Behavioural ecology meets oncology: quantifying the recovery of animal behaviour to a transient exposure to a cancer risk factor
Data files
Feb 08, 2024 version files 69.75 KB
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planaria_raw_dataset.csv
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README.md
Abstract
Wildlife is increasingly exposed to sublethal transient cancer risk factors, including mutagenic substances, which activate their anti-cancer defences, promote tumourigenesis, and may negatively impact populations. Little is known about how exposure to cancer risk factors impacts the behaviour of wildlife. Here, we investigated the effects of a sublethal, short-term exposure to a carcinogen at environmentally relevant concentrations on the activity patterns of wild Girardia tigrina planaria during a two-phase experiment, consisting of a 7-day exposure to cadmium period followed by a 7-day recovery period. To comprehensively explore the effects of the exposure on activity patterns, we employed the double hierarchical generalized linear model framework which explicitly models residual intraindividual variability in addition to the mean and variance of the population. We found that exposed planaria were less active compared to unexposed individuals and were able to recover to pre-exposure activity levels albeit with a reduced variance in activity at the start of the recovery phase. Planaria showing high activity levels were less predictable with larger daily activity variations and higher residual variance. Thus, the shift in behavioural variability induced by an exposure to a cancer risk factor can be quantified using advanced tools from the field of behavioural ecology. This is required to understand how tumourous processes affect the ecology of species.
README: Quantifying the recovery of animal behaviour (planaria) to a transient exposure to a cancer risk factor (cadmium).
https://doi.org/10.5061/dryad.zpc866tfv
To access comprehensive details about the protocol and the thorough rationale employed in gathering this dataset, kindly consult the publication referenced below:
Klaassen H et al. 2024 Behavioural ecology meets oncology: quantifying the recovery of animal behaviour to a transient exposure to a cancer risk factor. Proc. R. Soc. B 20232666. https://doi.org/10.1098/rspb.2023.2666
Description of the data and file structure
The "planaria_raw_dataset.csv" dataset is a .csv file of 8 columns and 1611 rows with variables as columns and measurements as rows. The first row of the dataset contains the name of each variables.
The variables are defined as followed:
ID: The individual ID code given to the planaria on which the activity measurement was collected (categorical variable)
Day: The day of the experiment ranging between 1 and 14 during which the activity measurement was collected (interval variable).
Phase: Categorical variable coded as "Exposure" or "Recovery" indicating if the activity measurement was collected during the Exposure or Recovery phase of the experiment.
Treatment: Categorical variable coded as "Control" or "Treatment" indicating if the activity measurement was collected on a planaria allocated to the control or treatment (cadmium exposed) group.
Distance_mm: The distance in millimetres (mm, i.e. the activity measured), travelled by a planaria during a behavioural trial (continuous variable).
Length_mm: The length in millimetres (mm) of the planaria on which the activity measurement was collected (continuous variable).
Temperature: The air temperature in degree Celsius (°C) of the laboratory at the time the behavioural trial was conducted (continuous variable).
Batch: The batch number (coded as 1, 2 or 3) of the activity measurement (categorical variable).
Methods
Description of the experiment
We used wild planaria (Girardia tigrina), a common freshwater invertebrate, as a study species to study how exposure to cancer risk factors may impact on animal behaviour, and individual behavioural variation at various hierarchical levels. For this purpose, we designed a 14-day-long two-phase experiment using planaria collected in the Saint Augustine Lagoon in September 2022 (Highton, Victoria, Australia, 38°11'30"S, 144°18'48"N).
To investigate the effects of cadmium exposure on behaviour, 60 planaria per treatment group were transferred into ten 6-well plates, with one individual per well, filled with either 10 mL of 0.5 ppm Cd2+ spring water water (Coles Natural Water Spring) solution (treatment group) or 10mL of spring water only (control group) and then placed in the dark in a 20°C incubator (Infors HT Ecotron) for seven days. On day eight of the experiment, the cadmium solution was replaced in both the control and the treatment group with 10 mL of clean spring water after gently rinsing each well with water after which the plate was replaced in the incubator for an additional seven days. In this experiment, we refer to the first seven days of the experiment as the exposure phase, and the subsequent seven days as the recovery phase.
Once per day, each 6-well plate was removed from the incubator and placed on a filtered light pad (Born LED Light Pad, model BOLEDLPA4, 279 lumens, white light) housed within a dark box that blocked out external light sources. Planaria activity was filmed using a tripod-mounted Canon camera for 11 minutes before being replaced in the incubator. Individual planaria trajectories were reconstructed from video recordings by applying a background subtraction method provided by the OpenCV python library (that we optimised for planaria activity), calculating the average coordinates of the pixels identified as being part of an animal. The first minute of the trajectory was discarded to allow the algorithm to accurately detect and track individuals. The trajectories were then standardised by interpolating them to one location per second and the activity of each planaria was calculated as the total distance (in mm) travelled by an individual during a trial. The video footage was also used to measure planaria body length (mm).
Since the video recordings were performed outside the incubator in the same room, we recorded the ambient air temperature (°C) to control for the potential confounding effects on the movement of the planaria.
The whole experiment was repeated three times (i.e. three batches) with 40 animals (20 in the control group and 20 in the cadmium-exposed group) for a total of 120 individuals.
In total, we obtained a total of 1,610 activity measurements, arising from 115 unique planaria. Over the course of the experiment, three planaria died in the control group and two in the treatment group and were excluded from the dataset.