Standing herbivory is not affected by tree sex or conspecific density in a dioecious understory tropical tree species
Data files
Jan 27, 2025 version files 121.21 KB
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README.md
1.31 KB
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Yasunidata_R_long.csv
119.90 KB
Abstract
Leaves are critical to plant photosynthesis and the loss of leaf area can have negative consequences for an individual’s performance and fitness. Variation in plant defences plays a large role in protecting their leaves from attack by insect herbivores. However, trade-offs in allocation among growth, reproduction, and defence may limit the availability of resources for any one aspect of a plant’s life-history strategy, which would lead to greater herbivory in those plants that allocate more resources to growth or reproduction than to defence. Patterns of sex-biased herbivory in dioecious plants are well documented yet are known to vary in the direction (female or male) of their bias. A greater concentration of conspecifics may also increase herbivore attack through negative density dependence. In order to test the hypothesis that sex-biased herbivory varies as a function of conspecific density, we measured standing herbivory on 2,350 leaves on 302 trees of the dioecious understory tree Iryanthera hostmannii (Myristicaceae) situated in a large forest dynamics plot in a lowland tropical rain forest in Ecuador. We found no difference in standing herbivory between the 169 male and 133 female trees, nor for focal trees surrounded by higher densities of conspecifics. The slow-growing, shade-tolerant growth patterns of I. hostmannii may contribute to suppressed differential expression of secondary sex characters in leaf defences, leading to similar levels of herbivory between males and females. Considering the factors that most strongly affect herbivory in dioecious species is important in understanding the evolution of sex-related traits more broadly.
README: Standing herbivory is not affected by tree sex or conspecific density in a dioecious understory tropical tree species
https://doi.org/10.5061/dryad.c59zw3rk3
Description of the data and file structure
Methods
Leaves collected from 303 mature trees selected at random throughout the plot, 6--10 leaves per tree. Leaves were scanned and area measured with LeafByte 1.3.0.
Questions
Q1. Do females suffer greater herbivory than males?
Q2. Do females suffer a greater negative effect of conspecifics and consexuals than males?
Files and variables
File: Yasunidata_R_long.csv
Description:
Variables
Rows
Each row is 1 leaf collected from a tree. Multiple leaves were collected from the same tree.
Columns
Date: Date leaf was collected
Q20: 20x20 subplot within which tree was located
Q5: 5x5 subplot
TreeTag: Tag number of tree, from the Yasuni forestgeo plot
Sex: Tree sex (m = male, f = female)
DBH: Tree diameter at 1.3m, recorded in the Yasuni forestgeo plot census
LeafNumber: Leaf ID
TCA: Total Consumed Area, the amount of leaf area lost, calculated using LeafByte. Units = cm^2
UA: Uneaten area: Leaf area remaining. Units = cm^2
Notes: Notes.
Code/software
We used R to analyse these data.