Frequency Of Agonistic Behaviour Research Articles

Differences in Behavior and Social Organization of Female Guinea Pigs as a Function of the Presence of a Male

AbstractObject of the study was the variability of social behavior and organization in female guinea pigs as a function of the presence of a male. Four groups of 8 females were observed. Two of these groups were without a male, the other two had a sexually experienced, sterilized male. All females were about 20 d old at the beginning of the study. In the groups without a male the females formed clear and stable dominance relationships resulting in a linear rank order. The frequency of agonistic behavior was higher compared to the other groups. Some of these females displayed male‐like courtship behavior. Among the females in the groups with a male only the alpha and omega positions were stable, while the dominance relations between the other females remained unstable. These females directed about 40–50 % of their contact behavior towards the male. In relation to the presence or absence of a male the females differed in their social orientation: those who lived with a male were strongly orientated towards it, those living without a male were strongly oriented towards each other. The hypothesis is put forward, that the females in the two situations differed in their motivational states. For the females living with a male this animal was a stable point of social reference, while for the females living without a male their stable dominance structure — with more agonistic behavior — was the most important stabilizing factor.

Social Status, Circulating Levels of Hormones, and Competition for Food in Winter Flocks of the White-Throated Sparrow

We measured plasma levels of luteinizing hormone (LH), testosterone (T), 5α-dihydrotestosterone (DHT) and corticosterone (B) in flocks of wintering white-throated sparrows. This species occurs in two colour morphs that are distinguishable by white or tan colour of the median crown stripe and differ in frequency of agonistic behaviour during the reproductive season. During winter, white-throated sparrows form flocks that are characterized by dominance hierarchies, in which social rank was correlated with sex and age, but not with crown colour. Plasma levels of LH and androgens (T and DHT) were basal in most free-living and captive birds and not correlated with sex, age, morph or social rank. Plasma levels of testosterone did not increase in captive groups, when aggressive interactions increased due to experimental manipulation of distribution and amount of food. These results suggest (1) that dominant-subordinate relationships during the wintering phase are not based on differential aggression of plumage types and (2) that they are not maintained by elevated plasma levels of androgens in high-ranking birds. Plasma concentrations of B increased rapidly with duration of capture stress in females and first-year males, but not in adult males. Since adult males were of highest rank it appears that high social status may restrain acute adrenal response to stress. Further, baseline levels of B were highest in low-ranking first-year females and lowest in high-ranking adult males. In captive groups, amount and distribution of food resources altered levels of B. Levels appeared to be most variable and very high in some birds of intermediate rank, when agonistic interactions in competition for food were most frequent. This suggests greater impact of change in food distribution on those birds, whose social status is less clear than that of high or low ranking birds.

Seasonal changes in territoriality and frequency of agonistic behavior in two densities of juvenile brown bullhead, Ictalurus nebulosus

Incidence of territoriality and frequency of six agonistic action patterns of juvenile brown bullhead, Ictalurus nebulosus, were observed in the laboratory over a two year period at two fish densities under conditions of constant light and temperature. High density fish showed little territoriality or agonistic behavior while low density fish displayed an annual cycle of agonistic behavior and territoriality. Agonistic behavior frequency and incidence of territoriality peaked in February and March and were higher the second year when compared with the first.

The effect of locomotor activity on the growth of brook charr, Salvelinus fontinalis Mitchill

Yearling hatchery-reared brook charr, Salvelinus fontinalis Mitchill, were trained during a 20-day period at different water velocities: 0.00, 0.85, 1.72, and 2.50 body lengths/s (bl/s). Our results indicate that growth (wet weight), food conversion efficiency, and the deposition of lipids on the digestive tract were maximized at 0.85 bl/s. The individual growth (wet weight) was also more homogeneous at this water speed. The storage of lipids in the white muscles was significantly lower in still water (0.00 bl/s) while the increase in length, the increase in the dry weight of the carcass (whole fish less internal organs), and the relative water content of the muscle showed no significant differences between the tested water velocities. Behavioural observations indicated that the frequency of agonistic behaviours between individuals was important in still water, but decreased significantly in the presence of a water current.

Seasonal changes in agonistic behaviour of the western red-backed salamander, Plethodon vehiculum

The objectives of this study were (1) to describe the behaviour of adult western red-backed salamanders, P. vehiculum, in intrasexual encounters, and (2) to test specific hypotheses to elucidate the adaptive contexts in which agonistic behaviour occurs in this species. Two alternative hypotheses were tested. (1) Levels of aggression peak during the mating season in the autumn and are relatively low among individuals of both sexes at other times of the year (agonistic behaviour is associated with mating), or (2) levels of aggression are relatively high among individuals of both sexes throughout the year (agonistic behaviour is associated primarily with competition for resources other than mates). A further prediction, based on the theory of sexual selection, was that males are more aggressive than females during the peak mating season in the autumn. The behaviour of P. vehiculum was to a large extent similar to that reported for other species of plethodontids, but a few behaviours, tentatively designated as threat displays have not been previously described. Seasonal changes and sexual differences in the frequency of agonistic behaviour were in accordance with hypothesis (1) as stated above. Agonistic behaviour was largely confined to male-male encounters in the autumn and was infrequent in these encounters outside the mating season as well as among females at all times of the year. As predicted, in the autumn males were more aggressive than females. Agonistic behaviour of P. vehiculum is therefore primarily associated with mating behaviour.

Sublethal effects of biologically treated petroleum refinery wastewaters on agonistic behavior of male orangespotted sunfish, Lepomis Humilis (girard)

Pairs of orangespotted sunfish were exposed to oil refinery wastewaters in acute, non-lethal toxicity tests. Frequencies of agonistic behaviors (approaches, fin erections, tail beats, operculum spreads, chases, bites and avoidances) were determined initially after a 10-d exposure to control water and then again after a 10-d exposure to the wastewaters. Changes in frequency were compared with changes in frequency for pairs of fish exposed to control water for both 10-d periods. Pairs of fish were observed for 60 min following each of the two 10-d exposures. Frequencies during the initial 15 and 30 min of the period and during the entire 60-min period were determined. For wastewater-exposed fish, the frequency of each behavior generally decreased following the 10-d exposure to wastewater. For fish exposed only to the control water, each behavior generally increased in frequency following the second 10-d period. The change in frequency for wastewater-exposed fish was significantly (p < 0.05) different from that for control fish for approaches, fin erections, chases, bites and avoidances at one or more of the three lengths (15, 30 and 60 min) of observation.

Social organization as an expression of role behavior among Old World monkeys

Except for a few hours after birth, maternal status or maternal role behavior does not reduce the frequency of agonistic behaviors toward a subordinate mother. Although each species social adaptations can be understood only within the framework of its lifeway and ecology, there are phylogenetic adaptations which structure both signal systems and role behaviors. The expression of an individual's role behaviors is shaped by social context. Performance of certain behavioral roles may alter individual physiology, and in turn alter appearance and activity to enhance the behavior. A phylogenetic adaptation which restricts each social group to one functional adult male with respect to certain roles is widespread among Old World monkeys. Where social adaptation to a particular lifeway has dispersed these roles among several males, the adaptation is expressed as an alpha role, leader role, or central hierarchy. Supported by the Wenner-Gren Foundation for Anthropological Research Incorporated and NIH Grant FR-00165.

Hormonal control of aggressive dominance in the female hamster

The hamster is unusual in that the intact sexually unreceptive female is aggressively dominant over the male. In this study the dominance of spayed females, which are also sexually unreceptive, was tested, as well as their response to various hormones. Spayed adult females were sequentially given no treatment, four doses of progesterone (250, 500, 1000 and 3000 μg), testosterone propionate (TP) (1000 μg) and oestradiol benzoate (25 μg). Untreated or TP treated spayed females were beaten in aggressive encounters with intact males. However, when they were given progesterone, the spayed females became dominant over the males. Twenty-five μg oestradiol benzoate produced a lordotic response in spayed females, which provoked mounting by males and a lowering in the frequency of agonistic behaviour by both animals. The dominance observed in progesterone-treated females may be a direct effect of the hormone on female behaviour or an indirect effect on male behaviour due to changes in olfactory cues.

Comb Type, Behavior and Body Weight in Chickens

Abstract THE associated effects of specific alleles for a qualitative trait on quantitative characteristics has been studied in several organisms. Examples in chickens, which involved body weight, were given in the reports of Warren and Payne (1945) with sex-linked early feathering, Jerome et al. (1956) and Jaap and Grimes (1956) with plumage color genes, and Briles (1957) with blood group alleles. Pea comb is qualitatively inherited in chickens (Bateson, 1902). Comparisons of differences between pea and single comb chickens for body weight have been made by Kan et al. (1959), Collins et al. (1961) and Smith (1961). Their results however, are inconclusive. Crawford and Smyth (1961) have studied the relationship of certain plumage alleles on social and sexual behavior. Although comb size has been shown to influence the frequency of agonistic behavior in flocks (Siegel and Hurst, 1962; Dawson and Siegel, 1962) and to be a factor in the determination of…