DOI: 10.5061/dryad.63xsj3vb6
title: Behavior and performance data of monarch butterfly caterpillars

description: Plants have evolved multiple defensive traits in response to herbivory; in
 turn, herbivore specialists evolved adaptive behaviors to avoid or
 tolerate such defenses. Here, we employ milkweeds
 (Asclepias spp.) to test two defenses, latex and trichomes, for
 their independent and interactive effects on behavior and performance of
 monarch caterpillars (Danaus plexippus). Latex exuded upon damage and the
 density of leaf trichomes positively correlate across milkweed species,
 suggesting they may have evolved together as synergistic defenses.
 Nonetheless, the complementary roles of these two traits have been
 little-studied. We focus on two behaviors: shaving, or the removal of
 trichomes, and chewing, which encompasses both deactivation of latex and
 leaf consumption. In an experiment with seven milkweed species, with and
 without manipulated latex flow, we found latex to be the primary
 determinant of reducing chewing, while both defenses positively predicted
 shaving behavior in the first instar. Next, we conducted a factorial
 experiment throughout the first three instars, manipulating latex and
 trichomes on a high latex, high trichome species, the woolly
 milkweed A. vestita. On plants with latex and trichomes intact,
 caterpillars spent the most time shaving and least time chewing of all
 treatment groups, suggesting a possible synergism. These defense-driven
 behavioral effects decreased later in larval development. Latex
 and trichomes both impacted monarch performance, additively increasing
 mortality and reducing growth of survivors. Thus, latex and trichomes
 represent two important plant defenses with effects on specialist
 herbivore behavior and implications for insect fitness.
description: # Craig and Agrawal 2024
 [https://doi.org/10.5061/dryad.63xsj3vb6](https://doi.org/10.5061/dryad.63xsj3vb6) ## Description of the data and file structure Data provided is from two experiments, one testing for behavioral effects of two plant defenses on monarch caterpillar behavior, and the other testing for both behavioral and performance-related effects of the plant defenses. ### Files and variables #### File: Craig\_\_\_Agrawal\_2024\_Data.xlsx ##### Variables, Experiment 1: * Replicate: Which of 5 temporal replicates an individual was a part of * Species: Which of seven milkweed species a caterpillar was reared on * Treatment: Which treatment, latex (intact plant) or no latex (cut leaf) * Latex exudation: Latex mass exuded upon plant damage, in milligrams * Trichome density: Number of trichomes, in hairs per millimeters squared * Chewing: Time caterpillar spent chewing, in seconds * Shaving: Time caterpillar spent shaving, in seconds * Walking: Time caterpillar spent walking, in seconds * Movement: Time caterpillar spent moving, in seconds * No Movement: Time caterpillar spent stationary, in seconds *Note: Missing values are indicated by N/A. Latex exudation and trichome density were only measured for 5 of each species, so additional cells are labeled N/A. **Variables, Experiment 2:** * Treatment: Which of 4 treatments; L+/L- indicates latex intact/removed, and T+/T- indicates trichomes intact/removed * Mortality 1: Mortality at the end of the first instar, (1 = alive, 0 = dead) * Mortality 2: Mortality at the end of the second instar, (1 = alive, 0 = dead) * Mortality 3: Mortality at the end of the third instar, (1 = alive, 0 = dead) * Mass 1: Mass at the beginning of the first instar, in milligrams * Mass 2: Mass at the beginning of the second instar, in milligrams * Mass 3: Mass at the beginning of the third instar, in milligrams * Mass 4: Mass at the beginning of the fourth instar, in milligrams * Days to 2nd instar: Number of days from the beginning of the study period to beginning of the second instar * Days to 3rd instar: Number of days from the beginning of the study period to beginning of the third instar * Days to 4th instar: Number of days from the beginning of the study period to beginning of the fourth instar * Chewing 1st instar: Time first instar caterpillar spent chewing, in seconds * Shaving 1st instar: Time first instar caterpillar spent shaving, in seconds * Feeding 3rd instar: Time third instar caterpillar spent feeding, in seconds * Trenching 3rd instar: Time third instar caterpillar spent trenching, in seconds * Shaving 3rd instar: Time third instar caterpillar spent shaving, in seconds *Note: Missing values are indicated by blank cells. This means either the caterpillar was one of 8 replacements (and first instar data was not collected), or the caterpillar died (and later instar data was not collected).