DOI: 10.5061/dryad.vmcvdnd23
title: Developmental plasticity does not improve performance during a species interaction: implications for species turnover

description: Species interactions can contribute to species turnover when the outcomes
 of the interactions are context dependent (e.g. change along environmental
 gradients). Plasticity may change this dynamic by altering the
 environmental tolerances of the species interacting. Here, we explored how
 the competitive interaction between two euryhaline fish, Poecilia
 reticulata and Poecilia picta, is influenced by acute and developmental
 responses to salinity. In Trinidad, P. reticulata is confined to
 freshwater despite being tolerant of brackish water. Poecilia reticulata
 may fail to occupy brackish water because of reduced tolerance to salinity
 or because P. picta competitively excludes them, and developing in
 brackish water could alter the dynamics of either scenario. To test this,
 we compared the salinity tolerances of both species in the absence of
 competition, reared P. reticulata individuals in freshwater or brackish
 water, and tested the consequences of developmental plasticity in
 experiments in which P. reticulata competed against conspecifics or P.
 picta during acute exposure to freshwater or brackish water. We found that
 1) P. reticulata has a weaker salinity tolerance than P. picta, 2) P.
 reticulata that developed in freshwater perform best when competing
 against P. picta in freshwater but perform poorly when competing against
 P. picta in brackish water, suggesting the species interaction is context
 dependent, and 3) developing in brackish water did not benefit P.
 reticulata in brackish water. Our results suggest that P. reticulata’s
 freshwater range limit is in part a product of a lower salinity tolerance
 leading to a decrease in competitive performance in brackish water.
 Adaptive plasticity has been suggested to be a crucial part of the
 colonization process, yet non-adaptive plastic responses as found here can
 limit range expansion and reinforce range limits.
description: This dataset includes an excel file containing all the data
 needed to carry out the analyses detailed in the manuscript and shown in
 full in Appendix S1 of the manuscript. The data is the raw input into the
 analyses conducted in the analysis. The first sheet in the excel file is a
 key and the other sheets contain data and are labeled according to the
 tables they relate to in Appendix S1 of the manuscript.
description: # Developmental plasticity does not improve performance during a species
 interaction: implications for species turnover
 [https://doi.org/10.5061/dryad.vmcvdnd23](https://doi.org/10.5061/dryad.vmcvdnd23) This dataset contains the input data for analyses examining specific growth rate in juvenile *Poecilia reticulata* and *Poecilia picta* (sheet entitled "TablesS1-3"), change in body condition in *P. reticulata* during competition experiments (sheets entitled "TablesS4-6" and "TableS7"), difference in aggressive behaviors between *P. reticulata* and *P. picta* competitors (sheets entitled "TablesS8-10" and "TableS11"), and total aggressive behavior counts in *P. reticulata* (sheet entitled "TableS12") and in *P. picta* (sheet entitled "TableS13"). ## Description of the data and file structure The first sheet of the excel file is a key explaining any non-obvious terms that relate to the various factors used in our analyses. The other sheets include the data and are organized by their corresponding table(s) in Appendix S1 of the manuscript.  ## Code/Software All analyses were conducted in R version 4.2.2. In addition to base R, the lsmeans package and the lme4 package are needed to conduct the analyses in the manuscript.