scholarly journals Costs and Benefits of Wax Production in the Larvae of the Ladybeetle Scymnus nubilus

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 458
Author(s):  
Paulo Pacheco ◽  
Isabel Borges ◽  
Beatriz Branco ◽  
Eric Lucas ◽  
António Onofre Soares
Keyword(s):  
Intraguild Predation ◽  
Defense Mechanism ◽  
Body Weight Gain ◽  
Metabolic Cost ◽  
Costs And Benefits ◽  
Trade Off ◽  
Physiological Cost ◽  
Intraguild Predator ◽  
Production Body ◽  
Wax Production

BACKGROUND: Larvae of the minute aphidophagous Scymnus nubilus Mulsant (Coleoptera: Coccinellidae) are common predators in apple orchards, covered by a wax layer that might act as a defense mechanism against natural enemies. However, the costs and benefits of protection conferred by wax remain to be assessed. We tested the following hypothesis: there is a trade-off in wax producing ladybeetles between the protection conferred by wax cover and the physiological or behavioral costs associated with its production. We predict that: (1) wax production is an efficient defensive mechanism (against intraguild predation), (2) wax production is associated with detrimental physiological (growth, reproduction) or behavioral effects (behavioral compensation: increased biomass consumption). RESULTS: Tests were carried out in the laboratory with wax and waxless larvae of S. nubilus, with and without lacewing larvae of Chrysoperla agilis (Neuroptera: Chrysopidae) being used as a potential intraguild predator of the coccinellid. Waxless individuals were more susceptible to intraguild predation by lacewing larvae. Adults originating from waxless larvae were lighter than the ones originating from wax larvae, suggesting a metabolic cost resulting from a constant need of wax production. Body-weight gain and conversion efficiency were lower in waxless larvae. Biomass consumption was similar, showing that waxless larvae did not compensate for the physiological cost by eating more aphid biomass. CONCLUSION: The results indicate the potential existence of a trade-off between growth and protection associated with wax production.

scholarly journals Variable costs and benefits of eavesdropping a green leaf volatile on two plant species in a common garden

2018 ◽  
Author(s):  
Grace E. Freundlich ◽  
Christopher J. Frost
Keyword(s):  
Plant Species ◽  
Defense Mechanism ◽  
Common Garden ◽  
Lima Bean ◽  
Phaseolus Lunatus ◽  
Green Leaf ◽  
Green Leaf Volatile ◽  
Costs And Benefits ◽  
Plant Communication ◽  
Bean Plants

AbstractHerbivore-induced plant volatile (HIPV)-mediated eavesdropping is a well-documented, inducible phenomenon that should—like any inducible phenomenon—incur fitness costs. Yet, ecological costs associated with volatile exposure alone are unclear. In a common garden experiment, we tested the hypothesis that exposure to a single HIPV would decrease herbivore damage at the cost of reduced plant growth and reproduction. Lima bean (Phaseolus lunatus) and pepper (Capsicum annuum) plants were exposed to a persistent, low-dose (~10ng/hour) of the green leaf volatile cis-3-hexenyl acetate (z3HAC), a ubiquitous HIPV. z3HAC-treated pepper plants were shorter, had less aboveground and belowground biomass, and produced fewer flowers and fruits relative to controls while z3HAC-treated lima bean plants were taller and produced more leaves and flowers than did controls. Natural herbivory was reduced in z3HAC-exposed lima bean plants, but not in pepper. Cyanogenic potential, a putative defense mechanism in lima bean, was lower in z3HAC-exposed leaves, suggesting a growth-defense tradeoffs from z3HAC exposure alone. Plant species-specific responses to an identical priming cue have important implications for ecological costs and benefits of volatile-mediated inter-plant communication under field conditions.

scholarly journals Prophylactic host behaviour discourages pathogen exploitation

2019 ◽  
Author(s):  
Evan Mitchell ◽  
Geoff Wild
Keyword(s):  
Population Dynamics ◽  
Disease Transmission ◽  
Costs And Benefits ◽  
Dual Nature ◽  
Trade Off ◽  
Pathogen Virulence ◽  
Prophylactic Measures ◽  
Host Behaviour

SummaryMuch work has considered the evolution of pathogens, but little is known about how they respond to changes in host behaviour. We build a model where hosts are able to choose to engage in prophylactic measures that reduce the likelihood of disease transmission. This choice is mediated by costs and benefits associated with prophylaxis, but the fraction of hosts engaged in prophylaxis is also affected by population dynamics. We identify a critical cost threshold above which hosts do not engage in prophylaxis. Below the threshold, prophylactic host behaviour does occur and pathogen virulence, measured by the extent to which it exploits its host, is reduced by the action of selection relative to the level that would otherwise be predicted in the absence of prophylaxis. Our work emphasizes the significance of the dual nature of the trade-off faced by the pathogen between balancing transmission and recovery, and creating new infections in hosts engaging or not engaging in prophylaxis.

scholarly journals Facultative predation can alter the ant-aphid population

2020 ◽  
Author(s):  
Atsuki Nakai ◽  
Yoko Inui ◽  
Kei Tokita
Keyword(s):  
Dynamical System ◽  
Growth Rate ◽  
Nonlinear Dynamical System ◽  
The Other ◽  
Two Dimensional ◽  
Intrinsic Growth Rate ◽  
Trade Off ◽  
Nonlinear Dynamical ◽  
Physiological Cost ◽  
Ant Attendance

Although ant--aphid interactions are the most typical example of mutualism between insect species, some studies suggest that ant attendance is not always advantageous for the aphids because they may pay a physiological cost. In this study, we propose a new mathematical model of an ant--aphid system considering the costs of ant attendance. It includes both mutualism and predation. In the model, we incorporate not only the trade-off between the intrinsic growth rate of aphids and the honeydew reward for ants, but also the facultative predation of aphids by ants. The analysis and computer simulations of the two-dimensional nonlinear dynamical system with functional response produces fixed points and also novel and complex bifurcations. These results suggest that a higher degree of dependence of the aphids on the ants does not always enhance the abundance of the aphids. In contrast, the model without facultative predation gives a simple prediction, that is, the higher the degree of dependence, the more abundant the aphids are. The present study predicts two overall scenarios for an ant--aphid system with mutualism and facultative predation: (1) aphids with a lower intrinsic growth rate and many attending ants and (2) aphids with a higher intrinsic growth rate and fewer attending ants. This seems to explain why there are two lineages of aphids: one is associated with ants and the other is not.

Sheep avoidance of faeces creates a foraging trade-off between nutrient and parasite intake

2001 ◽  
Vol 2001 ◽  
pp. 94-94
Author(s):  
M. R. Hutchings ◽  
I. J. Gordon ◽  
I. Kyriazakis ◽  
F. Jackson
Keyword(s):  
Parasite Species ◽  
Avoidance Behaviour ◽  
Infective Stage ◽  
Costs And Benefits ◽  
Trade Off ◽  
Survival And Reproduction ◽  
Parasite Avoidance ◽  
Grazing Behaviour

Gastrointestinal (GI) parasites, acquired by sheep through the action of foraging, are the most pervasive challenge to their survival and reproduction. The eggs of many GI parasite species are deposited on pasture in faeces where they develop into infective stage larvae that contaminate surrounding swards. We test the hypotheses that (1) faeces and hence parasite avoidance behaviour of sheep creates a grazing trade-off between nutrition and parasitism and (2) the relative costs and benefits of the trade-off in relation to animal state of infection (parasitized, non-parasitized, immune) determines their subsequent grazing behaviour.

scholarly journals Hitting the buffers: conspecific aggression undermines benefits of colonial breeding under adverse conditions

2008 ◽  
Vol 4 (6) ◽  
pp. 630-633 ◽  
Author(s):  
Kate Ashbrook ◽  
Sarah Wanless ◽  
Mike P Harris ◽  
Keith C. Hamer
Keyword(s):  
Social Dynamics ◽  
Alloparental Care ◽  
Costs And Benefits ◽  
Trade Off ◽  
Adverse Conditions ◽  
Avian Predators ◽  
Colonial Breeding ◽  
Conspecific Aggression ◽  
The Uk ◽  
Transfer Of Information

Colonial breeding in birds is widely considered to benefit individuals through enhanced protection against predators or transfer of information about foraging sites. This view, however, is largely based on studies of seabirds carried out under favourable conditions. Recent breeding failures at many seabird colonies in the UK provide an opportunity to re-examine costs and benefits of coloniality under adverse conditions. Common guillemots Uria aalge are highly colonial cliff-nesting seabirds with very flexible parental care. Although the single chick is normally never left alone, more than 50 per cent of offspring were left unattended at a North Sea colony in 2007, apparently because poor conditions forced both parents to forage simultaneously. Contrary to expectation, unattended chicks were not killed by avian predators. Rather, although non-breeders and failed breeders sometimes provided alloparental care, unattended chicks were frequently attacked by breeding guillemots at neighbouring sites, often with fatal consequences. These results highlight a previously unsuspected trade-off between provisioning chicks and avoiding conspecific attacks, and indicate that understanding how environmental conditions affect social dynamics is crucial to interpreting costs and benefits of colonial breeding.

scholarly journals How Consumers Trade Off Behavioural Costs and Benefits

1986 ◽  
Vol 20 (3/4) ◽  
pp. 19-34 ◽  
Author(s):  
Theo M.M. Verhallen ◽  
W. Fred van Raaij
Keyword(s):  
Costs And Benefits ◽  
Trade Off

scholarly journals Intraguild predation does not necessarily have negative effects on pest biological control: insights from a multiple consumer–multiple resource food web population model

2021 ◽  
Author(s):  
Michel Iskin da Silveira Costa ◽  
Lucas dos Anjos
Keyword(s):  
Food Web ◽  
Intraguild Predation ◽  
Population Model ◽  
Initial Population ◽  
Negative Effects ◽  
Orius Laevigatus ◽  
Proposed Model ◽  
Intraguild Predator ◽  
Multiple Resource

We develop a food web population dynamical based on an experimental pest biocontrol setup consisting of thrips and aphids (pests) being consumed by two agents Macrolophus pygmaeus and Orius laevigatus, and with O. laevigatus being an intraguild predator of M. pygmaeus. By means of numerical simulations, we show that pest biocontrol disruption can be avoided depending on initial population densities of pests and agents, despite the intraguild predation (IGP) of O. laevigatus upon M. pygmaeus. This possible avoidance of pest biocontrol disruption is in accordance with the referred experimental setup and moreover, the proposed model corroborates the importance of initial densities of pests and agents in the determination of the failure or success of pest biocontrol found in this and other biocontrol experimental setups.

scholarly journals Growth rate trades off with enzymatic investment in soil filamentous fungi

2018 ◽  
Author(s):  
Weishuang Zheng ◽  
Anika Lehmann ◽  
Masahiro Ryo ◽  
Kriszta Kezia Vályi ◽  
Matthias C. Rillig
Keyword(s):  
Growth Rate ◽  
Filamentous Fungi ◽  
Soil Fungi ◽  
Metabolic Cost ◽  
Ecosystem Processes ◽  
Implicit Assumption ◽  
Trade Off ◽  
Functional Complementarity ◽  
Soil Fungal Community ◽  
Investment Growth

AbstractSaprobic soil fungi drive many important ecosystem processes, including decomposition, and many of their effects are related to growth rate and enzymatic ability. In mycology, there has long been the implicit assumption of trade-off between growth and enzymatic investment, which we here test. Using a set of 31 filamentous fungi isolated from the same ecosystem, we measured growth rate (as colony radial extension) and enzymatic repertoire (activities of four enzymes: laccase, cellobiohydrolase, leucine aminopeptidase and acid phosphatase). Our results support the existence of a trade-off, however only for the enzymes representing a larger metabolic cost (laccase and cellobiohydrolase). Our study offers new insights into functional complementarity within the soil fungal community in a number of ecosystem processes, and experimentally supports an enzymatic investment/ growth rate tradeoff in explaining phenomena including substrate succession.

scholarly journals Coping with Health Threats: The costs and benefits of managing emotions.

2020 ◽  
Author(s):  
Angela Moriah Smith ◽  
Emily C Willroth ◽  
Arasteh Gatchpazian ◽  
amanda shallcross ◽  
Matthew Feinberg ◽  
...  
Keyword(s):  
Mental Health ◽  
Health Behaviors ◽  
Health Outcomes ◽  
Physical Health ◽  
Positive Emotions ◽  
Cognitive Strategies ◽  
Costs And Benefits ◽  
Trade Off ◽  
Health Threats ◽  
Mediation Models

How people respond to health threats can influence their own health and, when facing communal risks, even their community's health. We propose that people commonly respond to health threats by managing their emotions with cognitive strategies like reappraisal, which can reduce fear and protect mental health. However, because fear can also motivate health behaviors, reducing fear may also jeopardize health behaviors. In two diverse U.S. samples (N=1,241) tracked across three months, sequential and cross-lag panel mediation models indicated that reappraisal predicted lower fear about an ongoing health threat (COVID-19), and in turn, better mental health, but fewer recommended physical health behaviors. This trade-off was not inevitable, however: using reappraisal to increase socially-oriented positive emotions predicted better mental health without jeopardizing physical health behaviors. Examining the costs and benefits of how people cope with health threats is essential for promoting better health outcomes for individuals and communities.

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