scholarly journals Freezing or death feigning? Beetles selected for long death-feigning duration showed other tactics against different predators

2021 ◽  
Author(s):  
Masaya Asakura ◽  
Kentarou Matsumura ◽  
Ryo Ishihara ◽  
Takahisa Miyatake
Keyword(s):  
Prey Density ◽  
Prey Species ◽  
Antipredator Behavior ◽  
Freezing Behavior ◽  
Starvation Period ◽  
Feeding Rates ◽  
Death Feigning ◽  
Avoidance Behaviors ◽  
Long Duration ◽  
Independent Behaviors

Prey evolve anti-predator strategies against multiple enemies in nature. We examined how a prey species adopts different predation avoidance tactics against pursuit or sit-and-wait predators. As prey, we used two strains of Tribolium beetles artificially selected for short or long duration of death feigning. The results showed that, as prey, the short strains displayed the same behavior, escaping, against the two types of predators. On the other hand, death feigning is known to be effective for evading a jumping spider in the case of the long strains, while the present study showed that the long strain beetles used freezing behavior against a sit-and-wait type predator A. venator in this study. The short strain beetles were more easily orientated by predators and suffered a higher rate of predation than the long strains. The time to predation was also shorter in the short strains compared to the long strains. When the predator was starved, even the long strains were preyed upon when the predator was orientated toward the prey, suggesting the starvation period, i.e., prey density, is an important factor for antipredator behavior. Traditionally, death feigning has been thought to be the last resort in a series of anti-predator avoidance behaviors. However, our results showed that freezing and death feigning were not parts of a series of behavior, but independent behaviors against different predators, at least for these beetles. The results also suggest that the differences in feeding rates between the strains could be explained by differences in activity among the strains.

scholarly journals Effects of dead conspecifics, hunger states, and seasons on the foraging behavior of the purple urchin Heliocidaris crassispina

2020 ◽  
Author(s):  
Dominic Franco C. Belleza ◽  
Yuuki Kawabata ◽  
Tatsuki Toda ◽  
Gregory N. Nishihara
Keyword(s):  
Foraging Behavior ◽  
Field Experiments ◽  
Prey Species ◽  
Sea Urchins ◽  
Time Lapse ◽  
Aquatic Environments ◽  
Feeding Rates ◽  
Avoidance Behaviors ◽  
Time Lapse Photography

ABSTRACTTrophic cascades exerts a powerful effect between predator and prey relationships in an ecosystem. In aquatic environments, the signals associated with predators and predation are used by prey as a cue to avoid encountering predators when foraging for food. These cues are powerful enough to control prey populations and indirectly protect primary producers. We evaluated the effects of cues associated with predation on the purple urchin, Heliocidaris crassispina and examined effects of hunger state and season using time-lapse photography, we conducted a series of manipulative and in situ behavior experiments to determine foraging behavior patterns which demonstrate behavior modification. The results suggest that starved urchins were less sensitive to predation cues when compared to normally fed urchins. Field experiments indicated that 70% of fed urchins fled when exposed to a predation cue (presence of a dead urchin), whereas all starved urchins remained regardless of the cue, supporting the results from the laboratory using the dead urchin and algae treatment cues. Sea urchin activity and feeding rates were lower in winter-spring than in summer-autumn. We suggest that hunger state has a large influence over the behavioral-response of sea urchins, while also being affected by season due to metabolic control. In general, starvation overrides predator avoidance behaviors and exposes prey species to higher risks of predation.

scholarly journals Factors Affecting Thanatosis in the Braconid Parasitoid Wasp Heterospilus prosopidis

Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 48
Author(s):  
Mio Amemiya ◽  
Kôji Sasakawa
Keyword(s):  
Life History ◽  
Antipredator Behavior ◽  
Parasitoid Wasp ◽  
Ecological Perspective ◽  
Background Color ◽  
Factors Affecting ◽  
Death Feigning ◽  
Heterospilus Prosopidis ◽  
History Of

Thanatosis, also called death feigning, is often an antipredator behavior. In insects, it has been reported from species of various orders, but knowledge of this behavior in Hymenoptera is insufficient. This study examined the effects of sex, age (0 or 2 days old), temperature (18 or 25 °C), and background color (white, green, or brown) on thanatosis in the braconid parasitoid wasp Heterospilus prosopidis. Thanatosis was more frequent in 0-d-old individuals and in females at 18 °C. The duration of thanatosis was longer in females, but this effect of sex was weaker at 18 °C and in 0-d-old individuals. The background color affected neither the frequency nor duration. These results were compared with reports for other insects and predictions based on the life history of this species, and are discussed from an ecological perspective.

scholarly journals What drives interaction strengths in complex food webs? A test with feeding rates of a generalist stream predator

2018 ◽  
Author(s):  
Daniel L. Preston ◽  
Jeremy S. Henderson ◽  
Landon P. Falke ◽  
Leah M. Segui ◽  
Tamara J. Layden ◽  
...  
Keyword(s):  
Food Webs ◽  
Body Mass ◽  
Prey Density ◽  
Scaling Laws ◽  
Community Dynamics ◽  
Abiotic Factors ◽  
Interaction Strength ◽  
Feeding Rates ◽  
Predator Prey ◽  
Mass Ratios

AbstractDescribing the mechanisms that drive variation in species interaction strengths is central to understanding, predicting, and managing community dynamics. Multiple factors have been linked to trophic interaction strength variation, including species densities, species traits, and abiotic factors. Yet most empirical tests of the relative roles of multiple mechanisms that drive variation have been limited to simplified experiments that may diverge from the dynamics of natural food webs. Here, we used a field-based observational approach to quantify the roles of prey density, predator density, predator-prey body-mass ratios, prey identity, and abiotic factors in driving variation in feeding rates of reticulate sculpin (Cottus perplexus). We combined data on over 6,000 predator-prey observations with prey identification time functions to estimate 289 prey-specific feeding rates at nine stream sites in Oregon. Feeding rates on 57 prey types showed an approximately log-normal distribution, with few strong and many weak interactions. Model selection indicated that prey density, followed by prey identity, were the two most important predictors of prey-specific sculpin feeding rates. Feeding rates showed a positive, accelerating relationship with prey density that was inconsistent with predator saturation predicted by current functional response models. Feeding rates also exhibited four orders-of-magnitude in variation across prey taxonomic orders, with the lowest feeding rates observed on prey with significant anti-predator defenses. Body-mass ratios were the third most important predictor variable, showing a hump-shaped relationship with the highest feeding rates at intermediate ratios. Sculpin density was negatively correlated with feeding rates, consistent with the presence of intraspecific predator interference. Our results highlight how multiple co-occurring drivers shape trophic interactions in nature and underscore ways in which simplified experiments or reliance on scaling laws alone may lead to biased inferences about the structure and dynamics of species-rich food webs.

scholarly journals Observations of Interactions between Puma, Puma concolor, and Introduced European Red Deer, Cervus elaphus, in Patagonia

2004 ◽  
Vol 118 (1) ◽  
pp. 132 ◽  
Author(s):  
Werner T. Flueck
Keyword(s):  
Cervus Elaphus ◽  
Red Deer ◽  
Prey Species ◽  
Puma Concolor ◽  
Antipredator Behavior ◽  
Generalist Predator ◽  
Considerable Time ◽  
Direct Observations ◽  
Natural Predation ◽  
Large Predators

Direct observations of interactions between native Puma (Puma concolor) and introduced European Red Deer (Cervus elaphus) in Patagonia are discussed with respect to the absence of evolutionary sympatry. Although the founding stock of European Red Deer had been lacking natural predation pressure for considerable time due to the previous extinction of large predators, these observations suggested that inherent antipredator behavior of European Red Deer toward this novel predator, once detected, was effective and may partially explain the success of European Red Deer as an invasive species. Puma behavior supported the view that they are a generalist predator which opportunistically utilizes new prey species like European Red Deer.

Activity Differences influencing Food Selection in the Marine Fish Pomatoschistus microps

1986 ◽  
Vol 43 (1) ◽  
pp. 223-227 ◽  
Author(s):  
Carin Magnhagen
Keyword(s):  
Prey Density ◽  
Laboratory Experiments ◽  
Prey Species ◽  
Food Selection ◽  
Reproductive Period ◽  
Food Selectivity ◽  
Encounter Rate ◽  
Low Density ◽  
Low Activity ◽  
Prey Items

Diets of female and male Pomatoschistus microps during the reproductive period (May–July) differed. Males ate less but used a wider range of prey species than did females. While males guard the eggs and therefore are tied to a nest during the breeding season, females have a higher mobility which leads to a higher prey encounter rate and hence a higher food selectivity than in males. After reproduction the differences between the sexes in food intake and diet disappeared. In laboratory experiments the fish were less active in aquaria with a high prey density than in those with a low density. A decrease in food selectivity with an increasing prey density can thus be due to a decrease in the activity of the fish. At a high prey density, P. microps may benefit from having a low activity and taking unselectively the prey items in its vicinity. The advantages could be reduced detectability by predators and decreased energy expenditure due to locomotion.

Frequency-dependent selection by predators

1988 ◽  
Vol 319 (1196) ◽  
pp. 485-503 ◽  
Keyword(s):  
Prey Density ◽  
Prey Species ◽  
Colour Pattern ◽  
Supporting Evidence ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Apostatic Selection ◽  
High Selection ◽  
Very High

Sometimes predators tend to concentrate on common varieties of prey and overlook rare ones. Within prey species, this could result in the fitness of each variety being inversely related to its frequency in the population. Such frequency-dependent or ‘apostatic’ selection by predators hunting by sight could maintain polymorphism for colour pattern, and much of the supporting evidence for this idea has come from work on birds and artificial prey. These and other studies have shown that the strength of the observed selection is affected by prey density, palatability, coloration and conspicuousness. When the prey density is very high, selection becomes ‘antiapostatic’: predators preferentially remove rare prey. There is still much to be learned about frequency-dependent selection by predators on artificial prey: work on natural polymorphic prey has hardly begun.

Food web interaction strength distributions are conserved by greater variation between than within predator-prey pairs

2018 ◽  
Author(s):  
Daniel L. Preston ◽  
Landon P. Falke ◽  
Jeremy S. Henderson ◽  
Mark Novak
Keyword(s):  
Food Webs ◽  
Prey Density ◽  
Interaction Strength ◽  
Feeding Rates ◽  
Predator Prey ◽  
Space And Time ◽  
Individual Interaction ◽  
Species Pairs ◽  
The Mean ◽  
Strength Distributions

AbstractSpecies interactions in food webs are usually recognized as dynamic, varying across species, space and time due to biotic and abiotic drivers. Yet food webs also show emergent properties that appear consistent, such as a skewed frequency distribution of interaction strengths (many weak, few strong). Reconciling these two properties requires an understanding of the variation in pairwise interaction strengths and its underlying mechanisms. We estimated stream sculpin feeding rates in three seasons at nine sites in Oregon to examine variation in trophic interaction strengths both across and within predator-prey pairs. We considered predator and prey densities, prey body mass, and abiotic factors as putative drivers of within-pair variation over space and time. We hypothesized that consistently skewed interaction strength distributions could result if individual interaction strengths show relatively little variation, or alternatively, if interaction strengths vary but shift in ways that conserve their overall frequency distribution. We show that feeding rate distributions remained consistently and positively skewed across all sites and seasons. The mean coefficient of variation in feeding rates within each of 25 focal species pairs across surveys was less than half the mean coefficient of variation seen across species pairs within a given survey. The rank order of feeding rates also remained relatively conserved across streams, seasons and individual surveys. On average, feeding rates on each prey taxon nonetheless varied by a hundredfold across surveys, with some feeding rates showing more variation in space and others in time. For most species pairs, feeding rates increased with prey density and decreased with high stream flows and low water temperatures. For nearly half of all species pairs, factors other than prey density explained the most variation, indicating that the strength of density dependence in feeding rates can vary greatly among a generalist predator’s prey species. Our findings show that although individual interaction strengths exhibit considerable variation in space and time, they can nonetheless remain relatively consistent, and thus predictable, compared to the even larger variation that occurs across species pairs. These insights help reconcile how the skewed nature of interaction strength distributions can persist in highly dynamic food webs.

Effect of light, prey density, and prey type on the feeding rates of Hemimysis anomala

Hydrobiologia ◽  
2013 ◽  
Vol 720 (1) ◽  
pp. 101-110 ◽  
Author(s):  
Kathleen E. Halpin ◽  
Brent T. Boscarino ◽  
Lars G. Rudstam ◽  
Maureen G. Walsh ◽  
Brian F. Lantry
Keyword(s):  
Prey Density ◽  
Prey Type ◽  
Feeding Rates ◽  
Hemimysis Anomala ◽  
Effect Of Light

THE INFLUENCE OF PREY DENSITY, RELATIVE HUMIDITY, AND STARVATION ON THE PREDACIOUS BEHAVIOR OF PHYTOSEIULUS PERSIMILIS ATHIAS-HENRIOT (ACARINA: PHYTOSEIIDAE)

1966 ◽  
Vol 44 (3) ◽  
pp. 483-491 ◽  
Author(s):  
Hans Mori ◽  
D. A. Chant
Keyword(s):  
Relative Humidity ◽  
Functional Response ◽  
Tetranychus Urticae ◽  
Prey Density ◽  
Prey Species ◽  
Phytoseiulus Persimilis ◽  
Predacious Mite ◽  
Egg Consumption ◽  
Tetranychus Urticae Koch

The functional response of the predacious mite Phytoseiulus persimilis Athias-Henriot was tested at various densities of Tetranychus urticae (Koch), a prey species, and at several levels of humidity and hunger. The consumption of adult prey per predator rose at first with increasing prey density, but significantly decreased at high densities. This phenomenon was caused by an increase in abandonment of captures resulting from disturbance by other prey at high prey densities. Egg consumption by the predator increased with prey density.Prey consumption was greater at low than at high humidities. A significant increase in the rate of repeat feeding was found at higher levels of predator hunger, but the differences in consumption of prey between the three levels of hunger were not significant.

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