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PubMed1995

Behavior and progesterone levels in Callithrix jacchus females.

In callitrichids, and especially in the Callithrix and Saguinus genera, reproductive suppression maintains the breeding exclusivity of dominant females. It has been suggested that dominance may be inferred from agonistic behavior of females. The purpose of this study was to assess the adequacy of behaviors as indicators of hormonal status in Callithrix jacchus females. Two pairs of twin females were observed for affiliative, agonistic and sexual behaviors for 20 weeks, in four stages of increasingly potential competition for one male. During the same period, blood samples were taken regularly for progesterone determination by ELISA. The two pairs differed markedly as to behaviors and hormonal status: pair 1 showed a well established behavioral dominance and only one ovulating female from the beginning of the observation period; pair 2 showed competition for dominance until the last stage of observation, when one of the females started ovulating. Correlations between behaviors and progesterone levels showed differences between subordinate and dominant females mostly in pair 2. Although limited in number of animals studied, these results suggest that there is a relationship between behavior and hormones in female marmosets, but this relationship may be useful in the identification of the physiological status of females only in groups where the dominance is not well established.

Agonistic Behavior↗
PubMed2006

A social recognition test for female mice reveals behavioral effects of developmental chlorpyrifos exposure.

CD-1 mice were exposed to the organophosphate pesticide chlorpyrifos (CPF) both prenatally (gestational days 15-18; doses 0, 3 or 6 mg/kg) and postnatally (postnatal days 11-14, doses 0, 1 or 3 mg/kg). When four-month-olds, females underwent a social recognition test in which ultrasound vocalizations (USVs) and social investigation behavior emitted by a resident female in the presence of a female partner were measured during two subsequent 3 min sessions (interval between the two sessions 45 min). Throughout the social recognition test a marked increase in USVs was found in females prenatally treated with the highest CPF dose; USV increase was also paralleled by a selective increase in frequency and not in duration of social investigation. These results confirm that developmental exposure to CPF induces long-lasting alterations in the social behavior repertoire of the mouse, thus extending our previous observations on the effects of postnatal CPF on male agonistic behavior to the female sex. They also suggest that social recognition can be easily and rapidly assessed in the female mouse making it possible to evaluate, primarily by means of USV emission, even subtle alteration of social behavioral patterns dissociated from cognitive components of individual recognition.

Agonistic Behavior↗
PubMed2000

Intermale competition in sexually mature arctic charr: effects on brain monoamines, endocrine stress responses, sex hormone levels, and behavior.

Sexually mature Arctic charr (Salvelinus alpinus) males were allowed to interact in pairs for 4 days in the absence of females. Agonistic behavior was quantified, and at the end of the experiment, plasma levels of glucose, cortisol, testosterone (T), 11-ketotestosterone (11-KT), and 17alpha,20beta-dihydroxy-4-pregnen-3-one (17alpha, 20beta-P) were determined alongside brain concentrations of serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA, the major 5-HT metabolite), dopamine (DA), and 3,4-dihydroxyphenylacetic acid (DOPAC, a major DA metabolite). Plasma cortisol and glucose were significantly elevated in subordinate fish, and the number of aggressive acts received showed positive correlations with plasma levels of glucose on day 1, during the development of the dominance relationship, and of cortisol on day 4, when the dominance relationship was established. In contrast, plasma concentrations of T and 11-KT were significantly higher in dominant than in subordinate males, and there was a similar tendency in plasma concentrations of 17alpha,20beta-P. Further, plasma levels of these gonadal steroids were correlated with the number of aggressive acts performed on day 4, but not with the number of aggressive acts received. The plasma cortisol concentrations did not correlate with either 5-HIAA:5-HT or DOPAC:DA ratios in any of the brain parts analyzed. Plasma glucose levels showed positive correlations with brain 5-HIAA:5-HT ratios. Negative correlations were observed between 5-HIAA:5-HT ratios in the optic tectum and between plasma levels of T, 11-KT, and 17alpha,20beta-P. Telencephalic DOPAC/DA ratios displayed a negative correlation with plasma levels of T, 11-KT, and 17alpha,20beta-P, but only in dominant males.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2001

Consistency among different tasks of left-right asymmetries in lines of fish originally selected for opposite direction of lateralization in a detour task.

Lines of fish, Girardinus falcatus preferentially turning rightward (RD) or leftward (LD) when facing a dummy predator visible behind a barrier have been obtained through selective breeding. To check whether lateralization was maintained in other behavioral responses, five different tests were carried out. They comprised measures of (1) turning direction in a T-maze; (2) proportion of clockwise and anticlockwise direction of rotation in a circular arena; (3) preferential eye use by females during shoaling behavior (i.e. while looking at their own mirror image reflection); (4) preferential eye use by males during sexual behavior (i.e. while turning around a barrier to join a group of females); and (5) preferential eye use by males during agonistic behavior (i.e. while attacking a rival visible in a mirror). In all five tests the two selected lines showed opposite direction of lateralization. Results thus indicate that behavioral asymmetries in the detour test are predictive of lateralization in other types of behavioral tests. Moreover, results show that RD and LD fish have a similar but left-right reversed pattern of subdivision of cognitive/ behavioral functions, which is suggestive of a similarly left-right reversed (mirror image) brain organization.

Agonistic Behavior↗
PubMed1991

Investigating equine ingestive, maternal, and sexual behavior in the field and in the laboratory.

Some of the techniques that may be used to study social, reproductive, and ingestive behavior in horses are described in this paper. One of the aspects of equine social behavior is the dominance hierarchy or patterns of agonistic behavior. Paired or group feeding from a single food source may be used to determine dominance hierarchies quickly. Focal animal studies of undisturbed groups of horses may also be used; this method takes longer, but may reveal affiliative as well as agonistic relationships among the horses. Reproductive behavior includes flehmen, the functional significance of which can be determined using combinations of field observations of harem groups and laboratory studies of stallions exposed to female urine or feces in the absence of the donor mare. Ingestive behavior may include food, salt, or water intake. Direct and indirect measurements of intake can be made and used to answer questions regarding the ability of horses to control their energy intake when the diet is diluted, the effect of feral equids on the ecology of an area, and the abilities of horses to compensate for dehydration and hypovolemia.

Animals↗
PubMed1997

Biogenic amines and aggression: experimental approaches in crustaceans.

This review summarizes our experimental approaches attempting to link amines and their metabolites to aggression in crustaceans. The results demonstrate (i) that agonistic behavior in crustaceans can be quantified, (ii) that the amines themselves have telling and subtle effects on the fighting behavior of animals, (iii) that pharmacological interventions are possible that might allow a biochemical dissection of the underlying mechanisms involved in processes like decision making in these animals, and (iv) that selective metabolites of amines are excreted in the urine of lobsters where they may serve behavioral roles. Many of the studies presented here are preliminary. Nonetheless, we believe the results are provocative and nicely complement previous detailed physiological, morphological and biochemical studies exploring the roles of amines in aggression in crustaceans. We expect that the continued use of this invertebrate model system will allow us to gain considerable insight into, and understanding of, the role served by biogenic amines in a complex behavioral process like aggression.

Aggression↗
PubMed1982

Behavioral characteristics of beef steers administered estradiol, testosterone and dihydrotestosterone.

Twelve beef steers ranging in age from 6 to 8 mo were randomly assigned to one of four steroid treatment groups so the ability of each hormone to stimulate sexual and(or) agonistic behavior could be assessed. The steers received im injections of either 200 mg of testosterone (T), 200 micrograms of estradiol-17 beta (E2), 200 mg of dihydrotestosterone (DHT) or sesame oil vehicle as control (C), every other day for 10 d. During these 10 d, behavior was studied for 60 min at 0600, 1200, 1800 and 2400 h. Peak activity occurred during the first half of the experiment with maximum behavioral expression observed at the 2400-h observation period. Estradiol was most effective in stimulating eight of the 13 behaviors studied. These included: sniffs received, sniffs given, successful mounts, chin rests given, chin rests received, stands to be mounted, refusals to stand and head butts received. Testosterone was most effective in stimulating Flehmen lip curls, attempted mounts and head butts given. Testosterone significantly increased activity in seven other categories over that of controls. Dihydrotestosterone was never the most effective steroid. It was capable of stimulating several of the behaviors studied above that of controls, but reduced mounting activity of steers. In view of the major responses observed with E2 and the aromatizable androgen, T, these data are interpreted as an indication that E2 plays a significant direct role in sexual behavior in the male bovine.

Aggression↗
PubMed1988

Fetal gender and aggression in pregnant stumptail monkeys (Macaca arctoides).

Agonistic behaviors of pregnant female stumptail monkeys, members of a large, well-integrated group continuously living together, were studied during 480 observation hours (over 32 months). A total of 28 pregnancies of 20 females occurred, resulting in 12 male and 16 female live infants. The main finding was a significant decline in aggression, both received and performed, during the course of pregnancy. There was no clear unequivocal effect of fetal gender on aggressive behavior of the mothers-to-be.

Aggression↗
PubMed1986

Effects of zeranol implantation and late castration on sexual, agonistic and handling behavior in male feedlot cattle.

Seventy-two Angus feedlot bulls were observed to determine the effects of implanting with zeranol (0, 36 or 72 mg; four groups of six/level) at 8 mo of age (d 0), and of castration midway through the feedlot period (d 115) vs remaining intact (six groups/treatment) on sexual, agonistic and handling behaviors. All 36-mg-treated cattle were re-implanted (36 mg) on d 112; 72-mg-treated cattle were not re-implanted. Each group was observed for a total of 8 h at the time of sunset +/- 30 min for sexual and agonistic behaviors during the trial. Observations on handling were made during 15 weighings and on seven occasions in the pens of the animals. Zeranol did not affect sexual or agonistic behavior. Before imposition of castration, implanted bulls entered the scales more quickly, took longer to stand still on the scales and were less quiet than non-implanted bulls (P less than .05). Castration decreased the sexual behaviors of masturbation (.75 vs .08 X pen-1 X h-1; P less than .05), attempted mounts (.75 vs .33 X pen-1 X h-1; P less than .05) and chinning (10.70 vs 4.75 X pen-1 X pen-1; P less than .10) and the agonistic behavior of butting (42.42 vs 31.50 X pen-1 X h-1; P less than .01) in contrast to intact bulls. Castrated animals entered (P less than .10) and exited (P less than .05) the scales more quickly than did intact males.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2001

Homosexual behavior in wild Sumatran orangutans (Pongo pygmaeus abelii).

Wild male Sumatran orangutans at two study sites engaged in homosexual behavior. These observations demonstrate that homosexual behavior is not an artifact of captivity or contact with humans. In separate instances, homosexual behavior was associated with affiliative and agonistic behaviors. These observations add orangutans to the list of primates in which homosexual behavior forms part of the natural repertoire of sexual or sociosexual behavior.

Aggression↗
PubMed1987

Effects of the light-dark cycle and scheduled feeding on behavioral and reproductive rhythms of the cyprinodont fish, Medaka, Oryzias latipes.

Medaka were maintained on a 16:8 light-dark cycle and fed once daily on one of 5 different feeding schedules. The daily rhythm of agonistic behavior rapidly entrained to the scheduled feeding time and maintained this entrainment during a 3-day starvation period. In contrast the daily rhythms of egg laying and courtship stayed entrained to the L:D cycle regardless of the feeding schedule. Thus, temporal integration of this fish with its daily environment can involve multistimuli which concurrently and differentially entrain externally expressed circadian systems.

Agonistic Behavior↗
PubMed1980

Increase in aggressiveness of male mice after irradiation of paternal spermatozoa with 600 R of gamma-rays as dependent on fertility.

The agonistic behavior of unexperienced pairs of NMRI male mice was determined by counting the bites received from and delivered to the opponent within 24 hr. The first 10 min of agonistic encounters was recorded by video tape to analyze the frequency and duration of ten behavioral traits. Each pair consisted of two F1 males, one of which was derived from paternal spermatozoa irradiated with 600 R of gamma-rays (600-F1), while the other stemmed from a sham-treated father (control-F1). The 600-F1 males exhibited higher aggressiveness than their control F1 counterparts, in which the sterile and semisterile males (presumed to be translocation heterozygotes) showed a higher level of agonistic behavior and overall activity than the normally fertile F1 males of the same group. 600-F1 males released more urine drops than the control males. No significant differences between 600-F1 and control-F1 males or between fertile and sterile plus semisterile males were found for learning ability.

Aggression↗
PubMed1981

Agonistic and nonagonistic behaviors of pullets of dissimilar strains of White Leghorns when kept separately and intermingled.

Agonistic and nonagonistic behaviors were compared for pullets of two white Leghorn strains. One strain had been selected for part-year egg production; the other was the unselected control from which the selected strain was derived. There were two experiments in which the strains were kept separately and intermingled in laying-house floor pens. The selected strain had social dominance over the control at 5 months (before sexual maturity), but that dominance had diminished or disappeared when strangers of the two strains were placed together at 17 months. Nevertheless, because of social inertia, selected strain pullets maintained undiminished dominance over control pullets for the entire laying year when they were kept together from housing time onward. Selected strain females had more aggressive acts, more feeding activity, and spent less time resting than control females in both separated- and intermingled-strain housing environments. When pullets of the two strains were kept together, the relative frequencies of their agonistic behaviors were changed, but nonagonistic activities were not altered. Pullets had increased frequencies of pecking and fighting, but not of chases and threats, when they were hungry and feeding. Pullets with higher social status had more feeding activity when feed was constantly available, but that was not apparent when all were hungry and feeding. Preening activity increased as pullets aged.

Aggression↗
PubMed1975

Behavior of captive mouse deer, Tragulus napu.

1. The behavior of a breeding colony of larger Malayan mouse deer was observed for seven months. 2. Mouse deer produce a noise by stamping with one or both hind feet when slightly alarmed. Other individuals may or may not stamp in response. 3. Both males and females mark objects with the inter-mandibular gland. Males mark much more frequently than females. 4. Males often lick the urine of females; less frequently, females lick the urine of males. Mouse deer do not "flehmen" in response to urine. 5. Males court both receptive and unreceptive females. Courting males mark the female on the back or rump with the inter-mandibular gland and emit a series of squeaks. The behavior of both unreceptive and receptive females and copulation are described. 6. Females have a post-partum estrus and return to estrus at approximately 14 day intervals unless they become pregnant. 7. Mothers spend little time with infants. Mothers emit a vocalization which sounds like the squeak of courting males. Both mothers and infants emit a higher pitched vocalization. If her infant emitted this vocalization the mother answered and approached and stood by it. The mother nurses in a standing position and raises the hind leg on the side towards the infant. 8. Intense agonistic behavior was seen only when strange individuals were introduced into established groups. Males fight by facing each other and biting each other on the ears, neck, and shoulders with their large upper canines. Fighting males usually hold the tail in a vertical position, exposing the white ventral surface, and may emit loud growls. If one male flees, the other pursues and attempts to bite him on the neck and body. 9. Mouse deer are morphologically primitive and many of their motor patterns are also thought to be primitive. 10. The behavior of all four living tragulid species appears to be quite similar, both with respect to motor patterns and social behavior.

Agonistic Behavior↗
PubMed2006

Social isolation and aggressiveness in the Amazonian juvenile fish Astronotus ocellatus.

We tested the effect of social isolation on the aggressiveness of an Amazonian fish: Astronotus ocellatus. Ten juvenile fishes were transferred from a group aquarium (60 x 60 x 40 cm) containing 15 individuals (without distinguishing sex) to an isolation aquarium (50 x 40 x 40 cm). Aggressiveness was tested by means of attacks on and displays toward the mirror image. The behavior was video-recorded for 10 min at a time on 4 occasions: at 30 min, 1 day, 5 days and 15 days after isolation. The aggressive drive was analyzed in three ways: latency to display agonistic behavior, frequency of attacks and specific attacks toward the mirror image. The latency to attack decreased during isolation, but the frequency of mouth fighting (a high aggressive attack) tended to increase, indicating an augmented aggressive drive. Our findings are congruent with the behavior of the juvenile cichlid, Haplochromis burtoni but differ from the behavior observed in another cichlid, Pterophylum scalare. Increased aggressiveness in A. ocellatus may be mediated by means of the primer effect, the effect of prior residence or processes involving recognition of a conspecific.

Aggression↗
PubMed1996

Long-term chronic treatment with stanozolol lacks significant effects on aggression and activity in young and adult male laboratory mice.

1. Repeated doses of the anabolic-androgenic steroid stanozolol were assessed for their effects on agonistic behavior, motor activity, and body weight in both young and adult male laboratory mice. 2. Stanozolol significantly increased weight gain in young, but not older subjects, especially at the highest doses. 3. There were, however, no significant differences in motor activity or in ethologically assessed social behavior (including aggression) in young or adult mice.

Age Factors↗
PubMed1996

Issues in the genetics of social behavior: revisited.

Though social behavior has not been overlooked by behavior geneticists, the number of studies is small when compared to those on individual traits. One reason for the neglect may be the difficulty of making connections between genes and social behaviors, which by definition involve the interaction of two or more organisms. Fuller and Hahn (1976) addressed this issue and described three means of establishing social groups that would facilitate genetic analysis. We survey the literature on agonistic behavior in mice from 1976 through 1994 and describe interesting uses of those three methods. One of those methods (the standard tester design) often employs a "noninteractive" social partner. We present data showing that the standard tester design may be more valuable when using an evocative and interactive standard tester.

Aggression↗
PubMed1988

Effects of opiate agonists and antagonists on aggressive encounters and subsequent opioid-induced analgesia, activity and feeding responses in male mice.

The effects of peripheral administration of the mu, kappa and sigma opiate agonists, levorphanol (1.0 mg/kg), U-50,488 (1.0 and 10.0 mg/kg), (+/-) SKF-10,047 (10.0 and 30.0 mg/kg), respectively, as well as the delta opiate antagonists, ICI-154,129 (10.0 mg/kg), and the prototypic antagonist, naloxone (1.0 mg/kg), on the agonistic behaviors and subsequent analgesic, locomotory and ingestive responses of subordinate mice were examined in a "resident-intruder" paradigm. The latter behaviors were examined in both defeated and nondefeated mice that had received an equivalent level of aggression. The mu and delta opiate antagonists decreased, while the mu, kappa, and sigma opiate agonists selectively increased aggressive behavior (number of bouts of aggressive interactions, number of bites to defeat, time to defeat). Both naloxone and the delta antagonist suppressed defeat- and aggression-induced activity and feeding, while only naloxone blocked the analgesic response. Levorphanol enhanced, U-50,488 had variable dose related effects, and SKF-10,047 decreased the defeat and aggressive-induced responses. These results indicate that various opioid systems and opiate receptors are differentially involved in the mediation of various components of the agonistic encounters and in the expression of the consequences of social conflict and defeat-induced opioid activation.

Aggression↗