Verification versus falsification of existing theory

Hormones and Behavior, 2015

Social animals with hierarchal dominance systems are particularly susceptible to their social environment. There, interactions with conspecifics and hierarchal position can greatly affect an individual's behavior, physiology and reproductive success. Our experimental model, Cichlasoma dimerus, is a serially-monogamous Neotropical cichlid fish with a hierarchical social system, established and sustained through agonistic interactions. In this work, we aimed to describe C. dimerus social structure and its association with hormonal profiles and testicular cellular composition. We recorded and quantified agonistic interactions from the territorial pair, i.e. the top ranked male and female, and the lowest ranked male of stable social groups. Plasma levels of 11-ketotestosterone (11-KT), testosterone, 17β-estradiol (E 2 ) and cortisol were measured by ELISA. Results show that territorial pairs cooperatively guarded the territory, but rarely attacked in synchrony. Territorial males had higher testosterone and 11-KT plasma levels than non-territorial males, while E 2 and an index of its metabolization from testosterone were higher in non-territorial males. No difference was observed in cortisol levels. Plasma 11-KT and an index of the conversion of testosterone to 11-KT, positively correlated with the frequency of aggressiveness, while E 2 showed the opposite pattern. Territorial males had a higher gonadosomatic index than non-territorial males. The quantification of testicular cellular types revealed that the percentage of spermatocytes and spermatids was higher in non-territorial males, while territorial males showed a greater percentage of spermatozoa. Thus, C. dimerus male social position within a stable hierarchy is associated with distinct behaviors, steroid levels and testicular degree of development.

The Behavior Analyst, 2015

We examined the species used as subjects in every article published in the Journal of the Experimental Analysis of Behavior (JEAB) from 1958 through 2013. We also determined the sex of subjects in every article with human subjects (N=524) and in an equal number of randomly selected articles with nonhuman subjects, as well as the general type of experimental designs used. Finally, the percentage of articles reporting an inferential statistic was determined at 5-year intervals. In all, 35,317 subjects were studied in 3,084 articles; pigeons ranked first and humans second in number used. Within-subject experimental designs were more popular than between-subjects designs regardless of whether human or nonhuman subjects were studied but were used in a higher percentage of articles with nonhumans (75.4 %) than in articles with humans (68.2 %). The percentage of articles reporting an inferential statistic has increased over time, and more than half of the articles published in 2005 and 2010 reported one. Researchers who publish in JEAB frequently depart from Skinner's preferred research strategy, but it is not clear whether such departures are harmful. Finally, the sex of subjects was not reported in a sizable percentage of articles with both human and nonhuman subjects. This is an unfortunate oversight. Keywords Experimental subjects. Nonhuman. Experimental design. Statistical analyses. Inferential statistics. Gender Throughout his career, B. F. Skinner favored the use of within-subject experimental designs to intensively study a small number of subjects, whose data were displayed graphically and analyzed via visual inspection alone (e.g.,

Journal of Chemical Ecology, 1981

The importance of chemical cues for transmitting information concerning sexual identity, agonistic state, and stress-related condition in the crayfish Procambarus clarkii (Girard) was examined in a flow-through system. Experiments tested the effects of"conditioned water" from stimulus tanks on the behavior of solitary male or female crayfish. Twenty males and 20 females were subjected to a random sequence of five treatments: unconditioned water (control), conditioned water flowing through tanks containing a solitary male or female, and conditioned water from tanks holding either two males or two females. Durations of the following behaviors were recorded: chelae up, chela(e) in baffle hole, chela waving, climbing, digging, grooming, gross body movement, and meral spread. Results indicated that crayfish chemically detected another animal within 0.25 m without additional visual or tactile stimuli; however, crayfish apparently did not "communicate" information on sexual identity, agonistic state, or stress condition, nor does this detection necessarily imply discrimination between stimuli from crayfish and other taxa (e.g., fish). Our conclusions are contrasted with the two previous reports on chemical communication in crayfish in which experimental animals were tested in static systems. We suggest that a temporal separation of molting and copulation and a long reproductive receptivity period for females (which would allow abundant intersexual encounters) could account for a lack of selective pressure to evolve long-distance sex pheromones.

Animal behaviour, 2004

In male birds, the responsiveness of androgens to sexual and territorial behaviour is predicted to vary with mating system and the degree of paternal investment ('challenge hypothesis ', CH; Wingfield et al. 1990, American Naturalist, 136, 829-846). The CH predicts a higher and longer lasting 'breeding baseline' androgen level in males of polygynous species with no or only short-term paternal investment than in males of monogamous species with a high degree of paternal investment. Since the applicability of the CH to nonavian vertebrates has been unclear, we experimentally tested its predictions in several cichlid fish (Neolamprologus pulcher, Lamprologus callipterus, Tropheus moorii, Pseudosimochromis curvifrons and Oreochromis mossambicus) using a simulated territorial intruder protocol. Androgens (11-ketotestosterone: 11-KT; testosterone: T) were measured from fish-holding water. In all species sampled, the 11-KT patterns confirmed the predictions of the CH originating from the avian literature, but T patterns did not. Males of all species sampled were highly responsive to territorial intrusions; however, the magnitude and duration of this response, that is, the rapid return to baseline 11-KT levels, could not clearly be explained by the degree of paternal care. 11-KT responses to interactions with ovulating females were observed in maternal mouthbrooders but not in biparental species (e.g. Lamprologini). At the interspecific level, androgen responsiveness was greater among males of monogamous species, as predicted, but also in species with more intense pair bonding (e.g. Tropheus moorii). Thus, this study confirms the predictions of the CH in cichlid fish at both the intraspecific and the interspecific levels.

Bulletin of Integrative Psychiatry, 2020

The zebrafish (Danio rerio) is considered an experimental model organism, with numerous applications. The mechanisms underlying shoaling preferences are complex, and some studies documented sex-related differences in social partner selection, little is known about the behavioral response to artificial visual stimuli representing conspecifics. The aim of this research was to evaluate the shoaling preference in zebrafish between two sex-shaped superstimuli, social non-moving 2D images were created using a graphics software. For this study, 20 sexually-mature individuals (males, N=10, and females, N=10) underwent 5 non-56/Bulletin of Integrative Psychiatry New Series  December 2020  Year XXVI No. 4 (87) invasive behavioral tests and, for each animal, ethological measurements were recorded using EthoVision XT video-tracking software. The findings showed statistically significant differences on zebrafish behavioral response. All individuals, without sex discrimination, tended to shoal more at the contact with the "3 big females" stimulus and less with the "1 big female", but only female zebrafish showed a preference for same social stimulus and also, spent more time in the proximity of the "big male" image rather than the "small male". We concluded that conspecifics represented by 2D artificial stimuli are efficient in inducing a behavioral response in this species. Moreover, we validate the existence of sex-dependent discrepancies regarding the shoaling preferences, as well as discussion how the aforementioned data has a possible psychiatric and metabolic relevance in this context.

Behavioral Ecology and Sociobiology, 2014

The behaviour of animals towards their mirror image ("mirror test") is routinely used as a proxy to measure aggression levels, especially in fish. The lack of evidence for visual self-recognition in fish supports this method. However, recent work points towards different hormonal and gene expression responses when fish are exposed either to conspecific opponents or to their mirror image, urging for validation of this widespread method. Here, we test the predictive value of mirror tests in three sympatric cichlid species from Lake Tanganyika: the cooperative breeder Neolamprologus pulcher, the polygamous shell brooder Telmatochromis vittatus and the monogamous, biparental piscivore Lepidiolamprologus elongatus. In particular, we compare differences in restrained and overt aggression levels for individuals of each species when confronted with a mirror or a live conspecific. The three species differed in response to the two contest situations. While in N. pulcher both aggressive responses were correlated between the mirror test and the live opponent fight, there was no such relationship in T. vittatus and L. elongatus. Thus, the mirror test appears to be a suitable surrogate for intraspecific aggression in N. pulcher, while aggression against a mirror image has limited predictive value for intraspecific aggression in the other two species. These results underline the importance of validating the mirror test's predictive value in a study species before drawing conclusions from mirror tests about aggressiveness under natural, social conditions.

Scientific Reports, 2019

Mathematical modelling regarding evolutionary theory typically assumes that optimal strategies are not constrained through mechanistic processes. In contrast, recent studies on brain anatomy and neurobiology suggest that flexibility in social behaviour is rather constrained by the physiological state of the social decision-making network. Changing its state may yield selective advantages in some social contexts but neutral or even detrimental effects in others. Here we provide field evidence for such physiological trade-offs. We subjected wild female cleaner wrasse to injections of testosterone or of saline solution (control) and then observed both intraspecific interactions and interspecific cleaning behaviour with other reef fish, referred to as clients. Testosterone-treated females intensified intraspecific social interactions, showing more aggression towards smaller females and tendencies of increased aggressive and affiliative contacts with dominant males. Such testosterone-med...

Behavioral Ecology and Sociobiology, 2015

Behaviour, 2000

Despite the fact that most communication occurs in the context of networks of several individuals, the consequences of considering communication as a network on individuals' capacity for gathering information on congeners has been little investigated. Eavesdropping is the behaviour of a receiver extracting information from an interaction in which it is taking no part. Due to the fact that signals used in aggressive interactions are assumed to be reliable, eavesdropping could be an effective way of evaluating the quality of potential mates. We conducted two experiments designed to discover if female ghting sh (Betta splendens) monitor aggressive interactions between two males and if information gained by eavesdropping is used in the initial stages of subsequent mate choice. We found that females that had seen the interaction visited the winner rst more often and spent signi cantly more time near, looking at and displaying to the winner of the interaction. By contrast females that had not seen the interaction visited the loser rst more often and did not behave signi cantly differently to winner and loser. Overall these results are consistent with the idea that in the initial stages of mate choice females eavesdrop, i.e. use information gathered from male-male displays.

This thesis would not be possible without the generous support and guidance from my doctoral research supervisor Prof. Jean-Guy Godin. I thank him for his numerous contributions to both my thesis and my development as a scientist. The research described in my thesis was funded by Discovery Grants from the Natural Sciences and Engineering Research Council of Canada awarded to my supervisor, Jean-Guy Godin. Thank you to Carleton University for the support they have provided during my studies here. I would like to specifically thank the staff and faculty in the Department of Biology for their assistance, encouragement and support over the past years. Thank you to Prof. Sue Bertram and Prof. Howard Rundle for serving on my thesis committee. I would also like to thank the editors, especially Prof. Andrea Pilastro, and anonymous reviewers who provided helpful comments on manuscripts published from this thesis.

PeerJ, 2015

Flexibility in behavior is advantageous for organisms that transition between stages of a complex life history. However, various constraints can set limits on plasticity, giving rise to the existence of personalities that have associated costs and benefits. Here, we document a field and laboratory experiment that examines the consistency of measures of boldness, activity, and aggressive behavior in the young of a tropical reef fish, Pomacentrus amboinensis (Pomacentridae) immediately following their transition between pelagic larval and benthic juvenile habitats. Newly-settled fish were observed in aquaria and in the field on replicated patches of natural habitat cleared of resident fishes. Seven behavioral traits representing aspects of boldness, activity and aggression were monitored directly and via video camera over short (minutes), medium (hours), and long (3 days) time scales. With the exception of aggression, these behaviors were found to be moderately or highly consistent over all time scales in both laboratory and field settings, implying that these fish show stable personalities within various settings. Our study is the first to examine the temporal constancy of behaviors in both field and laboratory settings in over various time scales at a critically important phase during the life cycle of a reef fish. Supplemental information for this article can be found online at http://dx.doi.org/ 10.7717/peerj.961#supplemental-information. . 2012. Aggression and related behavioral traits: the impact of winning and losing and the role of hormones. Integrative and Comparative Biology 52:801-813 DOI 10.1093/icb/ics057. Chivers DP, McCormick MI, Mitchell MD, Ramasamy RA, Ferrari MCO. 2014. Background level of risk determines how prey categorize predators and non-predators. Barber I. 2009. Individual experience and evolutionary history of predation affect expression of heritable variation in fish personality and morphology. . Johnson J, Sih A. 2005. Pre-coupulatory sexual cannibalism in fishing spiders (Dolomedes triton): a role for behavioral syndromes. Behavioral Ecology and Sociobiology 58:390-396 DOI 10.1007/s00265-005-0943-5. Jones KA, Godin J-GJ. 2009. Are fast explorers slow reactors? Linking personality type and anti-predator behaviour.

Behavioral Ecology, 2001

The evolution of signals has mainly been considered in the context of an emitter-receiver dyadic interaction. However, communication usually occurs in the presence of individuals (an audience) that are not directly involved in the communication interaction, and it is more realistic to assume that signal evolution occurs in a network. Several types of information could be available to an audience, and, therefore, the presence of an audience could have effects on the behavior of the communicating animals and on signal evolution. We investigated whether the presence of an audience of conspecifics affected intrasexual aggressive communication in male fighting fish. We found that if the audience was a female, males increased the intensity of conspicuous displays that can be used in communication with both males and females and decreased highly aggressive displays that are solely directed to males. If the audience was a male of similar size, there was no significant change in the way in which males displayed. These results suggest that the presence of an audience could be one reason that many long-range and conspicuous signals are often shaped to transmit information to both males and females.

2014

Strong selection against heterospecific sex signals, which includes both receivers and signallers, is considered to be the most significant causal factor in animal signal modification and is expected to prevent mate misinterpretation. Using a simultaneous choice bioassay, we tested the continued use of primordial sex signals in distantly related and geographically separated fish species, Pseudorasbora parva and Pimephales promelas. Here, we show that intraspecific selection pressures have not caused significant sex chemical signal differentiation between the 2 species and that mate attraction is likely due to a combination of common ancestry and an absence of divergence in allopatry. In the absence of mate discrimination among species, which have evolved for long periods of time in allopatry, reunification through species translocation could represent an overlooked risk of pheromone pollution.

Physiology & Behavior, 2018

Can estrogens be considered as key elements of the challenge hypothesis? The case of intrasexual aggression in a cichlid fish. Phb (2018),