# Herbivory rate is elevated but orb-weaver spider growth unaffected by artificial light at night in subtropical forest

## TL;DR

Artificial light at night increases herbivory in subtropical forests but does not affect orb-weaver spider growth.

## Contribution

The study reveals ALAN's impact on herbivory in understudied tropical ecosystems.

## Key findings

- Illuminated plots showed higher herbivory rates during the early wet season.
- ALAN did not affect the growth or abundance of Nephila pilipes spiders.

## Abstract

Artificial light at night (ALAN) is a growing threat to biodiversity and ecosystems globally. However, a limited number of studies have focused on the effect of ALAN in the tropical or subtropical regions, and the impact of ALAN on species interactions and ecological processes is particularly understudied. We introduced ALAN into light-naïve forest plots to examine whether ALAN affects herbivory rate and alters the growth and abundance of Nephila pilipes, a common orb-weaver spider. We found illuminated plots had a higher herbivory rate than control plots in the early wet season. The growth rate and abundance of the spider species, however, were not affected by ALAN. Our results indicate that ecological processes in tropical ecosystems, such as herbivory, are potentially sensitive to ALAN. Additionally, this study highlights the importance of a more mechanistic understanding of the sensitivities of tropical species interactions to ALAN and the possible complications caused by environmental variation.