Evolution and classification of figs (Ficus, Moraceae) and their close relatives (Castilleae) united by involucral bracts

Abstract

Figs and fig wasps are a classic example of an obligate pollination mutualism. Decades of work untangling the ecology and evolution of these organisms has simultaneously contributed to development of the fields of mutualism, coevolution and plant–insect interactions at large. With > 800 species, figs (Ficus, Moraceae) are among some of the larger genera of angiosperms. Phylogenetic studies of Moraceae have supported the clade Castilleae as the sister lineage of Ficus. Compared to Ficus, Castilleae have many fewer species (60 species in 11 genera), suggesting changes in rates of diversification along these two branches. Relatively little is known about Castilleae compared to Ficus, and we argue that defining the clade comprising Ficus and Castilleae, hereafter Involucrata, focuses attention on opportunities for comparative studies of pollination mutualisms and diversification rates. In this study, we define Involucrata and propose a revised classification scheme that accounts for the phylogenetic reconstruction based on the most comprehensive sampling of this group to date. Moving forward, this classification will better guide and support evolutionary, ecological and comparative pollination biology studies of this group.

Exploring systematic biases, rooting methods and morphological evidence to unravel the evolutionary history of the genus Ficus (Moraceae)

“…Urostigma [i.e. the Mixtiflores group sensu Clement et al (2020)] and ii) all other species of Ficus (eigenvalues = 9.50% for PC1 and 8.57% for PC2, Figure S4Ab). Within the remaining species of Ficus, PC1 discriminated between i) sect.…”

“…Stilnophyllum sensu Berg & Corner (2005) is included in Conosycea as recovered in previous molecular studies. Nota: Subgenus Urostigma excluding section Urostigma is referred to as Mixtiflores by Clement et al (2020).…”

“…Several studies have attempted to reconstruct the phylogeny of Ficus using Sanger sequencing of chloroplast markers (Herre et al 1996), external and/or internal transcribed spacers (ETS, ITS) (Weiblen 2000, Jousselin et al 2003, a combination of nuclear markers (Rønsted et al 2005, Rønsted et al 2008, Xu et al 2011, Cruaud et al 2012, Pederneiras et al 2018, Zhang et al 2018, Clement et al 2020 or next-generation sequencing of chloroplast genomes (Bruun-Lund et al 2017). None of these studies successfully resolved the backbone of the phylogeny and there is no consensus on the relationships between major groups of Ficus yet.…”

“…subgenus Urostigma excluding sect. Urostigma, sensu Clement et al (2020)), and (iii) a monophyletic clade formed by subg. Synoecia, sect.…”

The synstigma turns the fig into a large flower

“…Ficus is taxonomically and ecologically diverse (Bruun-Lund et al, 2018;Clement et al, 2020), encompassing c. 750 of the 1100 species described for the family (Berg, 2005). This high level of diversity seems to result from the obligatory mutualistic interaction established with small Agaonidae wasps ( Kjellberg et al, 2005).…”