RESUMO

Whether prey species avoid predators and predator species track prey is a poorly understood aspect of predator-prey interactions, given measuring prey tracking by predators and predator avoidance by prey is challenging. A common approach to study these interactions among mammals in field situations is to monitor the spatial proximity of animals at fixed times, using GPS tags fitted to individuals. However, this method is invasive and only allows tracking of a subset of individuals. Here, we use an alternative, noninvasive camera-trapping approach to monitor temporal proximity of predator and prey animals. We deployed camera traps at fixed locations on Barro Colorado Island, Panama, where the ocelot (Leopardus pardalis) is the principal mammalian predator, and tested two hypotheses: (1) prey animals avoid ocelots; and (2) ocelots track prey. We quantified temporal proximity of predators and prey by fitting parametric survival models to the time intervals between subsequent prey and predator captures by camera traps, and then compared the observed intervals to random permutations that retained the spatiotemporal distribution of animal activity. We found that time until a prey animal appeared at a location was significantly longer than expected by chance if an ocelot had passed, and that the time until an ocelot appeared at a location was significantly shorter than expected by chance after prey passage. These findings are indirect evidence for both predator avoidance and prey tracking in this system. Our results show that predator avoidance and prey tracking influence predator and prey distribution over time in a field setting. Moreover, this study demonstrates that camera trapping is a viable and noninvasive alternative to GPS tracking for studying certain predator-prey interactions.

Debido a las dificultades en evaluar como los depredadores rastrean su presa, y como las presas eluden a depredadores, un aspecto todavía poco conocido en la interacción entre depredadores y presas es si estas evitan a depredadores o si estos rastrean las presas. Una enfoque común para estudiar estas interacciones entre mamíferos bajo condiciones de campo es de seguir la proximidad espacial de animales a intervalos fijos, usando marbetes de GPS ajustados a los individuos. Sin embargo, este método es invasivo y solo permite obtener información de un número limitado de individuos. En este estudio, usamos cámaras trampas como método alternativo y no invasivo, para monitorear el proximidad temporal entre depredadores y presas en sitios fijos en Isla Barro Colorado, Panamá, donde los ocelotes (Leopardus pardalis) son el principal mamífero depredador. Evaluamos dos hipótesis: (1) las presas evitan a los ocelotes, y (2) los ocelotes rastrean a las presas. Cuantificamos la proximidad temporal de depredadores y presas ajustando modelos paramétricos de supervivencia a los intervalos de tiempo ocurridos entre observaciones subsecuentes en las cámaras trampas, y luego comparamos los intervalos observados con permutaciones aleatorias que retuvieron la distribución espacio-temporal de la actividad de los animales. Encontramos que, si un ocelote había pasado por dicha área, el tiempo en el cual una presa aparece en una ubicación fue significativamente mayor que lo esperado aleatoriamente. También encontramos que, después de pasar una presa por un área, el tiempo en que un ocelote tarda en aparecer fue significativamente menor que lo esperado al azar. Estos resultados constituyen evidencia indirecta que las presas evitan a los depredadores y que estos rastrean a las presas. Nuestros resultados muestran que la evitación de los depredadores y el rastreo de las presas influyen en la distribución de presas y depredadores a lo largo del tiempo en un escenario natural. Este estudio también demuestra que las cámaras trampas son una alternativa viable y no invasiva, con respecto a marbetes de GPS, para estudiar ciertas interacciones entre presas y depredadores.

RESUMO

The Amazon forest has the highest biodiversity on Earth. However, information on Amazonian vertebrate diversity is still deficient and scattered across the published, peer-reviewed, and gray literature and in unpublished raw data. Camera traps are an effective non-invasive method of surveying vertebrates, applicable to different scales of time and space. In this study, we organized and standardized camera trap records from different Amazon regions to compile the most extensive data set of inventories of mammal, bird, and reptile species ever assembled for the area. The complete data set comprises 154,123 records of 317 species (185 birds, 119 mammals, and 13 reptiles) gathered from surveys from the Amazonian portion of eight countries (Brazil, Bolivia, Colombia, Ecuador, French Guiana, Peru, Suriname, and Venezuela). The most frequently recorded species per taxa were: mammals: Cuniculus paca (11,907 records); birds: Pauxi tuberosa (3713 records); and reptiles: Tupinambis teguixin (716 records). The information detailed in this data paper opens up opportunities for new ecological studies at different spatial and temporal scales, allowing for a more accurate evaluation of the effects of habitat loss, fragmentation, climate change, and other human-mediated defaunation processes in one of the most important and threatened tropical environments in the world. The data set is not copyright restricted; please cite this data paper when using its data in publications and we also request that researchers and educators inform us of how they are using these data.

Assuntos

RESUMO

Epiphytic lifestyles have evolved independently in ecologically, morphologically, and taxonomically diverse plant species. Although this adaptation is widespread among angiosperms, it is only known to have arisen in a single gymnosperm species, Zamia pseudoparasitica (Cycadophyta). Zamia pseudoparasitica is endemic to the mountains of Western Panama, and little is known about the ecology of this unusual cycad. Here, we provide the first report of a potential seed disperser of Z. pseudoparasitica. Between late October 2019 and March 2020, we conducted arboreal camera trapping at three sites along the Talamanca Cordillera in Western Panama, yielding an accumulated survey effort of 271 camera days. Weekly direct observations were also performed using handheld binoculars at one site. Arboreal camera trapping revealed at least seven mammal species that visit this epiphytic cycad. At all three sites, the Northern olingo (Bassaricyon gabbii) was seen visiting individuals of Z. pseudoparasitica repeatedly, both while cones were closed and after they had opened. We estimated the time-varying intensity of the visits throughout our sampling and used mixed models to compare the length of visits when cones were closed versus when they were open. Both duration and time-varying intensity of visits increased after cones had opened and we documented Northern olingo removing and carrying away seeds. We also observed predation by the yellow-eared toucanet (Selenidera spectabilis) which picked and destroyed mature Z. pseudoparasitica seeds. These results suggest that the Northern olingo could be an important seed dispersal agent for this rare epiphytic gymnosperm.

RESUMO

An arboreal lifestyle is thought to be central to primate origins, and most extant primate species still live in the trees. Nonetheless, terrestrial locomotion is a widespread adaptation that has arisen repeatedly within the primate lineage. The absence of terrestriality among the New World monkeys (Platyrrhini) is thus notable and raises questions about the ecological pressures that constrain the expansion of platyrrhines into terrestrial niches. Here, we report the results of a natural experiment, comparing patterns of terrestrial behavior in white-faced capuchin monkeys (Cebus capucinus imitator) living on two islands off the Pacific coast of Panama that lack mammalian predators (island sites) with the behavior of capuchins at three sites in central Panama with more intact predator communities (mainland sites). Surveys with camera traps revealed increased terrestriality in island vs. mainland sites. Capuchin detection rates were higher, the range of party sizes observed was larger, and individuals engaged in a wider range of terrestrial behaviors on the islands lacking mammalian predators. Furthermore, females carrying infants were frequently photographed on the ground at the island sites, but never at the mainland sites. These findings support the long-standing hypothesis that predators constrain the exploitation of terrestrial niches by primates. These results are also consistent with the hypothesis that arboreal locomotion imposes costs that primates will avoid by walking on the ground when predation risk is low.

Assuntos

RESUMO

Habitual reliance on tool use is a marked behavioural difference between wild robust (genus Sapajus) and gracile (genus Cebus) capuchin monkeys. Despite being well studied and having a rich repertoire of social and extractive foraging traditions, Cebus sp. rarely use tools and have never been observed using stone tools. By contrast, habitual tool use by Sapajus is widespread. We review theory and discuss factors which might explain these differences in patterns of tool use between Cebus and Sapajus. We then report the first case of habitual stone tool use in a gracile capuchin: a population of white-faced capuchins (Cebus capucinus imitator) in Coiba National Park, Panama who habitually rely on hammerstone and anvil tool use to access structurally protected food items in coastal areas including Terminalia catappa seeds, hermit crabs, marine snails, terrestrial crabs and other items. This behaviour has persisted on one island in Coiba National Park since at least 2004. From 1 year of camera trapping, we found that stone tool use is strongly male-biased. Of the 205 camera trap days where tool use was recorded, adult females were never observed to use stone tools, although they were frequently recorded at the sites and engaged in scrounging behaviour. Stone tool use occurs year-round in this population; over half of all identifiable individuals were observed participating. At the most active tool use site, 83.2% of days where capuchins were sighted corresponded with tool use. Capuchins inhabiting the Coiba archipelago are highly terrestrial, under decreased predation pressure and potentially experience resource limitation compared to mainland populations-three conditions considered important for the evolution of stone tool use. White-faced capuchin tool use in Coiba National Park thus offers unique opportunities to explore the ecological drivers and evolutionary underpinnings of stone tool use in a comparative within- and between-species context.