Impact of light intensity on sugar maple leaf physical traits and consequences for caterpillar preference and performance

This study investigates the impact of light intensity on the physical defenses of sugar maple (Acer saccharum) saplings and how these defenses affect interactions with insect herbivores. Conducted at the Kenauk Nature Reserve in Quebec, the study involved 12 sites representing both shaded and sunlit environments. Leaf traits, including thickness, specific leaf area (SLA), water content, and toughness, were measured from 216 leaves collected in 2021 and 40 in 2022. To explore herbivore interactions, two Erebid caterpillars including the invasive spongy moth (Lymantria dispar) and the native white-marked tussock moth (Orgyia leucostigma) were used in controlled bioassays that assessed caterpillar feeding preference and performance. The results revealed that sunlit leaves were significantly thicker and had lower SLA compared to shaded leaves across both years. While water content was lower in sunlit leaves in 2021, it showed no significant difference in 2022. Leaf toughness, measured only ..., Materials and Methods
Study site and Plant species
This study was conducted at the Kenauk Nature property, an old-growth natural forest spanning two regions from the Outaouais River valley to the Laurentian Mountains in southwestern Quebec, Canada (45°42'N; 74°53'W) in 2021 and 2022. In the first year, we selected 12 sites in this maple/bitternut hickory domain of temperate deciduous forest (Quebec Ministry of Forests, 2023) with each site over 10 meters apart. Tree species composition was relatively uniform across all sites and site selection was made based on the similarity in tree size (1–2 m height) and ease of access to the branches.
Each site comprised one healthy sugar maple sapling in the shade under almost full canopy cover and one healthy sugar maple sapling in the sun with less canopy cover. Temperature, humidity, and light intensity were measured 10 times at 4-day intervals at different times of the day from late May to early July, and 3 more times in August at 10-day interv..., , # Impact of light intensity on sugar maple leaf physical traits and consequences for caterpillar preference and performance

[https://doi.org/10.5061/dryad.tmpg4f57m](https://doi.org/10.5061/dryad.tmpg4f57m)

## Description of the data and file structure

### Files and variables

#### File: Per.leaf.traits.22.csv

**Description:** Leaf traits measured before doing performance bioassay using 1st instar white marked tussock moth in early June of 2022

##### Variables

* site: each site includes two treatments (one sunlit sapling and one shaded sapling) used to collect leaves
* leaf.type: These are our treatments including leaves collected from sunlit saplings versus leaves collected from shaded saplings
* toughness (N/mm): Leaf toughness was measured for all collected leaf samples
* thickness (mm): Leaf thickness was measured for all collected leaf samples
* water.content (%): Leaf water content was measured for all collected leaf samples
* leaf.area (cm^2): Leaf area was measured for all...

# 光照强度对糖槭叶片物理性状的影响及其对毛虫取食偏好与表现的效应

[https://doi.org/10.5061/dryad.tmpg4f57m](https://doi.org/10.5061/dryad.tmpg4f57m)

本研究探讨了光照强度对糖槭（Acer saccharum）幼苗物理防御的影响，以及这些防御机制如何作用于其与植食性昆虫的互作。该研究在魁北克省的Kenauk自然保护区开展，涉及12个代表遮荫与光照环境的样点。2021年采集的216片叶片及2022年采集的40片叶片用于测定叶片性状，包括厚度、比叶面积（specific leaf area, SLA）、含水量和韧性。为探究与植食者的互作，研究采用两种灯蛾科（Erebid）毛虫——入侵种spongy moth（Lymantria dispar，即舞毒蛾）和本地种白纹毒蛾（white-marked tussock moth, Orgyia leucostigma）——进行受控生物测定，评估毛虫的取食偏好与表现。结果显示，两年间光照叶片的厚度显著大于遮荫叶片，且比叶面积（SLA）显著更低。2021年光照叶片的含水量较低，但2022年两者无显著差异。叶片韧性仅...

## 材料与方法
### 研究地点与植物物种
本研究于2021年和2022年在加拿大魁北克省西南部的Kenauk自然保护区开展，该保护区为从渥太华河谷延伸至劳伦琴山脉的原始天然林（45°42'N；74°53'W）。第一年，我们在该温带落叶林的槭树/美国山核桃区域（魁北克森林部，2023）选取了12个样点，每个样点间距超过10米。所有样点的树种组成相对一致，样点选择基于树木大小（1–2米高）及枝条易达性。
每个样点包含一株生长于近全冠层遮荫下的健康糖槭幼苗，以及一株生长于冠层覆盖较少的光照环境中的健康糖槭幼苗。2022年5月末至7月初期间，每4天在一天的不同时间点测量温度、湿度和光照强度10次，8月再以10天为间隔测量3次...

## 数据与文件结构描述
### 文件与变量
#### 文件：Per.leaf.traits.22.csv
**描述：** 2022年6月初使用1龄白纹毒蛾进行表现生物测定前测量的叶片性状
##### 变量
* site：每个样点包含两种处理（一株光照幼苗和一株遮荫幼苗），用于采集叶片
* leaf.type：处理类型，包括从光照幼苗采集的叶片与从遮荫幼苗采集的叶片
* toughness（N/mm）：所有采集叶片样本的韧性测量值
* thickness（mm）：所有采集叶片样本的厚度测量值
* water.content（%）：所有采集叶片样本的含水量测量值
* leaf.area（cm²）：所有采集叶片样本的叶面积测量值...