R_code

Code for running analyse

Data from: The evolution of floral signals in relation to range overlap in a clade of California Jewelflowers (Streptanthus s.l.)

Because of their function as reproductive signals in plants, floral traits experience distinct selective pressures related to their role in speciation, reinforcement, and prolonged coexistence with close relatives. However, few studies have investigated whether population-level processes translate into detectable signatures at the macroevolutionary scale. Here, we ask whether patterns of floral trait evolution and range overlap across a clade of California Jewelflowers reflect processes hypothesized to shape floral signal differentiation at the population level. We found a pattern of divergence in floral scent composition across the clade such that close relatives had highly disparate floral scents given their age. Accounting for range overlap with close relatives explained additional variation in floral scent over time, with sympatric species pairs having diverged more than allopatric species pairs given their age. However, three other floral traits (flower size, scent complexity, and flower color) did not fit these patterns, failing to deviate from a null Brownian Motion model of evolution. Together, our results suggest that selection for divergence among close relatives in the composition of floral scents may play a key, sustained role in mediating speciation and coexistence dynamics across this group, and that signatures of these dynamics may persist at the macroevolutionary scale

Leaf morphospace in Euphorbia tithymaloides (Euphorbiaceae) was likely shaped by evolutionary contingencies rather than climate

Background and aims – Understanding whether variation in plant attributes is primarily driven by selection or historical contingencies is a main goal in evolutionary biology. We characterize leaf diversity in Euphorbia tithymaloides and identify patterns related to taxonomy, geography, biogeography, and climate that provide insights on the role of ecological and evolutionary forces in shaping its leaf diversity. Material and methods – We constructed a leaf morphospace using linear morphometric measurements derived from images (leaf maximum length and width, area, and perimeter), and calculated indexes that reflect aspects of leaf shape (leaf aspect ratio, area-perimeter ratio, obovate index, and circularity). Climatic data were extracted from WorldClim layers based on occurrence data. We visualized leaf and climate spaces with principal components analyses and used Kruskal-Wallis tests, linear models, and Mantel tests to test predictors of leaf variation (taxonomy, geography, climate). Key results – We document differences in the foliar morphospace occupied by subspecies of Euphorbia tithymaloides, and a substantial overlap in the climatic space they occupy, suggesting that foliar differences among subspecies are not likely driven by climate. Foliar morphology can be used as a proxy for subspecies in E. tithymaloides, as taxonomy explains a large proportion of variation in leaf morphology (10–60%). Geography and climate explain a small proportion of foliar variation not explained by subspecies (~3% and 5%, respectively). Temperature, precipitation, and seasonality are the climate variables with most explicative power. Conclusion – Leaf diversity in E. tithymaloides is not driven by climate, instead, it is likely the result of evolutionary contingencies faced by this species throughout its historical range expansion across the Caribbean Basin. This study shows that historical contingencies in addition to selection acting on ecological processes can shape foliar diversity and expand a lineage’s potential to explore morphological and climatic spaces

Data

Dat

consensus_tree

Trimmed majority-rule consensus tree that was constructed using the full post-burnin distribution from Cacho et al., 2014 and consensus branch lengths calculated using the least squares method via the ‘consensus.edges’ function in the package “phytools.

Climatic amplitude is a predictor of geographic range size in Mexican morning glories (<em>Ipomoea</em> L., Convolvulaceae)

Background: Elucidating the determinants of species’ geographic distributions is a fundamental goal of ecology and biogeography, as they can inform about key biological processes, with implications for conservation. Goal: Evaluate whether realized climatic amplitude (a proxy for niche breadth) is an ecological correlate of geographic range size in morning glories in Mexico, a highly diverse group of plants of worldwide socio-economic relevance, but still poorly studied. Methods: Based on a dataset of > 30,000 records of which > 7,000 were manually georeferenced, we calculated geographic range size (using convex hull polygons and buffered occurrence points), and climatic amplitude (using three first axes of Principal Components based on 19 Worldclim variables, and focusing on temperature, precipitation, and seasonality), and explored their relationship using general linear models and phylogenetic generalized least squares. Results: All models show that climatic amplitude explains a high proportion of variation in geographic range size for our dataset (up to > 69 %). We find no evidence of tradeoffs related to temperature and precipitation niche breadths. Through review of reported records, we update the number of species of Ipomoea reported for Mexico to 178. Conclusions: Much of the variation in geographic range size in Mexican Ipomoea can be explained by realized climatic amplitude, and this result is not driven by phylogenetic history. We discuss cases where despite large geographic range sizes, narrow climatic amplitudes can signify higher risks for species in the face of changing environments

1000_trees

1,000 trimmed trees randomly drawn from the posterior distribution of Cacho et al., 2014

Plant size, latitude, and phylogeny explain within-population variability in herbivory

Interactions between plants and herbivores are central in most ecosystems, but their strength is highly variable. The amount of variability within a system is thought to influence most aspects of plant-herbivore biology, from ecological stability to plant defense evolution. Our understanding of what influences variability, however, is limited by sparse data. We collected standardized surveys of herbivory for 503 plant species at 790 sites across 116° of latitude. With these data, we show that within-population variability in herbivory increases with latitude, decreases with plant size, and is phylogenetically structured. Differences in the magnitude of variability are thus central to how plant-herbivore biology varies across macroscale gradients. We argue that increased focus on interaction variability will advance understanding of patterns of life on Earth