DOI: 10.5061/dryad.5tb2rbpft
title: The same species, not the same invader: Metabolic responses of genetically distinct invasive populations of Dikerogammarus villosus and their intraspecific hybrid to environmental stresses

description: Climate change has a profound impact on ectotherms, which suffer
 suboptimum thermal conditions in their native areas or spread to
 previously unavailable locations. However, it is often neglected that
 responses to environmental changes are likely at a population level,
 rather than species-specific phenomenon. Two groups (Western and Eastern)
 of the invasive Ponto-Caspian amphipod Dikerogammarus villosus
 independently spread in Europe from two geographically isolated and
 genetically distinct source populations living in the Danube and Dnieper
 deltas, respectively. They are expected to meet in the near future in
 Polish inland waters. This makes this species a perfect model to
 investigate the intraspecific variability in responses to environmental
 changes, as well as effects of hybridization between different genetic
 units on invasiveness. We scaled maximal metabolic rate (MMR), standard
 metabolic rate (SMR), and aerobic scope (AS, a measure of physiological
 performance) of D. villosus at different temperatures (15 and 25 oC) and
 oxygen levels (9.5 or 7.5 mg/l at a temperature of 15 and 25 oC,
 respectively and 5.5 mg/l at both temperatures) to test for differences in
 responses to environmental changes among the distinct invasive groups and
 their hybrid. Large Western Group individuals showed a lower AS at a high
 temperature, compared to low temperature and to the Eastern group
 individuals, whereas small animals exhibited similar AS irrespective of
 temperature and group identity. Moreover, large individuals from both
 groups experienced a reduction in MMR and AS under low oxygen conditions,
 whereas small animals did not change these parameters in response to
 oxygen reduction. Although parental groups reduced their AS in response to
 oxygen reduction, AS of the hybrid remained unchanged. In conclusion,
 organism responses to climate change depend on intraspecific variation,
 which should be considered in studies related to this topic. Furthermore,
 D. villosus appears sensitive to oxygen deficits and temperature changes
 (especially the Western group and large individuals), but intraspecific
 hybridisation can enhance the environmental tolerance of invaders.
description: # The same species, not the same invader: Metabolic responses of
 genetically distinct invasive populations of Dikerogammarus villosus
 (Sowinsky, 1894) and their intraspecific hybrid to environmental stresses
 Dataset DOI: [10.5061/dryad.5tb2rbpft](10.5061/dryad.5tb2rbpft) ##
 Description of the data and file structure The authors collected matabolic
 response data (saved in wild.xlsx and hybdrids.xlsx files) during the
 experiment using intermittent flow-through respirometry setup. The data on
 river water temperatures (temperature data.xlsx) were obtained from the
 public repository of the Institute of Meteorology and Water Management
 (Instytut Meteorologii i Gospodarki Wodnej) in Poland
 ([https://danepubliczne.imgw.pl/data/dane_pomiarowo_obserwacyjne/](https://danepubliczne.imgw.pl/data/dane_pomiarowo_obserwacyjne/), accessed: 11.2024).  The compressed .zip file contains .xlsx files with data necessary to recreate all statistical analyses related to the study. It also includes the code prepared in R open software. ### Files and variables #### File: The\_same\_species\_\_not\_the\_same\_invader.zip **Description:**  **wild.xlsx** - the file contains raw data collected during the experiment on wild amphipods populations. Variables: id – numeric; amphipod identifier amph.group – categorical; amphipod group to which particular amphipod belong; Western group refers to animals collected from Oder River, Eastern group – Vistula River coll.site – categorical; amphipod collection site, unique for each river temp – categorical; experimental temperature used, 15 or 25 oC oxygen – categorical; oxygen conditions during the experiment, saturated or reduced (see main text for details) mass – numerical; amphipod body mass, expressed as log10-transformed body mass in grams mmr – numerical; maximum metabolic rate score, expressed as log10-transformed raw value measured in mg O2 h-1 smr – numerical; standard metabolic rate score, expressed as log10-transformed raw value measured in mg O2 h-1 as – numerical; aerobic scope score, expressed as log10-transformed difference between raw values of maximum and standard metabolic rate measured in mg O2 h-1   **hybrids.xlsx** - the file contains raw data collected during the experiment on F1 hybrids bred from wild populations. Variables: id – numeric; amphipod identifier amph.group – categorical; amphipod group to which particular amphipod belong; Western group refers to animals collected from Oder River, Eastern group – Vistula River oxygen – categorical; oxygen conditions during the experiment, saturated or reduced (see main text for details) mass – numerical; amphipod body mass, expressed as log10-transformed body mass in grams mmr – numerical; maximum metabolic rate score, expressed as log10-transformed raw value measured in mg O2 h-1 smr – numerical; standard metabolic rate score, expressed as log10-transformed raw value measured in mg O2 h-1 as – numerical; aerobic scope score, expressed as log10-transformed difference between raw values of maximum and standard metabolic rate measured in mg O2 h-1   **temperature data.xlsx** – data on water temperature recorded since 1984 on both rivers (Oder and Vistula) where the amphipods for the experiment were collected. The file contains two sheets: Sheet 1: annual mean – data with annual mean water temperatures for both rivers Sheet 2: annual max – data with annual maximum water temperatures for both rivers Variables: site – categorical; the name of the measurement station according to the Institute of Meteorology and Water Management in Poland river – categorical; the name of the river on which measurement station is located year – numeric; year of the measurement temp – numeric; water temperature measured expressed in oC ### Code/software The compressed .zip folder contains „The same species, not the same invader.Rproj” file, which is a project creater in R open software to analyze experimental data. Specific parts of Rcode are provided in .R files: Exp1 – wild.R – this file contains code neccesary to recreate all analyses using for the results of the first experiment - impact of varying oxygen and temperature conditions on the metabolic scaling of the wild invasive amphipod groups Exp2 – hybrids.R - this file contains code neccesary to recreate all analyses using for the results of the second experiment - impact of oxygen limitation on metabolic scaling of the F1 generation of amphipods bred in the mesocosm culture: two pure groups and their intraspecific hybrid River temp.R – this file contains code used to analyse long-term water temperature changes in the Vistula and Oder Rivers – amphipods collection sites All code provided was created and used with R open software, ver 4.2.1. The list of packages needed is provided at the beginning of the each code.