1. Institute of Marine Biology, National Sun Yat-sen University 2. Department of Biology, National Changhua University of Education Abstract Brain serotonin (5-hydroxytryptamine; 5-HT) generally serves an inhibitory role in aggressive behavior. But little is known about how 5-HT works during agonistic interaction and where the related works take place in the brain. Paradise fish has regular and ritual process of agonistic interaction which can be separated into three phases, namely, initial phase, threatening phase, and fighting phase. In initial phase, two fish encounter and swim close to each other. In threatening phase, two fish display shaking, head-tail swimming to threat their opponent. In fighting phase, two fish bite each other. With its stereotyped pattern of agonistic behaviors and amenability for pharmacological manipulation, paradise fish represents an excellent model for studies on neurochemical basis of aggressive behaviors. The results suggested that proper visual stimulus stemming from the interacting opponents elicits a socially stressful state that activates the telencephalic serotonergic system of the receipting paradise fish. The elevated serotonergic activity appears to inhibit the interacting individuals from entering fighting phase by constraining them to threatening phase. Presumably, diminishing activity of the telencephalic serotonergic system ushers in physical fighting behaviors.

Dissertation (Ph.D.)--Auburn University, 2006. / Abstract. Includes bibliographic references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Coexistence among ecologically similar species is often facilitated through temporal or spatial partitioning mechanisms that reduce or eliminate direct interaction. However, in many communities exhibiting guild structure, wherein potential competitors may also prey on one another, sympatric relationships persist despite species' similar life history strategies, spatial and temporal restrictions imposed by ephemeral habitats, and resource limitations that promote competition and predation. To identify the ecological roles of species-specific behavioral patterns within aquatic guilds, I quantified larval intraspecific agonistic behavior among two species of intraguild (IG) predators, Ambystoma opacum and A. tigrinum, and their shared intraguild prey, A. maculatum. All species exhibited similar ontogenetic patterns of aggression, characterized by peaks of aggression early in development and subsequent gradual decreases through metamorphosis. However, the intensity of aggression varied considerably among guild species through development, as did behavioral responses to varying levels of ambient water temperature, invertebrate prey density, and presence of predatory odonate naiads. The observed patterns suggest that guild species, despite morphological and physiological similarities, exhibit unique behavioral responses through ontogeny and in response to habitat variables, suggesting that temporally staggered breeding phenologies have contributed to behavioral divergence among these sympatric congeners. However, in situ observations of larval behavior, although largely in agreement with laboratory results on timing of increased aggression, indicated that IG predators exhibited pond-level species partitioning and do not necessarily co-occur despite being regarded as sympatric. These results, taken together with observed species-specific impacts of IG predators on IG prey, suggest that ecologically similar IG predators exert widely differing predatory pressure on shared prey, and that similarities among guild species may ultimately result in habitat partitioning across local scales.

Agonistic behavior and dominance are described for captive Townsend's chipmunks (Eutamias townsendii). A total of 10,739 encounters was recorded; 644l (59.9%) were agonistic. Chases (58.5%) and displacements (30.8%) were the predominant agonistic behaviors; threats (6.8%) and fights (4.l%) were relatively rare. Stable, non-triangular hierarchies were rapidly established in 11 of the 12 groups of chipmunks observed; the presence of individuals of equal rank in some groups precluded strict linearity. Dominance positions did not change within a group, but reversals in rank and changes from equal to dominant-subordinate reltionships occurred when the mebership of groups was changed. One hierarchy existed for both sexes; neither sex was consistently dominant. Experience and individual differences in activity and aggresiveness were more important determinants of an animal's position than were sex or size. No correlation was found between rank and encounter frequency, nor was closeness of rank strongly correlated with high numbers of agonistic encounters between any two chipmunks. The frequencies of recognitory and sexual behavior were inversely related to the frequency of agonistic behavior between the pairs of animals. Ritualized throats and appeasement behaviors did not replace overt aggression in established hierarchies. Members of hierarchies showed neither a reduction in numbers of asonistic encounters, nor temporal changes in froquency of the different types of agonistic behavior. Agonistic encounters increased in frequency from August to December, but seasonal variations wore much smaller than variations among the groups. Although dominance reduced neither the frequency of agonistic behavior nor the time and energy spent in chasing, it nay be advantageous in curtailing harmful confrontations and enhancing the establishment of tolerance among some individuals.

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Blue catfish, Ictalurus furcatus, are an invasive species in the James River, VA. They produce stridulation sounds and passive acoustic monitoring may prove useful in locating and monitoring their populations. Little is known about their behavior, therefore my goal was to examine agonistic behavior and the use of sound in defending a territory. This thesis consists of two manuscripts: 1) A passive acoustic study of the tidal freshwater James River, 2) An experimental study of agonistic behavior in juvenile Blue catfish, Ictalurus furcatus. The first study showed that three sounds (click, run croak) occurred more often in warmer months than cooler months. The second study showed that Blue catfish utilized a variety of agonistic behaviors in territory defense, with residency status and size having an effect on the type and number of displays used. Stridulation sounds were not present in territorial contests although Blue catfish produce stridulatory pulses when held.

The blue catfish, Ictalurus furcatus, is an invasive species introduced to Virginia in 1974 and is the largest catfish in the United States. Like other Ictalurids, they are capable of producing disturbance calls via stridulation of the pectoral spine. These sounds can be made in air and water, and catfish can be preyed upon by both aerial and underwater predators. I characterized these putative distress calls by recording them in air and in the fish’s natural habitat. Sounds exhibited a wide variation in acoustic parameters relative to fish ontogeny: larger fish produced higher amplitude sounds with lower frequency bands. Sweep and pulse duration increased with fish size, but pulse rate and the number of pulses per sweep decreased. Sounds were more robust in water with a 1400 fold increase in sound pressure compared to air. Frequency response was much more peaked underwater with a considerable amount of high frequency absorption. These sounds appear to be better adapted to water, suggesting that their use in air may be inconsequential.

In my several months of research I have been engaged in studying the distribution of affiliated and agonistic behaviour in a group and primarily towards a new female, over the course of ranking the new female into the group and changes in the social arrangement of the western lowland gorillas in Prague Zoo. For the research standardised observational methods were used, ad libitum sampling, focal animal sampling and scan sampling and statistical analysis on data was carried out with the aid of ethological software (Noldus- MatMan 1.0). Hypotheses stated that the agonistic contact towards Bikire would be initiated by females and above all from the female Shinda, also affiliated contact for Bikire would be initiated by the young and under aged, that the frequency of agonistic contact towards Bikire will gradually decline, that the other adults in the group are dominant to Bikire, that will result in lower affiliated contact and that the social structure will change in the group. From the results of the research it is confirmed, that agonistic contact towards the new female was initiated exclusively by females and in particular the female Shinda. Further it was confirmed, the initiators of the affiliated contact towards Bikire are the young and under aged female member Moja. It was revealed the other...