Abstract
Species interactions are known to be key in driving patterns of biodiversity across the globe. Plant-plant interactions through heterospecific pollen (HP) transfer by their shared pollinators is common and has consequences for plant reproductive success and floral evolution, and thus has the potential to influence global patterns of biodiversity and plant community assembly. The literature on HP transfer is growing and it is therefore timely to review patterns and causes of among-species variation in HP receipt at a global scale, thus uncovering its potential contribution to global patterns of biodiversity. Here we analyzed published data on 245 species distributed across five continents to evaluate latitudinal and altitudinal patterns of HP receipt. We further analyzed the role of floral symmetry and evolutionary history in mediating patterns of HP receipt. Latitude and elevation affected the likelihood and intensity of HP receipt indicating that HP transfer increases in species-rich communities and in areas with high abundance of vertebrate pollinators. Floral symmetry and evolutionary history determined HP load size across plant communities worldwide. Overall, our results suggest that HP receipt may have the potential to contribute to global geographic patterns of plant diversity by imposing strong selective pressures in species-rich areas across the globe.
Highlights
Understanding the factors that generate and organize plant diversity in nature has been a long-standing goal in ecology
Our results showed that heterospecific pollen (HP) load size (≥1 HP grain received) is significantly larger in radial (14.64 ± 3.6) compared to bilateral (11.6 ± 2.8) flowers (t211 = 3.06, P < 0.01), this effect varied with elevation
Our study revealed a high incidence of HP receipt at a global scale
Summary
Understanding the factors that generate and organize plant diversity in nature has been a long-standing goal in ecology. It is plausible that plant species growing in communities near the equator and at low elevations, where plant diversity tends to be the highest, will be at greater risk of receiving HP Evidence of such geographic pattern in HP receipt could suggest a potential role of HP in contributing to global patterns of floral diversification and plant diversity distribution. Plants with radial flowers are expected to be visited by a higher number of pollinator species and to receive larger and more diverse HP loads compared to those with bilateral flowers[21,24] This prediction has been tested within single communities with inconclusive results[20,21], and whether floral symmetry (pollinator generalization) is a mediator of HP transfer dynamics acting across large geographical scales is not yet tested. We ask the following questions: 1) Does the likelihood and intensity of HP receipt increase with decreasing latitude and/ or elevation? 2) Is the likelihood and intensity of HP receipt greater in flowers with radial (generalized) versus bilateral (specialized) symmetry? 3) Does the effect of floral specialization in mediating patterns of HP receipt depend on a plant species’ geographic location (latitude or elevation)? And 4) is there a phylogenetic signal on the likelihood and/or intensity of HP receipt?
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
