Data and code from Artificial light at night increases top-down pressure on caterpillars: experimental evidence from a light-naive forest - 2021-2022

This dataset has been prepared in support of a paper to be published in
Proceedings of the Royal Society B: Biological Sciences. It includes both data files and R
scripts used for the analysis in this publication: Deitch, J.F. and S.A. Kaiser. 2023. Artificial light at night increases
top-down pressure on caterpillars: experimental evidence from a
light-naive forest. Proceedings of the Royal Society B: Biological Sciences.
(https://doi.org/10.1098/rspb.2023.0153) Artificial light at night (ALAN) is a globally widespread and expanding
form of anthropogenic change that impacts arthropod biodiversity. ALAN
alters interspecific interactions between arthropods, including
predation and parasitism. Despite their ecological importance as prey
and hosts, the impact of ALAN on larval arthropod stages, such as
caterpillars, is poorly understood. We examined the hypothesis that ALAN
increases top-down pressure on caterpillars from arthropod predators and
parasitoids. We experimentally illuminated study plots with moderate
levels (10-15 lux) of LED lighting at light-naive Hubbard Brook
Experimental Forest, New Hampshire. We measured and compared between
experimental and control plots: 1) predation on clay caterpillars and 2)
abundance of arthropod predators and parasitoids. We found that
predation rates on clay caterpillars and abundance of arthropod
predators and parasitoids were significantly higher on ALAN treatment
plots relative to control plots. These results suggest that moderate
levels of ALAN increases top-down pressure on caterpillars. We did not
test mechanisms, but sampling data indicates that increased abundance of
predators near lights may play a role. This study highlights the
importance of examining the effects of ALAN on both adult and larval
life stages and suggests potential consequences of ALAN on arthropod
populations and communities. These data were gathered as part of the Hubbard Brook Ecosystem Study
(HBES). The HBES is a collaborative effort at the Hubbard Brook
Experimental Forest, which is operated and maintained by the USDA Forest
Service, Northern Research Station.