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

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.

To pupate or not to pupate: a case study of an obligate pollination mutualism in Glochidion ferdinandi (Phyllanthaceae) and Epicephala colymbetella (Gracillariidae)

Obligate pollination mutualisms have recently been recorded in the Glochidion genus with Epicephala moth associates (leaf-flower and leaf-flower moths). There is limited literature on Australian Glochidion species and their pollinators. Glochidion ferdinandi occurs predominantly across the east coast of Queensland, Australia and has an obligate pollination association with Epicephala colymbetella. Early descriptions of G. ferdinandi describe the encapsulation of the adult moth within the fruit. In the present study, observations and fruit dissections were recorded to analyse the role of symbionts within this mutualism, pollinator life history and the flowering phenology of the host. Our study confirmed this rare behaviour in which E. colymbetella pupated within G. ferdinandi fruit in which adult moths were retained until fruit dehiscence. Fruit dissections identified two other species alongside E. colymbetella, a seed consuming Spilomelinae moth and parasitoid Bracon wasp. Although both moth species were found to reduce the number of surviving ovules in the fruit, E. colymbetella also provided a pollination benefit to G. ferdinandi. Furthermore, the life histories of E. colymbetella and phenology of G. ferdinandi were observed to be highly synchronous, with larvae developing concurrently with ovules after flower fertilisation. Retention of the adult moth in fruit has only previously been recorded in one other Epicephala (lanceolaria).