Swimming behavior of Daphnia dentifera is influenced by Australozyma monospora infection
Data files
Apr 10, 2026 version files 90.55 KB
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phototactic_data_2024.csv
26.19 KB
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phototactic_data_2024.xlsx
35.41 KB
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phototactic_figure1.R
5.05 KB
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phototactic_supplement.R
19.38 KB
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README.md
4.53 KB
Abstract
By changing the behavior of infected hosts, pathogens can shape the outcome of both disease transmission and other interspecific interactions within the food web. This change in behavior is most often recognized in trophically-transmitted parasites, where changing the behavior of an intermediate host can increase the rate at which the parasite is transmitted to the next host. However, behavioral changes also occur in terminal hosts. In a laboratory experiment, we investigated whether infection by the ascomycete yeast Australozyma monospora (formerly Metschnikowia bicuspidata) and/or the time since infection changes the swimming behavior over time of its freshwater cladoceran host, Daphnia dentifera. Infection influenced the net distance and total distance traveled, as well as the swimming speed and mean depth of the Daphnia. Uninfected individuals traveled further, both in terms of net distance and total distance, and they also swam faster. The influence of time since infection was more nuanced. Swimming speed, net distance, and total distance traveled varied with time, but mean depth did not. Though we found no main effect of time since infection on mean swimming depth, time did interact with infection status to influence mean depth. A better understanding of how pathogens may alter the movement and habitat selection of infected hosts can help to inform predictive models of disease spread in lakes that are ever-changing due to increased anthropogenic stressors.
https://doi.org/10.5061/dryad.9kd51c5rz
This dataset contains measurements for the swimming and phototactic behavior of five genotypes of the zooplankton Daphnia dentifera, comparing populations infected with the fungal pathogen Australozyma monospora (formerly Metschnikowia bicuspidata) to uninfected populations across three trials. In our study, a "population" of Daphnia refers to a group of five D. dentifera of the same genotype and infection status (infected or uninfected) placed in a single acrylic tube for recording movement (a single population is also considered a "Replicate" in our study). Where possible, we performed three recording trials to compare swimming and phototactic behavior across time as late-stage infection progressed in the infected populations. In all cases, we waited two days between trials for each tested population. In each trial, we measured the average depth, swimming velocity, and total distance and net distance traveled of each of the five Daphnia in a given population/replicate. We analyzed each variable using linear mixed effects models and repeated measures ANOVAs. We also analyzed correlations between each combination of variables.
Description of the data and file structure
The main data file phototactic_data_2024.xlsx shows the measurements for each individual Daphnia dentifera. The data file has two sheets: "data", which holds all measurements, and "metadata", which provides a detailed explanation for each of the first five columns in the data. "Type" refers to genotype, where five different genotypes were used in this study. Trial refers to which observation trial to which the measurements in the row correspond, and Day refers to the days since visually-confirmed infection. In all cases, trial 1 corresponds to day 9-10, trial 2 corresponds to day 11-12, and trial 3 corresponds to day 13-14. Replicate refers to a population of five Daphnia dentifera of the same genotype and infection status in an experimental tube; we attempted to test three replicate populations (three tubes with five Daphnia per tube) for each combination of treatment groups. For each variable measured, there is a value corresponding to each of the five Daphnia included in a replicate/population. In cases where a cell is blank, that indicates a missing individual (e.g., if a cell is missing for mean depth Daphnia 5 in a given row, that means there were only four Daphnia included in that replicate).
The phototactic_data_2024.csv file is the csv version of the "data" sheet within the main data Excel file. This file was used for analysis in R Studio.
Code/Software
The workflow for the R scripts is as follows: phototactic_analysis_figure1.R > phototactic_figure1.R > phototactic_figure2.R > phototactic_analysis_figure2.R
The file phototactic_analysis_figure1.R is the R code used to analyze the data used to produce Figure 1. This code calculates average measurements for each replicate population by taking the mean of the measurements from each of the five Daphnia dentifera within a replicate. The population averages are used for subsequent analysis. Using the package "nlme" (version 3.1-163), each of the four variables (average depth, velocity, and total and net distance traveled) are analyzed using linear mixed models and repeated measures ANOVA.
The file phototactic_figure1.R is the R code used to produce Figure 1. The R packages "ggplot2" and "RColorBrewer" (version 1.1-3) are used to create individual box plots for each of the four variables. The packages "gridExtra" (version 2.3) and "ggpubr" (version 0.6.0) are used to combine the four box plots into one four-panel figure.
The file phototactic_figure2.R is the R code used to produce Figure 2 in the manuscript. The R packages "GGally" (version 2.1.2) and "RColorBrewer" (version 1.1-3) are used to create the pairs plot illustrating correlations between the four variables.
The file phototactic_analysis_figure2.R is the R code used to analyze the data used to produce Figure 2. This includes the tests for correlation between each pair of variables.
The file phototactic_supplement.R is the R code used to produce Supplemental Figure 1 in the Supplemental Information for the manuscript, as well as the analysis of the data used to produce Supplemental Figure 1. This analysis includes data from Trial 3.