https://doi.org/10.5061/dryad.7pvmcvf4f

Description of the data and file structure

The study investigated spatial and temporal variation in the fish-derived kairomone 5α-cyprinol sulfate (CPS) in Lake Klostersee and its relationship with diel vertical migration (DVM) in Daphnia longispina. Field measurements were combined with laboratory bioassays to determine genotype-specific CPS concentrations associated with the onset of DVM.

Field sampling design

Field sampling was conducted in Lake Klostersee, Bavaria, Germany, a mesotrophic prealpine lake with a maximum depth of 16 m.

Monthly daytime sampling was conducted from April to October 2022, with the exception of September, at the following water layers:

• 0–2 m
• 2–4 m
• 4–6 m
• 6–8 m
• 8–10 m
• 10–12 m

Additional high-resolution diel sampling was conducted on 17–19 August 2022 during daytime (approximately 12:00) and nighttime (approximately 21:30). At each depth and time point, duplicate water samples for CPS analysis and zooplankton samples for Daphnia longispina abundance measurements were collected.

Chemical analysis

CPS concentrations were quantified using ultra-high-performance liquid chromatography (UHPLC) coupled to a Q-Exactive HF mass spectrometer.

Lake-water samples were extracted using C18 solid-phase extraction (SPE). CPS concentrations are reported in ng L⁻¹.

Cholesteryl sulfate (CS) was used as an internal standard for quantification.

Laboratory bioassays

Laboratory experiments were conducted to determine the CPS concentrations associated with the onset of diel vertical migration in four Daphnia longispina genotypes isolated from Lake Klostersee:

• KLS1
• KLS2
• KL3
• KL83

Bioassays were conducted in vertically stratified plankton organs containing an experimental thermocline. Mean daytime depth was measured in cm.

For each genotype, mean daytime depth was regressed against log-transformed CPS concentration. The CPS concentration at which the fitted regression line intersected the experimental thermocline at 35 cm depth was defined as the genotype-specific migration threshold.

The resulting thresholds were:

• KLS2: 30.0 ng L⁻¹
• KL3: 73.9 ng L⁻¹
• KLS1: 107.9 ng L⁻¹
• KL83: 603.6 ng L⁻¹

These values correspond exactly to the threshold definition and values reported for Fig. 3 in the manuscript.

Files and variables

24092026_All_Datasets_LOF_AhlersJ.xlsx

Excel workbook containing the raw and processed data underlying the main and supplementary figures of the study. The workbook consists of nine worksheets:

Figure1A Heatmap CPS
Data underlying the seasonal depth profile of 5α-cyprinol sulfate (CPS) concentrations shown in Fig. 1A. The sheet contains sample identifiers, sampling month, sampling depth (m), replicate information, injection volume (µL), CPS and cholesteryl sulfate (CS) peak areas (PA), sample volume (mL), and chromatographic gradient information. These measurements were used to calculate and visualize seasonal CPS concentrations (ng L⁻¹) across the water column of Lake Klostersee.

Figure 1B Heatmap Temperature
Environmental profile data underlying Fig. 1B. Variables include sampling date, depth (m), dissolved oxygen saturation (%), pH, water temperature (°C), and conductivity. Temperature and depth data were used to visualize seasonal thermal stratification in Lake Klostersee. Figure 1 presents these seasonal CPS and temperature profiles together.

Figure 2 DayNight CPS
Data underlying the CPS component of Fig. 2. Samples were collected during daytime and nighttime on three consecutive days (17–19 August 2022) at different depths. Variables include sampling depth (m), replicate, sampling date, daytime category (day/night), injection volume (µL), CPS and CS peak areas (PA), CS recovery rate (%), calculated CPS concentration (ng L⁻¹), and chromatographic gradient.

Figure 2 Daphnia abundance
Data underlying the Daphnia longispina component of Fig. 2. Variables include sampling depth (m), D. longispina abundance (individuals L⁻¹), sampling date, and daytime category (day/night). For Fig. 2, abundance within each depth stratum was converted to relative abundance (% of total abundance within each sampling profile). The final figure displays mean relative abundance ± standard error together with the corresponding CPS depth profiles.

Figure 3 CLone KLS2, Figure 3 Clone KL83, Figure 3 Clone KL3, and Figure 3 Clone KLS1
Raw laboratory bioassay data for the four Daphnia longispina genotypes used in Fig. 3. Variables include observation ID, date and time, experimental column, observed vertical position/depth (cm), experimental day, and assay identifier.

The data were used to calculate mean daytime depth for each independent replicate under different CPS treatments. Mean daytime depth was subsequently regressed against log-transformed CPS concentration. The CPS concentration at which the fitted regression line intersected the experimental thermocline at 35 cm was defined as the genotype-specific migration threshold.

Figure S2 Calibration CS
Calibration data for the internal standard cholesteryl sulfate (CS), corresponding to Fig. S2 in the final manuscript. Variables include CS concentration (ng µL⁻¹), dilution, injection volume (µL), CS peak area (PA), chromatographic gradient duration (min), gradient identifier, and chromatographic column. These data were used to generate calibration curves for Gradients A, B, and C. In the final figure, injected CS mass is expressed in ng and plotted against CS peak area.

Analysis code

Rscript_AllPlots_LandscapeofFear.R

R script containing the data processing, statistical analyses, and code used to generate the main and supplementary figures.

Abbreviations

CPS – 5α-cyprinol sulfate
CS – cholesteryl sulfate
DVM – diel vertical migration
SPE – solid-phase extraction
UHPLC – ultra-high-performance liquid chromatography
SE – standard error
PA – peak area

Code/software

To view and analyze the provided datasets and code, Microsoft Excel and R software (version 4.1.0 or later) are required. Install.packages(c("dplyr", "ggplot2", "ggthemes", "ggpmisc", "tidyverse", "cowplot", "lme4", "lmerTest", "akima", "multcompView", "patchwork"))