Antonio Souto

Structure and Usage of the Vocal Repertoire of Callithrix jacchus

We recorded the vocal repertoire and behavior of individuals from 3 groups of wild common marmosets (Callithrix jacchus) via focal sampling and ad libitum sampling in a fragment of Atlantic Rain Forest in Pernambuco, northeast Brazil. Our aims were: 1) to provide a detailed quantitative description of the vocalizations and vocal repertoire of common marmosets in the wild, and to compare the repertoire with that described from conspecific captives; 2) to investigate if differences exist in vocal repertoire between wild individuals of different ages; and 3) to explore the behavioral contexts associated with specific vocalizations in free-living Callithrix jacchus. This is the first study describing common marmoset calls in the wild and it shows that their vocal repertoire comprises 13 different calls. Though wild and captive calls were similar, differences occurred in the form of the alarm calls given for different potential predators, the tsê call, and very brief whistle. In addition, the tsee call did not occur in wild individuals and wild infants did not utter the twitter call. The age of the subjects influenced the call types present in the vocal repertoire, e.g., the loud cry was specific to infants, whereas only adults gave alarm calls. The behavior of both the caller and the potential receivers seemed to affect the frequency of wild common marmoset calls. One could predict intricate vocalization-based communications for the system based on their relatively complex social organization and densely leafed arboreal habitat. Our study confirms the prediction.

Caatinga revisited: ecology and conservation of an important seasonal dry forest.

Besides its extreme climate conditions, the Caatinga (a type of tropical seasonal forest) hosts an impressive faunal and floristic biodiversity. In the last 50 years there has been a considerable increase in the number of studies in the area. Here we aimed to present a review of these studies, focusing on four main fields: vertebrate ecology, plant ecology, human ecology, and ethnobiology. Furthermore, we identify directions for future research. We hope that the present paper will help defining actions and strategies for the conservation of the biological diversity of the Caatinga.

The maintenance of traditions in marmosets: individual habit, not social conformity? A field experiment.

Background Social conformity is a cornerstone of human culture because it accelerates and maintains the spread of behaviour within a group. Few empirical studies have investigated the role of social conformity in the maintenance of traditions despite an increasing body of literature on the formation of behavioural patterns in non-human animals. The current report presents a field experiment with free-ranging marmosets (Callithrix jacchus) which investigated whether social conformity is necessary for the maintenance of behavioural patterns within groups or whether individual effects such as habit formation would suffice. Methods Using a two-action apparatus, we established alternative behavioural patterns in six family groups composed of 36 individuals. These groups experienced only one technique during a training phase and were thereafter tested with two techniques available. The monkeys reliably maintained the trained method over a period of three weeks, despite discovering the alternative technique. Three additional groups were given the same number of sessions, but those 21 individuals could freely choose the method to obtain a reward. In these control groups, an overall bias towards one of the two methods was observed, but animals with a different preference did not adjust towards the group norm. Thirteen of the fifteen animals that discovered both techniques remained with the action with which they were initially successful, independent of the group preference and the type of action (Binomial test: exp. proportion: 0.5, p<0.01). Conclusions The results indicate that the maintenance of behavioural patterns within groups 1) could be explained by the first rewarded manipulation and subsequent habit formation and 2) do not require social conformity as a mechanism. After an initial spread of a behaviour throughout a group, this mechanism may lead to a superficial appearance of conformity without the involvement of such a socially and cognitively complex mechanism. This is the first time that such an experiment has been conducted with free-ranging primates.

Critically endangered blonde capuchins fish for termites and use new techniques to accomplish the task

We report the spontaneous modification and use of sticks to fish for termites, above the ground, in wild blonde capuchins (Cebus flavius). These critically endangered Neotropical primates inhabit remnants of the Atlantic Forest. They used two previously undescribed techniques to enhance their termite capture success: nest tapping and stick rotation. The current ecologically based explanation for tool use in wild capuchins (i.e. terrestrial habits and bipedalism) must be viewed cautiously. Instead, remarkable manual skills linked to a varied diet seem important in promoting tool use in different contexts. The repertoire of tool-using techniques employed by wild capuchins has been expanded, highlighting the behavioural versatility in this genus.

Feeding behavior of the longsnout seahorse Hippocampus reidi Ginsburg, 1933

Hippocampus reidi is a threatened species and one of the most heavily traded seahorses in the aquarium trade. Nevertheless, little is known about its biology and ecology. This study encompasses the first description of the feeding behavior of H. reidi, with emphasis on preferred feeding time, feeding frequency, feeding behavior during nonreproductive and reproductive periods, and prey choice. Underwater observations were made in NE Brazil from May 2003 to September 2004, and the behavior of 57 specimens was recorded during 118 feeding events. In the laboratory, 8 specimens and 176 feeding events were recorded. Prey choice was tested among carideans, amphipods, live and frozen brine shrimp, with the most consumed prey being the caridean Hyppolyte curacoensis. H. reidi fed both at diurnal and crepuscular hours, its feeding frequency being directly proportional to luminous intensity. No feeding was observed at night. Males with a fully developed pouch exhibited a significantly higher feeding frequency than nonreproductive males. H. reidi generally is a “sit-and-wait” predator that occasionally pursues prey.

Can wild common marmosets (Callithrix jacchus) solve the parallel strings task

Patterned string tasks are a test of perceptual capacity and the understanding of means-end connections. Primates can solve complex forms of this task in laboratories. However, this may not indicate the level of such cognition that is commonly employed in the wild, where decision-making time is often short and distractions such as predator avoidance and competition between conspecifics are often prevalent. The current study tests whether wild common marmosets (Callithrix jacchus) can successfully complete the simplest form of the patterned string task, parallel strings, while in their natural environment. Although 12 out of 13 marmosets could successfully complete the task, in previous laboratory-based studies on primates, the errors at this task by all primate species tested were consistently lower than in the present study. This is probably explained by the added difficulties imposed by the natural setting of the task in the present study, exemplified by a significant increase in observed vigilance behaviour by subject animals prior to attempts at the task that were unsuccessful. The undertaking of such tasks by common marmosets in situ probably provides a more reasonable representation of the levels of cognitive capacity expressed by this species in the wild than do laboratory-based studies of the task.

Laboratory and field evaluation of an oviposition trap for Culex quinquefasciatus (Diptera: Culicidae)

An ovitrap (BR-OVT) based on physical and chemical stimuli for attracting gravid Culex quinquefasciatus (Diptera: Culicidae) females was developed and evaluated under laboratory and field conditions. Attractants were assayed using alternative chamber bioassays prior to being used in the BR-OVT oviposition trap. A significant preference of gravid females for sites containing conspecific egg rafts was observed, as a response to the natural oviposition pheromone, as well as for sites treated with the synthetic pheromone erythro-6-acetoxy-5-hexadecanolide. Five- to 20-day old grass infusion was strongly attractive to gravid females for laying eggs. On the other hand, entomopathogenic Bacillus sphaericus (Bs) did not influence the choice of an oviposition site when used in combination with grass infusion and can therefore be used as a larvicide in ovitraps. Results from field trials showed that the BR-OVT with grass infusion and with or without Bs works as a preferred oviposition site for Cx. quinquefasciatus. The BR-OVT was more effective for egg collection when placed indoors and comparison with the number of egg rafts laid in cesspits over 40 days indicates that this very simple ovitrap may be a useful tool for monitoring populations of the most important of the vectors of bancroftian filariasis.

Predation by the tayra on the common marmoset and the pale-throated three-toed sloth

Predation on arboreal mammals is rarely observed in the wild. Here we describe the first confirmed observations of predation on a juvenile wild common marmoset (Callithrix jacchus) and on a neonate wild pale-throated three-toed sloth (Bradypus tridactylus) by the mustelid carnivore Eira barbara, the tayra. We discuss predation on both of the prey species and review the nature of predation by the tayra.

The role of mammals in local communities living in conservation areas in the Northeast of Brazil: an ethnozoological approach

Humans have used animals and their products since the beginning of their shared history. Animals are used for different purposes, including food, medicines and magical-religious practices. This study analyzes two communities that reside in a conservation area to determine the role of mammals by these communities, considering the influences of factors such as gender and age on the knowledge and use of the mammals by individuals. Data were obtained through semi-structured interviews in the two communities in the Chapada do Araripe Environmental Protection Area (APA/Araripe) in Brazil. All of the inhabited houses in the communities were visited, and at most, two people were interviewed per household. A total of 229 interviews were conducted with local residents. A total of 32 species of mammals was recorded, with 8 used for medicinal purposes, 17 species used as food resources, and 23 species related to superstition. Men knew and used more mammals as zootherapeutics and as a food resource than women, whereas for superstition, there was no significant difference between the genders. Regarding age, adults knew and used more mammals as zootherapeutics, and the elderly used more mammals as a food resource. This study demonstrates that the use of wild mammals still occurs in rural communities in Brazil, even in conservation units where the federal laws are stricter.

Adaptability in stone tool use by wild capuchin monkeys (Sapajus libidinosus).

Capuchin monkeys are well known for population variation in the use of stone tools and the types of food items consumed. In order to determine adaptability in stone tool use, we investigated a never before studied population of wild capuchin monkey (Sapajus libidinosus) displaying terrestrial habits in a Caatinga environment. To carry out this study we recorded physical evidence of the use of stone tools as well as made direct observations through trap cameras. During a 15‐month period, we studied a group of Sapajus libidinosus in Serra Talhada, Pernambuco, Brazil. In total, 257 anvils and 395 hammers were identified, characterized, and monitored. We identified five types of food items exploited at these “tool use sites”: Syagrus oleracea (catolé palm), Manihot epruinosa (manioc), Pilosocereus pachycladus (facheiro), Tacinga inamoena (quípa), and Commiphora leptophloeos (imburana de cambão). Five hundred three video clips of capuchin monkeys were recorded, 43 of which involved the use of stone tools. The results indicated evidence of adaptability in tool use by the capuchins. We verified that the rigidity and size of the food item, along with the presence or absence of spines seem to influence the choice of stone tools made by the animals for processing the food. The recurring use of tools for the processing of cacti was especially noteworthy and it appears that the presence of spines predisposes the capuchins to use stones to process them. A significant difference was observed between the characteristics of the anvils and the weight of the hammers according to the food item consumed. The use of tools enabled the animals to access otherwise unavailable or difficult to acquire food items within a Caatinga habitat. Adaptability in the use of stone tools by the capuchin monkey population of Serra Talhada provides an example of the complexity that these primates demonstrate in food processing. Am. J. Primatol. 76:967–977, 2014.