Data from: Insect communities under skyglow: diffuse night-time illuminance induces spatio-temporal shifts in movement and predation

We conducted our experiment at the iDiv Ecotron experimental facility, which is an indoor mesocosm facility consisting of independent, experimental chambers called “EcoUnits”. The Ecotron is located in Bad Lauchstädt, Saxony-Anhalt, Germany, at the Experimental Research Station of the Helmholtz Centre for Environmental Research (UFZ, 51.3917° N, 11.8762° E). Multiple environmental conditions in the EcoUnits can be fully controlled (e.g., nutrient supply and irrigation). Each EcoUnit has internal dimensions of 1.46 m × 1.46 m × 1.50 m (L × W × H, aboveground) and 1.24 m × 1.24 m × 0.80 m (L × W × H, belowground) with the soil surface area measuring 1.54 m².

To assess the interactive effects of diffuse nighttime illuminance and landscape structure on animal movement patterns, we established a patch-grassland system which consisted of four meadow patches within each of the corners of an EcoUnit, separated by an area of bare ground. The EcoUnits were filled with 1.23 m3 of unsterilised and homogenised soil from the vicinity of the iDiv Ecotron, and plant communities of 16 plant species were sown on February 4th 2020. We allowed for a settlement phase of roughly 5 months before starting our measurements.

Each heading below describes columns in the two datasets that describe the movement activity (RFID sensor detections) and predation (bite marks left on artificial caterpillar prey dummies) by the experimental insect communities.

timestamp: Continuous value indicating the time and date (format: DD/MM/YYYY hh:mm:ss, timezone: UTC+2) at which a tagged individual was detected by an RFID sensor. We defined detections as distinct and only counted them when they (1) occurred on different sensors or when (2) at least 10 seconds had elapsed (without detection on the same sensor) between two consecutive detections on the same sensor. This prevented the repeated detection of resting or dead animals.

block_ID: Categorical value indicating whether an observation was made within the first or second temporal experimental block (b1, b2). Each block corresponded to a period of approximately one lunar cycle (i.e., 28 days: experimental block b1: 21.07.2020 - 18.08.2020, experimental block b2: 15.09.2020 - 13.10.2020).

rep_ID: Categorical value indicating the replicate prey dummy exposures (r2, r3, r4, r5) that took place within each 28-day temporal experimental block: r2 and r3 took place successively within block b1; r4 and r5 took place successively within block b2. NAs identify periods during each experimental block where prey dummies had not yet been deployed or were in the process of being collected/re-deployed.  

unit_ID: Categorical value indicating the identity of each of the 12 EcoUnits at the iDiv Ecotron experimental facility.

patch_ID: Categorical value indicating the identify of each of the four meadow patches within each EcoUnit. Patch identities correspond to their coordinates within the EcoUnit.

x: Continuous value indicating the X-coordinate position of an RFID sensor or prey dummy within the Ecotron unit with respect to the position of each EcoUnit’s control panel.

y: Continuous value indicating the Y-coordinate position of an RFID sensor or prey dummy within the Ecotron unit with respect to the position of each EcoUnit’s control panel. 

day_night: Categorical value indicating whether an individual was detected during the day (treatment lights off) or during the night (treatment lights on). Night includes the periods of dawn and dusk where daylight was gradually (i.e. linearly) brightened or dimmed over the course of two hours before sunrise and sunset, respectively.

habitat: Categorical value indicating whether a tagged individual was detected within a meadow patch (Patch) or within the area of bare ground (Matrix) which separates individual patches.

tag: Categorical value indicating the unique serial number associated with an RFID-tagged individual. This column is used to estimate local densities (sum of unique tag IDs detected).

species: Categorical value indicating the scientific name of the species according to the taxonomy of the Global Biodiversity Information Facility (accessed via GBIF.org during 2020). Note that Harpalus rufipes (De Geer) is referred to in the database by its synonym Pseudoophonus rufipes (De Geer). Poecilus includes the species Poecilus cupreus and Poecilus versicolor. , Harpalus affinis, Harpalus latus) are pooled together at the genus level. 

bodymass_mg: Continuous value indicating the live body mass of each tagged individual, excluding the added mass of the RFID tag.

detection: Integer with a fixed value of 1 representing the detection of a unique RFID tag. This column is used to estimate movement activity (sum of detections).

bite_count: Integer value indicating the number of bite marks recorded on an individual prey dummy during a 14-day exposure. Two independent observers scored the prey dummies by identifying and counting the bite marks left by carabid predators.

treatment_lux: Continuous value indicating the treatment of diffuse nighttime illuminance in Lux.