Report Number: 12835
Reporting
Year: 1998
Permit Number: CRLA199802-002
Date Received: Jan 01, 1999
Principal Investigator:
Shannon Datwyler,
Department of Evolution, Ecology and
Organismic Biology,
Ohio State University,
Columbus, OH
Park-assigned Study Id. #:
CRLA199802-002
Permit Expiration
Date:
Jan 01, 2000
Permit Start Date:
Jan 01, 1998
Study Starting
Date:
Jan 01, 1997
Study Ending Date:
Jan 01, 1999
Study
Status:
Completed
Activity Type:
Research
Subject/Discipline:
Plant Communities (Vegetation)
Objectives:
To investigate the patterns and frequency of
natural hybridization between Penstemon
rupicola and Penstemon davidsonii var.
davidsonii on Wizard Island, Crater Lake
National Park, with special focus on the
potential for hybrid speciation in an
isolated habitat.
Findings and Status:
Currently, I am investigating the gene flow
patterns observed in three different hybrid
swarms on Wizard Island based on both
morphological and molecular data.
Preliminary results indicate a
unidirectional pattern of gene flow from P.
rupicola into P. davidsonii based on
sampling from the 1997 field collections. In
the 1998 field season I increased sampling
of hybrid swarms to add two new populations
(total of three populations for both 1997
and 1998 field seasons).
Leaf tissue was
collected from a total of 68 hybrid plants
representing two hybrid swarms on the island
in addition to 12 individuals of P. rupicola
and 24 individuals of P. davidsonii. In
addition to sampling on the island, five
populations (12 individuals per population,
60 total individuals) were sampled at
various points around the western portion of
the rim of the lake in order to examine
population structure of these populations
and to subsample the genetic variation
existing around the rim. For each population
sampled, voucher specimens were collected
that will be deposited at Ohio State
University. ;Pollinator observations were
also made and several insect pollinators
were collected for identification.
Two Bombus species were collected after being
observed visiting Penstemon flowers and
three leafcutter bees (Megachilidae) were
also collected. In addition to these
pollinators, hummingbirds and syrphid flies
were observed to visit Penstemon flowers but
were not collected. ;In addition to
investigations of gene flow patterns in
hybrid swarms, I have initiated a study to
develop molecular markers that can be used
to study gene flow distances within
populations using microsatellite markers in
paternity analysis of seeds. Seed capsules
were collected from 60 individual plants
representing two hybrid swarms (20 capsules
from one population, 40 from the other).
Currently, these seeds are being germinated
and will be used for DNA extractions
following germination. The pollen donor for
each seed will then be determined by
paternity analysis to calculate gene flow
distances within and between populations.
Preliminary pollinator observations suggest
that bumblebees may facilitate pollen flow
over long distances because of long flights
between flower visits, whereas hummingbirds
were observed to travel very short distances
between floral visits, such as visiting the
nearest neighbor plant.
These observations
suggest that pollen flow would be limited in
populations that are visited largely by
hummingbirds and may be greater in
populations visited largely by bumblebees.
These predictions can be tested with the
paternity study. ;The final year of
investigation (1999) will be focused on
augmenting the pollinator observations
collected in 1998 as well as elucidating the
underlying factors related to the pattern of
unidirectional gene flow that I have
observed, including experiments testing
pollen tube growth rates in interspecific
crosses.
For
this study, were one or more specimens collected and
removed from the park but not destroyed during
analyses?
Yes
Funding provided
this reporting year by NPS:
0
Funding provided
this reporting year by other sources:
1500
Full name of
college or university: n/a
Annual funding
provided by NPS to university or college this
reporting year:
0
