Sex steroid hormones modulate responses to social challenge and opportunity in males of the monogamous convict cichlid, Amatitliana nigrofasciata

Sexually dimorphic control of aggression by androgen signaling in a cichlid

Innate social behaviors like aggression are modulated by sex steroid hormones such as androgens and estrogens. However, we know little about how the same hormone regulates similar behaviors in both sexes. We investigated the role of androgenic signaling in the regulation of aggression in Astatotilapia burtoni, a social fish in which males and females perform similar aggressive behaviors. We used ARa knockout (KO) animals for this study, which was recently shown to be required for male-typical aggression and mating. Surprisingly, ARα KO females did not show deficits in aggression. We also determined that females lacking the other AR, ARβ, showed normal levels of aggression. Blocking both ARs pharmacologically confirmed that neither AR is necessary for aggression in females. However, ARα KO males showed clear deficits in attacks. Thus, in A. burtoni there appears to be a sexual dimorphism in the role of ARα in the control of aggression.

Polycystic ovary syndrome: An exploration of unmarried women's knowledge and attitudes

Polycystic Ovary Syndrome (PCOS) is a common endocrine disorder among women of reproductive age and a chief cause of subfertility attributed to ovulation. Besides, lack of knowledge about PCOS, its treatment, and lifestyle changes influence the prognosis. The present qualitative inquiry investigates the knowledge and attitudes of unmarried women towards the syndrome, associated treatment, and necessary lifestyle changes in the fight against the same. A total of 15 participants with PCOS were selected using purposive sampling (n from southern parts of India viz. Kerala and Tamil Nadu states. The telephonic interviews were conducted in late November and early December 2020. He conventional content analysis emerged with six major themes. The themes capsulated women’s knowledge, causes, complications and risk factors, treatment of PCOS their perceived importance of health promotive behaviours such as physical activity, sleep patterns, and perceived support from society. The importance of diet, exercise and a healthy lifestyle were additional relevant factors stressed by the respondents. Although the medicines helped participants attain regular menstrual cycles, they also had side effects reported in the discussion. Few respondents reported that they lacked the necessary awareness of PCOS when diagnosed at a younger age. The study enhances the understanding of PCOS from a qualitative approach that has cultural relevance apart from pertinent clinical and lifestyle implications.

Endocrine and neuroendocrine regulation of social status in cichlid fishes

Position in a dominance hierarchy profoundly impacts group members' survival, health, and reproductive success. Thus, understanding the mechanisms that regulate or are associated with an individuals' social position is important. Across taxa, various endocrine and neuroendocrine signaling systems are implicated in the control of social rank. Cichlid fishes, with their often-limited resources of food, shelter, and mates that leads to competition, have provided important insights on the proximate and ultimate mechanisms related to establishment and maintenance of dominance hierarchies. Here we review the existing information on the relationships between endocrine (e.g., circulating hormones, gonadal and other tissue measures) and neuroendocrine (e.g., central neuropeptides, biogenic amines, steroids) systems and dominant and subordinate social rank in male cichlids. Much of the current literature is focused on only a few representative cichlids, particularly the African Astatotilapia burtoni, and several other African and Neotropical species. Many hormonal regulators show distinct differences at multiple biological levels between dominant and subordinate males, but generalizations are complicated by variations in experimental paradigms, methodological approaches, and in the reproductive and parental care strategies of the study species. Future studies that capitalize on the diversity of hierarchical structures among cichlids should provide insights towards better understanding the endocrine and neuroendocrine mechanisms contributing to social rank. Further, examination of this topic in cichlids will help reveal the selective pressures driving the evolution of endocrine-related phenotypic traits that may facilitate an individual's ability to acquire and maintain a specific social rank to improve survival and reproductive success.

Rapid effects of estradiol and its receptor agonists on object recognition and object placement in adult male zebrafish

In recent years, there has been a growing appreciation that 17β-estradiol (E2) can rapidly modulate learning and memory processes by binding to membrane estrogen receptors and cause the activation of a number of signaling cascades within the central nervous system. In this study, we sought to investigate the effects of post-training administration of E2 (100 ng/g, 1 μg/g, 10 μg/g) and involvement of the estrogen receptors (ERs) using selective ER agonists on the consolidation of object recognition (OR) and object placement memory (OP) in adult male zebrafish. The general activation of ERs with the highest E2 dose improved consolidation of memory in both learning tasks within 1.45 h of administration. Activation of classical ERs (ERα and ERβ) improved consolidation of OR memory, but had no effect on fish performance in OP task. On the other hand, activation of G protein-coupled ER1 impaired and enhanced consolidation of OR and OP memories, respectively. Memory improvement in both tasks was accompanied by a marked up-regulation in the expression of genes encoding ionotropic and metabotropic glutamate receptors in a task-dependent manner. In contrast, the down-regulation in the expression of certain ionotropic glutamate receptors was observed in fish with impaired OR memory. Moreover, our study also revealed an increase in the transcript abundance of genes associated with synaptic protein synthesis (brain-derived neurotrophic factor, synaptophysin, and the mechanistic target of rapamycin). These results suggest that E2 may affect consolidation of memory in zebrafish likely through rapid changes in synaptic morphology and function.

Hormonal regulation of social ascent and temporal patterns of behavior in an African cichlid

For many species, social rank determines which individuals perform certain social behaviors and when. Higher ranking or dominant (DOM) individuals maintain status through aggressive interactions and perform courtship behaviors while non-dominant (ND) individuals do not. In some species ND individuals ascend (ASC) in social rank when the opportunity arises. Many important questions related to the mechanistic basis of social ascent remain to be answered. We probed whether androgen signaling regulates social ascent in male Astatotilapia burtoni, an African cichlid whose social hierarchy can be readily controlled in the laboratory. As expected, androgen receptor (AR) antagonism abolished reproductive behavior during social ascent. However, we discovered multiple AR- and status-dependent temporal behavioral patterns that typify social ascent and dominance. AR antagonism in ASC males increased the time between successive behaviors compared to DOM males. Socially ascending males, independent of AR activation, were more likely than DOM males to follow aggressive displays with another aggressive display. Further analyses revealed differences in the sequencing of aggressive and courtship behaviors, wherein DOM males were more likely than ASC males to follow male-directed aggression with courtship displays. Strikingly, this difference was driven mostly by ASC males taking longer to transition from aggression to courtship, suggesting ASC males can perform certain DOM-typical temporal behavioral patterns. Our results indicate androgen signaling is necessary for social ascent and hormonal signaling and social experience may shape the full suite of DOM-typical behavioral patterns.

Rapid sex steroid effects on reproductive responses in male goldfish: Sensory and motor mechanisms

Contribution to Special Issue on Fast effects of steroids. Although we have learned a great deal about the molecular mechanisms through which sex steroids rapidly affect cellular physiology, we still know little about the links between those mechanisms and behavioral output, nor about their functional consequences in natural contexts. In this review, we first briefly discuss the contexts associated with rapid effects of sex steroids on reproductive behaviors and their likely functional outcomes, as well the sensory, motor, and motivational mechanisms associated with those effects. We then discuss our recent studies on the rapid effects of testosterone in goldfish. Those studies indicate that testosterone, through its aromatization and the subsequent activation of estrogen receptors, rapidly stimulates physiological processes related to the release of milt/sperm through likely influences on motor pathways, as well as behavioral responses to female visual stimuli that may reflect, in part, influences on early stages of sensory processing. Such motor and sensory mechanism are likely important for sperm competition and mate detection / tracking, respectively, in competitive mating contexts. We also present preliminary data on rapid effects of testosterone on responses to pheromones that may not involve estrogen receptors, suggesting a dissociation in the receptor mechanisms that mediate behavioral responses in different sensory modalities. Lastly, we briefly discuss the implications of our work on unresolved questions about rapid sex steroid neuromodulation in fish.

Effects of social experience on pair bonding in a monogamous fish (Amatitlania nigrofasciata)

For species in which individuals spend at least some time in groups, dominance relationships and various social cues are often important for mate assessment and choice. For pair bonding species, social experiences may affect reproductive decisions in both sexes. We tested whether prior experience in a mixed-sex group and having a higher dominance status coincides with faster pair formation or spawning in a monogamous fish. Individuals having prior experience in mixed-sex groups paired with a novel fish more frequently than fish from same-sex groups. Fish in mixed-sex groups performed more bites and lateral displays. Although spawning occurred infrequently across pairs, dominant fish from mixed-sex groups spawned more than dominant fish from same-sex groups. Otherwise, there were no clear behavioural relationships between treatment group and subsequent pair formation or spawning, nor were behaviours of the paired fishes related to their prior treatment group. We do not know how mixed-sex social experience may have affected the physiology of those individuals, although our results support a reproductive priming effect.

Hormonal and fitness consequences of behavioral assortative mating in the convict cichlid (Amatitlania siquia)

In monogamous species, partner compatibility is a key factor influencing pairing and reproductive success. In pairs with biparental care, studies have mostly focused on behavioral compatibility because it is likely to encourage the coordination of parental care within pairs, leading to a better reproductive success. Behavior modulation, throughout the breeding season and as a function of the social context, is under the regulatory feedback control of endocrine mechanisms. From this link, the idea of hormonal partner compatibility as a key component of pair cohesion and maintenance has recently emerged. Here, we investigated the link between partner behavioral assortment and their hormonal response to the pairing context. We formed assortative and disassortative pairs of convict cichlids based on their behavioral type (proactive or reactive) and took hormone and fitness measurements. Testosterone, 11-ketotestosterone, 17β-estradiol and cortisol levels were measured from fish-holding water before and after pair formation. We found no relationship between the behavioral type of individuals and their pre-pairing hormone levels. Only the level of cortisol was affected by the partner but independently of its behavioral type. Reproductive success was not affected by the level of hormonal similarity within pairs, but we found that the variation in 11-ketotestosterone similarity between the isolated context and the pairing context was related to spawning size, and the variation in cortisol similarity to the number of fry. Behavioral compatibility does not reflect hormonal compatibility in the convict cichlid, but the relationship between reproductive success and the flexibility of hormonal similarity between partners suggests hormonal adjustment within pairs in this species.

Extra-gonadal steroids modulate non-breeding territorial aggression in weakly electric fish

The neuroendocrine control of intraspecific aggression is a matter of current debate. Although aggression in a reproductive context has been associated with high levels of circulating androgens in a broad range of species, it has also been shown to occur during the non-breeding season when gonads are regressed and plasma steroid hormone levels are low. In mammals and birds the aromatization of androgens into estrogens plays a key role in the regulation of aggression in both the breeding and non-breeding seasons. This is the first study in a teleost fish to explore the role of steroids in the modulation of non-breeding aggression. Gymnotus omarorum is a highly aggressive teleost fish that exhibits aggression all year-round. We analyzed male-male non-breeding agonistic behavior, compared circulating 11-Ketotestosterone (11-KT) levels between dominants and isolated males, assessed the regulatory role of aromatization of androgens into estrogens, and evaluated the gonads as a source of these sex steroids. We found that high levels of aggression occurred in the non-breeding season despite low plasma 11-KT levels, and that there was no difference in 11-KT levels between dominant and isolated males. We demonstrated that acute aromatase inhibition decreased aggression, distorted contest dynamics, and affected expected outcome. We also found that castrated individuals displayed aggressive behavior indistinguishable from non-castrated males. Our results show, for the first time in teleost fish, that territorial aggression of G. omarorum during the non-breeding season depends on a non-gonadal estrogenic pathway.

Male convict cichlid 11-ketotestosterone levels throughout the reproductive cycle: an exploratory profile study in laboratory and field populations

The convict cichlid (Amatitlania nigrofasciata) has been extensively examined in relation to many behavioral topics, such as courtship, pair-bonding, bi-parental care, and territoriality. Recently, this model species has been utilized in studies on genetics, endocrinology, and neuroanatomy, with an ultimate goal of connecting behavior with its underlying mechanisms. The goal of this study was two-fold: (1) profile the circulating levels of plasma 11KT in the male convict cichlid at multiple points during the reproductive cycle and (2) generally compare the hormonal profiles of the widely used laboratory populations and those of a free-living population in the streams of Costa Rica. The results of the field experiment showed that male convict cichlids had higher levels of circulating 11KT during courtship and lower during the parental care and non-breeding phases. The profile of the laboratory population was similar to the profile of the free-living individuals, with significantly higher levels of 11KT occurring during courtship than during parental care, though the level of 11KT during non-breeding phase was elevated in the laboratory. The high levels of 11KT during courtship and low levels of 11KT during parental care found in both the field and the laboratory is similar to what has been reported in other species of teleosts, and may suggest an important function of 11KT in the expression of courtship behavior and the subsequent onset of parental behaviors in this model species.

A multidisciplinary study on social status and the relationship between inter-individual variation in hormone levels and agonistic behavior in a Neotropical cichlid fish

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 (E2) 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 E2 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 E2 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.

Social regulation of reproduction in male cichlid fishes

Social interactions and relative positions within a dominance hierarchy have helped shape the evolution of reproduction in many animals. Since reproduction is crucial in all animals, and rank typically regulates access to reproductive opportunities, understanding the mechanisms that regulate socially-induced reproductive processes is extremely important. How does position in a dominance hierarchy impact an individual's reproductive behavior, morphology, and physiology? Teleost fishes, and cichlids in particular, are ideally-suited models for studying how social status influences reproduction on multiple levels of biological organization. Here I review the current knowledge on the reproductive behavioral and physiological consequences of relative position in a dominance hierarchy, with a particular focus on male cichlids. Dominant and subordinate social status is typically associated with distinct differences in activity along the entire hypothalamic-pituitary-gonadal axis. Further, when transitions in social status occur between subordinate and dominant individuals, there are plastic changes from whole-organism behavior to molecular-level gene expression modifications that occur quickly. These rapid changes in behavior and physiology have allowed cichlids the flexibility to adapt to and thrive in their often dynamic physical and social environments. Studies in cichlid fishes have, and will continue, to advance our understanding of how the social environment can modulate molecular, cellular, and behavioral outcomes relevant to reproductive success. Future studies that take advantage of the extreme diversity in mating systems, reproductive tactics, and parental care strategies within the cichlid group will help generate hypotheses and careful experimental tests on the mechanisms governing the social control of reproduction in many vertebrates.

The endocrine regulation of cichlids social and reproductive behavior through the eyes of the chanchita, Cichlasoma dimerus (Percomorpha; Cichlidae)

Sociobiology, the study of social behavior, calls for a laboratory model with specific requirements. Among the most obvious is the execution of social interactions that need to be readily observable, quantifiable and analyzable. If, in turn, one focuses on the neuroendocrinological basis of social behavior, restrictions grow even tighter. A good laboratory model should then allow easy access to its neurological and endocrine components and processes. During the last years, we have been studying the physiological foundation of social behavior on what we believe fits all the aforementioned requirements: the so called "chanchita", Cichlasoma dimerus. This Neotropical cichlid fish exhibits biparental care of the eggs and larvae and presents a hierarchical social system, established and sustained through agonistic interactions. The aim of the current article is to review new evidence on chanchita's social and reproductive behavior.