Extreme heat reduces host and parasite performance in a butterfly-parasite interaction

Environmental temperature fundamentally shapes insect physiology, fitness, and interactions with parasites. Differential climate warming effects on host versus parasite biology could exacerbate or inhibit parasite transmission, with far-reaching implications for pollination services, biocontrol, and human health. Here, we experimentally test how controlled temperatures influence multiple components of host and parasite fitness in monarch butterflies (Danaus plexippus) and their protozoan parasites Ophryocystis elektroscirrha. Using five constant temperature treatments spanning 18-34°C, we measured monarch development, survival, size, immune function, and parasite infection status and intensity. Monarch size and survival declined sharply at 34°C, as did infection probability, suggesting that hot temperatures decrease both host and parasite performance. The lack of infection at 34°C was not due to greater host immunity or faster larval development but could instead reflect the thermal lim..., We used a constant temperature experiment to explore how temperature influences components of host and parasite performance in monarch butterflies (Danaus plexippus) and their protozoan parasite OE (Ophryocystis elektroscirrha). In lab incubators, we used five constant temperature treatments spanning 18-34°C to measure monarch development, survival, size, immune function, and OE infection status and intensity.
Data was entered using Excel and analyzed in R Studio., R and R Studio are required to open the data files included., # Extreme heat reduces host and parasite performance in a butterfly-parasite interaction

This file contains three datasets describing monarch performance and parasite infection outcomes across a gradient of five constant temperatures along with the code used to perform statistical analysis.

## Description of the data and file structure

File: mtemp_comp_Nov1_2021.csv
This file contains a row for each individual monarch \"ID,\" with columns on the temperature treatment, host genetic lineage, and parasite strain used (if inoculated). For each monarch, there are data on key dates in the experiment (e.g. date inoculated, date of death), monarch performance metrics, and infection and intensity measures. Cells for traits that were not measured for an individual contain \"NA\". This file is used for the majority of analysis, including generalized additive models and generalized linear models of traits across temperature.

File: Hemocyte_counts_June5.csv
This file contains raw hemocyte counts f...