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Abstract Detail

Symbioses: Plant, Animal, and Microbe Interactions

Barosh, Theresa [1], Hardlund, Linnea [2], Mahajan, Surabhi [2], Theiss, Kathryn E [2], Kephart, Susan [3].

Examining Camassia Phenology and Galling Herbivory in the Oregon Willamette Valley.

The genus Camassia (Asparagaceae, Agavoideae) offers an opportunity to explore species boundaries through classic morphological and phenological analyses as well as species-specific ecological interactions. Camassia leichtlinii and C. quamash often co-occur in the Willamette Valley; while they have distinctly different morphology, they overlap slightly in flowering phenology and are known to occasionally hybridize. Recently, detailed assesments in C. leichtlinii led to the discovery of a previously unrecognized gall midge Dasineura (Cecidomyiidae, Diptera) that affects floral morphology. These flies may significantly influence plant reproductive output because their larvae develop in the ovaries, preventing flowers from forming fruits. Dasineura are often species specific in host selection. To examine camas species boundaries and ecological interactions, we evaluated reproductive isolation via phenological measures throughout the flowering season while noting galling frequency by Dasineura and its species specifity. We asked four questions: 1.) Do differences in phenology help maintain species boundaries in Camassia? 2.) Which species are involved in the Camassia-Dasineura relationship and to what extent? 3.) How do phenology and herbivory vary among habitats, particularly with elevational change? 4.) How does herbivory frequency relate to flowering phenology, and does it influence reproductive fitness? We collected phenological data on C. leichtlinii and C. quamash from four sites in the Willamette Valley to track floral development over time and also noted the time and form of galling and flowering at reproductive nodes. We compared the phenologies of each species at all sites, using the extent of flowering overlap to estimate its potential contribution to reproductive isolation. Morphologically, plant height, the number of reproductive nodes, and number of open flowers were significantly different between species. Additionally, across sites and elevation, some overlap occurred in flowering phenology but C.quamash was consistently found to flower earlier than C. leichtlinii. We also compared levels of infestation by the Dasineura gall midge and detected a trend for smaller percentages of galls per stem in lower elevation sites. To understand the ecological implications of the interaction, we examined camas plants with and without galls and found that neither the height nor the inflorescence size of camas were correlated with the frequency of galling herbivory. Future studies on the genus Camassia should explore phenology and ecological relationships as they relate to climate change as well as alternative explanations for species boundaries and galling midge plant preference.

Broader Impacts:

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1 - Willamette University, Biology, 900 State Street Box H135, Salem, OR, 97301, USA
2 - Willamette University, 900 State Street, Salem, OR, 97301, United States
3 - WILLAMETTE UNIVERSITY, Department of Biology, SALEM, OR, 97301, USA

gall midge
galling midge
species concept.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:30 PM
Number: PSB001
Abstract ID:281
Candidate for Awards:None

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