DOI: 10.5061/dryad.w6m905qtq
title: Data from: Beyond pollen:ovule ratios: Evolutionary consequences of pollinator dependence and pollination efficiency for pollen and ovule production in angiosperms

description: Premise: The relative per‐flower production of ovules and pollen varies
 broadly with angiosperm mating systems, with outcrossing types commonly
 producing more pollen grains per ovule than selfing types. The
 evolutionary causes of this variation are contentious, especially the
 relevance of pollination risk. Resolution of this debate may have been
 hampered by its focus on pollen:ovule (P:O) ratios rather than on the
 evolution of pollen and ovule numbers per se. Methods: Using published
 mean ovule and pollen counts, we analyzed associations with the proportion
 of removed pollen that reaches stigmas (pollen‐transfer efficiency) and
 differences between pollinator‐dependent and autogamous forms within and
 among species. Analyses involved Bayesian methods that simultaneously
 considered variation in pollen and ovule numbers and accounted for
 phylogenetic relatedness. We also assessed the utility of P:O ratios as
 mating‐system proxies and their association with female outcrossing rates.
 Results: Median pollen number declined consistently with
 pollen‐transfer efficiency among species, whereas median ovule number did
 not. Similarly, in both intraspecific and interspecific analyses,
 pollinator‐dependent plants produced more pollen than autogamous plants,
 whereas ovule production did not differ statistically. Distributions of
 P:O ratios overlapped extensively for self‐incompatible and
 self‐compatible species and for different mating‐system classes, and P:O
 ratios correlated weakly with outcrossing rate. Conclusions: Our findings
 demonstrate that pollinator dependence and pollination efficiency commonly
 influence the evolution of pollen number per flower but have more limited
 effects on ovule number. P:O ratios provide ambiguous, possibly
 misleading, information about mating systems, especially when compared
 among clades.
description: Data compilation We searched for papers that
 reported pollen and ovule numbers using three complementary approaches: by
 searching the Web of Science (WoS) for papers that included the key words
 “pollen:ovule”, “pollen-ovule” and “pollen/ovule”; by using Erbar and
 Langlotz’s (2005, Botanische Jahrbucher 126: 71-132) compilation of
 published pollen:ovule ratios to identify older papers not abstracted by
 WoS; and by using the WoS citation information to identify papers that had
 cited Cruden's (1977, Evolution 31: 32-46) seminal paper on
 pollen:ovule ratios. We also recorded information concerning species
 characteristics, of which those relevant for this study are pollen-vector
 dependence, life history (annual, biennial, or monocarpic or iteroparous
 perennial), female outcrossing rate and pollen-transfer efficiency. If the
 source reference of the pollen and ovule records did not provide this
 information, we sought it from supplementary sources.
 Phylogeny construction Most analyses
 accounted explicitly for the phylogenetic relatedness of species. As
 described in more detail, phylogenetic trees were constructed using the
 online version of OneTwoTree (http://onetwotree.tau.ac.il/; Drori et al., 2018, Molecular Ecology Resources 18: 1492-1499). To facilitate taxon recognition by OneTwoTree, the list of species for an analysis (including subspecies and varieties) named in the original data sources was submitted to the Global Biodiversity Information Facility (https://www.gbif.org/) to retrieve currently accepted taxonomic names. 
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