DOI: 10.5061/dryad.12jm63z89
title: Data from: Influence of warming on the functional responses of invasive omnivores, Procambarus crayfishes

description: The red swamp crayfish (Procambarus clarkii) and the marbled crayfish
 (Procambarus virginalis) are congeneric invasive species whose potential
 impacts in the Great Lakes basin have generated concern. In laboratory
 experiments, we tested the functional responses of these omnivores to two
 common food resources, insect larvae (Chironomus bloodworms) and aquatic
 macrophytes (Eurasian milfoil Myriophyllum spicatum), to gain predictive
 information on their per capita effects under present (18°C) and projected
 future (26°C) climate scenarios for the basin. The maximum feeding rate of
 P. virginalis was higher at 18°C than at 26°C when presented with
 bloodworms but did not differ between temperatures when presented with
 macrophytes. By contrast, the feeding rate of P. clarkii did not change
 with temperature for either food resource. Due to their larger mean size,
 P. clarkii exhibited higher rates of resource (bloodworm and macrophyte)
 consumption than P. virginalis at both temperatures. These results suggest
 that trophic impacts of P. virginalis will dampen with increased warming,
 whereas P. clarkii will sustain larger impacts irrespective of temperature
 within the range tested.
description: # Influence of warming on the functional responses of invasive omnivores,
 Procambarus crayfishes
 [https://doi.org/10.5061/dryad.12jm63z89](https://doi.org/10.5061/dryad.12jm63z89) ## Description of the data and file structure We conducted a series of functional response feeding experiments that tested the relative abilities of marbled and red swamp crayfishes to exploit insect larvae (bloodworms) and aquatic macrophytes at current and future mean surface water temperatures. We use this information in our paper to inform how these species *per capita* effects could change with increasing temperatures in nearshore areas of the lower Great Lakes. Specifically, we tested the prediction that P. clarkii and *P. virginalis*, both presumably warm-adapted invaders, will have higher maximum feeding rates at higher temperatures for both resources. ### Files and variables #### File: Sheppard\_Ricciardi\_-\_Data.csv Description: Results from functional response trials ##### Variables * treatment: Combined variable of trial/species/temp * trial: "An" if bloodworms or "Pl" if macrophytes were given during the trial * spp: "redswamp" if tested crayfish was P. clarkii or "marble" if P. virginalis * temp: "18C" if trial temperature was 18C or "26C" if trial temperature was 26C * focus.prey: "bloodworms" if bloodworms or "macrophytes" if macrophytes were given during the trial * b.density: How many individual bloodworms were given in a trial (0 if macrophytes are focus prey) * m.density: How many grams of macrophytes were given in a trial (0 if bloodworms are focus prey) * b.left:How many individual bloodworms were left after a trial (0 if macrophytes are focus prey) * m.left:How many grams of macrophytes were left after a trial (0 if bloodworms are focus prey) * b.eaten:How many individual bloodworms were eaten during a trial (b.density-b.left) * m.eaten: How many grams of macrophytes were eaten during a trial (m.density-m.left) * ID: A unique identifier for each crayfish used during the trials * year: The year the trial was run * month: The month the trial was run * day: The date the trial was run * cl.mm: The size of the crayfish when it was last measured or since molting ## Code/software Software used: * Excel * RStudio2024.04.2 * R4.4.1 Packages * 'frair' version 0.5.100 * 'bbmle' version 1.0.25.1 * 'tidyverse' version 2.0.0 * 'purrr' version 1.0.2 * 'lme4' version 1.1-35.5