Fatores que influenciam a neofobia alimentar em fêmeas e filhotes de sagüis (Callithrix jacchus)

Considering the constant environmental changes, the ability to introduce new food items in the diet is crucial to omnivore animal survival. For optimal nourishment and lessening of intoxication risks, the animals must detect signs that indicate which items are adequate for their intake. We investigate some factors that interfere in the responses to non familiar food, modulating their neophobic behavior, of marmosets Callithrix jacchus, an omnivore and generalist primate, native to Northeast Brazil, known for being cautious in ingesting not known food. We analyzed the influence of food taste (sweet or salty), pregnancy and sex in feeding behavior and neophobic responses in these animals. 10 captive females were first selected, 5 of them being then pregnant. The females, pregnant or not, ate more when presented to the sweet items than to the salty ones. Pregnant females, however, themselves were less neophobic to both tastes, being also strongly neophilic to the sweets. We verified then the influence of nourishment during pregnancy on young males and females post natal feeding behavior. We observed 10 young divided in two groups, one whose mother ate that food item during pregnancy and one whose mother had no contact to it. In the first group that food was more easily accepted by the young, suggesting that neofobia and feeding behavior had a pre natal influence. Female young also ingested more food and were less neophobic than males, a difference already observed in behavior of adults of these specie. These results suggest that the low neophobic behavior to sweet food showed by females can be adaptive, and might have bestowed more fitness to those who presented it

Detecção de predadores por dicromatas e tricromatas humanos e a sua implicação na evolução da visão de cores em primatas

Among placental mammals, primates are the only ones to present trichromatic color vision. However, the distribution of trichromacy among primates is not homogeneous: Old World primates shows an uniform trichromacy (with all individuals being trichromats) and New World primates exhibit a color vision polymorphism (with dichromatic males and dichromatic or trichromatic females). Visual ecology studies have investigated which selective pressures may have been responsible for the evolution of trichromacy in primates, diverging from the dichromat standard found in other mammals. Cues associated with foraging and the socio-reproductive status were analyzed, indicating a trichromatic advantage for the rapid detection of visually conspicuous objects against a green background. However, dichromats are characterized by an efficient capture of cryptic and camouflaged stimuli. These advantages regarding phenotype may be responsible for the maintenance of the visual polymorphism in New World primates and for the high incidence of color blindness in humans (standing around 8% in Caucasian men). An important factor that has not yet been experimentally taken into account is the predation risk and its effect on the evolution of trichromacy in primates. To answer this question, we prepared and edited pictures of animals with different coats: oncillas (Leopardus spp.), puma (Puma concolor) and ferret (Galictis cuja). The specimens were taxidermized and the photographs were taken in three different vegetation scenarios (dense forest, cerrado and grassland). The images of the predators were manipulated so that they fit into two categories of stimulus size (small or large). After color calibration and photo editing, these were presented to 40 humans (20 dichromats and 20 trichromats) by a computer program, which presented a set of four photos at a time (one picture containing the taxidermized animal amid the background vegetation and three depicting only the background vegetation) and recorded the response latency and success rate of the subjects. The results show a trichromatic advantage in detecting potential predators. The predator detection was influenced by the background, the predator species, the dimension of the stimulus and the observer s visual phenotype. As humans have a high rate of dyschromatopsias, when compared to wild Catarrhini or human tribal populations, it is possible that the increased rate of dichromats is a result of reduced pressure for rapid predator detection. Since our species came to live in more cohesive groups and resistant to attack by predators, with the advent of agriculture and the formation of villages, it is possible that the lower risk of predation has reduced the selection in favor of trichromats

Participação do circuito dopaminérgico nas alterações do comportamento de medo inato de camundongos infectados pelo Toxoplasma gondii

The protozoan parasite Toxoplasma gondii transforms the innate aversion of rats for cat urine into a fatal attraction, that increases the likelihood of the parasite completing its life cycle in the cat s intestine. The neural circuits implicated in innate fear, anxiety, and learned fear all overlap considerably, raising the possibility, that T. gondii may disrupt all of these nonspecifically. In this study, we evaluated immunoreactivity for tyrosine hydroxylase (TH) in areas associated with innate fear of infected male swiss mice. The latent Toxoplasma infection converted the aversion of mice to feline odors into attraction. This loss of fear is remarkably specific, as demonstrated by Vyas et al (2007), because infection did not diminish learned fear, anxiety-like behavior, olfaction, or nonaversive learning. However, the neurochemical mechanism related to alterations in innate fear due to T. gondii infection remains poorly studied. 20 mice were inoculated with bradyzoites (25 cysts) from a Toxoplasma gondii (Me-49 strain). The brains were removed after 60 days, sectioned and processed for TH immunohistochemistry. The correlation between the amount of cysts per area and the densitometric analysis of neurotransmitter reactivity was low in the areas implicated in innate fear of infected animals, when comparated with noninfected controls

Influência da densidade de estocagem sobre o crescimento, ciclo de muda e o comportamento em juvenis do camarão marinho Litopenaeus vannamei

One of the factors that may interfere with the cultivation of Litopenaeus vannamei is the population density. This study aimed to assess the effect of density on growth, mortality, physical integrity and behavior of shrimp. The study was divided into two stages. At first, the shrimp were placed in tanks at densities of 50, 75 and 100 shrimp m-2. The animals were monitored in relation to the degree of proventricular filling, the stage of the molt cycle and physical integrity three times a week and in relation to the weight and length once a week. Mortality, growth and proventricular filling were not influenced by the density; frequency of records in specific stages of the molt cycle varied according to the density. The lower proportion of broken appendages and higher frequency of necrotic lesions occurred in lower density. The second stage of the research, conducted in aquaria, was divided into two parts. The first described social or feeding behavioral categories: slow displacement by contact, slow displacement by approximation, abrupt displacement by contact, abrupt displacement by approximation, reactivity, cannibalism, occupying the tray, get feed in the tray and get feed outside the tray. In the second part, these and other behavioral categories, described in the literature, were recorded in densities of 50, 75 and 100 shrimp m-2. Mortality was more frequent in higher density. The frequency of most behaviors mentioned above was very low, not differing between densities or being too low to determine differences between them. The behavioral profile of animals in different densities was, in general, very similar, with no difference in exploration, digging and cleaning between the densities. Even so, inactivity, feeding, crawling, burrowing, swimming, and proximity between animals were influenced by the density. These results suggest that some behaviors suffer greater interference from population density. However, the density may not have a broader influence on the animals when other factors, such as physico-chemical parameters of water and feed offering, are adequate

Ecologia alimentar e comportamento de forrageamento de Ameivula aff. ocellifera (Squamata: Teiidae) em área de caatinga do nordeste do Brasil

This study investigated the influence of intrinsic and extrinsic factors on the feeding ecology and foraging behavior of the whiptail lizard Ameivula aff. ocellifera, a new species widely distributed in the Brazilian Caatinga, and that is in process of description. In attendance to the objectives, the Dissertation was structured in two chapters, which correspond to scientific articles, one already published and the other to be submitted for publication. In Chapter 1 were analyzed the general diet composition, the relationship between lizard size and prey size, and the occurrence of sexual and ontogenetic differences in the diet. Chapter 2 contemplates a seasonal analysis of diet composition during two rainy seasons interspersed with a dry season, and the quantitative analysis of foraging behavior during two distinct periods. The diet composition was determined through stomach analysis of lizards (N = 111) collected monthly by active search, between September 2008 and August 2010, in the Estação Ecológica do Seridó (ESEC Seridó), state of Rio Grande do Norte. Foraging behavior was investigated during a rainy and a dry month of 2012 also in ESEC Seridó, by determining percent of time moving (PTM), number of movements per minute (MPM) and prey capture rate by the lizards (N = 28) during foraging. The main prey category in the diet of Ameivula aff. ocellifera was Insect larvae, followed by Orthoptera, Coleoptera and Araneae. Termites (Isoptera) were important only in numeric terms, having negligible volumetric contribution (<2%) and low frequency of occurrence, an uncommon feature among whiptail lizards. Males and females did not differ neither in diet composition nor in foraging behavior. Adults and juveniles ingested similar prey types, but differed in prey size. Maximum and minimum prey sizes were positively correlated with lizard body size, suggesting that in this population individuals experience an ontogenetic change in diet, eating larger prey items while growing, and at the same time excluding smaller ones. The diet showed significant seasonal differences; during the two rainy seasons (2009 and 2010), the predominant prey in diet were Insect larvae, Coleoptera and Orthoptera, while in the dry season the predominant prey were Insect larvae, Hemiptera, Araneae and Orthoptera. The degree of mobility of consumed prey during the rainy seasons was lower, mainly due to a greater consumption of larvae (highly sedentary prey) during these periods. Population niche breadth was higher in the dry season, confirming the theoretical prediction that when food is scarce, the diets tend to be more generalized. Considering the entire sample, Ameivula aff. ocellifera showed 61,0 ± 15,0% PTM, 2,03 ± 0,30 MPM, and captured 0,13 ± 0,14 per minute. Foraging mode was similar to that found for other whiptail lizards regarding PTM, but MPM was relatively superior. Seasonal differences were verified for PTM, which was significantly higher in the rainy season (66,4 ± 12,1) than in the dry season (51,5 ± 15,6). It is possible that this difference represents a behavioral adjustment in response to seasonal variation in the abundance and types of prey available in the environment in each season

Álcool e comportamento: efeitos na aprendizagem e memória

Excessive alcohol consumption is responsible for many harmful effects on individuals and society. Despite years of research, the mechanisms by which alcohol affects neurological functions and the exact causes of cognitive impairment related to long-term use are unknown. In this sense, this master study proposed to observe how different doses of alcohol affect the addiction response and the learning ability of two fish species: Betta splendens and Danio rerio, the latter a commonly model due to organizational and functional characteristics shared with mammals. For this, different concentrations of ethanol (0%, 0.1%, 0.25%, 1% and 1.5%) were used in acute, chronic and withdrawal treatments. We tested the fish in three experimental protocols: 1) alcohol addiction potential using conditioned place preference, 2) associative conditioning using light as unconditioned stimulus and food as conditioned stimulus and 3) spatial learning using a maze without cues. For the alcohol addiction potential, preference between two different places in a shuttle box was tested before and after alcohol exposure (chronic and acute). In this test, the animals intoxicated by 0.1% did not change behavior, while animals receiving 1% and 1.5% alcohol changed the initial preference to the side where they received alcohol For the associative conditioning, the results show that the groups undergoing low dose (0.1%), both in chronic and withdrawal treatment, learned the task faster than control; groups under 0.25 and 1% alcohol withdrawal learned the task after control; groups chronically intoxicated with these doses did not learn the task. For the spatial learning test, fish submitted to acute and chronic treatments decreased the time to exit the maze; there were significant differences in the animal s performance in a dose-dependent pattern. This difference was not observed for the withdrawal treatment. Given these results, we conclude that the effects of alcohol on learning are dependent on the dosage. Furthermore, low doses of alcohol seem to maximize animal performance on learning tasks and do not alter their seeking behavior, while higher doses induced addition and hinder learning

Influência de fotoperíodo artificial no comportamento de um primata neotropical diurno (Callithrix jacchus)

One of the main environmental cues for the adjustment of temporal organization of the animals is the light-dark cycle (LD), which undergoes changes in phase duration throughout the seasons. Photoperiod signaling by melatonin in mammals allows behavioral changes along the year, as in the activity-rest cycle, in mood states and in cognitive performance. The aim of this study was to investigate if common marmoset (Callithrix jacchus) exhibits behavioral changes under short and long photoperiods in a 24h cycle, assessing their individual behaviors, vocal repertoire, exploratory activity (EA), recognition memory (RM) and the circadian rhythm of locomotor activity (CRA). Eight adult marmosets were exposed to a light-dark cycle of 12:12; LD 08:16; LD 12:12 and LD 16:08, sequentially, for four weeks in each condition. Locomotor activity was recorded 24h/day by passive infrared motion detectors above the individual cages. A video camera system was programmed to record each animal, twice a week, on the first two light hours. From the videos, frequency of behaviors was registered as anxiety-like, grooming, alert, hanging position, staying in nest box and feeding using continuous focal animal sampling method. Simultaneously, the calls emitted in the experimental room were recorded by a single microphone centrally located and categorized as affiliative (whirr, chirp), contact (phee), long distance (loud shrill), agonistic (twitter) and alarm (tsik, seep, see). EA was assessed on the third hour after lights onset on the last week of each condition. In a first session, marmosets were exposed to one unfamiliar object during 15 min and 24h later, on the second session, a novel object was added to evaluate RM. Results showed that long days caused a decreased of amplitude and period variance of the CRA, but not short days. Short days decreased the total daily activity and active phase duration. On long days, active phase duration increased due to an advance of activity onset in relation to symmetric days. However, not all subjects started the activity earlier on long days. The activity offset was similar to symmetric days for the majority of marmosets. Results of EA showed that RM was not affected by short or long days, and that the marmosets exhibited a decreased in duration of EA on long days. Frequency and type of calls and frequency of anxiety-like behaviors, staying in nest box and grooming were lower on the first two light hours on long days. Considering the whole active phase of marmosets as we elucidate the results of vocalizations and behaviors, it is possible that these changes in the first two light hours are due to the shifting of temporal distribution of marmoset activities, since some animals did not advance the activity onset on long days. Consequently, the marmosets mean decreased because the sampling was not possible. In conclusion, marmosets synchronized the CRA to the tested photoperiods and as the phase angle varied a lot among marmosets it is suggested that they can use different strategies. Also, long days had an effect on activity-rest cycle and exploratory behaviors

Padrão de atividades do sagüi callithrix jacchus numa área de caatinga

Callithrix jacchus, as the other species in the family Callitrichidae, lives in social groups. The groups cam be found in different habitats, whose distinct floristic physiognomies and communities are intrinsically related to their behavioral ecology and social relations. Our objective was to describe the social relations and feeding behavior of Callithrix jacchus in the Bioma Caatinga. We observed a group at the FLONA (National Forest IBAMA), in Açu-RN, in northeastern Brazil, compose of five adults (2 females and 3 males) at the beginning of the study. The birth of five animals was registered along the study. The following behavioral categories were registered along eleven months, once a week, through instantaneous focal animal sampling: social grooming, contact, proximity, foraging, feeding, locomotion and rest. Foraging presented the highest levels comparing to other activities, and was more frequent in the dry season. Social grooming was the second more frequent activity, with higher levels in the rainy season, and between the reproductive couple. We found similar results for proximity. The most explored feeding item was the gum, specially in the rainy season. The most explored species for exudates feeding were Cirus limon (limão) and Pitecolobiun foliolosum (jurema branca). The comparision of fruit and insect ingestion between the seasons showed higher percentage for both in the dry season. The general activity pattern was similar to what is registeded in groups the inhabit the Atlantic Forest. These results indicate the flexibility of the species which survives and reproduces in such physically and biologically different environments

Análise do efeito higrotérmico no comportamento em fadiga de compósitos de PPS/fibras de carbono

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação do comportamento em fadiga de juntas estruturais de ligas de Al2024T3 coladas com adesivo epóxi

Ligas de alumínio são extensamente usadas em partes aeronáuticas devido às boas propriedades mecânicas e baixa densidade. Estas partes devem ser unidas para formar conjuntos maiores. Uma junta estrutural é definida como um segmento de estrutura que provê um meio de transferir carga de um elemento estrutural para outro. A maioria das juntas aeronáuticas é mecanicamente fixada com múltiplos prendedores (parafusos ou rebites). Estas juntas apresentam uma alta concentração de tensões ao redor do prendedor, porque a transferência de carga entre elementos da junta acontece em uma fração da área disponível. Por outro lado, as cargas aplicadas em juntas adesivas são distribuídas sobre toda a área colada e reduz os pontos de concentração de tensão. Juntas são a fonte mais comum de falhas estruturais em aeronaves e quase todos os reparos envolvem juntas. Portanto, é importante entender todos os aspectos de projeto e análise de juntas. O objetivo deste trabalho é comparar estaticamente juntas estruturais de ligas de Al2024-T3 em três condições: juntas mecanicamente rebitadas, juntas coladas e uma configuração híbrida rebitada e colada. Foi usada a norma NASM 1312-4 para confecção dos corpos-de-prova. Além disso, foram conduzidos testes de fadiga, sob amplitude de carregamento constante e razão de tensão igual a 0,1 para avaliar a eficiência dos elementos estruturais durante sua vida em serviço. Os resultados mostraram que a configuração híbrida apresenta maior resistência estática e uma vida em fadiga superior à configuração colada.

Comportamento plástico do aço inoxidável austenítico em baixa temperatura

Ensaios de tração uniaxiais foram empregados para deformar aços inoxidáveis austeníticos do tipo 304, em diferentes temperaturas abaixo da ambiente (de 77 K a 300 K). A relação entre a estabilidade da austenita e o encruamento, em função da temperatura de teste, é discutida quanto à transformação martensítica induzida por deformação e ao deslizamento de discordâncias na austenita. em curvas tensão-deformação que assumem a equação de Ludwik sigma = sigmao + képsilonn, na qual sigma é a tensão verdadeira e e a elongação plástica verdadeira, um modo conveniente para analisar o encruamento é por meio do diagrama log dsigma / dépsilon versus log épsilon. O aspecto significativo é a variação da taxa de encruamento dsigma / dépsilon com a elongação plástica verdadeira nas diferentes temperaturas. As mudanças no comportamento do encruamento motivando até três estágios de deformação são associadas a diferentes processos microestruturais. A transformação martensítica pode ser considerada como um processo de deformação que compete com o processo usual de deslizamento. A investigação desses estágios, na região plástica, produz uma referência qualitativa de como diferentes fatores, tais como o grau de deformação, temperatura e composição química da austenita, afetam a transformação austenita-martensita.

Correlato hormonal do comportamento reprodutivo de machos de sagüi comum (Callithrix jacchus) em ambiente natural

Contrary to what is recorded for Callithrix jacchus females, the social interactions and hormonal profiles of males are less studied, and mainly in wild groups. The goal of this study was to investigate the behavioral and endocrine profiles of reproductive (RMs) and non-reproductive (NRs) common marmoset adult free-ranging males living in two natural groups (GC1 and GR2). The groups inhabited the area of the Escola Agrícola de Jundiaí/UFRN, located in Macaíba, Brazil. Fecal collection for cortisol and androgen measurement and behavioral monitoring was carried out during the active phase from April to September, 2005. For behavioral data collection the focal instantaneous method was used every 5 min, for a total of 11.563 records. Statistical analysis was performed using non parametric tests and p < 0.05. Besides showing diurnal variation, the frequency of affiliative behaviors was significantly higher for RMs toward reproductive females than for NRs. Affiliative interactions of RMs with both reproductive females and NRs were similar, probably related to pair bond formation and helper recruitment, respectively. Parental care was also similar for both RMs and NRs. Both androgen and cortisol levels increased after the birth of the infants, mainly in RMs. The longitudinal profile of androgens fluctuates more in response to agonistic encounters and sexual behavior than that of cortisol. The mean basal excretion of both hormones was significantly higher in RMs and seems to reflect their higher participation in territorial vigilance and mate guarding behaviors. Significant positive correlations were found between agonism and cortisol and androgen hormones. These results describe, for the first time, the behavioral and hormonal profiles of common marmosets living in free-ranging groups and suggest that reproductive males are more responsive both behaviorally and hormonally to social group dynamics

Estudo sobre orçamento de atividade do Boto Cinza (Sotalia guianensis) no litoral sul do Rio Grande do Norte

A fundamental analysis on Behavioral Ecology is the construction of Activities Budget, which can be defined as the quantification of the time that each animal uses in activities that are important for its survival and reproduction. Initially developed for theoretical studies about Optimal Foraging, the construction of Activities Budgets has recently being used for analyses in Conservation Biology. However, the measurement of behavior through an adequate methodology that allows the comparison between different samples is a challenge for researchers in the area of Ethology. This problem is even bigger for the students of cetaceans behavior due to the difficulty of visualization of these animals. The present work deals with two aspects of the specialized literature on cetaceans: i) it explores possible variations of results in quantification of behavioral states decurrent of the application of different methods of data collection, and ii) it describes the activity budget of a population of Sotalia guianensis that inhabits coastal waters, south Rio Grande do Norte. The results showed that the use different methods of data collection result in significant differences, but of small scale, in the quantification of the behavioral frequency. The activity budget of Sotalia in the area here analyzed was similar to that described for other populations of this species inhabiting typically estuarine habitats. Tide and day-hour did not influence the dolphin s behavior, however, significant differences were found related to the position of the animals within the area. These results are discussed considering the dietary and behavioral flexibility of the species, contributing to the scientific knowledge and offering information that will be useful in comparative studies and for analyses on the determination of areas for species conservation

Variação diária e anual de freqüência e atividade do Boto Cinza Sotalia guianensis em Pipa, Nordeste do Brasil

The aim of this study was to investigate the daily and annual variation in frequency and in activity of an estuarine dolphin population, Sotalia guianensis, in Brazilian northeastern. Thus we estimated the daily variation and seasonality in frequency of adult and immature and in behavior of socialization, aerial activity, foraging of a boto equatorial population in the Curral inlet (6º13 00 S; 35º3 36 W). We detect some variation. Thus we associate the daily variation with daily period, tide fluctuation and annual season. And the seasonality variation we associate with the fotoperíodo and precipitation variation. From October 1999 to September 2003, through collect four times at month, we made instantaneous record at each five minute in six hours of survey. The surveys hours were ranged into light time of 24 hours, that is, between 06:00 and 17:00 o clock. These observations were developed simultaneous for two observers in a land-based survey at coastline cliff top of which observer have a fully visualization of whole inlet. We found that animals were more active and frequent during the morning. They were more active during low tide than high tide. However they did not show association with tide. We found yet that in a period from June to November (winter-spring) there was the highest socialization, aerial activity and foraging frequency. However adult and immature individual number did not have significance variation along the year. The larger concentration of this behaviors were not associate with photoperiod neither precipitation in the region. These results showed the existence of behavioral daily variation and seasonality in a species that live in equatorial region

Sincronismo comportamental em Boto cinza(Sotalia guianensis)

Synchronism is the efetivation of the same behavior at the same time by two or more individuals. In cetology only from 2000 we verify an increasing of efforts for studies of synchronic behaviors. The synchronism in cetaceans was reported for a variety of contexts, including feeding, socializing, parental care, while resting, traveling and play, during afilliation, in sexual behaviour and possible while teaching. The synchronism in behavior is influenced by environmental factors and can be modified during stress situations such as the presence of boats. The aim of this study is to explore behavior synchronism presented by the estuarine dolphin (Sotalia guianensis) in Pipa, Rio Grande do Norte state, Northeastern Brazil. A total of 414 hours of observation during the year 2006, using scan sampling method, from a land based sighting was conducted. Analyses were conducted in four steps. Firstly, we determined the pattern of activity of the groups within the bay, testing for the influence of bay configuration before and after rains periods on the activity of animals. Analyses show that forage occurs more frequently after the rainy period, but there was no change in the number of individuals or spatial cohesions between them. Secondly, we analysed the influence of turism boat traffic on the behavior of animals. We verified no changes on the bahavior of animals during the presence of boats. Finally, we tested seven hypotheses regarding the ecological and social dynamics of synchronic behavior. Environmental aspects were considered the main influence for the synchronism, no influences of age, and more selective exihibition of synchronic breathing in feeding and social displays were observed during the study period