Thesis
Does the early work get the herb? Correlates of Lupinus lepidus herbivory on Mount St. Helens
Washington State University
Master of Science (MS), Washington State University
2014
Handle:
https://hdl.handle.net/2376/101345
Abstract
On the primary successional Pumice Plain of Mount St. Helens, phosphorus (P) nutrition is hypothesized to mediate negative density-dependent herbivory by guilds of leaf-tying and root-boring lepidopteran larvae on the pioneer plant Lupinus lepidus. However, the role of P or other plant characteristics in mediating competition between these guilds is unknown. To understand how plant traits affect herbivory by these guilds, we collected L. lepidus leaf tissue and measured size and local L. lepidus density during the oviposition period, then measured later herbivory for 600 plants. We quantified leaf %N, %P, d 13C, and d 13N on a subset of high and low damage plants and tested for hypothesized P limitation to larvae through a P addition experiment. Leaf miner damage was negatively correlated with host density and root borer damage, but unaffected by foliar C, N, d 13C (an indicator of plant response to water stress), or d 15N (an indicator of plants' N source). However, where root borers were present, foliar P was a powerful negative predictor of leaf miner damage, indicating that borers outcompete miners in high-P plants. This trend is reversed for plants receiving P-supplementation during herbivory. Root v borer damage correlated positively with plant area and d 13C, and negatively with leaf miner damage. These findings establish that the effect of host density on leaf miners persists for decades, and that root borers monopolize high-P plants through a priority effect. These conclusions support prior research indicating P limitation structures leaf miner population dynamics on the Pumice Plain.
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Details
- Title
- Does the early work get the herb? Correlates of Lupinus lepidus herbivory on Mount St. Helens
- Creators
- Joseph Reeves Pitkin
- Contributors
- John G. Bishop (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Environment, School of the (CAHNRS)
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525391501842
- Language
- English
- Resource Type
- Thesis