Biochemical correlates of agonistic behaviour inBandicota bengalensis: Hepatic cholesterol and ascorbic acid (original) (raw)
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Physiological consequences of social descent: studies in Astatotilapia burtoni
Journal of Endocrinology, 2006
In many species, social interactions regulate reproductive capacity, although the exact mechanisms of such regulation are unclear. Since social stress is often related to reproductive regulation, we measured the physiological signatures of change in reproductive state as they relate to short-term stress and the stress hormone cortisol. We used an African cichlid fish, Astatotilapia burtoni, with two distinct, reversible male phenotypes: dominant (territorial, T) males that are larger, more brightly colored, more aggressive, and reproductively competent and non-dominant males (non-territorial, NT) that are smaller, camouflage colored, and have regressed gonads. Male status, and hence reproductive competence, depends on social experience in this system. Specifically, if a T male is placed among larger male fish, it quickly becomes NT in behavior and coloration, but complete regression of its reproductive axis takes ca. 3 weeks . Reproduction in all vertebrates is controlled by the hypothalamic-pituitary-gonadal axis in which the key signaling molecule from the brain to the pituitary is GnRH1. Here, we subjected T males to territory loss, a social manipulation which results in status descent. We measured the effects of this status change in levels of circulating cortisol and testosterone as well as mRNA levels of GnRH1 and GnRH receptor-1 (GnRH-R1) in the brain and pituitary, respectively. Following short-term social suppression (4 h), no change was observed in plasma cortisol level, GnRH1 mRNA expression, GnRH-R1 mRNA expression, or plasma testosterone level. However, following a somewhat longer social suppression (24 h), cortisol and GnRH1 mRNA levels were significantly increased, and testosterone levels were significantly decreased. These results suggest that in the short run, deposed T males essentially mount a neural 'defense' against loss of status.
Aggressive behaviour of captiveBandicota bengalensis
Proceedings: Animal Sciences, 1983
The aggressive behaviour rhythm of Bandicota bengalensis under different social conditions were studied in the laboratory. The number, intensity and duration of aggressive behaviour peaks varied depending on the number, sex and social status of the interacting conspecific Is. Significantly the peaks of aggression were recorded during the dark period. In heterosexual conflicts both sexes were equally belligerent. However in male interactions with more females, the former emerged dominant always. Similarly one male dominated another in male-male encounters. Confrontation amongst several males in the presence offemale indicated the existence of only alpha and omega males.
Behavior and serum cholesterol in a social group ofCercopithecus aethiops
Primates, 1981
This report describes the extent of associations between selected behaviors and serum cholesterol concentrations in vervets (Cercopithecus aethiops) living in a stable social group. Approximately 18 ~o of the behaviors performed by males and 7 ~o of behaviors performed by females demonstrated significant correlations with baseline serum cholesterol. Under conditions of dietary challenge, I 1 ~o of male behaviors and 8 ~o of female behaviors exhibited significant correlations. Although there are sex differences in the identity of behaviors correlated with cholesterol concentrations, subordinate individuals have higher serum cholesterol levels.
Rhythmic oscillations in non-aggressive social behaviour inBandicota bengalensis
Proceedings: Animal Sciences, 1982
Non-aggressive social behaviour rhythms of Bandicota bengalensis were studied in the laboratory. The species exhibited 95 % rhythmicity for social behaviour but the rhythms were uni-or bimodal and were influenced by the Dumber and sex of interacting conspecifics, Peaks occurred at 0900 and 1800 hr. Males were more socially active than females.
American Journal of Primatology, 1991
Among group-housed male Cercopithecus aethiops, dominant animals have higher concentrations of whole bood serotonin (WBS) than their subordinate counterparts. In contrast, there appears to be no relationship between social status and WBS in Macaca nemestrina. We report here the relationship between social status and WBS among 29 male Macaca fascicularis housed in groups of five. Membership in these groups was disrupted periodically (20 times in 26 months) with a reorganization manipulation. Concentrations of WBS were assessed just prior to the 20th (final) social reorganization and at 1, 2, and 5 weeks following that reorganization. Correlations between these repeated samples were high, indicating considerable intraindividual stability in WBS. Overall, there were no persistent differences in WBS between clearly dominant (ranked 1 or 2) and subordinate (ranked 3, 4, or 5) monkeys, despite the substantial behavioral differences between such animals and the stability of social status across time. A multivariate analysis indicated that WBS was best predicted by a model that included a positive relationship with the interaction between rate of grooming and social status (P < 0.0021, a negative relationship with extreme aggressiveness (P = 0.031, and a positive relationship with time spent alone (P < 0.04). Further analysis of the social status by grooming rate interaction revealed that WBS was higher in dominants than subordinates, but only if the dominants also initiated grooming frequently. These differences in the relationship between WBS and social status in C. aethiops and M. fascicularis may reflect differences in the behavioral dynamics underlying the dominance hierarchies in small groups of these two species.
Stress and Social Behavior in a Natural Population of Tamarisk Jirds
Doklady Biological Sciences, 2001
Until recently, the relationship between the stress level and individual characteristics of social behavior was mainly studied in the laboratory. Field studies were few (for example, ), which is mainly explained by limited possibilities of estimating the stress level by the levels of hormones in the blood plasma. The development of methods of the assessment of steroid hormones in feces, as well as the validation of adequacy of noninvasive approaches to the assessment of the endocrine status , considerably extended the possibilities of studying the stress level in mammals in their natural environment. Even the earliest results obtained using these methods revealed a diverse pattern of relationships between the hormonal and social statuses in various species .
The Stress Response of the Highly Social African Cichlid Neolamprologus pulcher
Physiological and Biochemical Zoology, 2009
In group-living species, dominant individuals are frequently aggressive toward subordinates, and such dominant aggression can lead to chronic stress, higher glucocorticoid levels, and decreased fitness for subordinates. However, in many cooperatively breeding species, it is surprisingly the dominants rather than the subordinates that exhibit higher levels of glucocorticoids, a possible consequence of the demands of maintaining high social rank and socially suppressing the reproduction of other group members. This study investigates the relationship between social status and circulating plasma cortisol in groups of the cooperatively breeding African cichlid Neolamprologus pulcher. Baseline (resting) levels of cortisol were quantified, as was the cortisol response following an acute stressor. Dominants had the higher cortisol concentrations, and these were not related to their social behavior. Cortisol concentrations correlated (positively) with social behaviors and general activity levels only in subordinate males, arguably the individuals with the least stability in the social group. No status-dependent differential responses to acute stress were detected, suggesting that the status-induced chronic stress has little effect on the capacity to mount a full stress response to large-scale, life-threatening risk.
Marine Biology, 2008
The inXuence of abiotic factors on the establishment and success of invasive species is often diYcult to determine for most marine ecosystems. However, examining this relationship is critical for predicting the spread of invasive species and predicting which habitats will be most vulnerable to invasion. Here we examine the mortality and physiological sensitivity to salinity of adult colonies of the colonial ascidians Botryllus schlosseri and Botrylloides violaceus. Adult colonies of each species were exposed to abrupt changes in salinity (5, 10, 15, 20, 25, 30 psu) in the laboratory. Salinity ranges used in the laboratory corresponded with those of the Weld distributions of B. violaceus and B. schlosseri in the Great Bay Estuary, NH. Heart rate was used as a proxy for health to assess the condition of individual colonies. Heart rates were monitored daily for approximately 2 weeks. Results revealed that both species experienced 100% mortality after 1 day at 5 psu and that their heart rates declined with decreasing salinity. Heart rates of B. schlosseri remained consistent between 15 and 30 psu and slowed at 10 psu. Heart rates of B. violaceus remained constant between 20 and 30 psu, but slowed at 15 psu. These laboratory results corresponded to the distribution of these species in estuaries, indicating salinity is a key factor in the distribution and dominance of B. schlosseri and B. violaceus among coastal and estuarine sites.
Pheromone, juvenile hormone, and social status in the male lobster cockroach Nauphoeta cinerea
Archives of Insect Biochemistry and Physiology, 2008
In this study, the major pheromone component, 3-hydroxy-2-butanone (3H-2B), released by dominants was measured during early scotophase. Both the JH III titer in the hemolymph and the 3H-2B content of the sternal glands of the dominants and subordinates were then measured during late scotophase and late photophase. These investigations were performed on encounter days 1, 2, 3, 5, 7, 9, 12, and 20. The results showed that, for non-aggressive posture (AP)-adopting socially naïve males (SNMs), both the 3H-2B release and the hemolymph JH III titer were maintained at a low level. Once a fight occurred, 3H-2B release was raised significantly in the AP-adopting dominants, but not in non-AP-adopting subordinates, and remained raised throughout the entire experimental period. At 30 min after the first encounter, the hemolymph JH III titer was significantly increased in dominants, but not in subordinates. A significantly higher hemolymph JH III titer was observed in dominants during late scotophase on days 3, 5, 12, and 20 and during late photophase on days 3, 5, and 20. After fighting, the sternal gland 3H-2B content of the dominants or subordinates was significantly lower than in SNMs. In dominants, the sternal gland 3H-2B content during late scotophase was significantly lower than that during late photophase in the first 9 domination days, while, in the subordinates, the 3H-2B content during late scotophase was either similar to, or significantly higher than, that in late photophase. In the dominants, 3H-2B release and JH III titer were positively correlated. In rank switchers, the switched social status was positively correlated with both 3H-2B release and JH III titer. Comparison of 3H-2B release and JH III titer in 1-time, 3-time, or 5-time dominants showed that, although winning significantly increased both 3H-2B release and JH III titer, there is no significant difference in 3H-2B release between 3-and 5-time winners, while the JH III titer was most significantly increased in the 3-time winners. The possible relationship between pheromone release, JH III titer, and social status is discussed. Arch. Insect Biochem. Physiol. 68:144-155, 2008.
Behavioral Ecology and Sociobiology, 2011
Sexual harassment by males has the potential to affect almost any aspect of female behavior and life history. Using Atlantic mollies (Poecilia mexicana) as a model—a species in which males do not court but almost constantly try to forcefully mate with females—we asked whether and how male harassment influences (a) females’ time budgets and (b) feeding rates (e.g., through frequent flight from male approaches), and (c) whether metabolic rates are increased as a response to stress. Field observations in a natural P. mexicana population revealed that males (average feeding rate 15%) spent far less time feeding than females (60%), and clearly traded off frequent pursuit of females with foraging. Most importantly, females’ feeding times were dramatically reduced when being pursued by a harassing male. Also in standardized lab experiments, females spent significantly less time feeding when accompanied by a male as compared to being in the presence of another female. This effect was also observed when partner fish (male or female) were presented only visually, but could not interact physically with the focal female. It seems, therefore, that females increase vigilance when a harassing male is around, which keeps them from feeding even before males actually approach them. Based on the latter result, we asked whether a stress-induced increase in metabolic rates would be discernible. We measured oxygen consumption and gill ventilation frequencies (opercular rates) of females in different social contexts (alone, with another female, or a male). The predicted, strong body mass dependency of both physiological parameters was uncovered, but no evidence for an effect of social context was detected. We argue that male harassment represents such a constant (but non-lethal) stressor for poeciliid females that their metabolic stress responses have adapted to this through habituation.