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Casorso JG, DePasquale AN, Romero Morales S, Cheves Hernandez S, Lopez Navarro R, Hockings KJ, Carrigan MA, Melin AD. Seed dispersal syndrome predicts ethanol concentration of fruits in a tropical dry forest. Proc Biol Sci 2023; 290:20230804. [PMID: 37464751 DOI: 10.1098/rspb.2023.0804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 06/22/2023] [Indexed: 07/20/2023] Open
Abstract
Studying fruit traits and their interactions with seed dispersers can improve how we interpret patterns of biodiversity, ecosystem function and evolution. Mounting evidence suggests that fruit ethanol is common and variable, and may exert selective pressures on seed dispersers. To test this, we comprehensively assess fruit ethanol content in a wild ecosystem and explore sources of variation. We hypothesize that both phylogeny and seed dispersal syndrome explain variation in ethanol levels, and we predict that fruits with mammalian dispersal traits will contain higher levels of ethanol than those with bird dispersal traits. We measured ripe fruit ethanol content in species with mammal- (n = 16), bird- (n = 14) or mixed-dispersal (n = 7) syndromes in a Costa Rican tropical dry forest. Seventy-eight per cent of fruit species yielded measurable ethanol concentrations. We detected a phylogenetic signal in maximum ethanol levels (Pagel's λ = 0.82). Controlling for phylogeny, we observed greater ethanol concentrations in mammal-dispersed fruits, indicating that dispersal syndrome helps explain variation in ethanol content, and that mammals may be more exposed to ethanol in their diets than birds. Our findings further our understanding of wild fruit ethanol and its potential role as a selective pressure on frugivore sensory systems and metabolism.
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Affiliation(s)
- Julia G Casorso
- Department of Anthropology and Archaeology, University of Calgary, Calgary, Alberta, Canada
| | - Allegra N DePasquale
- Department of Anthropology and Archaeology, University of Calgary, Calgary, Alberta, Canada
| | | | | | | | | | | | - Amanda D Melin
- Department of Anthropology and Archaeology, University of Calgary, Calgary, Alberta, Canada
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Mahandran V, Hakkim H, Sinha V, Jain M. Fruit scent as an indicator of ripeness status in ‘bat fruits’ to attract ‘fruit bats’: chemical basis of chiropterochory. Acta Ethol 2022. [DOI: 10.1007/s10211-022-00405-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mahandran V, Murugan CM, Anisha PS, Wang G, Chen J, Nathan PT. Chemical components change along the ontogeny of a bat fruit (Neolamarckia cadamba) with ripening asynchrony in favour of its fruit selection and seed dispersal. Naturwissenschaften 2021; 108:46. [PMID: 34581964 DOI: 10.1007/s00114-021-01756-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/08/2021] [Accepted: 09/09/2021] [Indexed: 10/20/2022]
Abstract
An asynchronous fruit-ripening strategy can enhance the chance of seed dispersal by providing ripe fruits for an extended period to foragers. However, mechanisms associated with this strategy that can facilitate seed dispersal are understudied. This study aimed to investigate whether the chemical components (minerals and secondary metabolites) of a bat fruit with ripening asynchrony change along its ontogeny (Rubiaceae: Neolamarckia cadamba). We predicted that the seed-to-pulp ratio would increase along with fruit ripeness. The chemical components of the fruit were also predicted to change along their ontogenesis in favour of fruit selection and seed dispersal by fruit bats. Our study shows that the asynchronous fruiting strategy limited the number of ripe fruits daily so that fruits were available at a steady rate. As predicted, the seed-to-pulp ratio of each fruit increased along with fruit development. A fruit's mineral concentration also increased as fruit developed, with a sharp jump at full ripeness, when fruit colour also changed. In contrast, the concentration of secondary metabolite compositions decreased gradually during the process of ontogeny. Fruit bats (Pteropodidae: Pteropus giganteus and Cynopterus sphinx) were the only nocturnal frugivore visitors of these trees and their fruit selection was driven by fruit size and colour. Both bats preferably consumed ripe fruits, which had a higher concentration of attractants (essential minerals) and a lower concentration of deterrents (secondary metabolites), supplemented with a higher seed-to-pulp ratio. The bats exhibited different foraging patterns and home ranges resulting in dispersal (as measured by feeding roost location) occurring across different spatial scales. Our study shows that the chemical components involved in an asynchronous fruit-ripening process could select for extended fruit availability by intensifying the demand for each ripe fruit among legitimate seed dispersers, which increases the likelihood of fruits being dispersed away from parent crowns.
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Affiliation(s)
- Valliyappan Mahandran
- CAS-Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, 666303, Yunnan, China
| | | | | | - Gang Wang
- CAS-Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, 666303, Yunnan, China
| | - Jin Chen
- CAS-Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, 666303, Yunnan, China
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Sangavi D, Murugan CM, Mahandran V, Marimuthu G, Thiruchenthil Nathan P. Adaptive foraging tactics of greater short-nosed fruit bats on a spiny shrub and its effect on seed dispersal. J ETHOL 2021. [DOI: 10.1007/s10164-021-00711-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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