title: Life on the edge: rare and restricted episodes of a pan-tropical mutualism adapting to drier climates.
abstract: • The fig tree-fig wasp obligate pollination mutualism has strong ancestral affinities with tropical communities, but is present in much drier contemporary biomes, especially at higher latitudes at the edge of their range. The extent to which adaptation to environmental variables is evolutionarily conserved and whether environmental differences function in ecological speciation of the mutualism are unknown. • Here we use climate models and phylogenetic reconstructions to test whether the Ficus-fig wasp mutualism has adapted and radiated into drier climates and led to ecological speciation in both plant and insect. • The results showed phylogenetic correspondence between closely related Ficus species with either savanna, forest, or riparian habitat categories, were most strongly explained by both climate and environmental variables. Rare episodes of adaptation to dry apotypic conditions have resulted in substantial radiations into savanna. • Inferences were consistent with predictions of niche conservatism and support the postulate that ecological speciation of the mutualism occurs, but under contrasting and intertwined circumstances among plant-pollinator adaptation and tolerance to the environment.
authors: Department of Botany and Zoology, DST-NRF Centre of Excellence for Invasion Biology, University of Stellenbosch, Private Bag X1, Matieland, 7602, South Africa.
authors: Michael
authors: M
authors: McLeish
authors: Climate Change and Bioadaptation Division, South African National Biodiversity Institute, Kirstenbosch Research Center, Private Bag X7 Claremont, 7735, Cape Town, South Africa.
authors: Danni
authors: D
authors: Guo
authors: Natural History Department, Iziko South African Museum, PO Box 61, Cape Town, 8000, South Africa.|Department of Zoology, University of Cape Town, Private Bag, Rondebosch, 7701, South Africa.
authors: Simon
authors: S
authors: van Noort
authors: Climate Change and Bioadaptation Division, South African National Biodiversity Institute, Kirstenbosch Research Center, Private Bag X7 Claremont, 7735, Cape Town, South Africa.
authors: Guy
authors: G
authors: Midgley
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D002980:Climate; D021901:DNA, Intergenic / Q000737:chemistry; D018744:DNA, Plant / Q000737:chemistry; D030681:Ficus / Q000235:genetics / Q000502:physiology*; D049810:Genetic Speciation; D008954:Models, Biological; D010802:Phylogeny; D014329:Tropical Climate; D014863:Wasps / Q000235:genetics / Q000502:physiology*
chemical_list: D021901:DNA, Intergenic; D018744:DNA, Plant