scholarly journals Subjective and objective components of resource value additively increase aggression in parasitoid contests

2013 ◽  
Vol 9 (4) ◽  
pp. 20130391 ◽  
Author(s):  
Bernard C. Stockermans ◽  
Ian C. W. Hardy
Keyword(s):  
Parasitoid Wasp ◽  
Host Size ◽  
Resource Holding Potential ◽  
Resource Value ◽  
Contest Behaviour

Two major categories of factors are predicted to influence behaviour in dyadic contests; differences in the abilities of the contestants to acquire and retain resources (resource holding potential), and the value of the contested resource (resource value, RV; which comprises objective and subjective components). Recent studies indicate that subjective components affect contest behaviour in several animal taxa but few have simultaneously investigated objective RV components. We find that both an objective (host size) and a subjective (contestant age) component of RV affect contest intensity in the parasitoid wasp Goniozus legneri. These additively influence aggressiveness, with a larger effect from the subjective component than the objective component. The greater influence of subjective RV adds weight to the recent surge of recognition of this RV component's importance in contest behaviour.

Life history of aggression in Anastatus disparis (Hymenoptera: Eupelmidae) with extreme male–male combat

2020 ◽  
pp. 1-7 ◽  
Author(s):  
Peng-Cheng Liu ◽  
De-Jun Hao ◽  
Wei Hu ◽  
Jian-Rong Wei ◽  
Jian-Jun Wang
Keyword(s):  
Life History ◽  
Parasitoid Wasp ◽  
Reproductive Value ◽  
Supporting Evidence ◽  
Resource Holding Potential ◽  
Wasp Species ◽  
Young Males ◽  
Study Results ◽  
History Of ◽  
Older Males

Abstract Aggressive behaviour is common in animals and typically has lifetime consequences. As younger males have higher residual reproductive value than older males and lose more from injuries than older males do, the propensity for fighting tends to increase with age in many empirical reports and species. However, fighting patterns in those empirical reports cannot confirm the hypothesis that individuals cannot readily inflict injuries on their opponents. To address this shortcoming, a parasitoid wasp species, Anastatus disparis (Hymenoptera: Eupelmidae), was used as an experimental model to explore the characteristics of aggression from a life-history perspective; this wasp exhibits extreme fighting, resulting in contestants experiencing injury and death. Results showed that the energetic costs of fighting to injury significantly shortened life and caused the loss of most mating ability. Inconsistent with general predictions, the frequency and intensity of fighting in A. disparis significantly decreased with male age. Further study results showed significantly more young males were received by and successfully mated with virgin females, and most genes related to energy metabolism were downregulated in aged males. Our study provided supporting evidence that young A. disparis males show more aggression likely because of their resource holding potential and sexual attractiveness decline with age.

Using effects of parasitoid size on fitness to test a host quality model assumption with the parasitoid wasp Spalangia endius

2006 ◽  
Vol 84 (11) ◽  
pp. 1678-1682 ◽  
Author(s):  
B.H. King ◽  
M.E. Napoleon
Keyword(s):  
Sexual Size Dimorphism ◽  
Parasitoid Wasp ◽  
Host Size ◽  
Female Size ◽  
Host Quality ◽  
Quality Model ◽  
Male Size ◽  
Model Assumption ◽  
Size Dimorphism ◽  
Spalangia Endius

How body size affects fitness of males relative to females is relevant to understanding the evolution of sexual size dimorphism and maternal sex-ratio manipulation. In most parasitoid wasps, mothers oviposit a greater proportion of daughters in larger hosts. The host-quality model describes how this may be adaptive. A major assumption of the model is that host size has a greater effect on the fitness of daughters than of sons. The assumption has often been tested indirectly by examining the effects of parasitoid size on fitness, because a parasitoid’s size generally increases with the size of the host on which it develops. The validity of this indirect method is examined here for the parasitoid wasp Spalangia endius Walker, 1839 parasitizing Musca domestica L., 1758. If the method is valid, effects of parasitoid size on fitness should match the effects of host size on fitness that were shown in a previous study. The effects matched in that both parasitoid size and host size affected the fitness of females but not of males. However, the aspects of female fitness that were affected differed. That female size but not male size affected fitness was consistent with the female-biased sexual size dimorphism of S. endius.

scholarly journals Extrinsic stressors modulate resource evaluations: insights from territoriality under artificial noise

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Kyriacos Kareklas ◽  
Hansjoerg P. Kunc ◽  
Gareth Arnott
Keyword(s):  
Betta Splendens ◽  
Anthropogenic Activity ◽  
Nest Size ◽  
Artificial Noise ◽  
Combined Effects ◽  
Resource Value ◽  
Acoustic Environment ◽  
It Impacts ◽  
Contest Behaviour ◽  
Motivational Changes

Abstract Background Competition is considered to rely on the value attributed to resources by animals, but the influence of extrinsic stressors on this value remains unexplored. Although natural or anthropogenic environmental stress often drives decreased competition, assumptions that this relies on resource devaluation are without formal evidence. According to theory, physiological or perceptual effects may influence contest behaviour directly, but motivational changes due to resource value are expected to manifest as behavioural adjustments only in interaction with attainment costs and resource benefits. Thus, we hypothesise that stressor-induced resource devaluations will impose greater effects when attainment costs are high, but not when resource benefits are higher. Noise may elicit such effects because it impacts the acoustic environment and imposes physiological and behavioural costs to animals. Therefore, we manipulated the acoustic environment using playbacks of artificial noise to test our hypotheses in the territorial male Siamese fighting fish, Betta splendens. Results Compared to a no-playback control, noise reduced defense motivation only when territory owners faced comparatively bigger opponents that impose greater injury costs, but not when territories also contained bubble nests that offer reproductive benefits. In turn, nest-size decreases were noted only after contests under noise treatment, but temporal nest-size changes relied on cross-contest variation in noise and comparative opponent size. Thus, the combined effects of noise are conditional on added attainment costs and offset by exceeding resource benefits. Conclusion Our findings provide support for the hypothesised modulation of resource value under extrinsic stress and suggest implications for competition under increasing anthropogenic activity.

scholarly journals Let the most motivated win: resource value components affect contest outcome in a parasitoid wasp

2018 ◽  
Vol 29 (5) ◽  
pp. 1088-1095 ◽  
Author(s):  
Anthony G E Mathiron ◽  
Patrice Pottier ◽  
Marlène Goubault
Keyword(s):  
Parasitoid Wasp ◽  
Resource Value ◽  
Contest Outcome
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