Abstract Detail

Ecology

Rodriguez, Rosa [1], Wolfe, Andi [2].

Morphological divergence in Penstemon and the role pollinator-mediated natural selection.

Penstemon is primarily insect-pollinated, and that syndrome is thought to be ancestral. Most pollinator studies have focused on the differences in flower morphology between species pollinated by birds and those pollinated by insects. Very few studies have characterized morphological variations within a species, and those that have, are restricted to only a few sites. Consequently, although there are many studies on the pollination of Penstemon, little is known about floral trait evolution across large distribution ranges both within species and between species that show the same pollination syndrome. The main goal of this study is to determine whether flower morphology changes across a wide distribution range because of pollinator-mediated natural selection in four species of Penstemon (P. albidus, P. glandulosus, P. fruticosus, and P. speciosus). We sampled in 42 sites and in each we measured 22 morphological trails indicative of pollinator syndrome, recorded coordinates from each individual and survey pollinators in each site. Additionally, 19 bioclimatic variables were extracted from worldclim.org/bioclim. We also collected leaves' tissue for future DNA studies. To address our questions we used geometric morphometric, multiple matrix regression and generalized least squares. Penstemon albidus sample sites from New Mexico have significantly smaller corolla than the rest of the site study y for that species. Corolla length was significantly negatively correlated with annual precipitation, the percentage of small pollen-collecting bees and the longitude, and positively correlated with the latitude. Corolla length was positively correlated with longitude in P. fruticosus. Morphological variables were not significantly correlated with environmental variables. Nevertheless, larger and wider corolla was associated with a high percentage of medium size nectar-collecting bees. Penstemon glandulosus varieties are morphologically distinct and our results suggest that the separation of these two varieties is mostly due to environmental difference than pollinator difference. Bees from the genus Bombus and Hoplitis were observed sonicating P. speciosus flowers. Larger and narrower corollas are pollinated by Pseudomasaris wasps, and sites were anther sonication was observed corollas were wider than. In conclusion, flower variation in P. albidus and P. speciosus were more correlated functional groups of pollinators than with bioclimatic or geographic variables. In contrast, flower differentiation between sites in P. glandulosus and P. fruticosus is more correlated with geographic distribution and environmental differences.

1 - The Ohio State University, Evolution, Ecology And Organismal Biology, 318 W 12th Ave, Building 131, Columbus, OH, 43210, United States
2 - Ohio State University, Department Of Evolution, Ecology And Organismal Biology, 318 W. 12th Avenue, Columbus, OH, 43210, United States

Keywords:
Penstemon
geometric morphometrics
pollination
pollinator functional groups.

Presentation Type: Oral Paper
Session: 14, Ecology Section - Reproductive Biology
Location: 106/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 5:15 PM
Number: 14015
Abstract ID:875
Candidate for Awards:None