DOI: 10.5061/dryad.hdr7sqvrb
title: Data from: Crustacean photoreceptor damage and recovery: Applying a novel scanning electronic microscopy protocol in artificial light at night studies

description: As sources of artificial light at night (ALAN) expand worldwide, research
 on their impacts has also increased. Most of these studies, including
 those in coastal habitats, have focused on behavioral and ecological
 responses to ALAN, overlooking impacts on the photoreceptor, the basic
 functional structure of animals to absorb light. Examining structural
 changes in the photoreceptor is essential to understand the mechanisms by
 which ALAN may be impacting species, particularly those adapted to
 different light backgrounds. This study examined the photoreceptor
 (rhabdom) of two sandy beach crustaceans exhibiting different light
 tolerances at night: the amphipod Orchestoidea tuberculata and the isopod
 Tylos spinulosus. We developed a novel protocol to measure these species’
 photoreceptor areas and quantify the damage caused by ALAN using
 histological sections and scanning electron microscopy (SEM). Our results
 showed that in the isopod, a species naturally adapted to lower light
 intensities at night than the amphipod, the rhabdom surface was 20-times
 larger, and presented a tapetum, an adaptive feature found in species
 living in low light conditions. This confirmed that this species is
 potentially more sensitive to ALAN than the amphipod. Consistently, a
 brief period of exposure to ALAN (1 h, 20 lux) caused 3-6 times more
 damage in the isopod’ rhabdom. In fact, ALAN caused structural damage in
 the isopod’ but not in the amphipod’ rhabdom, a damage that did not show
 signs of recovery from ALAN after 1 and 24 h. Thus, the damage caused by
 ALAN on an organism’s photoreceptors is likely to be more severe and
 persistent in species naturally adapted to lower light levels at night.
 Installation of permanent ALAN sources nearby the burrowing area of these
 light sensitive species may have differential effects on their activity
 and interactions at night. ALAN may also become a new selection pressure
 on these species, a concern with wide implications given the ubiquity
 among animals of the photoreceptor structure and its response to light.
description: To assess photoreceptor membrane loss and recovery, data were
 obtained from SEM photographs obtained from organisms exposed to ALAN (1
 h) and recovery times (1 h and 24 hr). The photographs came from one
 randomly chosen eye, removed from one of the specimens associated with
 each experimental replicate.  
 These eyes were processed for scanning electron microscopy, in
 which the total area of the photoreceptor surface (Rhabdom) was estimated.
 Then, using several cross-sections of each rhabdom, the loss of surface
 photoreceptor membrane was quantified using Image Pro 6. Lastly, these
 estimations of the photoreceptor membrane loss were used to estimate
 averages per species and to conduct statistical comparisons.
description: # Data from: Crustacean photoreceptor damage and recovery: Applying a
 novel scanning electronic microscopy protocol in artificial light at night
 studies
 [https://doi.org/10.5061/dryad.hdr7sqvrb](https://doi.org/10.5061/dryad.hdr7sqvrb) The dataset includes the percentage of photoreceptor damage caused by ALAN and the recovery of this structure after 1 and 24 hours. Additionally, the total photoreceptor area of both species (for interspecific comparisons) is provided. ## Description of the data and file structure Data is provided in an Excel file with two tabs.  The first tab, "Photoreceptor membrane loss" includes i) Species (i.e., Orchestoidea tuberculata and Tylos spinulosus), ii) Treatments (i.e., Control; 1 hr. of recovery and 24 hrs. of recovery), iii) Photoreceptor membrane loss (raw data in %), and iv) Log-transformed data used in the statistical analysis.  The second tab, "Photoreceptor areas", contains i) Species (i.e., Orchestoidea tuberculata and Tylos spinulosus) and ii) Total photoreceptor area.