  
pp. 150537 ◽  
Author(s):  
Adam M. Siepielski ◽  
Eric Fallon ◽  
Kate Boersma

Most animals are faced with the challenge of securing food under the risk of predation. This frequently generates a trade-off whereby animals respond to predator cues with reduced movement to avoid predation at the direct cost of reduced foraging success. However, predators may also cause prey to be apprehensive in their foraging activities, which would generate an indirect ‘apprehension cost’. Apprehension arises when a forager redirects attention from foraging tasks to predator detection and incurs a cost from such multi-tasking, because the forager ends up making more mistakes in its foraging tasks as a result. Here, we test this apprehension cost hypothesis and show that damselflies miss a greater proportion of their prey during foraging bouts in response to both olfactory cues produced by conspecifics that have only viewed a fish predator and olfactory cues produced directly by fish. This reduced feeding efficiency is in addition to the stereotypical anti-predator response of reduced activity, which we also observed. These results show that costs associated with anti-predator responses not only arise through behavioural alterations that reduce the risk of predation, but also from the indirect costs of apprehension and multi-tasking that can reduce feeding efficiency under the threat of predation.

2019 ◽  
Vol 286 (1907) ◽  
pp. 20190826 ◽  
Author(s):  
Jesse Balaban-Feld ◽  
William A. Mitchell ◽  
Burt P. Kotler ◽  
Sundararaj Vijayan ◽  
Lotan T. Tov Elem ◽  
...  

Refuges offer prey animals protection from predation, but increased time spent hiding can reduce foraging opportunities. Within social groups, individuals vary in their refuge use and willingness to forage in the presence of a predator. Here, we examine the relative foraging benefits and mortality costs associated with individual refuge use and foraging behaviour within groups of goldfish ( Carassius auratus ) under predation risk from an avian predator (little egret— Egretta garzetta ). We assessed individual order of emergence from the refuge and participation over 15 group foraging outings, and assigned each fish a daily outing index score. The individual fish that emerged from the refuge earlier than the other group members and that participated in more outings received high outing index scores and consumed more food compared with fish that tended to emerge in posterior positions and participate in fewer outings. However, individual fish that attained high outing index scores suffered a higher risk of predation. Furthermore, the amount of time the egret spent at the pool affected group foraging behaviour: as predation risk increased, groups of fish consumed significantly less food. Our results exemplify the trade-off between foraging success and safety from predation that prey species regularly experience.


The Auk ◽  
1986 ◽  
Vol 103 (1) ◽  
pp. 14-22 ◽  
Author(s):  
Yutaka Watanuki

Abstract Diurnal activity patterns of Leach's Storm-Petrels (Oceanodroma leucorhoa) and Slaty-backed Gulls (Larus schistisagus) were investigated. The petrels reduced activity in moonlight in May and June when the predation rate by gulls was relatively high. Petrel activity levels were inversely correlated with light intensities and the corresponding risk of predation by the gull. This suggests that nocturnal activity and moonlight avoidance by the petrel in its colony are an effective defense against diurnal predators. Activity synchronization of the petrel was most marked during the full moon, further supporting the predator-avoidance hypothesis.


Behaviour ◽  
1997 ◽  
Vol 134 (5-6) ◽  
pp. 463-475 ◽  
Author(s):  
Benoist Schaal ◽  
Frédéric Lévy ◽  
Pierre Orgeur ◽  
Richard H. Porter ◽  
Raymond Nowak

AbstractA series of experiments was conducted to elucidate the stimuli that mediate twin/non-twin discrimination among 2-3 week old lambs. After being separated from their mother, lambs emitted more distress bleats when tested in isolation than when penned with their familiar twin, but separated from that lamb by a barrier of evenly spaced wood bars. A similar, albeit weaker effect was found for paired vs isolated non-twins. Twins separated by the barrier bleated less than did the non-twins in this condition. In contrast, bleat rates did not differ when subject lambs were tested in the presence of their twin vs a non-twin on the opposite side of a solid opaque barrier. Intact lambs in a final experiment bleated less when tested with their tranquillized twin vs a tranquillized non-twin agemate. The tranquillized stimulus lambs displayed atypical behavior patterns, including suppression of bleats and reduced activity levels. These data indicate that full bodily contact, vocalizations or normal behavioral patterns are not necessary for lambs to be recognized by their twin. Rather, twin/non-twin discrimination (and the effect of a twin on the rate of distress bleating) appears to depend upon visual, and possibly olfactory cues.


1988 ◽  
Vol 66 (6) ◽  
pp. 1249-1253 ◽  
Author(s):  
Marc Naud ◽  
Pierre Magnan

Northern redbelly dace, Phoxinus eos (Cope), exhibit diel onshore–offshore migrations in a small oligotrophic Quebec lake. The fish swim in shoals in the littoral zone during the day, migrate to the pelagic zone at sunset, where the shoals break up into single fish, and then go back to the littoral zone at sunrise. Dace eat mainly two cladocerans, Daphnia and Holopedium. Zooplankton sampling indicated that Daphnia were significantly more abundant in the pelagic zone than in the littoral zone, and Holopedium were rarely found in the littoral zone. Dace showed a significant preference for a dense cover habitat over a sparse cover habitat in the littoral zone during the day. Our results support the hypothesis that dace migrate to the pelagic zone at sunset to increase their feeding efficiency on zooplankton. The foraging benefits of remaining in the offshore zone may be offset by increased risk of predation by brook charr, Salvelinus fontinalis (Mitchill), during the daylight hours, thus resulting in diel onshore–offshore migrations.


2000 ◽  
Vol 48 (2) ◽  
pp. 155 ◽  
Author(s):  
Eve McDonald-Madden ◽  
Lian K. Akers ◽  
Deena J. Brenner ◽  
Sarah Howell ◽  
Blair W. Patullo ◽  
...  

Many eutherian mammals adjust their foraging behaviour according to the presence or threat of predators. Here, we examine experimentally whether an urban population of brushtail possums, Trichosurus vulpecula, similarly adjust their foraging behaviour. Our field experiments manipulated the quantity of food items in artificial feeders placed at different distances from trees. These experiments showed that the possums remained longer at feeders placed far from the trees, but their foraging behaviour did not change with the initial amount of food. The scanning behaviour of possums did not simply increase with distance from the trees, as predicted from studies of other vertebrates. Nevertheless, the number of physical conflicts between individuals increased as the amount of available food decreased. These data suggest that the changes in the foraging behaviour of the possums in this population do not reflect a simple trade-off between foraging efficiency and the risk of predation or competition.


1993 ◽  
Vol 50 (2) ◽  
pp. 241-246 ◽  
Author(s):  
Robert S. Gregory

The effect of turbidity on the predator avoidance behaviour of juvenile chinook salmon (Oncorhynchus tshawytscha) was determined in controlled laboratory experiments. Bird and fish models were used to simulate predator risk. In the absence of risk, juvenile chinook were distributed randomly within an experimental arena in turbid conditions (≈23 NTU), but in clear conditions (<1 NTU) they associated with the bottom. When introduced to bird and fish predator models, the chinook altered their distribution and occupied deeper parts of the arena regardless of turbidity level. However, their responses in turbid conditions were less marked and of shorter duration. Turbidity apparently reduced the perceived risk of predation in juvenile chinook.


2008 ◽  
Vol 4 (4) ◽  
pp. 392-394 ◽  
Author(s):  
Zoe E Squires ◽  
Paul C.E Bailey ◽  
Richard D Reina ◽  
Bob B.M Wong

Human-induced environmental change is occurring at an unprecedented rate and scale. Many freshwater habitats, in particular, have been degraded as a result of increased salinity. Little is known about the effects of anthropogenic salinization on freshwater organisms, especially at sublethal concentrations, where subtle behavioural changes can have potentially drastic fitness consequences. Using a species of Australian frog ( Litoria ewingii ), we experimentally examined the effects of salinization on tadpole behaviour and their vulnerability to a predatory dragonfly nymph ( Hemianax papuensis ). We found that tadpoles exposed to an ecologically relevant concentration of salt (15% seawater, SW) were less active than those in our freshwater control (0.4% SW). Tadpoles in elevated salinity also experienced a higher risk of predation, even though the strike rate of the predator did not differ between salt and freshwater treatments. In a separate experiment testing the burst-speed performance of tadpoles, we found that tadpoles in saltwater were slower than those in freshwater. Thus, it would appear that salt compromised the anti-predator response of tadpoles and made them more susceptible to being captured. Our results demonstrate that environmentally relevant concentrations of aquatic contaminants can, even at sublethal levels, severely undermine the fitness of exposed organisms.


1999 ◽  
Vol 47 (1) ◽  
pp. 29 ◽  
Author(s):  
Robbie J. Henderson ◽  
Mark A. Elgar

Many animals adjust their behaviour according to the presence or threat of predators. However, the foraging behaviour of sit-and-wait predators is typically thought to be inflexible to short-term changes in the environment. Here we investigate the foraging behaviour of the nocturnally active black house spider, Badumna insignis. Experiments in which different kinds of prey were introduced into the web during either the day or night indicated that the foraging success of Badumna is compromised by behaviours that reduce the risk of predation. During the day, spiders generally remain within the retreat and take longer to reach the prey, which may reduce their foraging success. In contrast, spiders sat exposed at the edge of the retreat at night, and from here could usually reach the prey before it escaped. The spiders were able to escape from a model predator more rapidly if they were at the edge of the retreat than if they were out on the web. These data suggest that the costs to Badumna of reduced fecundity through poor foraging efficiency may be outweighed by the benefits of reducing the risk of predation


2019 ◽  
Vol 286 (1916) ◽  
pp. 20192347 ◽  
Author(s):  
Anne A. Innes-Gold ◽  
Nicholas Y. Zuczek ◽  
Justin C. Touchon

Like many animals, tadpoles often produce different, predator-specific phenotypes when exposed to risk of predation. It is generally assumed that such plasticity enhances survival in the presence of the predator and is costly elsewhere, but evidence remains surprisingly scarce. We measured (1) the survival trade-off of opposing phenotypes developed by Dendropsophus ebraccatus tadpoles when exposed to different predators and (2) which specific aspects of morphology drive any potential survival benefit or cost. Tadpoles developed predator-specific phenotypes after being reared with caged fish or dragonfly predators for two weeks. In 24 h predation trials with either a fish or a dragonfly, survival was highest in the groups with their matched predator, and lowest among with those the mismatched predator, with predator-naive controls being relatively intermediate. Then, using a large group of phenotypically variable predator-naive tadpoles, we found that increased survival rates are directly related to the morphological changes that are induced by each predator. This demonstrates that induced phenotypes are indeed adaptive and the product of natural selection. Furthermore, our data provide clear evidence of an environmental cost for phenotypic plasticity in a heterogeneous environment. Such costs are fundamental for understanding the evolution and maintenance of inducible phenotypes.


1995 ◽  
Vol 73 (5) ◽  
pp. 955-960 ◽  
Author(s):  
Douglas P. Chivers ◽  
Grant E. Brown ◽  
R. Jan F. Smith

We exposed groups of four fathead minnows (Pimephales promelas) that were familiar to each other and had been taken from naturally occurring shoals, and groups of four fish unfamiliar to each other, taken from four separate shoals, to either chemical stimuli from pike or a model fish predator (northern pike, Esox lucius). In response to both chemical stimuli from pike and the pike model, minnows from familiar groups showed greater shoal cohesion than those from unfamiliar groups. Tighter shoal cohesion should result in a higher probability of surviving an encounter with a predator. Fish in familiar shoals also exhibited more dashing, a known antipredator response, than those in unfamiliar groups. In addition, groups of familiar fish showed less freezing behaviour than unfamiliar groups. In response to the model fish predator, familiar shoals exhibited a greater number of predator inspections, and the number of inspectors per inspection visit was greater, than those in unfamiliar groups. These results suggest that preferential shoaling with familiar conspecifics leads to an increase in cooperative antipredator behaviour and may thereby lower a minnow's risk of predation.


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