DOI: 10.5061/dryad.crjdfn3f9
title: Data from diet C:N ratio and temperature influence the performance and coloration of tobacco hornworms

description: Insect coloration mediated by melanization can assist in dealing with
 environmental temperatures. However, melanin synthesis can be costly and
 depends on the ability of insects to acquire enough energy and nutrients
 from their diets. Due to the increased plant C:N ratio associated with
 elevated CO2 concentrations, insect herbivores’ melanization could be
 limited by the amount of nitrogen they acquire from their host plants. To
 investigate how diet C:N impacts the potential color response to
 temperature, we used Manduca sexta caterpillars reared at different
 combinations of temperatures and diet C:N ratio, and measured pupal mass
 and development time (performance metrics) and color morphology. The
 high-temperature treatment (27°C) had a positive impact on larvae
 performance, whereas a nitrogen-poor diet was related to lower
 performance. Using a fitness metric that considers both pupal mass and
 development time, we found a positive effect of both high-temperature and
 nitrogen-rich diet treatments on larvae fitness. We found that diet and
 temperature affected the coloration of larvae, in which larvae reared at
 the low-temperature treatment (18°C) and fed a nitrogen-rich diet were
 darker than their counterparts. Our results provide experimental evidence
 of the impact of diet on melanization and suggest that CO2-related changes
 in plant quality could be associated with changes in insect herbivore
 performance and coloration.
description: # Data for diet C:N ratio and temperature influence the performance and
 coloration of tobacco hornworms
 [https://doi.org/10.5061/dryad.crjdfn3f9](https://doi.org/10.5061/dryad.crjdfn3f9) ## Description of the data and file structure Soon after eclosion, *Manduca sexta* larvae were reared under two temperature conditions (18 or 27 degrees Celsius) and two diet treatments (N-poor or N-rich). We measured pupal mass, development time, and survival as performance metrics, all data are in the 'Performance' csv file. We photographed the 5th instar larvae before the wandering stage and measured color as RGB, Luminance, and Value, and all data are in the 'Color' csv file. **R and Python codes are available in the Github repository: [https://github.com/mayracvidal1/Manduca_color](https://github.com/mayracvidal1/Manduca_color)** ### Files and variables #### File: Color.xlsx **Description:** Data file for color metrics ##### Variables * ID: individual larva identifier * Diet: type of diet treatment (High-quality = N-rich; Low-quality = N-poor) * Temperature: type of temperature treatment (18 or 27 Celsius) * Year: year the experiment was performed, which also corresponds to the 'trial' or egg sources  * Size (px/cm): the larva image size measured as pixels per cm * Red Mean: mean of R * Red Median: median of R * Red Variance: variance of R * Green Mean: mean of G * Green Median: median of G * Green Variance: variance of G * Blue Mean: mean of B * Blue Median: median of R * Blue Variance: variance of R * Value Mean: mean of V * Value Median: median of V * Value Variance: variance of V * Luminance Mean: mean of L * Luminance Median: median of L * Luminance Variance: variance of L #### File: Performance\_clean.xlsx **Description:** Data file for performance metrics.  ##### Variables * ID: individual larva identifier * Diet: type of diet treatment (High-quality = N-rich; Low-quality = N-poor) * Temperature:  type of temperature treatment (18 or 27 Celsius) * Hatch Date: date the larva hatched from egg * Pupa Date: date the larva pupated. Inidividuals that did not pupate (i.e., died before pupation) received a n/a. * Death Date: if larva died, the date of death. Inidividuals that did survived received a n/a. * Survived?: binary value of survival (0 = dead, 1 = alive). * Development Time: the number of days from hatch date to pupa date. Inidividuals that did not pupate (i.e., died before completing development) received a n/a. * Pupal Mass (g): mass of pupa after 10 days of pupation measured in grams. Inidividuals that did not pupate (i.e., died before pupation), or that emerged before pupal weighting, received a n/a.  * Year: year the experiment was performed