Volume 114, Issue 6,
, Pages 335-339
Author links open overlay panel, , , , ,
https://doi.org/10.1016/j.zool.2011.07.001Get rights and content
Eye darkening has been linked to social status in fish. The subordinate's eyes darken, while the eyes of the dominant fish become pale. Although this phenomenon has been described in salmonid fishes and in the African cichlid Nile tilapia Oreochromis niloticus, it is unclear whether eye darkening correlates with a reduction in aggressive behaviour. Thus, we evaluated the link between social status and eye darkening. We evaluated whether the eye colours of subordinate fish correlate with the frequency of received attacks in a neotropical fish, the pearl cichlid Geophagus brasiliensis. We paired pearl cichlids and quantified both the aggressive behaviour and the eye darkening of each fish. As has been described for Nile tilapia and Atlantic salmon, a clear-cut hierarchical relationship formed, where dominance and subordination were associated with pale and dark eye colours, respectively. Initially, eye colour darkening was positively correlated with the frequency of received attacks; however, a negative association occurred following eye darkening, in which the intensity of aggressive interactions decreased. Thus, fish that initially received a high number of attacks signalled subordination more rapidly and intensely (rapid and dramatic eye darkening), thereby inducing a negative social feedback mechanism that led to reduced aggression.
In nature, the most common type of resource competition is an aggressive dispute (Ridley, 1995, Wootton, 1998). Although it is not always the case that the most aggressive animals become dominant and/or secure access to the contested resource (Francis, 1988, Francis et al., 1992, Mazur and Booth, 1998, Staffan et al., 2002), the most aggressive ones are often more successful in exploiting a shared resource (Metcalfe, 1986, Alanärä et al., 2001, Delicio et al., 2006, Ang and Manica, 2010, Magellan and Kaiser, 2010). Moreover, the presence of a contested resource may increase aggressive activities in fish (Barreto et al., 2011). The fitness of the individual fish may be enhanced due to increased access to these resources. Thus, it is expected that aggressive individuals would be favoured by natural selection. Nevertheless, aggressive interactions may have an energetic cost for the individuals (Glass and Huntingford, 1988, Alvarenga and Volpato, 1995, Kelly and Godin, 2001, Briffa and Elwood, 2004). Therefore, it is likely that natural selection also favours mechanisms that decrease the occurrence of serious fighting. For example, ritualised displays may facilitate opponent assessment and the establishment of social hierarchies and/or territories without the need for costly physical combat (Maynard-Smith and Price, 1973, Maynard-Smith and Parker, 1976, Parker and Rubenstein, 1981, Enquist and Leimar, 1983, Enquist and Leimar, 1990, Enquist et al., 1990, Grosenick et al., 2007; review by Arnott and Elwood, 2009).
In the case of social hierarchies, the signalling of social status is necessary for the maintenance of stable social structures (Giaquinto and Volpato, 1997, Volpato et al., 2003); otherwise, a high rate of aggressive encounters could persist (Oliveira and Almada, 1996, Goncalves-de-Freitas et al., 2008).
Changes in body colour have been recognised as a reliable signal of social status in certain fish species. In the case of some cichlids, a subordinate status is usually associated with a darker appearance (appearance of dark stripes), while dominant fish are typically paler (Falter, 1987, Beeching, 1995). It is assumed that this link between social status and body colour is an intraspecific signal that may function to decrease aggression and to aid in the establishment of a hierarchy (O’Connor et al., 1999). Body colour is the characteristic that has been most extensively studied in this context (Abbott et al., 1985, Hulscher-Emeis, 1992, Beeching, 1995, O’Connor et al., 1999, O’Connor et al., 2000, Hoglund et al., 2000); however, some investigations have concentrated on eye colour, in species such as Atlantic salmon, Salmo salar (Suter and Huntingford, 2002), and the Nile tilapia, Oreochromis niloticus (Volpato et al., 2003).
Eye colour is easy to identify, but its adequacy as an indicator of social status in other fish species has yet to be thoroughly investigated. It is not clear whether variation in eye colour always corresponds to shifts in body colour. A highly significant association was reported between the body colour and the sclera colour of juvenile Atlantic salmon (O’Connor et al., 1999), and this relationship has been verified by ad hoc observations for this salmon species (Suter and Huntingford, 2002). However, for pairs of Nile tilapia (Volpato et al., 2003), it is known that eye colour is independent of body stripes because darkened stripes (vertical, horizontal, or both) can appear without alteration of eye colour. The pairs of Nile tilapia in the study by Volpato et al. (2003) varied in the number of aggressive actions they perpetrated, but there were no differences between the eye darkening levels of the two contesters in pairs with high numbers of aggressive encounters. The opposite occurred in pairs with low levels of confrontation, in which subordinate fish presented a darker eye colour than dominant fish. In these pairs of Nile tilapia, the social hierarchy was stable and, therefore, eye colour was clearly associated with social rank. These results suggest that the association between eye colour and social rank may function to reduce aggression. Although it is known that eye colour is a clear indicator of social status in cichlid fish (Volpato et al., 2003), the relationship between eye colour and a reduction in aggressive behaviour has not yet been tested.
In the present study, we examined the correlation between eye colour, social rank, and aggressive behaviour of the pearl cichlid Geophagus brasiliensis. This species was chosen because it is an aggressive fish species that changes eye colour during intraspecific confrontations (Kadry and Barreto, 2010). The Cichlidae are a group composed of several species with evident aggressive behaviour that have variously been used as models for studying aggression in vertebrates (Oliveira et al., 2001, Oliveira et al., 2005, Cruz and Brown, 2007, Korzan et al., 2008).
Fish and holding conditions
Specimens of the pearl cichlid G. brasiliensis (Quoy and Gaimard 1824) were collected from a lagoon system (in a rural area of São Paulo city, Jardim Britânia – 23°25′46.34″S, 46°47′19.47″W). The fish were of both sexes and were sexually immature (8.91±4.7g, 6.51±0.45cm). Fish were held in two indoor tanks with a holding density of one fish per 1.5l of water. This stock population was held for at least one month before the test. During this time, the water was kept at a mean temperature of 25±1
A dominance hierarchy was clearly established in all 18 of the pairs tested. The wide range of attack frequencies (43–474) between pairs was used to assess the relationship between attacks and hierarchical ranking, as well as the link to eye colour.
Based on the total number of aggressive interactions, the pairs were subdivided into two classes by quartile analysis. The first and second quartiles represented the low-attack pairs (43–178 attacks), and the third and fourth quartiles represented
In the present study, we confirmed the association between dark eye colour and social subordination in pearl cichlids, similar to what was observed for Nile tilapia (Volpato et al., 2003) and Atlantic salmon (Suter and Huntingford, 2002). We further demonstrated that this association is dependent on attack intensity. In this context, eye colour is a visual signal that reduces intraspecific aggression. Eye colour was correlated with both contest intensity and social status, suggesting that it
This study has been financially supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazil (grant no. 307380/2009-2).
- G.F. Turner et al.
A problem for game-theory analysis – assessment and intention in male mouthbrooder contests(Video) Clint Penick, Dominance Hierarchy Formation and Brain Changes in a Socially Flexible Ant, 5 Oct 2021
- G.F. Turner
The fighting tactics of male mouthbrooding cichlids – the effects of size and residency
- R.R. Rodrigues et al.
Color changing and behavioral context in the Amazonian dwarf cichlid Apistogramma hippolytae (Perciformes)
- T.G. Pottinger et al.
Stress responsiveness affects dominant–subordinate relationships in rainbow trout
- G.A. Parker et al.
Role assessment, reserve strategy, and acquisition of information in asymmetric animal conflicts
- K.I. O’Connor et al.
Familiarity influences body darkening in territorial disputes between juvenile salmon
- K.I. O’Connor et al.
Does darkening signal submission in territorial contests between juvenile Atlantic salmon, Salmo salar?
- W.J. Korzan et al.
Color change as a potential behavioral strategy
- P.L. Hurd
Cooperative signalling between opponents in fish fights
- E. Goncalves-de-Freitas et al.
Effect of water renewal on dominance hierarchy of juvenile Nile tilapia
Appl. Anim. Behav. Sci.
Chemical communication, aggression, and conspecific recognition in the fish Nile tilapia
A test of the sequential assessment game-fighting in the cichlid fish Nannacara anomala
The evolution of fatal fighting
Evolution of fighting behavior – decision rules and assessment of relative strength
J. Theor. Biol.
Repeated measures analysis of contests and other dyadic interactions: problems of semantics, not statistical validity
Hormonal control of brood care and social status in a cichlid fish with brood care helpers
An experimental model of aggressive dominance in Xiphophorus helleri (Pisces, Poeciliidae)
The aggressive behavior of Nile tilapia introduced into novel environments with variation in enrichment
Assessment of fighting ability in animal contests
Information-gathering and decision-making about resource value in animal contests
Agonistic profile and metabolism in alevins of the Nile tilapia
The interaction of size and experience in dominance relationships of juvenile steelhead trout (Salmo gairdneri)
Intraspecific resource partitioning in brown trout: the temporal distribution of foraging is determined by social rank
J. Anim. Ecol.
Benefits and costs of dominance in the angelfish Centropyge bicolor
Stress responses of the fish Nile tilapia subjected to electroshock and social stressors
Braz. J. Med. Biol. Res.
Methods for assessing social status in Arctic charr
J. Fish Biol.
Colour pattern and inhibition of aggression in the cichlid fish Astronotus ocellatus
J. Fish Biol.
Use of energy reserves in fighting hermit crabs
Proc. R. Soc. Lond. Ser. B
Evolution of stress responses refine mechanisms of social rank
2021, Neurobiology of Stress
Social rank functions to facilitate coping responses to socially stressful situations and conditions. The evolution of social status appears to be inseparably connected to the evolution of stress. Stress, aggression, reward, and decision-making neurocircuitries overlap and interact to produce status-linked relationships, which are common among both male and female populations. Behavioral consequences stemming from social status and rank relationships are molded by aggressive interactions, which are inherently stressful. It seems likely that the balance of regulatory elements in pro- and anti-stress neurocircuitries results in rapid but brief stress responses that are advantageous to social dominance. These systems further produce, in coordination with reward and aggression circuitries, rapid adaptive responding during opportunities that arise to acquire food, mates, perch sites, territorial space, shelter and other resources. Rapid acquisition of resources and aggressive postures produces dominant individuals, who temporarily have distinct fitness advantages. For these reasons also, change in social status can occur rapidly. Social subordination results in slower and more chronic neural and endocrine reactions, a suite of unique defensive behaviors, and an increased propensity for anxious and depressive behavior and affect. These two behavioral phenotypes are but distinct ends of a spectrum, however, they may give us insights into the troubling mechanisms underlying the myriad of stress-related disorders to which they appear to be evolutionarily linked.
Fighting cichlids: Dynamic of intrasexual aggression in dyadic agonistic encounters
2018, Behavioural Processes
Aggression is an extremely complex behaviour and female aggression is understudied when compared to males. Despite the fact that it has been suggested that conflict among females may be more frequently resolved peacefully, in many species females show high levels of aggression. We used Cichlasoma dimerus to describe dynamics and conflict outcome in intrasexual agonistic encounters. We performed encounters of two sex-matched animals in a neutral arena and we recorded agonistic interactions during one hour. All aggressive and submissive behaviours were described and quantified to perform the ethogram. Encounters followed three phases: pre-contest, contest and post-resolution. Latency, time of resolution and frequency of aggressive displays did not differ between sexes. Relative variations in size between female opponents better explained aggression outcome in each contest, since higher levels of aggression occurred in dyads of more similar fish. However, this was not observed in males, suggesting that probably morphological characteristics could be less relevant in male conflict resolution. Altogether these results suggest that in this ethological context, C. dimerus females are as aggressive as males and that they have similar motivation towards territorial aggression, emphasizing the need of deepening the study of aggression in females and not only in males.
Bayesian analysis improves experimental studies about temporal patterning of aggression in fish
2017, Behavioural Processes
Citation Excerpt :(Video) They Have Uncrowned Him-From Liberalism to Apostasy by Archbishop Lefebrve
As the numbers of less intensive aggressive behaviors (displays) were much higher than the numbers of the more intensive ones (attacks), they prevailed on the total attacks, shaping its distribution through time. In the literature, there are many articles using total attacks (e.g. Almazán-Rueda et al., 2004; Wessel et al., 2006; Castro and Caballero, 2004; Earley et al., 2006; Miyai et al., 2011; Carvalho et al., 2012; Pinho-Neto et al., 2014). However, our results highlight that adding attacks to displays diminishes the posterior probability between the days compared to using displays alone, losing their statistical significance considering a 95% credible interval (Figs. 1 A-2 and 5 A-1).
This study aims to describe a Bayesian Hierarchical Linear Model (HLM) approach for longitudinal designs in fish’s experimental aggressive behavior studies as an alternative to classical methods In particular, we discuss the advantages of Bayesian analysis in dealing with combined variables, non-statistically significant results and required sample size using an experiment of angelfish (Pterophyllum scalare) species as case study. Groups of 3 individuals were subjected to daily observations recorded for 10min during 5days. The frequencies of attacks, displays and the total attacks (attacks+displays) of each record were modeled using Monte Carlo Markov chains. In addition, a Bayesian HLM was performed for measuring the rate of increase/decrease of the aggressive behavior during the time and to assess the probability of difference among days. Results highlighted that using the combined variable of total attacks could lead to biased conclusions as displays and attacks showed an opposite pattern in the experiment. Moreover, depending of the study, this difference in pattern can happen more clearly or more subtly. Subtle changes cannot be detected when p-values are implemented. On the contrary, Bayesian methods provide a clear description of the changes even when patterns are subtle. Additionally, results showed that the number of replicates (15 or 11) invariant the study conclusions as well that using a small sample size could be more evident within the overlapping days, that includes the social rank stability. Therefore, Bayesian analysis seems to be a richer and an adequate statistical approach for fish’s aggressive behavior longitudinal designs.
Social stress effects on pigmentation and monoamines in Arctic charr
2015, Behavioural Brain Research
Citation Excerpt :
This is often evident in agonistic interactions where aggression, dominance, and/or subordinance can be signalled with colours. For instance, eye darkening signals dominance in lizards [2,3], whereas eye darkening signals subordinance in several teleost fish [4–8]. Further, melanin-based pigmentation correlates positively with aggression in birds [9–11] and mammals .
Pigmentation often signals status and in general melanin-based pigmentation is indicative of aggression and stress resilience in vertebrates. This is evident in the salmonids Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) where more melanin spotted individuals are more stress resilient. However, in the salmonid Arctic charr (Salvelinus alpinus) it seems as if it is carotenoid-based pigmentation that signals aggression and stress resilience. In our study, social stress effects on carotenoid-based spots, and behavioural and physiological stress responses were investigated. Socially stressed individuals have more spots, and behavioural stress responses were associated with spots. Some of the results concerning physiological stress responses, such as plasma cortisol levels and monoaminergic activity, are associated with spottiness. Further, the earlier proposed lateralization of spots, with left side connected to stress responsiveness and right side to aggression, is to some extent validated although not conclusively. In conclusion, this study provides further evidence that more stressed charr have more carotenoid spots, and for the first time monoaminergic activity is shown to be connected with carotenoid pigmentation.
Dominance and stress signalling of carotenoid pigmentation in Arctic charr (Salvelinus alpinus): Lateralization effects?
2015, Physiology and Behavior
Citation Excerpt :
A common type of cue is pigmentation. For instance, in the lizard Anolis carolinensis eye spot darkening signals dominance [3–5] and eye darkening signals subordinance in several teleost fish [6–9]. Further, melanin-based pigmentation has in general been linked to behaviour in various vertebrates [10,11].
Social conflicts are usually solved by agonistic interactions where animals use cues to signal dominance or subordinance. Pigmentation change is a common cue used for signalling. In our study, the involvement of carotenoid-based pigmentation in signalling was investigated in juvenile Arctic charr (Salvelinus alpinus). Size-matched pairs were analysed for pigmentation both before and after being tested for competitive ability. We found that dominant individuals had fewer carotenoid-based spots on the right and left sides as well as lower plasma cortisol levels compared to subordinate individuals. Further, the number of spots on both sides was positively associated with plasma cortisol levels. These results indicate that carotenoid-based pigmentation in Arctic charr signals dominance and stress coping style. Further, it also appears as if carotenoid-based pigmentation is lateralized in Arctic charr, and that the right side signals aggression and dominance whereas the left side signals stress responsiveness.
Eye darkening as a reliable, easy and inexpensive indicator of stress in fish
Citation Excerpt :
ED has been associated with social stress in Atlantic salmon (Suter and Huntingford, 2002) and Nile tilapia (Volpato et al., 2003; Vera Cruz and Brown, 2007). Recently, ED was shown to generate negative social feedback, as displayed by subordinate fish, which reduces the dominant's aggression in pearl cichlid (Miyai et al., 2011). Because these studies are all concerned with social stressors, in the present experiment we tested a possible generalization of ED as a response to non-social stressors (confinement and air exposure).
We expand the use of eye darkening (ED) to indicate non-social stress in the fish Nile tilapia Oreochromis niloticus (L.). ED is easily estimated, not requiring any sophisticated equipment, and is non-invasive, facilitating the collection of several measures of stress over time. In the current study, we showed the following: (i) high- and low-ED occur spontaneously, indicating different fish reactions to adjustments to a novel environment; (ii) fish confinement or air exposure clearly increases ED (air exposure is a stronger stressor than confinement), and the time to restore basal values indicates the severity of the impact of the stressor on the fish (this response is not affected by period of the day, e.g., morning or afternoon); and (iii) in adults, females were more responsive (slower recovery) to 2-min air exposure than to 30-min confinement.
Dopaminergic control of anxiety in young and aged zebrafish
Pharmacology Biochemistry and Behavior, Volume 157, 2017, pp. 1-8(Video) The Will to Power by Friedrich Wilhelm Nietzsche (Volume 2, Book 3 and 4) - Full Audiobook
Changes in the expression of the dopamine transporter (DAT), or the sensitivity of dopamine receptors, are associated with aging and substance abuse and may underlie some of the symptoms common to both conditions. In this study, we explored the role of the dopaminergic system in the anxiogenic effects of aging and acute cocaine exposure by comparing the behavioral phenotypes of wild type (WT) and DAT knockout zebrafish (DAT-KO) of different ages. To determine the involvement of specific dopamine receptors in anxiety states, antagonists to D1 (SCH23390) and D2/D3 (sulpiride) were employed. We established that DAT-KO results in a chronic anxiety-like state, seen as an increase in bottom-dwelling and thigmotaxis. Similar effects were produced by aging and acute cocaine administration, both leading to reduction in DAT mRNA abundance (qPCR). Inhibition of D1 activity counteracted the anxiety-like effects associated with DAT deficit, independent of its origin. Inhibition of D2/D3 receptors reduced anxiety in young DAT-KO, and enhanced the anxiogenic effects of cocaine in WT, but did not affect aged WT or DAT-KO fish. These findings provide new evidence that the dopaminergic system plays a critical role in anxiety-like states, and suggest that adult zebrafish provide a sensitive diurnal vertebrate model for elucidating the molecular mechanisms of anxiety and a platform for anxiolytic drug screens.
Group response to social perturbation: impacts of isotocin and the social landscape
Animal Behaviour, Volume 105, 2015, pp. 55-62
Conflict is an inherent part of group living, and the mediation of conflict is essential for the stability of social groups. Response to within-group social conflict should depend on the external social environment. Individuals in dense social neighbourhoods have greater opportunities to disperse and join a nearby group compared to individuals in sparse social neighbourhoods with few nearby groups. To explore the influence of the social neighbourhood on responses to conflict, we experimentally perturbed groups of wild Neolamprologus pulcher, a cooperatively breeding cichlid fish, by temporarily removing a subordinate individual. Such removals typically increase the amount of within-group aggression. As predicted, aggression towards the returning subordinate and the rate of eviction from the group increased with the density of neighbouring social groups. Furthermore, we predicted that the returning subordinate could improve its likelihood of reacceptance into the group by displaying submissively. To test this prediction, we attempted to manipulate submissive behaviour by injecting the removed individuals with isotocin, a nonapeptide hormone that has been shown in the laboratory to increase the expression of submissive behaviour in this species. As predicted, subordinates that received isotocin showed more submission when returned to their group. However, contrary to our prediction, these isotocin-treated fish received more aggression from their group-mates and were more likely to be evicted than fish receiving a saline control injection. Our results emphasize the importance of the social neighbourhood in determining within-group dynamics but surprisingly contradict the notion that submissive behaviour reduces aggression and facilitates group stability.
Death-associated odors induce stress in zebrafish
Hormones and Behavior, Volume 65, Issue 4, 2014, pp. 340-344
Living animals exploit information released from dead animals to conduct adaptive biological responses. For instance, a recently published study has shown that avoidance behavior is triggered by death-associated odors in zebrafish. Stress can clearly act as an adaptive response that allows an organism to deal with an imminent threat. However, it has not been demonstrated whether these chemical cues are stressful for fish. Here, we confirmed that dead zebrafish scents induce defensive behavior in live conspecifics. Additionally, we show for the first time in fish that these scents increase cortisol in conspecifics. To reach this conclusion, firstly, we exposed zebrafish to multi-sensorial cues (e.g., visual, tactile, chemical cues) from dead conspecifics that displayed defensive behaviors and increased cortisol. Also, when we limited zebrafish to chemical cues from dead conspecifics, similar responses arose. These responses coincide with the decaying destruction of epidermal cells, indicating that defensive and stress responses could take place as an effect of substances emanating from decaying flesh, as well as alarm substance released due to rupture of epidermal cells. Taken together, these results illustrate that living zebrafish utilize cues from dead conspecific to avoid or to cope with danger and ensure survival.
Chemical communication in cichlids: A mini-review
General and Comparative Endocrinology, Volume 221, 2015, pp. 64-74
The family Cichlidae is well-known for pair-formation, parental care, territoriality, elaborate courtship and social organization. Do cichlids use chemical communication to mediate any of these behaviours? Early studies suggest that parent cichlids can discriminate between conspecific and heterospecific wrigglers (but not eggs) using olfactory cues. Some species are able to discriminate between their own brood and other conspecific broods based on olfaction. The young recognise conspecific adults (although not necessarily their parents) through the odorants they release. In both scenarios, protection of the young from predation is the likely selective force. Some male cichlids use urinary pheromones during courtship and spawning to attract females and induce ovulation. Females – in their turn – may base their mate-choice in part on assessment of those self-same pheromones. The same pheromonal system may be involved in establishing and maintaining the social hierarchies in lek-breeding cichlids. Individual recognition is also mediated by chemical communication. Finally, there is ample behavioural evidence that cichlids – like ostariophysan fish – release alarm cues that alert conspecifics to predation danger. Although the effects of these cues may be similar (e.g., increased shelter use, tighter schooling), they are different substances which remain to be identified. Cichlids, then, use chemical communication associated with many different behaviours. However, given the diversity of cichlids, little is known about the mechanisms of chemical communication or the chemical identity of the cues involved. The aim of this mini-review is to persuade those working with cichlids to consider the involvement of chemical communication, and those working in chemical communication to consider using cichlids.
Agonistic interactions elicit rapid changes in brain nonapeptide levels in zebrafish
Hormones and Behavior, Volume 84, 2016, pp. 57-63
The teleost fish nonapeptides, arginine vasotocin (AVT) and isotocin (IT), have been implicated in the regulation of social behavior. These peptides are expected to be involved in acute and transient changes in social context, in order to be efficient in modulating the expression of social behavior according to changes in the social environment. Here we tested the hypothesis that short-term social interactions are related to changes in the level of both nonapeptides across different brain regions. For this purpose we exposed male zebrafish to two types of social interactions: (1) real opponent interactions, from which a Winner and a Loser emerged; and (2) mirror-elicited interactions, that produced individuals that did not experience a change in social status despite expressing similar levels of aggressive behavior to those of participants in real-opponent fights. Non-interacting individuals were used as a reference group. Each social phenotype (i.e. Winners, Losers, Mirror-fighters) presented a specific brain profile of nonapeptides when compared to the reference group. Moreover, the comparison between the different social phenotypes allowed to address the specific aspects of the interaction (e.g. assessment of opponent aggressive behavior vs. self-assessment of expressed aggressive behavior) that are linked with neuropeptide responses. Overall, agonistic interactions seem to be more associated with the changes in brain AVT than IT, which highlights the preferential role of AVT in the regulation of aggressive behavior already described for other species.
Submerged plus maze: A novel test for studying anxiety-like behaviour in fish
Behavioural Brain Research, Volume 362, 2019, pp. 332-337
The elevated plus maze is a prominent and well-documented test for studying anxiety in rodents. Fish are becoming more prevalent in studies of anxiety, yet the elevated plus maze has not been adapted and validated for fish. In the present study, we created an aquatic version of the elevated plus maze called the ‘submerged plus maze,’ which is shaped like a plus symbol with four arms alternating between black and transparent walls. We used convict cichlid fish (Amatitlania nigrofasciata) and administered diazepam to validate the apparatus for studying anxiety-like behaviour. After diazepam exposure, fish spent more time in and entered more open arms than after vehicle exposure, consistent with the effect of benzodiazepines on rodents in the elevated plus maze. The submerged plus maze maintains construct validity for testing anxiety in convict cichlid fish.(Video) Chapter 3 Lecture China in Antiquity
Copyright © 2011 Elsevier GmbH. All rights reserved.