Abstract Detail


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

Floral adaptation to climate and pollinators during Silene diversification across two continents.

Both biotic and abiotic selective factors are known to influence morphological diversification in plants. Pollinator-mediated selection is a well-known driver of floral trait evolution, but less is known about the influence of climate on this species interaction. Shifting climate conditions have the potential to both impose constraints on floral morphology directly and influence the pollinator community, which can drive selection on floral traits and result in the indirect influence of climate on floral morphology. We used phylogenetic comparative methods to test for associations among climate variables, pollinators, and morphology in Silene from 50 species in North America and 89 species in Europe and the Mediterranean. We conducted analyses separately for the two continents to explore similarities in morphological diversification. We found that leaves are smaller in hotter and drier climates on both continents. Similarly, climate influenced floral morphology, and smaller flowers were found in warmer and drier habitats in Europe and the Mediterranean, following the same pattern as the leaves. However, in North America flowers with smaller calyces were more likely to occur in habitats with a greater average daily temperature range. We also found evidence for pollinator-mediated selection on flower shape in Europe and the Mediterranean, where nocturnally-pollinated flowers tend to have elongated calyces. Climate may also be influencing floral trait evolution indirectly due to its effect on pollinator distribution. Ecological Niche Models for families of nocturnal and diurnal pollinators of Silene showed similar constraints on pollinator distributions between continents, and climate variables differed between modes of pollination on both continents. While climate can directly influence both vegetative and floral morphology, we found that it can also indirectly influence floral morphology by affecting the insect communities available to function as pollinators. Our findings point toward the generality of climate as a complex factor in the evolution of floral morphology. Climate mediates the influence of species interactions on trait evolution by imposing selective demands on floral traits directly as well as indirectly determining the participants in pollinator-mediated selection.

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

 ecological niche modelling
Phylogenetic comparative methods.

Presentation Type: Oral Paper
Number: MACRO II010
Abstract ID:895
Candidate for Awards:None

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