Data from: Double mutualism: Dual rewards or redundancy? Insights from the interactions between mistletoes and their avian partners in the tropical hotspot of Southwest China
Data files
Jul 14, 2025 version files 137.56 KB
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fruit_crop_size.xlsx
11.62 KB
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host_mistletoe.xlsx
61.25 KB
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mistletoe_birds_trait.xlsx
19.22 KB
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passerine.nex
588 B
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Raw_visit.xlsx
39.51 KB
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README.md
5.38 KB
Abstract
Mistletoes, recognized as keystone species, supply plentiful floral and fruit resources for birds, thereby facilitating mutualistic interactions in pollination and seed dispersal. Some avian species are “double mutualists”, engaging in both functions. However, their precise roles and effectiveness as mutualists remain inadequately understood. In this study, we conducted 690 hours of video-recorded observations of avian pollinators and dispersers of the mistletoe species Dendrophthoe pentandra (Loranthaceae) across three sites in the seasonal tropical forests of Xishuangbanna, a biodiversity hotspot in Southwest China. We also performed a phylogenetic analysis of avian traits, including beak length, body length, and body mass. Our findings documented a total of 833 visits by 13 bird species from 8 families, with 11 species probing flowers (528 visits) and 7 species consuming fruits (43 visits). Three species – Dicaeum minullum, D. ignipectus, and Zosterops simplex – were identified as double mutualists, as they visited the plants during both the flowering and fruiting phases. Notably, double-mutualist birds accounted for 87.5% of flower visits and 95.5% of fruit visits. The generalist frugivore Z. simplex was the most frequent floral visitor, while the mistletoe-specialist frugivore D. minullum emerged as the primary pollinator and seed disperser across all sites, demonstrating the highest efficiency. All double-mutualist species exhibited high mobility and specialized morphology, characterized by small to medium-sized, slightly curved beaks and lower body mass, which contributed to greater effectiveness in pollination and seed dispersal, confirming their roles as “double mutualists” of this plant. Phylogenetic analysis indicated that ancestral mistletoe-associated birds typically possessed short to medium beaks and medium body masses, whereas double-mutualist birds appear to have evolved shorter beaks and smaller bodies. Our findings show that mistletoe-associated birds that perform both pollination and dispersal are morphologically adapted to the floral structure of mistletoes, fostering closer mutualistic relationships with host plants and enhancing fitness of both plants and their avian partners.
Dataset DOI: 10.5061/dryad.nvx0k6f48
Description of the data and file structure
host_mistletoe: dataset from section Biological traits and reproductive phenology of mistletoe of MATERIAL AND METHODS
Raw_visit: dataset from section Visitation of avian pollinators and frugivores of MATERIAL AND METHODS
fruit_crop_size: dataset from section Fruit crop size and quantity of seeds removed of MATERIAL AND METHODS
mistletoe_bird_trait: dataset from section Flower, fruit and bird morphology of MATERIAL AND METHODS
passerine: phylogeny from section Phylogenetic relationships and ancestral state reconstruction of birds of MATERIAL AND METHODS
Files and variables
File: host_mistletoe.xlsx
Description: contains columns with data on the following:
Variables
- site: site
- plot: plot
- host_id: host identifier
- host_species: host species
- host_family: host family
- host_growth_form: growth form of host; It can be "Tree" or "Woody vine".
- host_fruit_type: fruit type of host; It can be "fleshy" or "not fleshy".
- host_deciduousness: host deciduousness; It can be "Evergreen" or "Deciduous".
- host_DBH: diameter at breast height of host, unit: centimeter
- host_height: host height, unit: meter
- host_crown_size: host crown size, unit: square meter
- host_latitude: latitude of host
- host_longitude: longitude of host
- host_elevation: elevation of host, unit: meter
- host_infection_intensity: host infection intensity, defined as the number of mistletoes per host tree
- mistletoe_id: mistletoe identifier
- mistletoe_species: mistletoe species
- mistletoe_height: mistletoe height, unit: meter
- mistletoe_crown_size: mistletoe crown size, unit: square meter
- mistletoe_light: light levels for each mistletoe; Light levels were visually assessed for each mistletoe on a standardized scale ranging from 0 to 10. A light score of 10 would be assigned to a mistletoe whose entire foliage was exposed to full sunlight throughout the day, and a score of 0 would be assigned when the entire foliage was in dense shade throughout the day.
- Flowering2018: flowering period of the mistletoe in 2018, unit: day; "n/a" in the column "Flowering2018" means no flowering was observed on this mistletoe in 2018.
- Fruiting2018: fruiting period of the mistletoe in 2018, unit: day; "n/a" in the column "Fruiting2018" means no fruiting was observed on this mistletoe in 2018.
- Flowering2019: flowering period of the mistletoe in 2019, unit: day; "n/a" in the column "Flowering2019" means no flowering was observed on this mistletoe in 2019.
- Fruiting2019: fruiting period of the mistletoe in 2019, unit: day; "n/a" in the column "Fruiting2019" means no fruiting was observed on this mistletoe in 2019.
File: Raw_visit.xlsx
Description: contains columns with data on the following:
Variables
- Site: site
- Observers: observer
- Years: years
- Date: date
- Host_ID: host identifier; "n/a" in the column "Host_ID" means the host identifier was not recorded.
- Mistletoe_ID: mistletoe identifier; "n/a" in the column "Mistletoe_ID" means the mistletoe identifier was not recorded.
- Bird_species: identified bird species
- Behavior: specific behaviors of the bird; It contains two categorical variables: "probe_flower" and "forage_fruit". "probe_flower" means probing of corollas, indicative of potential pollination. "forage_fruit" means the plucking of fruits, suggestive of seed dispersal.
- Number_of_flowers/fruits: the number of flowers probed or fruits consumed
- duration: duration of each visit for each bird, unit: seconds
- Phenophase: phenophase; It contains four categories: "Flowering2019", "Fruiting2019", "flowering2015", and "fruiting2015". "Flowering2019" means the visit happened in the flowering stage in 2019. "Fruiting2019" means the visit happened in the fruiting stage in 2019. "flowering2015" means the visit happened in the flowering stage in 2015. "fruiting2015" means the visit happened in the fruiting stage in 2015.
- duration_per_visit: mean duration per flower at each visit for each bird, unit: seconds
File: fruit_crop_size.xlsx
Description: contains columns with data on the following:
Variables
- site: site
- plot: plot
- host_id: host identifier
- mistletoe_id: mistletoe identifier
- exocarp: the number of exocarps found in the traps
- ripe_fruit: the number of ripe fruits found in the traps
File: mistletoe_birds_trait.xlsx
Description: contains columns with data on the following:
Variables
- Bird_species: bird species
- Gender: gender; "n/a" in the column "Gender" means the gender is not recorded in the specimen.
- Specimen_Number: specimen number
- BodyWeight(g): the weight of bird body, unit: gram; "n/a" in the column "BodyWeight(g)" means the body weight is not recorded in the specimen.
- BodyLength(cm): the length of bird body, unit: centimeter; "n/a" in the column "BodyLength(cm)" means the body length is not recorded in the specimen.
- BeakLength(mm): the length of bird beak, unit: millimeter
File: passerine.nex
Description: Phylogenetic tree of 14 avian species based on Bayesian methods