Abstract Detail

Macroevolution

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

The relative importance of pollination and climate on floral morphology in the genus Silene.

This study aims to explore the relationships between habitat, plant morphology, and flower color in the genus Silene in an effort to better understand the diversification of pollinator syndromes. Colonization of new habitats during lineage evolution could result in a shift in pollinator community, which then could result in adaptive changes in floral morphology. While pollinators are expected to exert selection pressure on flower morphology directly, habitat shifts in a lineage may also result in floral adaptation to climate, which then affects pollinator attraction. To determine the relative importance of climate on floral traits, we used phylogenetic comparative methods to test associations between environmental niche variables and vegetative and floral morphology. Seventeen species of Mediterranean Silene were collected in the field in Greece, and were used to obtain DNA sequences and morphological data, including calyx, leaf, and internode size. Additionally, we included data from Genbank for another 53 species classified in the same sections and estimated a phylogeny based on Bayesian analysis for these species. We also collected morphological measurements from herbarium specimens for species not collected in the field. Species flower color was categorized as white or pink, with the expectation that white flowers are more likely to be visited by nocturnal pollinators. We used GBIF records and Bioclim layers to determine the averages of Bioclim variables across all coastal Mediterranean and European occurrences in each species. Species with white flowers tend to have longer internodes and larger flowers, suggesting that plant morphology is influenced by pollinators. In addition, a narrower temperature range during the day is associated with white flowers, suggesting daily changes in temperature may influence the prevalence of nocturnal pollinators. While floral morphology showed no relationship with climate variables, we did find evidence that leaf morphology responds to climate; smaller leaves are associated with habitats that have greater mean temperatures in the driest quarter and less precipitation in the warmest quarter. Given these findings, it seems likely that habitat shifts resulted in new pollinator communities, which then led to pollinator-mediated selection on floral traits. Therefore, while abiotic habitat is associated with leaf morphology, it would appear that pollinators are more influential in floral characteristics.

1 - Christopher Newport University, Organismal and Environmental Biology, 1 Avenue Of The Arts, Newport News, VA, 23606, USA

Keywords:
macroevolution
morphology
pollinators
climate.

Presentation Type: Poster
Session: P, Macroevolution Posters
Location: Virtual/Virtual
Date: Wednesday, July 29th, 2020
Time: 5:00 PM Time and date to be determined
Number: PMC004
Abstract ID:756
Candidate for Awards:None