scholarly journals Producers and scroungers: feeding-type composition changes with group size in a socially foraging spider

2016 ◽  
Vol 283 (1828) ◽  
pp. 20160114 ◽  
Author(s):  
Marlis Dumke ◽  
Marie E. Herberstein ◽  
Jutta M. Schneider
Keyword(s):  
Group Size ◽  
Size Effects ◽  
Feeding Behaviour ◽  
Prey Capture ◽  
Cost Benefit ◽  
Theoretical Models ◽  
Food Sources ◽  
Feeding Types ◽  
Trade Offs ◽  
Feeding Type

In groups of socially foraging animals, feeding behaviour may change with group size in response to varying cost–benefit trade-offs. Numerous studies have described group-size effects on group-average feeding behaviour, particularly emphasizing an increase in scrounging incidence for larger groups, where individuals (scroungers) feed from the food sources others (producers) discovered. However, individual variation in feeding behaviour remains unconsidered in the vast majority of these studies even though theoretical models predict individuals to specialize in feeding tactic and anticipate higher scrounger-type frequencies in larger groups. We combined group-level and individual-level analyses of group-size effects on social foraging in the subsocial spider Australomisidia ergandros . Lending novel experimental support to model predictions, we found that individuals specialize in feeding tactic and that higher scrounging and lower producing incidence in larger groups were mediated through shifts in the ratio of feeding types. Further, feeding-type specialization was not explained by innate individual differences in hunting ability as all feeding types were equally efficient in prey capture when foraging alone. Context adaptivity of feeding behaviour might allow this subsocial species to succeed under varying socioecological conditions.

Mate availability facilitates cannibalistic behaviour in a nest brooding fish: effects of timing during the brood cycle

Behaviour ◽  
2011 ◽  
Vol 148 (2) ◽  
pp. 247-264 ◽  
Author(s):  
Masanori Kohda ◽  
Nobuhiro Ohnishi ◽  
Noboru Okuda ◽  
Tomohiro Takeyama ◽  
Omar Myint
Keyword(s):  
Laboratory Experiments ◽  
Gravid Female ◽  
Theoretical Models ◽  
Filial Cannibalism ◽  
Mate Availability ◽  
Stimulus Female ◽  
Trade Offs ◽  
Future Reproduction ◽  
Cannibalistic Behaviour ◽  
The Subject

AbstractFilial cannibalism, eating one's own viable offspring, is accepted as an adaptive response to trade-offs between current and future reproduction. Theoretical models predict that high mate availability may induce more filial cannibalism, but this prediction is rarely tested. To examine this prediction, we performed laboratory experiments using the nest breeding goby Rhinogobius flumineus. Subject males were allowed to mate with a gravid female and care for the broods. A separate gravid female housed in a small cage (stimulus-female) was shown to the subject males at one of three different points during the brood cycle: prior to spawning, within 1 day after spawning and 1 week after spawning. Empty cages were shown as a control. Males that were shown the stimulus-female before spawning cannibalised more eggs than control males. In contrast, males that were shown the stimulus-females after spawning cannibalised as few eggs as control males did. Additionally, males that were shown the stimulus-female prior to spawning did not court females more intensively than other males. Thus, we suggest that the presence of an additional mate, rather than energy expenditure associated with courtship directed toward an additional mate, can facilitate males to cannibalise their eggs.

Experimental field exclosure of birds and bats in agricultural systems — Methodological insights, potential improvements, and cost-benefit trade-offs

2019 ◽  
Vol 35 ◽  
pp. 1-12 ◽  
Author(s):  
Bea Maas ◽  
Sacha Heath ◽  
Ingo Grass ◽  
Camila Cassano ◽  
Alice Classen ◽  
...  
Keyword(s):  
Cost Benefit ◽  
Agricultural Systems ◽  
Experimental Field ◽  
Trade Offs

Yellow-Footed Rock-Wallaby Group Size Effects Reflect A Trade-Off

Ethology ◽  
2001 ◽  
Vol 107 (7) ◽  
pp. 655-664 ◽  
Author(s):  
Daniel T. Blumstein ◽  
Janice C. Daniel ◽  
Christopher S. Evans
Keyword(s):  
Group Size ◽  
Size Effects ◽  
Trade Off

Sustainable Distribution Design: Contrasting Disposable, Recyclable, and Reusable Strategies for Packaging Materials Using a Total Cost Analysis With an Illustration of Milk Distribution

2010 ◽  
Author(s):  
Sri Satya Kanaka Nagendra Jayanty ◽  
William J. Sawaya ◽  
Michael D. Johnson
Keyword(s):  
Cost Benefit ◽  
Packaging Materials ◽  
Policy Makers ◽  
Specific Product ◽  
Cost Structures ◽  
Trade Offs ◽  
Technological Advances ◽  
The Cost ◽  
Total Cost Analysis ◽  
Plastic Containers

Engineers, policy makers, and managers have shown increasing interest in increasing the sustainability of products over their complete lifecycles and also from the ‘cradle to grave’ or from production to the disposal of each specific product. However, a significant amount of material is disposed of in landfills rather than being reused in some form. A sizeable proportion of the products being dumped in landfills consist of packaging materials for consumable products. Technological advances in plastics, packaging, cleaning, logistics, and new environmental awareness and understanding may have altered the cost structures surrounding the lifecycle use and disposal costs of many materials and products resulting in different cost-benefit trade-offs. An explicit and well-informed economic analysis of reusing certain containers might change current practices and results in significantly less waste disposal in landfills and in less consumption of resources for manufacturing packaging materials. This work presents a method for calculating the costs associated with a complete process of implementing a system to reuse plastic containers for food products. Specifically, the different relative costs of using a container and then either disposing of it in a landfill, recycling the material, or reconditioning the container for reuse and then reusing it are compared explicitly. Specific numbers and values are calculated for the case of plastic milk bottles to demonstrate the complicated interactions and the feasibility of such a strategy.

The relationship between forelimb morphology and behaviour in North American carnivores (Carnivora)

1999 ◽  
Vol 77 (7) ◽  
pp. 1064-1074 ◽  
Author(s):  
Andrew N Iwaniuk ◽  
Sergio M Pellis ◽  
Ian Q Whishaw
Keyword(s):  
North American ◽  
Significant Relationship ◽  
Feeding Behaviour ◽  
Prey Capture ◽  
Relative Size ◽  
Independent Contrasts ◽  
Important Indicator ◽  
Predatory Behaviour ◽  
Olecranon Process ◽  
The Relationship

We tested the validity of previously described relationships between forelimb structure and behaviour in mammals by measuring the forelimbs of 22 species of North American carnivores. Nine ratios were calculated from these measurements and made independent of the effects of allometry and phylogeny through the use of log-transformed regressions and independent contrasts analysis. The ratios were then directly compared with two behavioural traits: arboreal locomotion and vertebrate predation. Only five of the nine ratios exhibited a significant relationship with arboreal locomotion and three with vertebrate predation. It was concluded that the brachial index, relative size of the olecranon process, and total forelimb robusticity may be reliable predictors of arboreal locomotion, and that the brachial index, relative size of the olecranon process, and radial robusticity may be accurate predictors of vertebrate predation. The data also suggest that the morphology of the lower forelimb may be an important indicator of prey-capture and feeding behaviour in carnivores and could be used in conjunction with craniodental variables to extrapolate predatory behaviour of extinct species.

scholarly journals COVID-19: Rethinking the Lockdown Groupthink

2021 ◽  
Vol 9 ◽  
Author(s):  
Ari R. Joffe
Keyword(s):  
Public Health ◽  
High Risk ◽  
Cost Benefit Analysis ◽  
Health Care Systems ◽  
Herd Immunity ◽  
Cost Benefit ◽  
Risk Groups ◽  
School Closures ◽  
Trade Offs ◽  
Care Systems

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has caused the Coronavirus Disease 2019 (COVID-19) worldwide pandemic in 2020. In response, most countries in the world implemented lockdowns, restricting their population's movements, work, education, gatherings, and general activities in attempt to “flatten the curve” of COVID-19 cases. The public health goal of lockdowns was to save the population from COVID-19 cases and deaths, and to prevent overwhelming health care systems with COVID-19 patients. In this narrative review I explain why I changed my mind about supporting lockdowns. The initial modeling predictions induced fear and crowd-effects (i.e., groupthink). Over time, important information emerged relevant to the modeling, including the lower infection fatality rate (median 0.23%), clarification of high-risk groups (specifically, those 70 years of age and older), lower herd immunity thresholds (likely 20–40% population immunity), and the difficult exit strategies. In addition, information emerged on significant collateral damage due to the response to the pandemic, adversely affecting many millions of people with poverty, food insecurity, loneliness, unemployment, school closures, and interrupted healthcare. Raw numbers of COVID-19 cases and deaths were difficult to interpret, and may be tempered by information placing the number of COVID-19 deaths in proper context and perspective relative to background rates. Considering this information, a cost-benefit analysis of the response to COVID-19 finds that lockdowns are far more harmful to public health (at least 5–10 times so in terms of wellbeing years) than COVID-19 can be. Controversies and objections about the main points made are considered and addressed. Progress in the response to COVID-19 depends on considering the trade-offs discussed here that determine the wellbeing of populations. I close with some suggestions for moving forward, including focused protection of those truly at high risk, opening of schools, and building back better with a economy.

scholarly journals Hydrodynamic trait coordination and cost-benefit trade-offs throughout the isohydric-anisohydric continuum in trees

Ecohydrology ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. e2041 ◽  
Author(s):  
Golnazalsadat Mirfenderesgi ◽  
Ashley M. Matheny ◽  
Gil Bohrer
Keyword(s):  
Cost Benefit ◽  
Trade Offs

A systematic review of the literature on supply chain agility

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bharat Singh Patel ◽  
Murali Sambasivan
Keyword(s):  
Supply Chain ◽  
Cost Benefit ◽  
Business Environment ◽  
Future Research ◽  
Research Directions ◽  
Content Type ◽  
Trade Offs ◽  
Supply Chain Agility ◽  
Agility Assessment ◽  
Future Research Directions

Purpose The purpose of this study is to critically examine the scholarly articles associated Murali Sambasivan with the diverse aspects of supply chain agility (SCA). The review highlights research insights, existing gaps and future research directions that can help academicians and practitioners gain a comprehensive understanding of SCA. Design/methodology/approach The present study has adopted author co-citation analysis as the research methodology, with a view to thoroughly investigating the good-quality articles related to SCA that have been published over a period of 22 years (1999-2020). In this study, 126 research papers on SCA – featuring diverse aspects of agility – from various reputed journals have been examined, analysed and assimilated. Findings The salient findings of this research are, namely, agility is different from other similar concepts, such as flexibility, leanness, adaptability and resilience; of the 13 dimensions of agility discussed in the literature, the prominent ones are quickness, responsiveness, competency and flexibility; literature related to SCA can be categorised as related to modelling the enablers, agility assessment, agility implementation, leagility and agility maximisation. This research proposes a more practical definition and framework for SCA. The probable areas for future research are, namely, impediments to agility, effective approaches to agility assessment, cost-benefit trade-offs to be considered whilst implementing agility, empirical research to validate the framework and SCA in the domain of healthcare and disaster relief supply chains. Practical implications This paper provides substantial insights to practitioners who primarily focus on measuring and implementing agility in the supply chain. The findings of this study will help the supply chain manager gain a better idea about how to become competitive in today’s dynamic and turbulent business environment. Originality/value The originality of this study is in: comprehensively identifying the various issues related to SCA, such as related concepts, definitions, dimensions and different categories of studies covered in literature, proposing a new definition and framework for SCA and identifying potential areas for future research, to provide deeper insights into the subject and highlight areas for future research.

Unilateral ciliary reversal and motor responses during prey capture by the ctenophore Pleurobrachia

1985 ◽  
Vol 114 (1) ◽  
pp. 443-461 ◽  
Author(s):  
S. L. Tamm ◽  
A. G. Moss
Keyword(s):  
High Frequency ◽  
Feeding Behaviour ◽  
High Speed ◽  
Prey Capture ◽  
Reverse Direction ◽  
Motor Responses ◽  
Ciliary Reversal ◽  
High Speed Cinematography

High-speed cinematography of feeding Pleurobrachia revealed a stereo-typed sequence of ciliary motor responses underlying the feeding behaviour of this ctenophore. Prey capture by a tentacle first elicited high frequency beating in all comb rows, propelling the animal forward at a rapid speed for several seconds. This was followed by a brief period of inactivity on some or all comb rows. Then comb rows adjacent to the catching tentacle beat in the reverse direction, causing the ctenophore to spin rapidly toward this side and sweeping the prey-catching tentacle to the opened mouth, which bent towards it. After engulfing the prey, the animal slowly swam forward to re-set the relaxed tentacles as a fishing net. The patterns, timing, onset and coordination of these ciliary responses, particularly the unilateral reversal of comb rows on the catching side, are analysed with respect to possible conducting pathways mediating this behaviour.

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