Navegando por Autor "Araújo, Arrilton"
Agora exibindo 1 - 13 de 13
- Resultados por página
- Opções de Ordenação
Artigo Adjustments in the time, distance and direction of foraging in dinoponera quadriceps workers(Springer, 2014) Azevedo, Dina L. O.; Medeiros, Jeniffer C.; Araújo, ArriltonWe measured individual decisions regarding the adjustments of time, distance and direction of foraging in Dinoponera quadriceps.We observed two colonies in an area of secondary Atlantic Forest, FLONA-ICMBio, in Northeastern Brazil. The workers were individually marked. We recorded the displacement of workers, their returns to the nest with and without food, the time spent searching for food, maximum and total distance, inter-trip latency and direction of trips. The time spent searching for food, maximum distance and transport velocity did not vary with food size. The previous trip success reduced the latency between foraging trips and increased the percentage of success on the next trip. However, this previous success did not demonstrate a significant variation relative to the time spent searching on the next trip or direction of search. The workers maintained an individual directional fidelity during foraging. The adjustments of these foraging variables under individual control contributed to the efficiency at the colony level. D. quadriceps is compatible with the central place theory and risk sensitivity model of behaviorArtigo Anticonvulsant effects of fractions isolated from dinoponera quadriceps (Kempt) ant venom (Formicidae: ponerinae)(Multidisciplinary Digital Publishing Institute, 2017) Nôga, Diana Aline Morais Ferreira; Brandão, Luiz Eduardo Mateus; Cagni, Fernanda Carvalho; Silva, Delano; Azevedo, Dina Lilia Oliveira de; Araújo, Arrilton; Santos, Wagner Ferreira dos; Miranda, Antonio; Silva, Regina Helena da; Ribeiro, Alessandra MussiNatural products, sources of new pharmacological substances, have large chemical diversity and architectural complexity. In this context, some toxins obtained from invertebrate venoms have anticonvulsant effects. Epilepsy is a neurological disorder that affects about 65 million people worldwide, and approximately 30% of cases are resistant to pharmacological treatment. Previous studies from our group show that the denatured venom of the ant Dinoponera quadriceps (Kempt) protects mice against bicuculline (BIC)-induced seizures and death. The aim of this study was to investigate the anticonvulsant activity of compounds isolated from D. quadriceps venom against seizures induced by BIC in mice. Crude venom was fractionated by high-performance liquid chromatography (HPLC) resulting in six fractions referred to as DqTx1–DqTx6. A liquid chromatography-mass spectrometry (LC/MS) analysis revealed a major 431 Da compound in fractions DqTx1 and DqTx2. Fractions DqTx3 and DqTx4 showed a compound of 2451 Da and DqTx5 revealed a 2436 Da compound. Furthermore, the DqTx6 fraction exhibited a major component with a molecular weight of 13,196 Da. Each fraction (1 mg/mL) was microinjected into the lateral ventricle of mice, and the animals were observed in an open field. We did not observe behavioral alterations when the fractions were given alone. Conversely, when the fractions were microinjected 20 min prior to the administration of BIC (21.6 nM), DqTx1, DqTx4, and DqTx6 fractions increased the latency for onset of tonic-clonic seizures. Moreover, all fractions, except DqTx5, increased latency to death. The more relevant result was obtained with the DqTx6 fraction, which protected 62.5% of the animals against tonic-clonic seizures. Furthermore, this fraction protected 100% of the animals from seizure episodes followed by death. Taken together, these findings indicate that compounds from ant venom might be a potential source of new anticonvulsants moleculesArtigo Body weight of wild and captive common marmosets (callithrix jacchus)(Springer Velag, 2000) Araújo, Arrilton; Arruda, M. F.; Alencar, A. I.; Albuquerque, F.; Nascimento, M. C.; Yamamoto, M. E.Captive studies and occasional trappings of wild individuals indicate that callitrichids have small size and body weight and lack sexual dimorphism. We compared body weights of captive and wild Callithrix jacchus obtained by repeatedly weighing subjects from two populations in Brazil. We obtained captive data by routinely weighing 138 individuals from the Universidade Federal do Rio Grande do Norte colony and wild data via regular trapping of 243 individuals in 15 free-ranging groups from IBAMA’s field site in Nı´sia Floresta. We assigned all subjects to one of four age classes—infant, juvenile, subadult, and adult—according to their birth dates or size, reproductive status, and dental development. There is no significant difference between males and females in any of the four age classes, but captive subjects were heavier than wild ones in all age classes but infant. Reproductive and nonreproductive adult females showed no statistical difference in weight. These results accord with previous reports of lack of body size sexual dimorphism in common marmosets and suggest that differences between wild and captive common marmosets are not constitutional, but are instead a consequence of diet and physical activity. The absence of weight difference between reproductive and nonreproductive females suggests that any possible advantage from high rank is outweighed by the costs of reproduction in common marmosetsTCC Competição entre colônias de Dinoponera quadriceps (Hymenoptera, Formicidae, Ponerinae)(Universidade Federal do Rio Grande do Norte, 2018-11-26) Vieira, Maria Eduarda de Lima; Araújo, Arrilton; Azevedo, Dina Lillia Oliveira de; Miranda, Maria de Fátima Arruda de; Medeiros, Jeniffer da CâmaraA competição por acesso às fontes de recursos alimentares, território e parceiros reprodutivos entre indivíduos, de mesma espécie ou não, abrange uma série de comportamentos, muitas vezes custosos aos envolvidos. O estabelecimento e manutenção de territórios e áreas de uso, em insetos sociais, são baseados em um complexo sistema de comunicação e na divisão de trabalho. Nesse estudo, o objetivo foi analisar a competição intraespecífica entre colônias vizinhas de Dinoponera quadriceps. Para isso, três colônias vizinhas de D. quadriceps foram escolhidas dentro da área de Mata Atlântica secundária da FLONA de Nísia Floresta/RN. As observações ocorreram entre os meses de maio e agosto de 2018. Elas aconteceram dois dias por semana, dez horas por dia e, totalizou 300 horas de observação. Era observada uma formiga por vez, do momento em que esta saia do ninho até o seu retorno. Os comportamentos de captura de alimento, interação afiliativa, interação agonística e marcação química foram registrados através da técnica todas as ocorrências. Os deslocamentos e locais onde ocorreram tais comportamentos foram marcados com bandeirolas numeradas e depois medidos com bússola e trena. Nossos achados apontam que ninhos de D. quadriceps tem uma grande área de uso para forrageio e que essa se encontra muito sobreposta a áreas de colônias vizinhas. O tamanho da área de uso não variou em relação a densidade populacional do ninho. Os comportamentos de marcação química e interação agonística não apresentaram diferença significativa em áreas de sobreposição e não sobreposição e também entre as distâncias em que a formiga se encontrava do ninho, porém, se mostrou mais frequente no limite de cada área utilizada pelas formigas. Características do comportamento competitivo de D. quadriceps foram encontradas também em outras espécies de formigas e se relacionam a provável diminuição do custo da defesa ativa de um território fixo.TCC Escolha do local de dormir de Callithrix jacchus em diferentes habitats(Universidade Federal do Rio Grande do Norte, 2019-12-13) Lima, Matheus Amiel Costa; Araújo, Arrilton; Miranda, Maria de Fátima Arruda de; Terceiro, Francisco Edvaldo de OliveiraEm primatas o local de dormir pode fornecer uma série de vantagens tais como: proteção contra predação, conforto, higiene, termorregulação, proximidade a recursos como comida e água, abrigo contra chuva e vento, proteção contra parasitas e território. A escolha desses locais é influenciada por diversas características físicas e ambientais. O objetivo desse estudo foi o de comparar a escolha dos locais de dormir de grupos de Callithrix jacchus vivendo em diferentes habitats. A primeira hipótese um foi a de que a escolha do local de dormir sofrerá influência das características físicas das árvores de cada habitat, sendo esperado que grupos da Mata Atlântica dormam em locais mais altos que os da Caatinga. A segunda hipótese é a de que a densidade de cobertura vegetal das árvores de dormir varia dependendo do habitat, sendo esperado que grupos da Caatinga sejam menos influenciados pela densidade da cobertura vegetal na árvore de dormir. Foram acompanhados seis grupos de C. jacchus, quatro na FLONA de Nísia Floresta/RN e dois na FLONA de Açu/RN e os grupos de Nísia Floresta foram divididos em função da área que ocupavam, sendo classificados como grupo plantação e mata secundária. Cada grupo era seguido ao longo do dia e ao final da tarde era registrado a altura da árvore e do local de dormir. Além disso, a cobertura do dossel foi classificada em função da presença de folhagem. O número de noites passadas em cada local de dormir também foi registrado. Os animais de Nísia Floresta foram acompanhados por cerca de 12 meses enquanto os de Açu foram acompanhados por dois meses. Ao todo foram registrados 259 locais de dormir e 29 árvores foram identificadas como árvores de dormir. As alturas das árvores e dos locais de dormir variaram nos três habitats e forte correlação positiva foi encontrada entre a altura das árvores e do local de dormir dentro de cada habitat. A comparação da cobertura vegetal dentro de cada habitat quanto à altura das árvores foi significativa apenas na Caatinga e a comparação quanto à altura do local de dormir não apresentou diferença significativa em nenhum dos habitats. A frequência de escolha quanto a cobertura vegetal dentro de cada habitat mostrou diferença significativa somente na mata secundária. As hipóteses desse estudo não foram corroboradas estatisticamente, mas ao observar os dados é possível observar certos padrões que mostram diferenças nas árvores de dormir entre os saguis de Mata Atlântica e Caatinga e um estudo com grupos de C. jacchus durante a estação chuvosa na Caatinga complementaria esse trabalho.Artigo Foraging activity rhythms of dinoponera quadriceps (Hymenoptera: formicidae) in its natural environment(Oxford University Press, 2014) Medeiros, Jeniffer; Azevedo, Dina L. O.; Santana, Melquisedec A. D.; Lopes, Talita R. P.; Araújo, ArriltonThis study characterizes the foraging activity of the queenless ant Dinoponera quadriceps (Kempf) (Hymenoptera: Formicidae) in its natural environment by testing the hypotheses that foraging activity presents both daily and seasonal rhythmic variations, and that these rhythms are related to environmental variables. Four colonies of D. quadriceps were observed in an area of secondary Atlantic forest in northeastern Brazil. Data collection was performed over 72 h every three months during an annual cycle. Both daily and seasonal foraging activity rhythms of D. quadriceps colonies were related to environmental factors, but colony differences also explained part of foraging variations. Foraging activity of D. quadriceps colonies was predominantly diurnal independently of season. In the early dry season, the colonies had two activity peaks, one in the morning and another in the afternoon, with a decrease in foraging at midday; however, during the rest of the year, foraging activity was distributed more evenly throughout the daylight hours. The daily rhythm of foraging activity was likely determined by an endogenous circadian rhythm year-round, but in the dry season, temperature and relative humidity also influenced daily foraging activity, with a negative effect of temperature and a positive effect of relative humidity. On a seasonal scale, foraging activity peaked in the early dry season and suddenly declined at the end of this season, increasing again at the late rainy season. The seasonal rhythm of foraging was negatively related to relative humidity and positively related to prey availabilityArtigo Male and female breeding strategies in a cooperative primate(Elsevier, 2014) Yamamoto, Maria Emilia; Araújo, Arrilton; Arruda, Maria de Fátima; Lima, Ana Karinne Moreira; Siqueira, Jose de Oliveira; Hattori, Wallisen TadashiMarmosets are cooperative breeders organized as extended family groups, but breeding is generallyrestricted to a single pair. Breeding competition is fierce in female marmosets; males, on the other hand,show low levels of intragroup aggression. We investigated male and female breeding strategies andthe resulting reproductive output in 9 wild groups. Reproductive output, tenure of breeding animals,identification of the breeding system, breeding position replacements, migration and infanticide wererecorded; also, we recorded grooming and aggression. Replacement of the breeding male or female wasobserved on nine occasions. On four occasions, the son of the breeding male inherited the breeding post,but we never observed inheritance of a breeding post by a daughter. Mostly, females attained a breedingpost by immigrating to a group that had a breeding vacancy. Our results showed that Callithrix jacchusmales and females use different strategies to attain a breeding position and maintain it for as long aspossible. These strategies prolong the tenure of the breeding position, which is the best way to producea large number of offspringArtigo Nest maintenance activity of dinoponera quadriceps in a natural environment(Springer, 2016) Medeiros, Jeniffer; Azevedo, Dina Lillia Oliveira de; Santana, Melquisedec Abiare Dantas de; Araújo, ArriltonIn social insects, task allocation can be more complex than workers merely falling into discrete task groups. Any activity performed by the colony cannot be fully understood in isolation from other activities because they may be interrelated. Investigating activities other than foraging is crucial to understanding the global functioning and organization of ant colonies. This study attempts to characterize the nest maintenance activity of the ponerine queenless ant, Dinoponera quadriceps, in its natural environment to determine the effects of environmental variables on the variations in both seasonal and daily rhythms and to discuss its differences and possible relationships to foraging. Four colonies of D. quadriceps were observed in an area of Atlantic Forest in northeastern Brazil. Data collection was performed over a period of 72 h every three months during an entire annual cycle. Nest maintenance activity in D. quadriceps colonies was observed during both the light and dark phases of the day. There was no significant difference between the day phases in the number of workers involved in this task. On the other hand, D. quadriceps colonies exhibited seasonal variation in nest maintenance activity, peaking in the early rainy season. The seasonal rhythm of nest maintenance was positively correlated with relative humidity and negatively correlated with prey availability and rainfall. Our results indicate the existence of an annual variation in the nest maintenance activity of D. quadriceps associated with environmental variables. However, it occurs equally both at night and day, countering the hypothesis that there is a daily rhythmArtigo Pro-and anticonvulsant effects of the ant dinoponera quadriceps (Kempf) venom in mice(Springer, 2015) Ferreira, Diana Aline Nôga Morais; Cagni, Fernanda Carvalho; Santos, J. R.; Silva, D.; Azevedo, D. L. O.; Araújo, Arrilton; Silva, R. H.; Ribeiro, A. M.Epilepsy affects at least 50 million people worldwide, and the available treatment is associated with various side effects. Approximately 20–30% of the patients develop seizures that persist despite careful monitored treatment with antiepileptic drugs. Thus, there is a clear need for the development of new antiepileptic drugs, and the venoms can be an excellent source of probes. In this context, while there are studies on venoms from snakes, scorpions, and spiders, little is known regarding venom from ants. The aim of this study was to investigate the potential pro- and anticonvulsant effects of the venom from the ant Dinoponera quadriceps (Kempf) in Swiss mice. After the injection of the crude venom (DqTx—5, 50, and 500 mg/mL) in the lateral ventricle of mice, we observed a reduction of exploration and grooming behaviors, as well as an increase in immobility duration. In addition, the crude venom induced procursive behavior and tonicclonic seizures at the highest concentration. Conversely, the preadministration of the denatured venom (AbDq) at the concentration of 2 mg/mL protected the animals against tonic-clonic seizures (66.7%) and death (100%) induced by administration of bicuculline. Taken together, the findings demonstrate that D. quadriceps venom might be potential source of new pro- and anticonvulsants moleculesArtigo Seasonal activity of dinoponera quadriceps santschi (formicidae, ponerinae) in the semi-arid caatinga of northeastern Brazil(Universidade Federal da Paraíba (UFPB), 2012) Medeiros, Jeniffer; Araújo, Arrilton; Araújo, Helder F. P.; Queiroz, João Paulo C.; Vasconcellos, AlexandreSeasonal activity of Dinoponera quadriceps Santschi (Formicidae, Ponerinae) in the semi-arid Caatinga of northeastern Brazil. We studied seasonal foraging patterns of the queenless ant D. quadriceps (Formicidae, Ponerinae) for 24 months in a Caatinga area of northeastern Brazil, an ecosystem characterized by strong climatic changes throughout the year, in order to determine if regulation of worker activity is based on environmental conditions (air temperature, relative humidity, precipitation) and/or food resources (potential prey: Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera, Orthoptera, Araneae, Chilopoda and Diplopoda). Foraging activity of D. quadriceps varied over the course of both years, with the highest frequency occurring from May to August, corresponding to the late rainy season and early dry season. This foraging activity was negatively correlated with temperature and positively correlated with the availability of potential prey, but not with total abundance of soil arthropods or with rainfall and relative humidity. Diet composition, in relation to the main taxonomic prey groups, seems to be common to the species, regardless of habitat. Our results suggest that D. quadriceps workers adjust foraging activity to the most suitable period of the year, to avoid thermal stress and increase efficiency. Thus, they present an appropriate behavioral response to seasonal fluctuations in the caatingaArtigo Testicular volume and reproductive status of Wild Callithrix jacchus(International Journal of Primatology, 2008) Araújo, Arrilton; Sousa, Maria Bernardete Cordeiro deArtigo When the fledglings red-footed boobies (Sula sula) acquire flight capacity(2016) Rodrigues, Marcelo Câmara; Araújo, Arrilton; Arruda, Maria de FátimaThe high cost of parental care may sometimes result in a conflict of interest between parents and offspring. To achieve the benefits of producing viable offspring and/or additional breeding opportunities, tropical seabirds must be able to afford the costs of searching for food in an oligotrophic environment. In order to verify the behavioral variation of Red-footed Boobies (Sula sula) during the late phase of its development, over a 12 week period was recorded the behavior of 15 fledglings. The behavioral records were made with the instantaneous focal animal method in windows of 15 minutes and records every minute. Records of feeding, agonism and frigates attacks were recorded ad libitum during the days of observation. No differences in the frequency of activities displayed by offspring at advanced stages of fledgling development, or in the frequency of parental presence during the transitional period to full capacity for flight were detected. On the other hand, it was observed that fledglings synchronized their presence at the nest with that of the adults even after achieving full flight capacity and that during periods of absence neighboring offspring were likely to occupy vacant nests. We speculate that with this behavior they apparently are trying to acquire, opportunistically, extra food resources from other, not directly related adults. However, we did not observe any fledgling being fed by a non-related adult. We also recorded the expression of aggressive behaviors of a fledgling towards a neighboring fledgling on the nest. These observations suggest the presence of a behavioral strategy in this species that is motivated by the continuously high demand for sustenance as the frequency of parental provisioning declines during the more advanced stages of offspring development. Although we did not verify changes in the fledglings’ behavioral repertoire, the occurrence of agonistic behavior among them suggests that they must try alternative strategies to get food while not quite ready to live independentlyArtigo Workers’ extra-nest behavioral changes during colony fission in dinoponera quadriceps (Santschi)(Springer, 2014) Medeiros, J.; Araújo, ArriltonAnt colonies can reproduce by two strategies: independent foundation, wherein the queen starts a new colony alone, and dependent foundation, in which workers assist the queen. In the queenless species Dinoponera quadriceps (Santschi), the colony reproduces obligatorily by fission, a type of dependent foundation, but this process is not well understood. This study describes a colony fission event of D. quadriceps in the field and analyzes the influence of the fission process on workers’ extra-nest behavior. Based on observations of workers outside the nest, five distinct stages were identified: monodomic stage, polydomic stage, split stage, conflict stage, and post-conflict stage. The colony was initially monodomic and then occupied a second nest before it split into two independent colonies, indicating a gradual and opportunistic dependent foundation. After the fission event, the daughter colony had aggressive conflicts with the parental colony, resulting in the latter’s disappearance. Colony fission affected workers’ extra-nest behavior by increasing the frequency of rubbing the gaster against the substrate (which probably has a chemical marking function) and by decreasing the frequency of foraging during the split stage. After the fission event, the number of foragers was halved and foragers remained nearer to the nest during extra-nest activity. The spatial closeness of the parental and daughter colonies led to competition that caused the extinction or migration of the parental colony. Intraspecific competition was indicated by foraging directionality at the colony level, whereby areas of neighbor colonies were avoided; this directionality was stronger while both colonies coexisted