scholarly journals Ocean warming increases availability of crustacean prey via riskier behavior

2019 ◽  
Vol 31 (2) ◽  
pp. 287-291 ◽  
Author(s):  
Emma Marangon ◽  
Silvan U Goldenberg ◽  
Ivan Nagelkerken

Abstract Marine prey and predators will respond to future climate through physiological and behavioral adjustments. However, our understanding of how such direct effects may shift the outcome of predator–prey interactions is still limited. Here, we investigate the effects of ocean warming and acidification on foraging behavior and biomass of a common prey (shrimps, Palaemon spp.) tested in large mesocosms harboring natural resources and habitats. Acidification did not alter foraging behavior in prey. Under warming, however, prey showed riskier behavior by foraging more actively and for longer time periods, even in the presence of a live predator. No effects of longer-term exposure to climate stressors were detected on prey biomass. Our findings suggest that ocean warming may increase the availability of some prey to predators via a behavioral pathway (i.e., increased risk-taking by prey), likely by elevating metabolic demand of prey species.

Author(s):  
Xavier Lambin

The dependency of mustelid demographic rates on prey abundance has the potential to cause a strong coupling between predator-prey populations. Data on mustelid dynamics show that such strong reciprocal interactions only materialise in some restricted conditions. Bite-size mustelid predators searching for scarce, depleted prey expose themselves to increased risk of predation by larger predators of small mammal that are themselves searching for similar prey species. As voles or muskrats become scarcer, weasels and mink searching for prey over larger areas become increasingly exposed to intra-guild predation, unless they operate in a habitat refuge such as the sub-nivean space. Where larger predators are sufficiently abundant or exert year-round predation pressure on small mustelids, their impact on mustelids may impose biological barrier to dispersal that are sufficient to weaken the coupling between small mustelids and their rodent prey, and thus impose a degree of top down limitation on mustelids.


Author(s):  
Brian J. Wilsey

Top predators have effects that can ‘cascade down’ on lower trophic levels. Because of this cascading effect, it matters how many trophic levels are present. Predators are either ‘sit and wait’ or ‘active’. Wolves are top predators in temperate grasslands and can alter species composition of smaller-sized predators, prey, and woody and herbaceous plant species, either through direct effects or indirect effects (‘Ecology of Fear’). In human derived grasslands, invertebrate predators fill a similar ecological role as wolves. Migrating populations of herbivores tend to be more limited by food than non-migratory populations. The phenology and synchrony of births vary among prey species in a way that is consistent with an adaptation to predation. Precocious species have highly synchronous birth dates to satiate predators. Non-precocious species (‘hiders’) have asynchronous births. Results from studies that manipulate both predators and food support the hypothesis that bottom-up and top-down effects interact.


Author(s):  
Shawna Bellamy ◽  
Barry W Alto

Abstract Non-lethal predator-prey interactions during the immature stages can cause significant changes to mosquito life history traits and their ability to transmit pathogens as adults. Treatment manipulations using mosquitoes Aedes aegypti (L.) and Toxoryhnchites rutilus (Coquillett) were performed during the immature stages to explore the potential impacts of non-lethal interactions on adult susceptibility to infection, disseminated infection and saliva infection of Ae. aegypti following ingestion of Zika virus-infected blood. Treatments inducing density reduction resulted in reduced development time and survivorship to adulthood. However, effects of treatment did not alter infection, dissemination, or saliva infection. These observations indicate that, while non-lethal predation may impact some traits that influence population dynamics and transmission of pathogens, there were no direct effects on mosquito-arbovirus interactions.


1986 ◽  
Vol 64 (11) ◽  
pp. 2624-2633 ◽  
Author(s):  
Peter F. Major ◽  
Lawrence M. Dill ◽  
David M. Eaves

Three-dimensional interactions between grouped aerial predators (frontal discs of aircraft engines), either linearly arrayed or clustered, and flocks of small birds were studied using interactive computer simulation techniques. Each predator modelled was orders of magnitude larger than an individual prey, but the prey flock was larger than each predator. Expected numbers of individual prey captured from flocks were determined for various predator speeds and trajectories, flock–predator initial distances and angles, and flock sizes, shapes, densities, trajectories, and speeds. Generally, larger predators and clustered predators caught more prey. The simulation techniques employed in this study may also prove useful in studies of predator–prey interactions between schools or swarms of small aquatic prey species and their much larger vertebrate predators, such as mysticete cetaceans.The study also provides a method to study problems associated with turbine aircraft engine damage caused by the ingestion of small flocking birds, as well as net sampling of organisms in open aquatic environments.


2010 ◽  
Vol 2010 ◽  
pp. 1-12
Author(s):  
Xiangzeng Kong ◽  
Zhiqin Chen ◽  
Li Xu ◽  
Wensheng Yang

We propose and study the permanence of the following periodic Holling III predator-prey system with stage structure for prey and both two predators which consume immature prey. Sufficient and necessary conditions which guarantee the predator and the prey species to be permanent are obtained.


2008 ◽  
Vol 2008 ◽  
pp. 1-15 ◽  
Author(s):  
Can-Yun Huang ◽  
Min Zhao ◽  
Hai-Feng Huo

A stage-structured three-species predator-prey model with Beddington-DeAngelis and Holling II functional response is introduced. Based on the comparison theorem, sufficient and necessary conditions which guarantee the predator and the prey species to be permanent are obtained. An example is also presented to illustrate our main results.


2021 ◽  
Author(s):  
Cai Xing ◽  
Tingting Liu ◽  
Xi Zhang

It has been well documented that men are much more likely to provide heroic assistance in emergencies (Johnson, 1996). However, such heroic rescue disobeys the theory of evolution (Darwin, 1871). Studies investigated charitable donations suggested that public prosocial behaviors might be considered as costly signaling behaviors, serving the function of displaying one’s wealth and generosity, with the ultimate goal of attracting potential mates (Griskevicius et al., 2007). Although heroic rescue meets the four criteria of costly signaling behaviors, there was no direct evidence supporting the notion that heroic rescue, like public charity, also serves the function of attracting potential mates. The present study directly tests this possibility by examining the effect of mating motivation on men and women’s heroic rescue tendencies in emergent situations. The present study used a 2 (gender: male vs. female) × 2 (mating motivation induction vs. control condition) study design, and participants (N = 196, 90 males and 106 females; Mage = 22.36, SD = 2.89) were randomly assigned to the mating condition and control condition. In line with the previous studies (Durante & Li, 2009; Griskevicius et al., 2007; Hill & Durante, 2011; Roney, 2003; Wilson & Daly, 2004), mating motivation was induced by photographs of highly attractive opposite sex. Then, heroic rescue tendencies were measured by the questionnaire of Griskevicius et al. (2007), which consisted of five emergent situations. Participants’ risk-taking tendencies on financial decisions were also measured by a 10-item questionnaire developed by Liu (2010). The total scores of each of these two questionnaires served as the dependent variables. The results of the experiments showed a significant interaction between gender and mating priming on heroic behaviors: after mating motivation induction, male participants showed higher intentions of heroic rescue, whereas female participants showed lower intentions of heroic rescue. The present study also replicated previous findings (McAlvanah, 2009; Li & Zhang, 2010) regarding the effect of mating motivation priming on financial risk taking: mating motivation induction increased risk-taking tendency in financial decisions, males tend to be more risk seeking in making financial decisions, and there was no significant interaction between gender and mating priming on financial risk-taking decisions. Results from the financial decisions further confirmed the representativeness of the sample recruited in the current study and further validated the results on heroic behaviors. Based on the Costly Signaling Theory (Smith & Bird, 2001), these results concurred with the hypotheses that heroic behaviors served the function of displaying men’s advantages, such as vigor and responsibility, to potential mates and winning the intersexual selection (Farthing, 2005; Kelly & Dunbar, 2001). However, for women, the high-risk of heroic behaviors have potential harm to their offspring and are unattractive to men (Taylor et al., 2000). Thus, after eliciting the mating motivation, women would avoid the risk and reduced their intentions to offer heroic rescue in emergencies.


2020 ◽  
Author(s):  
Ali AYTEMUR ◽  
Liat Levita

Sense of agency (SoA), the fundamental feeling of control over our actions and their consequences, may show key developmental changes during adolescence. We examined SoA in childhood (9-10), mid-adolescence (13-14), late-adolescence (18-20) and adulthood (25-28) using two tasks (Libet Clock and Stream of Letters). SoA was implicitly indexed by intentional binding that reflects the agency effect on action-outcome temporal association. We found age effects on the sub-processes in both tasks. In the Libet Clock task, where performance was more reliable, we observed a U-shaped developmental trajectory of intentional binding suggesting an adolescent-specific reduction in the experience of control. This study provides evidence for the developmental effects on the implicit agency experience and suggests adolescence as a critical period. Our findings may have implications for understanding increased risk-taking behaviour and greater vulnerability for agency related disorders such as schizophrenia during adolescence.


PEDIATRICS ◽  
1990 ◽  
Vol 86 (3) ◽  
pp. 448-454
Author(s):  
Kathleen M. Dwyer ◽  
Jean L. Richardson ◽  
Kathleen L. Danley ◽  
William B. Hansen ◽  
Steven Y. Sussman ◽  
...  

The purpose of this paper is to examine whether children who care for themselves for longer periods of time are at increased risk of poor grades, truancy, anger, family conflict, stress, risk-taking, and peer influences (in addition to the increased risk of substance use previously reported). Demographic characteristics of eighth-grade students who initiate self-care in junior high school are compared with those initiating self-care in elementary school. Further, increased risks for those initiating self-care in elementary school are examined. Over two thirds of the respondents (67.8%) cared for themselves after school without adult supervision at some time during the week; 23.5% for 1 to 4 hours per week, 15.7% for 5 to 10 hours per week, and 28.6% for 11 or more hours per week. Of those in self-care, 48.5% initiated self-care during elementary school and 51.5% during junior high school. Students who were in the highest category of self-care (≥11 hours per week) vs those in self-care zero hours per week were 1.5 to 2 times as likely to score high on risk-taking, anger, family conflict, and stress, to be more likely to see their friends as their major source of influence, and to attend more parties. The self-reports of academic grades did not differ. The grade of initiation of self-care (elementary vs junior high school) conferred additional risk for drinking alcohol (odds ratio = 1.4), risk-taking tendencies (odds ratio = 1.5), and attending parties (odds ratio = 1.6).


2020 ◽  
Vol 287 (1928) ◽  
pp. 20200652
Author(s):  
Johannes Cairns ◽  
Felix Moerman ◽  
Emanuel A. Fronhofer ◽  
Florian Altermatt ◽  
Teppo Hiltunen

Predator–prey interactions heavily influence the dynamics of many ecosystems. An increasing body of evidence suggests that rapid evolution and coevolution can alter these interactions, with important ecological implications, by acting on traits determining fitness, including reproduction, anti-predatory defence and foraging efficiency. However, most studies to date have focused only on evolution in the prey species, and the predator traits in (co)evolving systems remain poorly understood. Here, we investigated changes in predator traits after approximately 600 generations in a predator–prey (ciliate–bacteria) evolutionary experiment. Predators independently evolved on seven different prey species, allowing generalization of the predator's evolutionary response. We used highly resolved automated image analysis to quantify changes in predator life history, morphology and behaviour. Consistent with previous studies, we found that prey evolution impaired growth of the predator, although the effect depended on the prey species. By contrast, predator evolution did not cause a clear increase in predator growth when feeding on ancestral prey. However, predator evolution affected morphology and behaviour, increasing size, speed and directionality of movement, which have all been linked to higher prey search efficiency. These results show that in (co)evolving systems, predator adaptation can occur in traits relevant to foraging efficiency without translating into an increased ability of the predator to grow on the ancestral prey type.


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