Thais Almeida

Bio: Thais Almeida is an academic researcher. The author has contributed to research in topics: Cacajao melanocephalus & Predation. The author has an hindex of 4, co-authored 5 publications receiving 227 citations.

Primary seed dispersal by three Neotropical seed-predating primates (Cacajao melanocephalus ouakary, Chiropotes chiropotes and Chiropotes albinasus)

Abstract: The Neotropics house two guilds of large arboreal vertebrate seed predators: parrots and the pitheciin primates. Both have diets dominated by immature fruits. The possibility of members of the Pitheciinae (genera Cacajao, Chiropotes and Pithecia) acting as occasional seed dispersers has been mooted, but not experimentally shown. We combined primate behavioural data and seed germination data from three separate field studies in the Brazilian states of Amazonas and Para to analyse patterns of post-consumption seed survivorship for seeds discarded by three pitheciin species (Cacajao melanocephalus ouakary, Chiropotes chiropotes and Chiropotes albinasus). We then calculated the frequency of dispersal events for four species eaten by C. m. ouakary. All three primate species dropped intact seeds while feeding, and 30.7% of 674 dropped seeds germinated ex situ. Undamaged seeds from unripe and ripe samples germinated (29.3% and 42.7%, respectively), and all three primate species carried some fruits up to 20 m from the parent tree before consuming them. Potential seed-dispersal events varied from 1 (Macrolobium acaciifolium) per fruiting cycle to more than 6500 (Duroia velutina), suggesting that there are differences in dispersal potential. In summary, although they are highly specialized seed predators, these primates may also act as important dispersers for some plant species, and effective dispersal is not restricted to ripe fruits, as immature fruits removed from a tree may continue to mature and the seeds later germinate, a much-neglected aspect of dispersal ecology. The possibility that similar events occur in parrots should be experimentally investigated.

Terrestrial Foraging by Cacajao melanocephalus ouakary (Primates) in Amazonian Brazil:: Is Choice of Seed Patch Size and Position Related to Predation Risk?

Abstract: We analyse the behaviour of Cacajao melanocephalus ouakary feeding at patches of germinating seedlings in dried-out flooded forest. Seedlings of Eschweilera tenuifolia (Lecythidaceae) were the most commonly eaten (88.9%). Some seed patches were revisited over several days, while others were consistently ignored. We tested 3 predictions relating uacari terrestrial foraging behaviour to: (1) arboreal escape route proximity, (2) seed patch size choice and (3) temporal patterns of repeat exploitation. Comparison of fed-at and ignored patches revealed significant preferences for larger patches, and for those close to arboreal refuges but distant from dense ground-based vegetation. Support for these predictions is interpreted as evidence for predation risk-sensitive foraging.

Arthropod Predation by a Specialist Seed Predator, the Golden-backed Uacari ( Cacajao melanocephalus ouakary , Pitheciidae) in Brazilian Amazonia

Abstract: Morphological adaptations related to food processing generally reflect those elements of the diet that represent the greatest biomechanical challenge or that numerically dominate the diet. However, in periods of the annual cycle when the availability of such foods is low, items to which a species has low apparent morphological adaptation may be included in the diet. Here we test the responses of a diet-specialist primate to limitations in the supply of the resource it is specialized to exploit. Uacaris are primarily predators of immature seeds, in seasonally flooded forests in Amazonian Brazil, and have dental specializations to open hard-shelled fruits. We investigated the importance of arthropods in the diet of golden-backed uacaris (Cacajao melanocephalus ouakary), examining their seasonal importance in the uacari diet, and the ways C. m. ouakary used to access them. Using scan and ad libitum sampling of feeding and phenology from botanical study plots to assess fruit availability, we conducted an 18-mo study in Jau National Park, Amazonas State, Brazil. We recorded arthropod predation 298 times, with Cacajao melanocephalus ouakary feeding on 26 invertebrate taxa in ≥11 families and 9 different orders. Uacaris extracted wood-boring beetles dentally from rotting wood and smaller larvae from twigs, stems, and petioles, but this food class did not predominate. This food class (encapsulated foods) constituted 23.4 % of the arthropod records. The majority of arthropod food items were either manually removed from substrates (ants, beetle larvae, caterpillars, fulgorid bugs, grasshoppers, mayflies, spiders, termites, wasps, and a whip-scorpion) or plucked from the air (volant Lepidoptera). Uacaris appeared to avoid toxic caterpillars. Insectivory was most frequent when fruit and seeds were least available. Arthropods seem to be seasonally important to this primate, supplementing or making up for shortfalls in the hard fruits and immature seeds for which uacaris have highly developed dental, and possibly intestinal, adaptations.

Ants in their plants: Pseudomyrmex ants reduce primate, parrot and squirrel predation on Macrolobium acaciifolium (Fabaceae) seeds in Amazonian Brazil

Abstract: Although plant-inhabiting ants are known to act as effective deterrents to a variety of vertebrate and invertebrate herbivores, this has been reported only once before for primates, a group better known for their predation of ants. In the present study, we investigated the effects that colonies of Pseudomyrmex viduus ants living in individual Macrolobium acaciifolium (Fabaceae) trees have on the rates of visitation and fruit removal by four taxa of seed-predating vertebrates: the primate Cacajao melanocephalus ouakary; macaws (Ara spp.); large parrots (Amazona spp.); and the Northern Amazonian red squirrel (Sciurus igniventris). We found that ant presence significantly reduced both rates of visitation and of fruit removal by C. m. ouakary. The same pattern of reduced fruit removal was also observed for other seed predators (parrots, macaws, and squirrels) but not for visitation rates (although this may be a result of the small sample size). This appears to be only the second-known demonstration of the repellent effect of ants on primates and, indeed, the first for squirrels and psittacine birds. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114, 260–273.

Synzoochory: the ecological and evolutionary relevance of a dual interaction.

Abstract: J.M.G. and P.J. were supported by CYTED program (Red Tematica 418RT0555). E.W.S. is supported by the Ecology Center and the Utah Agricultural Experiment Station (UAES), Utah State University. P.J. is supported by grant CGL2017‐82847‐P from the Spanish Ministry of Science, Innovation, and Universities (AEI).

Neotropical fish-fruit interactions: eco-evolutionary dynamics and conservation.

Abstract: Frugivorous fish play a prominent role in seed dispersal and reproductive dynamics of plant communities in riparian and floodplain habitats of tropical regions worldwide. In Neotropical wetlands, many plant species have fleshy fruits and synchronize their fruiting with the flood season, when fruit-eating fish forage in forest and savannahs for periods of up to 7 months. We conducted a comprehensive analysis to examine the evolutionary origin of fish-fruit interactions, describe fruit traits associated with seed dispersal and seed predation, and assess the influence of fish size on the effectiveness of seed dispersal by fish (ichthyochory). To date, 62 studies have documented 566 species of fruits and seeds from 82 plant families in the diets of 69 Neotropical fish species. Fish interactions with flowering plants are likely to be as old as 70 million years in the Neotropics, pre-dating most modern bird-fruit and mammal-fruit interactions, and contributing to long-distance seed dispersal and possibly the radiation of early angiosperms. Ichthyochory occurs across the angiosperm phylogeny, and is more frequent among advanced eudicots. Numerous fish species are capable of dispersing small seeds, but only a limited number of species can disperse large seeds. The size of dispersed seeds and the probability of seed dispersal both increase with fish size. Large-bodied species are the most effective seed dispersal agents and remain the primary target of fishing activities in the Neotropics. Thus, conservation efforts should focus on these species to ensure continuity of plant recruitment dynamics and maintenance of plant diversity in riparian and floodplain ecosystems.

Primates of the Biological Dynamics of Forest Fragments Project: A History

Abstract: The Biological Dynamics of Forest Fragments Project (BDFFP), located approximately 80 km north of Manaus, Brazil, is the longest-running study of forest fragmentation in the world. The BDFFP was created in 1979 and the first primate census occurred in 1980. Six primate species inhabit the study area: red howler (Alouatta macconnelli), black spider (Ateles paniscus), brown capuchin (Sapajus apella), northern bearded saki (Chiropotes satanas chiropotes), golden-faced saki (Pithecia chrysocephala), and golden-handed tamarin (Saguinus midas). The distribution of these six species throughout the forest fragments has varied during the past three decades with some species (i.e., howler monkeys) being more prevalent than others (i.e., spider monkeys), particularly in the smaller fragments. Researchers did not find primates in some of the 1-ha forest fragments prior to 2007. Here we present a history of primate research at the BDFFP, including findings from three decades of primate censuses and behavioral and ecological studies of several species in the forest fragments, the surrounding matrix, and the continuous forest. These primate studies have provided information on seed dispersal in forest fragments, parasite infections, use of the matrix, and changes in group size, activity budget, and diet of groups in the forest fragments. Many of the once-cleared pastures surrounded by continuous primary forest are now dominated by various stages of secondary growth. Unfortunately, deforestation continues in many areas of the continuous forest north of Manaus. We discuss the implications of these land-cover changes on the primate community and suggest avenues for future primate research at the BDFFP.

Crying tapir: the functionality of errors and accuracy in predator recognition in two neotropical high-canopy primates.

Abstract: Predation is often considered to be a prime driver in primate evolution, but, as predation is rarely observed in nature, little is known of primate antipredator responses. Time-limited primates should be highly discerning when responding to predators, since time spent in vigilance and avoidance behaviour may supplant other activities. We present data from two independent studies describing and quantifying the frequency, nature and duration of predator-linked behaviours in 2 high-canopy primates, Ateles belzebuth and Cacajao ouakary. We introduce the concept of 'pseudopredators' (harmless species whose appearance is sufficiently similar to that of predators to elicit antipredator responses) and predict that changes in behaviour should increase with risk posed by a perceived predator. We studied primate group encounters with non-primate vertebrates across 14 (Ateles) and 19 (Cacajao) months in 2 undisturbed Amazonian forests. Although preliminary, data on both primates revealed that they distinguished the potential predation capacities of other species, as predicted. They appeared to differentiate predators from non-predators and distinguished when potential predators were not an immediate threat, although they reacted erroneously to pseudopredators, on average in about 20% of the responses given toward other vertebrates. Reacting to pseudopredators would be interesting since, in predation, one error can be fatal to the prey.

Arthropod Predation by a Specialist Seed Predator, the Golden-backed Uacari ( Cacajao melanocephalus ouakary , Pitheciidae) in Brazilian Amazonia

Abstract: Morphological adaptations related to food processing generally reflect those elements of the diet that represent the greatest biomechanical challenge or that numerically dominate the diet. However, in periods of the annual cycle when the availability of such foods is low, items to which a species has low apparent morphological adaptation may be included in the diet. Here we test the responses of a diet-specialist primate to limitations in the supply of the resource it is specialized to exploit. Uacaris are primarily predators of immature seeds, in seasonally flooded forests in Amazonian Brazil, and have dental specializations to open hard-shelled fruits. We investigated the importance of arthropods in the diet of golden-backed uacaris (Cacajao melanocephalus ouakary), examining their seasonal importance in the uacari diet, and the ways C. m. ouakary used to access them. Using scan and ad libitum sampling of feeding and phenology from botanical study plots to assess fruit availability, we conducted an 18-mo study in Jau National Park, Amazonas State, Brazil. We recorded arthropod predation 298 times, with Cacajao melanocephalus ouakary feeding on 26 invertebrate taxa in ≥11 families and 9 different orders. Uacaris extracted wood-boring beetles dentally from rotting wood and smaller larvae from twigs, stems, and petioles, but this food class did not predominate. This food class (encapsulated foods) constituted 23.4 % of the arthropod records. The majority of arthropod food items were either manually removed from substrates (ants, beetle larvae, caterpillars, fulgorid bugs, grasshoppers, mayflies, spiders, termites, wasps, and a whip-scorpion) or plucked from the air (volant Lepidoptera). Uacaris appeared to avoid toxic caterpillars. Insectivory was most frequent when fruit and seeds were least available. Arthropods seem to be seasonally important to this primate, supplementing or making up for shortfalls in the hard fruits and immature seeds for which uacaris have highly developed dental, and possibly intestinal, adaptations.