Biology subjects

Bicca-Marques, J. C.

Publications and source records attributed to Bicca-Marques, J. C..

4 recordsLinked to original sources

bioRxiv2025

Diet, Climatic Conditions, and Sex Affect the Mycobiome of Wild Common Marmosets (Callithrix jacchus)

Recent research on the gut mycobiome, or the fungal portion of the gut microbial community, suggests that it interacts with host physiology and impacts host health. However, fundamental questions about how the mycobiome is assembled remain unanswered. It remains unclear whether the fungi detected in the gut are predominantly residents of the gastrointestinal tract or if they are largely transient and pass through. To address this question, we sought to determine whether host factors (e.g., sex) or external environmental factors (e.g., variable climatic conditions and diet) were more strongly correlated with the gut mycobiome of common marmosets (Callithrix jacchus), a primate species living in the semi-arid Caatinga biome of northeastern Brazil. A stronger correlation with host factors, would suggest a more resident mycobiome, while a stronger association with external environmental factors suggests a more transient mycobiome. We collected 52 marmoset fecal samples across a 2-year period and DNA metabarcoding was used to assess both the mycobiome and diet of each sample. We used FUNGuild to assign ecological roles to the fungi, which were sorted into resident (e.g. animal pathogens) and transient (e.g. plant pathogens) groups. We found that mycobiome richness and evenness varied by host sex and correlated with the arthropod component of the diet while mycobiome composition varied between wetter and drier periods and correlated with the plant portion of the diet. The fact that external environmental factors were associated with the presence of specific taxa led us to conclude that the mycobiome is largely made up of transient taxa. ImportanceOther than causing infectious diseases, the function of the mycobiome is poorly understood. There is evidence that the mycobiome can play a positive role, such as training the hosts immune system, and a negative role, such as causing cancer and Alzheimers disease. To fully understand these associations, basic questions about which taxa live in the host and which pass through, must be addressed. We used DNA metabarcoding and a tool that can group fungi based on their ecological roles, to determine whether the mycobiome of Caatinga marmosets was more strongly correlated with host sex or host diet and environment. We found that the marmoset mycobiome was more strongly correlated with diet and environment and most fungi passed through the host rather than lived in the hosts gut.

microbiology↗

bioRxiv2021

Wildlife is imperiled in peri-urban landscapes: threats to arboreal mammals

Urbanization and deforestation impose severe challenges to wildlife, particularly for forest-living vertebrates. Understanding how the peri-urban matrix impacts their survival is critical for designing strategies to promote their conservation. We investigated the threats faced by brown howler monkeys (Alouatta guariba clamitans) in peri-urban regions of Rio Grande do Sul (RS) and Santa Catarina (SC) states, southern Brazil, by compiling negative interaction events (hereafter NIE) reported over more than two decades. We assessed the major NIEs, their distribution among age-sex classes, and the predictors of NIE-related mortality. After 20+ years of monitoring, we compiled 540 NIEs (RS = 248 and SC = 292). Electrocution by power lines was the most frequent cause of death or injury (37%), followed by dog attack (34%), vehicle collision (17%), and human mistreatment (12%). The occurrence of lethal injuries ranged from 5% to 69% depending on the type of NIE and on which state it occurred in. The overall post-NIE mortality was 56%. Adults of both sexes were the most affected individuals in both study regions. The minimal adequate GLM model explained 83% of the variation in NIE-related mortality. State, NIE type, and age-sex class were the main predictors of mortality. Overall, mortality was lower in SC and higher among adult females than in the other classes. We found that the survival of brown howler monkeys in the forest-urban interface is constrained by both the urban infrastructure and the growing interactions with humans and domestic and stray dogs (Canis familiaris). We propose the placement of aerial bridges, road signs and speed bumps in areas of frequent animal crossing, the sterilization of stray dogs, and the sensitization of local inhabitants on the importance of respecting and protecting wildlife to reduce their NIEs with humans and domestic animals in the forest-urban interface.

ecology↗

bioRxiv2020

Leaf and flower consumption modulate the drinking behavior in a folivorous-frugivorous arboreal mammal

Water is vital for the survival of any species because of its key role in most physiological processes. However, little is known about the non-food-related water sources exploited by arboreal mammals, the seasonality of their drinking behavior and its potential drivers (including diet composition, temperature, and rainfall). We investigated this subject in 14 wild groups of brown howler monkeys (Alouatta guariba clamitans) inhabiting small, medium, and large Atlantic Forest fragments in southern Brazil. We found a wide variation in the mean rate of drinking among groups (range=0-16 records/day). Streams (44% of 1,258 records) and treeholes (26%) were the major types of water sources, followed by bromeliads in the canopy (16%), pools (11%), and rivers (3%). The type of source influenced whether howlers used a hand to access the water or not. Drinking tended to be evenly distributed throughout the year, except for a slightly lower number of records in the spring than in the other seasons, but it was unevenly distributed during the day. It increased in the afternoon in all groups, particularly during temperature peaks around 15:00 and 17:00. We found via generalized linear mixed modelling that the daily frequency of drinking was mainly influenced by flower (negatively) and leaf (positively) consumption, whereas fruit consumption, fragment size, rainfall, and mean ambient temperature played negligible roles. The influence of leaf consumption is compatible with the metabolite detoxification hypothesis, which states that the processing of this fibrous food requires the ingestion of larger volumes of water to help in the detoxification/excretion of its metabolites. In sum, we found that irrespective of habitat size and climatic conditions, brown howlers seem to seek a positive water balance by complementing preformed and metabolic water with drinking water, even when it is associated with a high predation risk in terrestrial sources.

animal behavior and cognition↗

bioRxiv2019

Prey abundance drives habitat occupancy by jaguars in Amazonian floodplain fluvial islands

The jaguar (Panthera onca) is widely distributed across a broad range of habitat types, where its feeding habits and habitat use patterns vary significantly. The jaguar and its main arboreal prey - the brown-throated sloth (Bradypus variegatus) and the red howler monkey (Alouatta juara) - are widespread in the Amazonian floodplain forests of the Mamiraua Reserve. These forest-dwelling species are the most common mammal species both in the continuous forest and the forest patches surrounded by a river matrix - the fluvial islands - of the Solimoes and Japura rivers. We used sign surveys along line-transects to assess the pattern of habitat occupancy by jaguars in Amazonian floodplain forests. Specifically, we (i) tested whether habitat occupancy by jaguars differs between river islands and continuous forest; and (ii) evaluated whether and how the local abundance of sloths and howler monkeys influence the probability of site occupancy by jaguars. We built an occupancy model and used Bayesian inference to reach these goals. The proportion of sites estimated to be used by jaguars was{psi} = 0.75 (HPD95: 0.36-1.00), and it did not differ between islands and continuous forest. The abundance of both prey species had a direct influence on jaguars habitat use, whereas the aquatic matrix seems to have a negligible effect on the use of islands by jaguars. We conclude that the isolation of the river islands within the aquatic matrix does not hamper jaguars to use them. We also conclude that prey search modulates jaguars habitat occupancy patterns with both prey species having a similar effect. This finding is compatible with the previously reported importance of sloths to the diet of jaguars in the study region despite its lower abundance than howlers. Finally, we suggest that sign surveys are an alternative method to assess the pattern of jaguar habitat occupancy in floodplain forests.

ecology↗