Fruit color and odor are the main features regulating the rate of fruit predation and dispersal. The aim of this study was to analyze the effect of odor and color on fruit predators and dispersers. The present study was conducted in a 30ha area of secondary forest in Southeastern Atlantic Brazil. This area was divided into two transects, in which four points were marked with a 30m ]]>
2=7.57, df=5, p=0.182) between bitten and pecked fruit. Fruit color and odor are important in attracting predators and dispersers, which explains the high rate of predation of red/vanilla and red/pineapple, and the absence of predated fruits in the green/control group. Regarding the potential disperser, there was no statistically significant difference between pecked fruit and bitten fruit. As a result, it should be taken ]]>
El olor y el color de los frutos son las características principales que regulan el nivel de ]]>
2=7.57, gl=5, p=0.182) entre frutos mordidos y picoteados. El color y el olor de los frutos son aspectos importantes para atraer depredadores y dispersores, lo que explica los niveles de consumo de los frutos rojos/vainilla y rojo/ananá y la ausencia de frutos comidos en el tratamiento del verde/control. En cuanto al potencial dispersor, no hubo una diferencia estadística significativa entre frutos mordidos y picoteados, por lo que se debe tomar en cuenta que la dispersión principal ]]>
Palabras clave: frugivoría, mamalocoria, ornitocoria, interacción planta-animal, depredación, dispersión de semillas, zoocoria. ]]>
In plant communities, the dispersal syndrome deserves special mention, because of the strong dependence of plants on dispersers (Lomáscolo & Schaefer 2010). The survival of a species depends on seed dispersal and a suitable place for germination. In tropical forests, the most frequent dispersal syndrome found is zoochory, i.e. fruits are eaten and dispersed by animals. Mammalochory, dispersal by mammals, and ornithochory, ]]>
1983, Fleming 1987, Tabarelli & Peres 2002, Galetti et al. 2003).
The main characteristics that regulate the predation rate of different groups of animals include fruit size, color, odor, consistency, quantity and nutritional quality (Gautier-Hion et al. 1985, Galetti et al. 2003, Cáceres et al. 2009). This causes fruits to develop a large number of strategies and special characteristics to attract consumer-dispersing species (Arruda et al. ]]>
et al. 2004, Lomáscolo et al. 2008). However, the contrast between fruit color and its background had never been included in any study on dispersal syndromes (Lomáscolo & Schaefer 2010).
Few studies have ]]>
Materials and methods
Study site: The Atlantic Forest is one of the most threatened ecosystems on the planet, retaining only 8% of its original area (Myers et al. 2000, Galindo-Leal & Câmara 2005). The study was conducted in the municipality of Marechal Floriano, Espírito Santo State. The study area (20°26’32” S - 40°464’4” W) is located 720m above sea level and ]]>
et al. 2005).
Data collection: Four samples were taken between November 2009 and January 2010 with 15 day-intervals. ]]>
et al. 2008). Fruit was considered predated when it was moved from where it was placed.
Potential predators of artificial ]]>
Treatments were compared using Kruskal Wallis (p<0.05) and Tukey’s nonparametric tests (p<0.05). ]]>
Results
]]>
Of the 960 artificial fruits used in the experiment, 258 (26.9%) were predated. Considering the predation rate on the artificial fruit per treatment, the red/pineapple treatment had the highest predation rate (81.9%), followed by red/vanilla (46.3%), while green/control fruits were not predated (Table 1). The mean of fruit predation was higher with red/pineapple (4.1±0.78) followed by red/vanilla (2.3±0.47) (Fig. 1).
Throughout the experiment, pecking (41.7%) and bites (58.3%) were recorded but no significant differences were detected (x2=7.57, gl=5, p=0.182). The red/control treatment registered only pecks, and for the green/control treatment no predated fruits were found(Fig. 2 and 3).
Discussion
The results of this study show that fruits with red color were more frequently eaten by birds. This finding is in concordance with Arruda et al. ]]>
et al. (1999) and Alves-Costa & Lopes (2001) and in captivity by McPherson (1988) and Willson et al. (1990). The cryptic color of fruit functions mainly to attract the attention of potential dispersers that use vision as the key sense to search for ]]>
et al. 1990, Arruda et al. 2008).
Burns & Dalen (2002), Schmidt et al. (2004), Schaefer et al. (2006) and Schaefer
et al. (2007) attribute birds´ preference for red fruits to the contrast with the background foliage. Furthermore, the red color has a longer wavelength, more visible to birds than other colors (Arruda et al. 2008). However, according to Pizo (2003), some birds prey less attractive colors, such as green, for another type of dispersal; this was observed by Spironello et al. (2004) who registered 3 910 unmoved fruits, that is, 0.5% was predated in an immature phase by parrots and ]]>
The low predation rate of green fruit helps understand the co-evolution between plants and seed dispersers, where dispersed plants, mainly by ornithocoric means, have immature green fruits as a strategy to avoid dispersal of those that are not yet ready to germinate (Schaefer et al. 2007, Lomáscolo & Schaefer 2010). For Burns et ]]>
(2009) and Cazetta et al. (2007) fruit color is related to the detection of potential dispersers, and tropical regions generally have higher diversity of fruit color, as they have the highest number of seed dispersers due to the increased plant diversity. In addition, Burns et al. (2009) mention that the fruit color evolution hypothesis is not exclusively ascribed to the selection of potential ]]>
to the reflective properties of leaves.
Birds have good vision and hearing, but a poorly developed sense of smell, while mammals have a sharper sense of smell, but not good color definition, especially nocturnal ]]>
et al. 2008); therefore, according to Janson (1983), fruits eaten by nocturnal species are probably large and odorous. The results of this study indicating that 58.3% of fruit was bitten differed from those of Arruda et al. (2008), who reported 1.3% of the fruit being bitten. However, Arruda et al. (2008) did not use essences, which evidences smell as the main sense of orientation in mammals and confirms the work by Vieira
et al. (2011) and Iob & Vieira (2008), who used vanilla extract in traps to attract grid mammals having a high capture rate, these being rodents, followed by marsupials. Nevertheless, few studies have discussed mammalian odor attraction in the process of predation and dispersal of fruits.
Wheelwright & Janson (1985) and Lomáscolo et al. ]]>
et al. 2003) and the regeneration state of the hábitat (Tabarelli & Peres 2002). ]]>
Treatments using essences showed a higher percentage of bitten fruit, while treatments with red color presented more pecking, although no significant differences were observed between pecked and bitten fruit, indicating that there is no preference between birds and mammals. For Gauthier-Hion et al. (1985), this dichotomy between fruit dispersed by birds or mammals is not strong, unlike aspects related to fruit size, protection or color. ]]>
Regarding the potential disperser, no statistically significant differences were found between pecked fruit and bitten fruit, which clearly suggests that both birds and mammals are potential fruit dispersers, thus, indispensable elements in ]]>
et al. (2008), who confirmed that artificial fruits are effective to record fruit consumption, assist in the identification of potential dispersers, and are easy to handle in ]]>
In order to specifically determine the disperser of a plant, further studies should be conducted related to fruit color, size, nutritional value and position, as well as animal characteristics and fragment size, edge effects, species composition and plant regeneration time.
Acknowledgments
We would like to thank Cesar Abel Krohling for his help during fieldwork and his support on the logistics and Dominik Lenz and Elieth Salazar for editing the English. ]]>
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*Correspondencia a: Aliny Oliveira Barcelos: Universidade Vila Velha, Programa de Mestrado em Ecologia de Ecossistemas-Rua Comissário José Dantas de Melo, 21, Boa Vista, Vila Velha, Espírito Santo, Brazil, CEP 29102-770; oliveira.aliny@gmail.com Clayton Perônico: Instituto Federal do Espírito Santo – IFES campus Piúma - Rua Augusto Costa de Oliveira, 660, Praia Doce Piúma, Espírito Santo, Brazil, CEP 29285-000; cperonico@ifes.edu.br Frederico Jacob Eutrópio: Universidade Vila Velha, Programa de Doutorado em Ecologia de Ecossistemas-Rua Comissário José Dantas de Melo, 21, Boa Vista, Vila Velha, Espírito Santo, Brazil, CEP 29102-770; eutropiofj@gmail.com 1. Universidade Vila Velha, Programa de Mestrado em Ecologia de Ecossistemas-Rua Comissário José Dantas de Melo, 21, Boa Vista, Vila Velha, Espírito Santo, Brazil, CEP 29102-770; oliveira.aliny@gmail.com 2. Instituto Federal do Espírito Santo – IFES campus Piúma - Rua Augusto Costa de Oliveira, 660, Praia Doce Piúma, Espírito Santo, Brazil, CEP 29285-000; cperonico@ifes.edu.br 3. Universidade Vila Velha, Programa de Doutorado em Ecologia de Ecossistemas-Rua Comissário José Dantas de Melo, 21, Boa Vista, Vila Velha, Espírito Santo, Brazil, CEP 29102-770; eutropiofj@gmail.com
Received 09-V-2011. Corrected 20-IX-2011. Accepted 19-X-2011.