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.

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.

Made available in DSpace on 2015-04-17T14:55:29Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1643253 bytes, checksum: 663b93e288d71dbedb37bcae9e72b850 (MD5) Previous issue date: 2013-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Damselfishes play key roles in reef environments and are widely used as models in ecological and behavioral studies.During the reproductive period, the damselfishes present strategies involving benthonic spawning. The parental care is performed by the male who, during the days of egg development, expelled all potential predators that try to attack their territory. It was studied here the behavioral ecology during spawning period and the reproductive success of Stegastes sanctipauli, a damselfish endemic to the remote St. Peter and St. Paul s Archipelago (Mid Atlantic Ridge, Brazil). Nest abundance was negatively influenced by depth and abundance of Caranx lugubris, an important damselfish predator. The number of clutches within male s nests was positively influenced by depth, nest area, and substrate inclination, with deeper, bigger and more inclined nests sheltering more clutches. Number of clutches within nests varied along the lunar cycle, peaking at two days before the new moon. Egg loss per clutch per day ranged from 3.5% to 50% and was positively influenced by the initial number of eggs laid by females and moon phase, with highest losses recorded also in the days before the new moon. Frequency of agonistic interactions increased with nest size. Bigger nests, that shelter more clutches, are possibly more attractive to potential egg predators. Species most frequently recorded attempting to predate S. sanctipauli eggs were the conspecifics, heterospecifics damselfishes (Chromis multillineata and Abudefduf saxatilis), Malacoctenus sp. and Halichoeres radiatus. Although, no successful predation events was witnessed, experimental offer of clutches and analysis of bite scars revealed Melichthys niger as the main potential predator of S. sanctipauli eggs. Filial cannibalism of eggs was frequently observed, and may be pointed as a major cause of S. sanctipauli embryo mortality. / Os peixes donzeladesempenham um importante papel nos ambientes recifais e são amplamente utilizados como modelo para estudos comportamentais. Durante o período reprodutivo, as donzelas apresentam estratégias que envolvem desova bentônica. O cuidado parental é realizado pelo macho que, durante o período de desenvolvimento dos ovos, expulsa todos os potenciais predadores que tentam invadir seu território.Neste estudo foi avaliada a ecologia comportamental durante a desova e o sucesso reprodutivo de Stegastes sanctipauli, donzela endêmica do remoto Arquipélago de São Pedro e de São Paulo. A abundância de ninhos foi influenciada negativamente pela profundidade e abundância de Caranx lugubris, um importante predador de donzelas. O número de desovas dentro dos ninhos de cada macho foi positivamente influenciado pela profundidade, área do ninho, e inclinação do substrato. Ninhos mais fundos, maiores e mais inclinados apresentaram um maior número de desovas. O número de desovas variou ao longo do ciclo lunar, atingindo um pico dois dias antes da lua nova. A perda de ovos por desova por dia variou de 3,5% a 50% e foi influenciado positivamente pelo número inicial de ovos desovados pelas fêmeas e pelas fases da lua, com as maiores perdas registradas também nos dias que antecedema lua nova. A frequência de interações agonísticas foi influenciada positivamente pelo tamanho do ninho. Ninhos maiores, que abrigam mais desovas, são possivelmente mais atraentes para potenciais predadores de ovos. As espécies registradas com maior frequência tentando invadir o território de S. sanctipauli foram os próprios coespecíficos, donzelas heteroespecíficas (Chromis multillineata e Abudefduf saxatilis), Malacoctenus sp e Halichoeres radiatus. Apesar de não ter sido registrado sucesso em tentativas de predação de ovos durante as observações comportamentais, a oferta experimental de desovas e análise de cicatrizes de mordidas revelou Melichthys niger como o principal potencial predador de ovos de S. sanctipauli. O canibalismo filial de ovos foi um comportamento frequentemente observado, e pode ser apontadotambém comouma das principais causas de mortalidade embrionária de S. sanctipauli.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Em muitas espÃcies animais, os machos brigam por territÃrios os quais aumentam as chances de cÃpulas. Os comportamentos de luta dos machos podem variar desde embates sem contato fÃsico atà lutas com injÃrias e possÃveis mortes. Existem pelo menos trÃs modelos propostos para explicar as regras usadas pelos machos para decidirem o vencedor de um confronto territorial: Guerra de Atritos (GDA), Acesso Sequencial de InformaÃÃes (ASI) e Acesso Cumulativo de InformaÃÃes (ACI). PorÃm, para sermos capazes de testar tais modelos à necessÃrio identificar primeiro quais traÃos dos machos determinam funcionalmente sua capacidade de luta (RHP). Para isso, usamos machos da libÃlula Macrothemis imitans para avaliar duas hipÃteses: 1) se as brigas ocorrerem com contato fÃsico, caracterÃsticas ligadas ao tamanho determinarÃo o RHP e 2) se os machos nÃo exibirem contato fÃsico durante as brigas, caracterÃsticas que conferem maior resistÃncia determinarÃo o RHP. Realizamos coletas de campo em campanhas de dois dias seguidos. Nessas campanhas realizamos captura, marcaÃÃo, observaÃÃo comportamental e recaptura de duas categorias de machos: os que possuÃam posse dos territÃrios (machos residentes) e os machos que ocuparam o local apÃs a remoÃÃo experimental dos machos residentes (machos substitutos). ApÃs a recaptura, levamos os machos residentes e substitutos para laboratÃrio para realizar as medidas: Ãrea alar, peso fresco, massa muscular torÃcica e quantidade de gordura. Os resultados indicaram que os machos residentes apresentaram maior quantidade de massa muscular e possivelmente gordura do que os substitutos. Uma vez que as brigas ocorreram com contato fÃsico, a maior quantidade de massa muscular e gordura dos machos residentes indica que a relaÃÃo funcional entre comportamento de luta e traÃos determinantes do RHP deve ser rejeitada. Alternativamente, à possÃvel que a maior quantidade de mÃsculo proporcione maior desempenho para causar injÃrias nos rivais ou evitar acÃmulo acelerado de danos. / In many animal species, males fight for the possession of territories that increase their mating chances. The fighting behavior of males may range from conflicts without physical contact to disputes with injuries and possible deaths. There are three models aiming to explain the rules adopted by males to decide the winner of a contest: war of attrition (WOA), sequential assessment model (SAM) and cumulative assessment model (ACM). However, to be able to test these models it is necessary to identify male traits functionally related to fighting ability (RHP). In this sense, we used males of the dragonfly Macrothemis imitans to evaluate two hypotheses: 1) if contests occur with physical contact, traits related to the size define RHP and 2) if disputes occur without physical contact, traits which confer endurance define male RHP. We did field experiments during campaigns with two consecutive days. In each campaign we captured, marked, made behavioral observations and recaptured males that were defending a territorial site (resident males) and males that stablished territories in this sites after the experimental removal of the resident male (substitute males). After recapturing, we transported all males them to lab to measure total wing area, male fresh weight, muscle mass and fat content.The results indicated that resident males presented higher muscle mass and probably fat content than substitute males. Since disputes occurred with physical contact, these differences in muscle mass and fat content indicate that the functional relationship between fight behavior and traits linked to RHP should be rejected. Alternativelly, it is possible that the higher muscle mass confers higher ability to cause injuries or to avoid damage accrual.