Context-dependent agonistic response to neighbours along territory boundaries in a cichlid fish

Behaviour ◽  
2020 ◽  
Vol 157 (6) ◽  
pp. 559-573
Author(s):  
Kazunori Matsumoto ◽  
Yuki Okamoto ◽  
Yuka Tsurumi ◽  
Masanori Kohda
Keyword(s):  
Cichlid Fish ◽  
Dear Enemy ◽  
Context Dependent ◽  
Dear Enemy Effect ◽  
Boundary Paradigm ◽  
Over Time

Abstract In many territorial animals, the level of aggression exhibited toward conspecifics depends on the magnitude of the threat they pose and/or their familiarity. We conducted aquarium experiments to investigate whether the territorial cichlid fish Julidochromis transcriptus has a context-dependent agonistic response to neighbouring conspecifics. The attacking rate of territory-holding males decreased against neighbour males in an adjacent aquarium over time but increased when stranger males replaced the neighbours in the same aquarium, indicating that males displayed the ‘dear enemy effect’ toward familiar neighbours. Females were not aggressive and the dear enemy effect was not apparent among them. Interestingly, territory-holding males also increased their attacking rate against neighbour males shifted to the opposite aquarium. Territory-holding males will modify their agonistic response to conspecific males according to the relative threat of their opponents in the context of the ‘correct-incorrect boundary paradigm’.

Differential attack by a cichlid fish on resident and non-resident fish of another cichlid species

Behaviour ◽  
2012 ◽  
Vol 149 (1) ◽  
pp. 99-109 ◽  
Author(s):  
Satoshi Awata ◽  
Masanori Kohda ◽  
Haruki Ochi
Keyword(s):  
Field Experiment ◽  
Lake Tanganyika ◽  
Cichlid Fish ◽  
Previous Experience ◽  
Alternative Mechanism ◽  
Differential Attack ◽  
Dear Enemy ◽  
Resident Fish ◽  
Cichlid Species ◽  
Dear Enemy Effect

AbstractAn algivorous cichlid, Variabilichromis moorii( Vm), defends permanent territories in Lake Tanganyika, Africa. A zoobenthivorous cichlid, Neolamprologus mustax( Nm), spends 60% of daylight hours foraging in Vmterritories, from which other zoobenthivorous fishes are chased out and consequently which are much richer in prey animals than areas outside of Vmterritories. We conducted a field experiment to examine whether Nmresidents and non-residents received different degrees of attacks from Vm. Nmfish were caught in their territories, released at a point distant from these territories, and followed to observe interactions with Vmfish. The frequency of attacks received by the displaced Nmfish was greater than attacks received by Nmresidents, indicating that Nmresidents had easier access to Vmterritories than non-residents did. A possible mechanism for this is reduced aggression of Vmtowards Nmresidents, as a result of the ‘dear enemy’ effect that has been reported in territorial contests between rivals. An alternative mechanism is that tolerance towards Nmdiffers among Vmfish and Nmresidents selectively visit more tolerant Vmfish due to previous experience while non-residents randomly approach both tolerant and hostile Vmfish. The ability of Vmto discriminate between Nmresidents and non-residents is essential to the former mechanism but not to the latter. To more specifically examine which mechanism works in the Vm– Nmcommensal system, we will need to follow individually identified Vmfish interacting with Nmresidents and non-residents.

A dear enemy relationship in a territorial cichlid: evidence for the threat-level hypothesis

Behaviour ◽  
2016 ◽  
Vol 153 (4) ◽  
pp. 387-400 ◽  
Author(s):  
Shumpei Sogawa ◽  
Kazutaka Ota ◽  
Masanori Kohda
Keyword(s):  
Cichlid Fish ◽  
Experimental Tank ◽  
Territorial Defence ◽  
Neolamprologus Pulcher ◽  
Dear Enemy ◽  
Threat Level ◽  
Dear Enemy Phenomenon ◽  
Focal Fish ◽  
Boundary Paradigm ◽  
Aggression Level

Despite competing for resources such as space, food and mates, many territorial animals are less aggressive towards neighbours who rarely go beyond their territorial boundaries. This so-called dear enemy phenomenon is advantageous in territorial defence, but it has not been well studied in fish. In this work, we tested the ‘correct–incorrect boundary paradigm’ of the dear enemy phenomenon using the territorial cichlid fishNeolamprologus pulcher, which exhibits dear enemy relationships. When the fish was placed in a small experimental tank, in which fish established its territory, it was initially very aggressive against a neighbouring fish in an adjacent tank, but the aggression level decreased rapidly (within 4 days). When the tank containing the neighbour was shifted to the opposite side, the focal fish was more aggressive than the day before, but it exhibited less aggression than it did against a stranger placed on the shifted side. This lower level of aggression suggested that the focal fish did not regard the shifted neighbour as a stranger. Our observations provide support for the threat-level hypothesis, according to which territory owners will modulate aggression intensity based on the threat level.

Aggression towards unfamiliar intruders by male lizards Eurolophosaurus nanuzae depends on contestant’s body traits: a test of the dear enemy effect

Behaviour ◽  
2017 ◽  
Vol 154 (6) ◽  
pp. 693-708 ◽  
Author(s):  
Eduardo C. Quintana ◽  
Conrado A.B. Galdino
Keyword(s):  
Saving Energy ◽  
Potential Threat ◽  
Dear Enemy ◽  
Holding Power ◽  
Resource Holding Power ◽  
Dear Enemy Phenomenon ◽  
Dear Enemy Effect ◽  
Tail Condition

A reduction of territory owners’ aggression towards their neighbours in relation to the intrusion of strangers characterises the dear enemy phenomenon. Supposedly, the disparity in aggression levels of territory owners is due to a higher threat imposed by strangers compared to the threat imposed by neighbours. To evaluate the occurrence of the phenomenon in males of the small-sized lizard Eurolophosaurus nanuzae we performed a field manipulative study. We considered three models to run intrusions in males’ territories: neighbour, tailed stranger (unfamiliar) and tailless stranger intruders. Our results lend support to the presence of dear enemy for this species as residents acted more aggressively towards strangers than to neighbours. In addition, the information we provide supports the relative threat hypothesis as territory owners were more aggressive towards tailed stranger intruders than to tailless stranger intruders. In this sense, tail condition can represent a trait that signals the ‘resource holding power’ (RHP) of a lizard. Therefore, we show that beyond neighbourhood recognition, residents are able to evaluate the potential threat of stranger intruders in general, thereby extending the evolutionary gains of the dear enemy by saving energy even in the context they are expected to acts with higher costs.

Dear enemy effect in the Mexican volcano mouse Neotomodon alstoni: Implications of sex in the agonistic behaviour among neighbours

2020 ◽  
Vol 181 ◽  
pp. 104251
Author(s):  
Jorge Vázquez ◽  
Juan A. Fargallo ◽  
Nallely Jiménez ◽  
Fernando Aguilar-Montiel ◽  
Luisa Rodríguez-Martínez
Keyword(s):  
Agonistic Behaviour ◽  
Dear Enemy ◽  
Dear Enemy Effect

Enemies are not always dear: male song sparrows adjust dear enemy effect expression in response to female fertility

2017 ◽  
Vol 126 ◽  
pp. 17-22 ◽  
Author(s):  
Christopher Moser-Purdy ◽  
Elizabeth A. MacDougall-Shackleton ◽  
Daniel J. Mennill
Keyword(s):  
Female Fertility ◽  
Dear Enemy ◽  
Male Song ◽  
Song Sparrows ◽  
Dear Enemy Effect

scholarly journals Intraspecific competition in the ant Camponotus cruentatus: should we expect the ‘dear enemy’ effect?

2007 ◽  
Vol 74 (4) ◽  
pp. 985-993 ◽  
Author(s):  
Raphaël Boulay ◽  
Xim Cerdá ◽  
Tovit Simon ◽  
María Roldan ◽  
Abraham Hefetz
Keyword(s):  
Intraspecific Competition ◽  
Dear Enemy ◽  
Dear Enemy Effect

scholarly journals Time-resolved mapping of genetic interactions to model rewiring of signaling pathways

2018 ◽  
Author(s):  
Florian Heigwer ◽  
Christian Scheeder ◽  
Thilo Miersch ◽  
Barbara Schmitt ◽  
Claudia Blass ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Genetic Interactions ◽  
Ras Signaling ◽  
Multiple Time ◽  
Time Resolved ◽  
External Stresses ◽  
Cellular Pathways ◽  
Context Dependent ◽  
Multiple Time Points ◽  
Over Time

AbstractContext-dependent changes in genetic vulnerabilities are important to understand the wiring of cellular pathways and variations in different environmental conditions. However, methodological frameworks to investigate the plasticity of genetic networks over time or in response to external stresses are lacking. To analyze the plasticity of genetic interactions, we performed an arrayed combinatorial RNAi screen in Drosophila cells at multiple time points and after pharmacological inhibition of Ras signaling activity. Using an image-based morphology assay to capture a broad range of phenotypes, we assessed the effect of 12768 pairwise RNAi perturbations in six different conditions. We found that genetic interactions form in different trajectories and developed an algorithm, termed MODIFI, to analyze how genetic interactions rewire over time. Using this framework, we identified more statistically significant interactions compared to endpoints assays and further observed several examples of context-dependent crosstalk between signaling pathways such as an interaction between Ras and Rel which is dependent on MEK activity.

scholarly journals Exploiting context-dependent preferences to protect borrowers

2021 ◽  
Author(s):  
Linda Dezső ◽  
Barna Bakó ◽  
Gábor Neszveda
Keyword(s):  
Experimental Studies ◽  
Making Choices ◽  
Context Dependent ◽  
Over Time ◽  
Choice Set

AbstractFocusing bias is one of the key contributors to over-borrowing. It describes how people, when making choices, give disproportionate attention and weight to attributes in which their options differ more. In a loan decision, a consumer excessively focuses on the eye-catching difference between getting the loan and not getting it, while ignoring the smaller differences between making and not making repayments. Here, we show a simple trick that nudges the consumer to increase attention on the repayment dimension. In two experimental studies involving one hypothetical loan decision, we demonstrate that the salience of getting the loan can be decreased if one offered plan includes high initial installments. This steeply decreasing installment plan (i.e., with initially high installments that decrease over time) offered alongside the usual flat installments plan (i.e., with equally sized repayments through the whole term) increases consumers’ attention to making repayments, and consequently, they attend less to obtaining the loan. When the choice set includes the steeply decreasing plan, we observe a decreased preference for the flat installment plan and a shift toward not borrowing. Additionally, making repayments on the loan is perceived as a greater burden, and more attention is given to making repayments when the steep plan is present. Policy may combat harmful loan consumption by prescribing the presentation of loan offers such that at least one option includes high initial repayments, which increases attention on making repayments.

scholarly journals Neurostimulation Reveals Context-Dependent Arbitration Between Model-Based and Model-Free Reinforcement Learning

2019 ◽  
Vol 29 (11) ◽  
pp. 4850-4862 ◽  
Author(s):  
Sebastian Weissengruber ◽  
Sang Wan Lee ◽  
John P O’Doherty ◽  
Christian C Ruff
Keyword(s):  
Reinforcement Learning ◽  
Neural Mechanism ◽  
Ventrolateral Prefrontal Cortex ◽  
Control Behavior ◽  
Model Based ◽  
Model Free ◽  
Context Dependent ◽  
The Brain ◽  
Over Time ◽  
Environmental Demands

Abstract While it is established that humans use model-based (MB) and model-free (MF) reinforcement learning in a complementary fashion, much less is known about how the brain determines which of these systems should control behavior at any given moment. Here we provide causal evidence for a neural mechanism that acts as a context-dependent arbitrator between both systems. We applied excitatory and inhibitory transcranial direct current stimulation over a region of the left ventrolateral prefrontal cortex previously found to encode the reliability of both learning systems. The opposing neural interventions resulted in a bidirectional shift of control between MB and MF learning. Stimulation also affected the sensitivity of the arbitration mechanism itself, as it changed how often subjects switched between the dominant system over time. Both of these effects depended on varying task contexts that either favored MB or MF control, indicating that this arbitration mechanism is not context-invariant but flexibly incorporates information about current environmental demands.

Dear-enemy effect between two sympatric bird species

2022 ◽  
Vol 184 ◽  
pp. 19-26
Author(s):  
Jan Jedlikowski ◽  
Marcin Polak ◽  
Paweł Ręk
Keyword(s):  
Bird Species ◽  
Dear Enemy ◽  
Dear Enemy Effect
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