Abstract
The relative importance of food quality vs. enemy-free space remains an unresolved but central issue in the evolutionary ecology of host use by phytophagous insects. In this study, we investigate their relative importance in determining host-plant use by a generalist caterpillar, Estigmene acrea (Lepidoptera: Arctiidae). In nature, E. acrea late-instar caterpillars preferred Senecio longilobus (Asteraceae), which contains pyrrolizidine alkaloids that the caterpillars sequester, over Viguiera dentata (Asteraceae), a natal host, and typically suffered a 28% mortality risk from parasitoids. We hypothesized that the natural, mixed diet of caterpillars provides high-quality food via hosts like Viguiera as well as antiparasitoid defense via sequestered toxins from Senecio. We found that a pure Viguiera diet provides superior growth performance over a pure Senecio or mixed diet in the absence of parasitism. However, when parasitism risk is at least moderate, the mixed diet provides a survival advantage over the pure diets of Viguiera or Senecio. We therefore conclude that the balance between benefits of growth (food quality) and defense (enemy-free space) maintains the use of a mixed diet in nature. Furthermore, the value of enemy-free space supercedes the value of food quality in determining the host-plant preference of late-instar caterpillars.
Original language | English (US) |
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Pages (from-to) | 2747-2753 |
Number of pages | 7 |
Journal | Ecology |
Volume | 85 |
Issue number | 10 |
DOIs | |
State | Published - Oct 2004 |
Keywords
- Arctiidae
- Diet choice
- Enemy-free space
- Estigmene acrea
- Generalist insect herbivore
- Host preference
- Parasitoids
- Polyphagy
- Senecio longilobus
- Tachinidae
- Tritrophic interactions
- Viguiera dentata
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
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Appendix B. A list of parasitoid species recovered from collections of Estigmene acrea (1996–2001) in southeastern Arizona.
Singer, M. S. (Creator), Rodrigues, D. (Creator), Stireman III, J. O. (Contributor) & Carrière, Y. (Creator), figshare, 2016
DOI: 10.6084/m9.figshare.3523769, https://wiley.figshare.com/articles/dataset/Appendix_B_A_list_of_parasitoid_species_recovered_from_collections_of_Estigmene_acrea_1996_2001_in_southeastern_Arizona_/3523769
Dataset
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Appendix A. A table showing plant species eaten by Estigmene acrea caterpillars during field collections to assess parasitism, and during behavioral observations.
Singer, M. S. (Creator), Rodrigues, D. (Creator), Stireman III, J. O. (Contributor) & Carrière, Y. (Creator), Wiley, 2016
DOI: 10.6084/m9.figshare.3523772.v1, https://wiley.figshare.com/articles/dataset/Appendix_A_A_table_showing_plant_species_eaten_by_Estigmene_acrea_caterpillars_during_field_collections_to_assess_parasitism_and_during_behavioral_observations_/3523772/1
Dataset
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Appendix C. An ANOVA table showing effects of diet, sex, and their interaction on performance of surviving insects in experiment 1.
Singer, M. S. (Creator), Rodrigues, D. (Creator), Stireman III, J. O. (Contributor) & Carrière, Y. (Creator), Wiley, 2016
DOI: 10.6084/m9.figshare.3523766.v1, https://wiley.figshare.com/articles/dataset/Appendix_C_An_ANOVA_table_showing_effects_of_diet_sex_and_their_interaction_on_performance_of_surviving_insects_in_experiment_1_/3523766/1
Dataset