12848 – Examination of the factors promoting hybridization between Penstemon davidsonii and P. rupicola

Investigator’s Annual Reports (IAR’s) for Crater Lake National Park

An examination of the factors promoting hybridization between Penstemon davidsonii and P. rupicola (Scrophulariaceae) on Wizard Island


Report Number: 12848

Reporting Year: 1999

Permit Number: CRLA199902-008

Date Received: Jan 01, 2000

Principal Investigator: Shannon Datwyler, Department of EEOB, Ohio State University, Columbus, OH

Park-assigned Study Id. # CRLA199902-008

Permit Expiration Date: Jan 01, 2000

Permit Start Date: Jan 01, 2000

Study Starting Date: Jan 01, 1997

Study Ending Date: Jan 01, 2000

Study Status: Completed

Activity Type: Research

Subject/Discipline: Vascular Plants

Objectives: The research conducted in 1999 is part of a larger study to examine patterns of gene flow between the two species of Penstemon (P. rupicola and P. davidsonii) on Wizard Island. Specifically the objectives for 1999 were to a) examine pollinator preferences for P. davidsonii and P. rupicola, in addition to hybrid zones and b) examine differences in seed set from both inter- and intraspecific crosses in order to better understand the observed pattern of unidirectional gene flow.

Findings and Status: Initial observations demonstrate that several animals visit Penstemon flowers including Hymenopterans (including Megachilidae, Halictidae, and Apidae), Dipterans (Syrphidae), and hummingbirds. Three different families of bees in addition to syrphid flies visit Penstemon davidsonii, whereas P. rupicola is visited by the same combination of bees and flies in addition to hummingbirds. Field observations indicate that the latter groups of potential pollinators visit putative hybrid plants regularly as well (Datwyler, unpubl. data). Visitation behaviors, however, vary among visitors, which likely influences effectiveness of pollination. Seed set data indicate that intraspecific crosses produced more filled fruits than interspecific crosses. For each treatment, 30 replicates were performed, but less than 50% of flowers set fruit. Seeds from each fruit set are being counted and germinated to test for survivorship of seedlings.

For this study, were one or more specimens collected and removed from the park but not destroyed during analyses? No

Funding provided this reporting year by NPS:

Funding provided this reporting year by other sources: 0

Full name of college or university: n/a

Annual funding provided by NPS to university or college this reporting year: 0


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