Echoes of ancient introgression punctuate stable genomic lineages in the evolution of figs.

Studies investigating the evolution of flowering plants have long focused on isolating mechanisms such as pollinator specificity. Some recent studies have proposed a role for introgressive hybridization between species, recognizing that isolating processes such as pollinator specialization may not be complete barriers to hybridization. Occasional hybridization may therefore lead to distinct yet reproductively connected lineages. We investigate the balance between introgression and reproductive isolation in a diverse clade using a densely sampled phylogenomic study of fig trees (Ficus, Moraceae). Codiversification with specialized pollinating wasps (Agaonidae) is recognized as a major engine of fig diversity, leading to about 850 species. Nevertheless, some studies have focused on the importance of hybridization in Ficus, highlighting the consequences of pollinator sharing. Here, we employ dense taxon sampling (520 species) throughout Moraceae and 1,751 loci to investigate phylogenetic relationships and the prevalence of introgression among species throughout the history of Ficus. We present a well-resolved phylogenomic backbone for Ficus, providing a solid foundation for an updated classification. Our results paint a picture of phylogenetically stable evolution within lineages punctuated by occasional local introgression events likely mediated by local pollinator sharing, illustrated by clear cases of cytoplasmic introgression that have been nearly drowned out of the nuclear genome through subsequent lineage fidelity. The phylogenetic history of figs thus highlights that while hybridization is an important process in plant evolution, the mere ability of species to hybridize locally does not necessarily translate into ongoing introgression between distant lineages, particularly in the presence of obligate plant-pollinator relationships.

Engagement with indigenous people preserves local knowledge and biodiversity alike.

Indigenous peoples are important stewards of biodiversity, often living near and possessing intimate knowledge of ecosystems. As a result, species new to science may be long known to indigenous people. While the scientific endeavor has long benefitted from indigenous knowledge, it has usually not engaged with it on equal footing1,2. While Linnaean taxonomy offers a broad framework for global comparisons, it may lack the detailed local insights possessed by indigenous peoples. This study illustrates how meaningful engagement with indigenous knowledge - throughout the scientific process - can improve biodiversity science and promote conservation1,2, particularly in studies of crop wild relatives, an international priority3 for food security in the face of climate change4. Two species of fruit trees recognized as distinct by the Iban and Dusun peoples, but considered a single species in current Linnaean taxonomy, were confirmed as distinct taxa by molecular studies. They correspond to Artocarpus odoratissimus Blanco and Artocarpus mutabilis Becc., whose distinguishing characteristics were clarified by members of indigenous communities.