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In this review, we consider the definitions and experimental approaches to emotional contagion and prosocial behaviour in mammals and explore their evolutionary conceptualisation for studying their occurrence in the evolutionarily divergent vertebrate group of ray-finned fish. We present evidence for a diverse set of fish phenotypes that meet definitional criteria for prosocial behaviour and emotional contagion and discuss conserved mechanisms that may account for some preserved social capacities in fish. Finally, we provide some considerations on how to address the question of interdependency between emotional contagion and prosocial response, highlighting the importance of recognition processes, decision-making systems, and ecological context for providing evolutionary explanations. • Emotional contagion can explain ancestral forms of prosocial behaviour in fish. • The testable basis is state transfer triggering appropriate benefit from others' acts. • Recognition processes are a paramount component to elucidating this link. • Comparative approaches can reveal evolutionary substrates for higher-order functions. [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2009.03.006 Byline: Albert F.H. Ros (a), Teresa Fagundes (a), Rui F. Oliveira (a)(b) Abstract: In maximizing reproductive success, individuals face a trade-off between parental care for their current offspring and investing in androgen-dependent sexual traits to produce further offspring. It has thus been proposed that parental effort would suppress androgen levels. Here, we studied parental effort by manipulating brood size in the peacock blenny, Salaria pavo, a littoral fish species in which males show long periods of paternal care. We focused on the effects of brood size on female spawning rate (measured as number of eggs received in the nest by focal males) and androgen levels. We found a positive linear relationship between brood size and the number of eggs received subsequently. Accordingly, spawning rate increased for males with experimentally enlarged broods while it decreased for males in which brood size was reduced. However, over a longer time interval, brood sizes of both treatments returned to the nonmanipulated brood size, suggesting an effect of additional factors such as male quality. Brood size did not show the expected negative relationship with levels of testosterone and 11-ketotestosterone. On the contrary, testosterone levels were positively correlated with brood size. However, in agreement with the prediction, changes in the level of parental care by manipulation of brood size showed an inverse relationship with testosterone levels. As with brood size, given time, testosterone levels tended to return to nonmanipulated levels. Such changes suggest that males adjust their brood size to an individual value through androgen modulation of courtship or other traits influencing female spawning rate. Author Affiliation: (a) Unidade de Investigacao em Eco-Etologia, Instituto Superior de Psicologia AplicadaPortugal (b) Champalimaud Neuroscience Programme, Instituto Gulbenkian de CiA*ncia, Portugal Article History: Received 5 March 2008; Revised 27 June 2008; Accepted 16 March 2009 Article Note: (miscellaneous) MS. number: 08-00148R

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2007.04.016 Byline: Molly E. Cummings, Joana M. Jordao, Thomas W. Cronin, Rui F. Oliveira Abstract: We investigated the visual ecology of the coloration of the eastern Atlantic fiddler crab, Uca tangeri, with particular attention to predator (e.g. avian) and conspecific vision. Spectral reflectance measurements were made on different body parts used in possible intraspecific communication as well as background habitats including crab-made materials (e.g. mudballs). Avian-based and crab-based visual models were used to obtain different estimates of crab conspicuousness to potential predators and conspecifics. We found that male body parts (except for dorsal carapace) were significantly more conspicuous to conspecific viewers than female equivalent body parts, and showed greater within-body contrast estimates. Moreover, male major claw areas differed in reflectance properties, producing variation in conspicuousness that fit signalling predictions: areas visible during claw-waving events were most conspicuous against the background sky, whereas areas visible in nonwaving positions were more conspicuous against substrate backgrounds. For avian vision, sexually dimorphic coloration results in males being generally more conspicuous than females (in terms of brightness contrast) against all backgrounds, however, there was no sexual dimorphic conspicuousness of carapace coloration. Furthermore, one of the most conspicuous features of both male and female crabs is an area that is likely to be more visible to crabs (mouthparts) than to avian predators from above. While conspicuousness varies with background, the most conspicuous background for male signalling parts (major claw) is dark mudballs, suggesting that males may increase the conspicuousness of their signals by modifying their signalling environment. Author Affiliation: (a) Section of Integrative Biology, University of Texas at Austin, U.S.A. (a ) Unidade de Investigacao em Eco-Etologia, Instituto Superior de Psicologia Aplicada, Lisboa, Portugal (a ) Department of Biology, University of Maryland at Baltimore County, U.S.A. Article History: Received 19 June 2006; Revised 24 September 2006; Accepted 9 April 2007 Article Note: (miscellaneous) MS. number: A10479R

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2005.04.014 Byline: Katharina Hirschenhauser, Rui F. Oliveira Abstract: The challenge hypothesis (Wingfield et al. 1990, American Naturalist, 136, 829-846) predicts varying androgen responses to mating, breeding or territorial behaviour in avian males. At the interspecific level, the highest androgen responsiveness has been observed in males from monogamous species with paternal incubation, and the lowest in males from promiscuous, nonpaternal species. Studies of a number of vertebrate species have discussed the extension of the challenge hypothesis predictions to nonavian vertebrates, but a general 'vertebrate consensus' has not been achieved. For this quantitative review we included data from all vertebrate species available in the literature into several meta-analyses. We distinguished between the effects of androgens on sexual, aggressive and paternal behaviour and the effects of behaviour on androgen levels and compared these effects between taxa, mating systems and types of parental care. We observed large variations between taxa in all data sets. Nevertheless, at the vertebrate level the challenge hypothesis predictions originating from the avian literature were confirmed for the modulation of androgen responsiveness (1) to sexual behaviour by paternal care but not by mating system, and (2) to paternal behaviour by mating system but not the degree of paternal care. In contrast, our results provide (3) no support for the predicted modulation of androgen levels in response to agonistic interactions by mating and parental care system at the vertebrate level. Furthermore, our meta-analyses suggest that the effects of exogenous testosterone on sexual and agonistic behaviour, as a rule of thumb, may be expected to be larger in nonpaternal than in paternal systems. Author Affiliation: Unidade de Investigacao em Eco-Etologia, ISPA, Portugal Article History: Received 24 September 2004; Revised 5 November 2004; Accepted 10 April 2005 Article Note: (miscellaneous) MS. number : RV54

Visual communication in the marine fish, Salaria pavo, was studied using video playbacks.

Both male and female European fiddler crab, Uca tangeri, produce mudballs. Among females this is merely a by-product of nest digging but among males, mudballs serve two other functions. Experimental removal of mudballs increased aggression among neighboring males while placing mudballs next to crab dummies encouraged females to approach and enter the burrows. These results suggest that mudballing behavior serves to reduce competition among males and attract female conspecifics.

The ecological modulation affects sex roles in a natural population of the blenniid fish, Salaria pavo. The female initiation of mating predominates over male intra-sexual competition, active courtship and developed epigamic characters in males. More than one female of S. pavo comes to the nest and each female mates with different males during the breeding season. The males are selective in admitting the females to the nest. The ability of females to spawn determines the male courtship behavior for the nest sites.

Typically, animals choose to mate with animals they have seen courted or been in close contact with sexual partners. Research was conducted on mate copying, to determine if it is adaptive. Peacock blennies were used as subjects.

Highlights: [•] We examined female mate choice mechanisms in a captive neotropical passerine. [•] Male attributes were less important to females than novelty in preference trials. [•] Females behaved aggressively towards familiar males when novel ones were available. [•] Males were unresponsive behaviourally to female contact with novel male. [•] They also did not respond physiologically to threat of novel males. [ABSTRACT FROM AUTHOR]

‘Social competence’ refers to the ability of an individual to optimise its social behaviour depending on available social information. Although such ability will enhance social interactions and thus raise Darwinian fitness, its evolutionary and ecological significance has been largely ignored. Social competence is based on behavioural flexibility. We propose that the study of social competence requires an integrative approach that aims to understand how the brain translates social information into flexible behavioural responses, how flexibility might be constrained by the developmental history of an individual or by trade-offs with other (ecological) competences, and how social plasticity feeds back on fitness. Finally we propose a hypothesis of how social competence can become a driver of social evolution. [Copyright &y& Elsevier]

Androgens are classically thought of as the sex steroids controlling male reproduction. However, in recent years evidence has accumulated showing that androgens can also be affected by the interactions between conspecifics, suggesting reciprocal interactions between androgens and behaviour. These results have been interpreted as an adaptation for individuals to adjust their agonistic motivation and to cope with changes in their social environment. Thus, male–male interactions would stimulate the production of androgens, and the levels of androgens would be a function of the stability of its social environment [‘challenge hypothesis’, Gen. Comp. Endocrinol. 56 (1984) 417]. Here the available data on social modulation of androgen levels in male teleosts are reviewed and some predictions of the challenge hypothesis are addressed using teleosts as a study model. We investigate the causal link between social status, territoriality and elevated androgen levels and the available evidence suggests that the social environment indeed modulates the endocrine axis of teleosts. The association between higher androgen levels and social rank emerges mainly in periods of social instability. As reported in the avian literature, in teleosts the trade-off between androgens and parental care is indicated by the fact that during the parental phase breeding males decreased their androgen levels. A comparison of androgen responsiveness between teleost species with different mating and parenting systems also reveals that parenting explains the variation observed in androgen responsiveness to a higher degree than the mating strategy. Finally, the adaptive value of social modulation of androgens and some of its evolutionary consequences are discussed. [Copyright &y& Elsevier]

• We tested how the social environment and cortisol exposure (acute/chronic) affect adult neurogenesis in zebrafish. • Cell proliferation is dependent on the valence of the social environment (positive > negative). • Cell proliferation is independent of either acute or chronic cortisol exposure. • Thus, there is a key role of the social environment in adult neurogenesis in zebrafish independently of cortisol modulation. In Mammals adult neurogenesis is influenced by environmental conditions, and the glucocorticoid hormones (GC) play a major role in this regulation. In contrast in fish, the study of the effects of cortisol on the regulation of environmental driven adult neurogenesis has produced conflicting results. While in some species elevated cortisol levels impair cell proliferation, in others, it promotes cell proliferation and differentiation. This lack of consistency may be explained by methodological differences across studies, namely in the stimuli and/or cortisol treatments used. Here, we tested the effects of the social environment on adult neurogenesis, considering a positive and a negative social context, and different durations of cortisol exposure. We hypothesise that there is an interaction between the valence of the social environment and cortisol, such that elevated acute cortisol experienced during social interactions only have a detrimental effect on neurogenesis in negative social contexts. Therefore, fish were exposed to a positive (conspecific shoal) or negative (predator) social experience, and the interaction between the valence of the social context and cortisol exposure (acute and chronic) was tested. Our results indicate that adult neurogenesis is modulated by the social environment, with the number of newly generated cells being dependent on the valence of the social information (positive > negative). These effects were independent of cortisol, either for acute or chronic exposure, highlighting the social environment as a key factor in the modulation of cell proliferation in the adult zebrafish brain, and rejecting a role for cortisol in this modulation. [ABSTRACT FROM AUTHOR]

Research shows that testosterone (T) is lower among partnered women, but not for women with a more unrestricted sociosexuality. There are fundamental personality traits, which are indices of mating effort and might moderate the association between T and relationship status. Two such traits are extraversion (E) and sensation seeking (SS). The present study tests if E and SS moderate the association of women’s T with relationship status and parental care. Seventy-three Portuguese women completed a short form of the NEO-FFI and the Sensation Seeking Scale (SSS-V). Salivary T was assayed using luminescence immunoassays. Being involved in a committed relationship was related to lower T for the total sample, and for the subgroups low in E and SS, but not for the subgroups high in E and SS. Parental care was related to lower T in the subgroup low in E, and marginally in the subgroup low in SS. In multivariate analyses, only relationship status predicted T in the total sample and in the subgroups low in E and SS. The results were not confounded by age and oral contraception. These results provide support for lower T being important for monogamous pair bonding rather than for being partnered per se . [ABSTRACT FROM AUTHOR]

Cooperation between unrelated individuals usually involves investments that often mean a decrease in immediate payoffs, but ensure future benefits. Here we investigated the potential role of the neuropeptides Arginine-vasotocin (AVT) and Isotocin (IT) as proximate agents affecting individuals' cooperative levels in the Indo-pacific bluestreak cleaner wrasse Labroides dimidiatus . Their ‘client’ reef fish partners only benefit from interacting if cleaners eat ectoparasites and refrain from gleaning preferred client mucus. Thus, cleaners must control their impulse to eat according to their preference, and eat less preferred items to maintain ongoing interactions and avoid clients' leaving or punishing. We found that solely the experimental transient higher dosage of AVT led to a decrease of cleaners' willingness to feed against their preference, while IT and AVT antagonists had no significant effects. The sole effect of AVT on cleaner's performance may imply a link between AVT's influence and a potential activation of a stress response. Our results confirm the importance of the AVT/AVP system as an agent affecting levels of cooperation, offering a potential mechanistic pathway for the reported flexible service quality that cleaners provide their clients. [ABSTRACT FROM AUTHOR]

Abstract: In recent years there has been an increasing interest in the cognitive abilities of fish with implications for animal welfare and management of rearing operations. Although it is known that psychological factors can modulate the stress response in mammals, this aspect has seldom been investigated within stress in fish. In this study we investigate whether the perception (appraisal) that fish make of significant environmental events modifies their behavioural and physiological response. For this purpose we have used a predictable vs. unpredictable paradigm for positive (feeding) and negative (confinement) events using the cichlid fish Oreochromis mossambicus as a model species. Results show that there is a differential effect of predictability for the feeding and confinement events. In the confinement experiment, predictability involved more attention to the visual cue and lower cortisol. The feeding event triggered higher levels of anticipatory behaviour and a tendency for higher cortisol in the predictable group. Therefore, predictable negative events reduce the cortisol response. Predictable positive events may elicit an anticipatory response, and when there is a significant delay between the visual cue and the actual occurrence of the event, it may also contain elements that can be interpreted as a stress response. These findings demonstrate that fish can appraise relevant aspects of the environment, with welfare implications for housing, husbandry and experimental procedures. [ABSTRACT FROM AUTHOR]

Abstract: Recent behavioural, cognitive and neurophysiological studies strongly suggest that fish are capable of psychological experiences. Therefore, identifying needs from the animals’ point of view is likely to be one of the best approaches to understand their welfare. Motivational tests, as a measure of what animals want, have been developed and refined for some decades. Despite numerous studies on fish motivational systems, none have attempted to quantify their motivation using this approach. Motivation studies often imply operant tasks for which various devices are used. The aim of this study was to adapt a push-door to quantify motivation in a cichlid fish, the Mozambique tilapia (Oreochromis mossambicus). Males of this species have strong snouts which they use for a number of activities and are thus suited to push. Twelve males of different social status were tested for three kinds of reinforcers: food, social partner and a control (additional space with substrate only). The animals were required to work the door (push/touch) at an ascending cost in order to have access to the resources. Measures of motivation included latency to open the door, work attention and maximum price paid. Latency to open the door increased with increasing cost for all resources, with the highest latency for the control reinforcer. Work attention was constant with increasing costs for social partners and food, and higher than the control. Work attention decreased for the control as cost increased. Maximum price paid was consistent with these results, being higher for social partners and food than for the control. The results of the three measures were consistent with each other and showed that the push-door can be used to measure motivation in this species. Further refinement of the present experimental set up will allow the use of this paradigm in the future, in order to improve knowledge on how this species values and ranks its needs. [ABSTRACT FROM AUTHOR]

Abstract: Many cichlid species dig spawning pits or nests in soft bottoms and exhibit many substrate oriented activities. Despite this fact being of general knowledge, captive cichlids in laboratory and aquaculture set-ups are often kept in the absence of a soft substrate that they can manipulate. This raises a potential welfare issue, depending on how the substrate is valued by cichlid fish. The aim of this study is to assess the importance of substrate for male Mozambique tilapia (Oreochromis mossambicus) in social and non-social contexts. Preferences were established as a measure of time spent in two choice compartments, before and after the presence of a female. Locomotory activity, social interactions and substrate-related behaviours were recorded. Results show that dominant males prefer the area with substrate regardless of social context, and that female''s presence strengthens this preference. The same preference is not apparent in the subordinate males, except for foraging. To draw conclusions on the importance of substrate to subordinates, preferences should also be assessed in agonistic contexts, during which substrate may serve to displace aggression. These results, together with related previous studies, show that the lack of substrate is particularly deleterious in a reproductive context, and thus it is likely to decrease the welfare state of breeding males of Mozambique tilapia. [Copyright &y& Elsevier]

Abstract: We studied the role of steroid hormones for parental and alloparental brood care and social status in a cooperatively breeding fish. We measured excretion levels of testosterone and 11-ketotestosterone in males, estradiol-17β in females and cortisol in both sexes at different stages of the breeding cycle, and compared these values to data measured in non-reproductive fish. Brood care behaviour does not seem to relate to steroid hormone excretion levels in this species. Steroid hormones varied with social status, however. Non-territorial male aggregation members, for example, showed high testosterone and low 11-ketotestosterone excretion levels, suggesting that they might pursue a “stand-by strategy” for breeding to react quickly if an occasion for breeding arises. Cortisol excretion levels are high in juvenile helpers compared to same-size aggregation members, suggesting higher stress levels in subordinate members of reproductive groups. This is the first study assessing if steroid hormone control mechanisms are involved in brood care and social roles in a cooperatively breeding fish. [Copyright &y& Elsevier]

Abstract: We have investigated the effect of mirror-elicited agonistic behaviour on oxygen consumption in the Mozambique tilapia, Oreochromis mossambicus (Cichlidae). Males exposed to their mirror image showed higher frequencies of both lateral display and tail-beating and escalated aggression more frequently than males exposed to a transparent glass that was used as a control for the presence of a novel object in the tank. This aggressive response was correlated with an increase in oxygen consumption. Overt aggression was highly correlated with display behaviour and with locomotor activity. Bivariate analyses showed high correlation (explaining about 64% of variation) between overt aggression, locomotor activity and metabolic rates. Weakly positive bivariate correlations between displays and metabolic rates turned spurious after partialling out aggression. The data suggest that energetic costs only emerge late during the conflict, when animals escalate their aggressive behaviour. [Copyright &y& Elsevier]

Abstract: Animal welfare has been defined as the balance between positive and negative experiences or affective states. Despite the growing evidence of complex cognitive abilities and the expression of affective states such as pain and fear, very little is known about ability to experience memory based affective states in non-mammalian animal models. The goal of this study was to validate conditioned place preference/avoidance (CPP/CPA) tests as a method to assess the affective valence of environmental stimuli in teleost fishes. Physiological and behavioural indicators of affective state were used to characterise the response to a priori appetitive and aversive stimuli in CPP/CPA tests in gilthead sea bream (Sparus aurata). Fish were tested individually in a CPP/CPA tank divided into two halves, with one half uniformly white and one half marked by dotted wall patterns. During an initial habituation phase fish were placed in a central alley for 10min and afterwards allowed to swim freely throughout the whole tank during 20min in order to determine their initial preferred and non-preferred side (IPS/INPS). During the training phase, fish were presented either with a single aversive stimulus in the IPS (chasing with a dip net) or with a repeated appetitive stimulus (release of pellets) in the INPS. The test phase consisted of the same procedure as the habituation phase. The behaviour of each individual was video-recorded and analysed with video-tracking software. Fish submitted to appetitive stimulus increased significantly the time spent and the distance moved in the stimulation side, while fish exposed to aversive stimulus decreased significantly the time spent in the stimulation side, increased the distance moved in the non-stimulation side and showed an increase in cortisol level. Therefore, the use of behavioural (individual swimming activity) and physiological (plasma cortisol concentration) indicators of affective state during the CPP/CPA test allowed to validate the use of this test as a way to assess the affective valence attributed by fish to different environmental stimuli. Finally, this study also shows that fish are able to retain memories of events with positive/negative valence which are retrieved by environmental cues. [Copyright &y& Elsevier]

Highlights: [•] Zebrafish were exposed to different fighting experiences: winning, losing and mirror-fighting. [•] Winners show higher serotonergic and dopaminergic activity in the telencephalon. [•] Losers show higher serotonergic in the optic tectum. [•] No significant changes in monoamine activity were observed in mirror fighters. [•] Monoamines are differentially regulated by social interactions in different brain regions. [Copyright &y& Elsevier]

Abstract: Phenotypic change in response to variation in environmental cues has been widely documented in fish. Transitions in social dominance, in particular, have been shown to induce a rapid switch in reproductive phenotypes in many species. However, this effect has been mainly studied in adults and focused on behavioural transitions. The way social cues constraint the phenotypic development of juveniles remains poorly studied in fish. We tested the importance of social dominance and density in the phenotypic development of juveniles of the peacock blenny Salaria pavo. This species shows sequential male alternative reproductive tactics. In the first breeding season males can reproduce as nest-holders or as parasitic males (female-mimicking), or postpone reproduction; from the following season afterwards all males reproduce as nest-holders. Parasitic males have relatively larger testes that lack a testicular gland, present in the testes of nest-holders. The testicular gland is the main source of androgens in the testes and accordingly nest-holders have higher circulating androgen levels. In addition, exogenous androgen administration to parasitic males promotes the development of secondary sexual characters (SSC) only present in nest-holders such as a head crest and an anal gland. We raised juveniles under a high or low-density treatment and monitored social interactions for 1month. No significant effect of density on the development of juvenile males was detected. However, within each replicate, the relative body size of juvenile males at the beginning of the experiment determined their dominance status, with dominant males developing towards the nest-holder morphotype. Dominant males engaged in more nest defence behaviour, showed larger testicular glands, had higher levels of 11-ketotestosterone (11-KT) and testosterone (T) and developed more SSC, as compared to subordinate males. However, these effects of social dominance were moderated by body condition as only dominant males in good body condition developed SSC. The effect of social dominance and of the area of the testicular gland on the development of SSC was mediated by 11-KT and on the expression of nest defence behaviour by T. Interestingly, in spite of the higher androgen levels and more pronounced morphologic development of SSC in dominant individuals, gonadal development was independent of social dominance and most fish still had underdeveloped testis at the end of the experiment. In conclusion, social dominance promoted the development of the testicular gland, an increase in circulating androgen levels and the development of SSC, but did not promote testicular development. This suggests a dissociation of mechanisms underlying sexual maturation and the expression of male reproductive traits. This dissociation seems to be the key for the occurrence of female-mimicking males in this species, which are sexually mature despite lacking the SSC typical of nest-holders. [Copyright &y& Elsevier]

In this paper, we present the results of cellular and molecular studies on the neuroendocrine correlates of male sexual polymorphism in a population of the blenniid fish Salaria pavo (Risso). Bigger and older males defend nests, whereas smaller and younger males mimic female nuptial coloration and behavior to gain access to nests and sneak fertilizations. In this population, sex-role reversal in courtship also occurs (i.e., females are the courting sex). Immunocytochemistry and in situ hybridization were used to examine the production of arginine vasotocin (AVT) peptide and messenger RNA, respectively. The expression of AVT mRNA on a per-cell basis was correlated with mating behavior, rather than with sex morphotype, which suggests that the greater level of AVT mRNA expression in females and sneakers is correlated with the production of courtship behavior. On the other hand, the number and size of AVT peptide-producing cells in both male types is higher or larger, respectively, than in females, which suggests that it is correlated with sex morphotype, rather than with mating behavior. [Copyright &y& Elsevier]