Abstract Detail

Macroevolution

Miladin, Jenna [1], Steven, Janet [2], Collar, David [1].

A comparative approach to understanding floral adaptation to climate and pollinators during Silene diversification.

Morphological diversification in plant lineages is often a result of selection imposed by both abiotic and biotic factors, although it is unknown how these factors combine to shape evolution of different plant organs. Habitat shifts can result in changes in pollinator community, which would drive floral trait adaptation, and can alter the climatic niche, which can also contribute to adaptation of plant traits, including floral morphology. We tested associations between environmental niche variables, pollinator presence, and vegetative and floral morphology in the genus Silene using phylogenetic comparative methods. We collected DNA sequence and morphological data for 70 European Silene species; 17 species were collected from the field in Greece, and 53 species from the same taxonomic sections were added with data from Genbank and morphological measurements of herbarium specimens. We estimated phylogeny based on Bayesian analysis and used GBIF occurrence records to determine climatic niche for each species. We found an association between leaf size and climate that suggests adaptation to water stress in Silene species in drier environments. Changes in abiotic environment, however, did not appear to directly influence floral trait evolution. Instead, pollinators are potentially more influential in shaping floral characteristics. Silene with white flowers, which we expect to be visited by nocturnal pollinators, are more likely to occur in areas with relatively limited daily temperature fluctuations (i.e., low isothermality) than diurnally-pollinated pink Silene. Pollinator distribution appears to be similarly influenced by the environment; species in the moth genus Hadena, a known nocturnal Silene pollinator, also tend to occur in areas where isothermality is low. In addition, white-flowered Silene were more likely to have longer internodes and larger flowers. These findings suggest that changing environmental conditions led to a new pollinator community, which then resulted in pollinator-mediated selection on plant height and floral traits.

1 - Christopher Newport University, 1 Avenue Of The Arts, Newport News, VA, 23606, United States
2 - Christopher Newport University, Department Of Organismal And Environmental Biology, 1 Avenue Of The Arts, Newport News, VA, 23606, United States

Keywords:
pollination
floral traits
climate
Silene
macroevolution.

Presentation Type: Oral Paper
Session: MACROII, Macroevolution II
Location: Virtual/Virtual
Date: Thursday, July 22nd, 2021
Time: 1:30 PM(EDT)
Number: MACROII005
Abstract ID:608
Candidate for Awards:None