Data from: The adaptive role of melanin plasticity in thermally variable environments
Data files
Sep 18, 2024 version files 18.52 KB
Abstract
Understanding the evolution of adaptive plasticity is fundamental to our knowledge of how organisms interact with their environments and cope with environmental change. Plasticity in melanin pigmentation is common in response to variable environments, especially thermal environments. Yet, the adaptive significance of melanin plasticity in thermally variable environments is often assumed, but rarely explicitly tested. Furthermore, understanding the role of plasticity when a trait is responsive to multiple environmental stimuli and plays many functional roles remains poorly understood. We test the hypothesis that melanin plasticity is an adaptation for thermally variable environments using Hyles lineata, the white-lined sphinx moth, which shows plasticity in melanin pigmentation during the larval stage. Melanin pigmentation influences thermal traits in H. lineata, as melanic individuals had higher heating rates and reached higher body temperatures than non-melanic individuals. Importantly, melanin pigmentation has temperature specific fitness consequences. While melanic individuals had an advantage in cold temperatures, neither phenotype had a clear fitness advantage at warm temperatures. Thus, the costs associated with melanin production may be unrelated to thermal context. Our results highlight the importance of explicitly testing the adaptive role of plasticity and considering all the factors that influence costs and benefits of plastic phenotypes across environments.
README: Data from: The adaptive role of melanin plasticity in thermally variable environments
Description of data
The data can be found in three files.
The first file, “Exp1_ThermalTraits.csv” contains the data used for the first experiment. Below is a description of all variables.
ID = individual larval label
Devo_Day = The developmental day that the individual was tested (with Day 0 being the day that the egg was laid). All individuals are in the 5th (final) instar.
Weight = Larval mass in grams
Melanism = Melanin level (max and min refer to melanic and non-melanic
Ambient = Ambient temperature under the light in degrees C
Initial_temp = Body temperature of the larva at minute 0 in degrees C
4 = Body temperature of the larva at minute 4 in degrees C
24 = Body temperature of the larva at minute 24 in degrees C
Rate_4 = Linear heating rate of larva over first 4 minutes ((4-Initial Temp) / 4) measured as degrees C/ minute
Rate_24 = Linear heating rate of larva over first 24 minutes ((24-Initial Temp) / 4) measured as degrees C/ minute
Temp_Excess = Larval body temperature above ambient temperature (24-Ambient) measured as degrees C
The second file, “Exp2_FitnessTraits.csv” contains the data used for the second experiment. Below is a description of all variables.
ID = individual larval label
Melanin = Melanin level (maximum and minimum refer to melanic and non-melanic
Melanin_Percent = quantitative measure of melanin that was done for a subset of individuals (measured as percent area with melanic pixels, as explained in the text)
Block = experimental block (due to space constraints experiment was conducted over 2 blocks)
Treatment = temperature treatment (cold vs warm)
Family = full sibling family designation
Light position = whether larvae were placed under lights in the front, middle, or back of the chamber
Initial_weight = Mass of larva at beginning of 5th instar (grams)
Peak_weight = mass of larva at peak weight (grams)
Development = number of days in 5th instar
Growth_Rate_2to4 = growth rate from days 2-4 of the 5th instar, measured as grams/day
Growth_Percent_2to4 = growth percentage from days 2-4 of the 5th instar, measured as growth rate/ initial weight
Growth_Rate_Total = growth rate from day 2 to final day of 5th instar, measured as grams/day
Growth_Percent_Total = growth percentage from day 2 to final day of the 5th instar, measured as growth rate/ initial weight
Pupal_Weight = pupal mass (grams)
Survival = binary measure of survival (for tallies see "Survival" file)
Empty cells in this file indicate that an individual did not survive until that particular measurement. For example, if a larva died during the experiment and did not pupate there will not be a measurement for pupal weight.
The third file, “Survival” is a simple summary of the survival among the four treatment groups.
Code/ Software
All statistical analyses and data figures were run in R. R file “Melanin_Adaptation.R” is included and can be run to replicate results once the data files are downloaded.