DOI: 10.5061/dryad.9ghx3ffv7
title: A colonial epiphyte with a twist: Morphological variation and potential division of labour in the fern <em>Platycerium bifurcatum</em>

description: Division of labour, a hallmark of complex animal societies, remains poorly
 understood in plants. The staghorn fern (Platycerium bifurcatum,
 Polypodiaceae), a colonial epiphyte, offers a unique model to explore this
 phenomenon in plants inhabiting the challenging tree canopy. This study
 investigates how ramet position and colony size influence morphological
 differentiation and functional roles, focusing on strap frond variation.
 By analysing 87 strap fronds across 29 colonies on Lord Howe Island (NSW,
 Australia), we found significant morphological differentiation along the
 vertical profile of the colony. Top-positioned ramets produce rigid,
 curved, erect strap fronds optimized for water capture, while
 lower-positioned ramets produce pendulous, flexible, flattened strap
 fronds better adapted to shaded conditions. Furthermore, reproductive
 allocation was highest in upper ramets, reinforcing a potential functional
 distinction between colony levels. Larger colonies exhibited greater
 morphological specialization, consistent with the size-complexity
 hypothesis, which predicts increased task specialization with colony size.
 Our findings provide new insights into the complex life history of the
 staghorn fern, offering a fresh perspective into how morphological
 differentiation contributes to emergent collective strategies in plants.
description: # A colonial epiphyte with a twist: Morphological variation and potential
 division of labour in the fern *Platycerium bifurcatum* ### Description of
 the data and file structure This dataset was collected as part of an
 experimental study investigating morphological differentiation and
 functional specialization within *Platycerium bifurcatum* colonies. The
 study aimed to determine how strap frond traits vary across different
 ramet positions within the colony and whether these differences correlate
 with water capture efficiency and other possible functions within the
 colony. **Strapfrond_measurement_data.csv** * Contains measurements of
 strap frond morphological traits, as well as reproductive data at the
 ramet level. * **Columns:** * Colony_ID: Unique identifier for each colony
 * Ramet_Position: Vertical position within the colony (upper, middle,
 lower) * StrapFrond_Angle: Angle of the strap frond relative to the colony
 center (degrees) * StrapFrond_Rigidity: Measured force (Newtons) required
 to bend the frond to a 30° angle * StrapFrond_Curvature_Width: Width of
 the curved section of the strap frond (cm) * StrapFrond_Curvature_Height:
 Height of the curved section of the strap frond (cm) *
 StrapFrond_Curvature: Estimated surface of the curved section of the strap
 frond (cm^2) * Total_Strap_Fronds: Total number of strap fronds on the
 ramet * Reproductive_Strap_Fronds: Number of strap fronds bearing spores *
 Ratio: Ratio of reproductive to non-reproductive strap fronds in a ramet *
 Colony_Size: Total number of ramets in the colony **WaterCapture.csv** *
 Includes data from the water capture experiment, where strap frond
 morphology was tested for its ability to channel water. * **Columns:** *
 Colony_ID: Unique identifier for each colony * Ramet_Position: Position
 within the colony (upper, middle, lower) * Water_Captured_ml: Amount of
 water captured per strap frond (ml) * Condition: Control or taped
 treatment (where taped fronds had their guttering function disabled)
 **Colony_radius.csv** * Contains measurements of colony radius taken at
 different vertical locations to assess colony shape. * **Columns:** *
 Colony_ID: Unique identifier for each colony * Position: Vertical position
 (upper, middle, lower, midpoint categories) * Radius_cm: Measured radius
 of the colony at the given position (in cm) **light_measurements.csv** *
 Contains light intensity data recorded at different vertical positions
 within colonies to assess self-shading effects. * **Columns:** *
 Colony_ID: Unique identifier for each colony * Position: Vertical position
 (upper, middle, lower) * Light_intensity_lux: Measured light intensity
 (lux) ### **Data Collection and Processing** * Data were collected from
 **29 colonies** across a tropical dry forest, with each colony divided
 into **upper, middle, and lower positions** for measurements. * Water
 capture experiments were performed on a subset of **10 similarly sized
 colonies**, with and without taped fronds to assess guttering function. *
 Colony radius and light intensity measurements were taken at different
 heights to examine self-shading and shape development. * Statistical
 analyses, including **PCA, ANCOVA, GLMs, beta regression, and ANOVA**,
 were conducted in **RStudio (version 4.4.1)** after testing for normality
 and applying transformations where necessary ### **Usage Notes** * Missing
 values are indicated as **NA**. * Units: * **Angles** are in **degrees
 (°)** * **Rigidity** is in **Newtons (N)** * **Lengths** (curvature
 width/height, colony radius) are in **centimeters (cm)** * **Water
 capture** is in **milliliters (ml)** * **Light intensity** is in **lux** *
 This dataset can be used for **comparative ecological studies on
 epiphytes, morphological adaptations, and functional trait variation**.