title: Divergence in an obligate mutualism is not explained by divergent climatic factors.
abstract: Adaptation to divergent environments creates and maintains biological diversity, but we know little about the importance of different agents of ecological divergence. Coevolution in obligate mutualisms has been hypothesized to drive divergence, but this contention has rarely been tested against alternative ecological explanations. Here, we use a well-established example of coevolution in an obligate pollination mutualism, Yucca brevifolia and its two pollinating yucca moths, to test the hypothesis that divergence in this system is the result of mutualists adapting to different abiotic environments as opposed to coevolution between mutualists. We used a combination of principal component analyses and ecological niche modeling to determine whether varieties of Y. brevifolia associated with different pollinators specialize on different environments. Yucca brevifolia occupies a diverse range of climates. When the two varieties can disperse to similar environments, they occupy similar habitats. This suggests that the two varieties have not specialized on distinct habitats. In turn, this suggests that nonclimatic factors, such as the biotic interaction between Y. brevifolia and its pollinators, are responsible for evolutionary divergence in this system.
authors: Department of Biology, University of Idaho, Moscow, ID 83844, USA.
authors: William
authors: W
authors: Godsoe
authors: Rangeland Ecology and Management, University of Idaho, Moscow, ID 83844, USA.
authors: Eva
authors: E
authors: Strand
authors: Willamette University, Salem, OR 97301, USA.
authors: Christopher Irwin
authors: CI
authors: Smith
authors: Department of Biology, University of Idaho, Moscow, ID 83844, USA.
authors: Jeremy B
authors: JB
authors: Yoder
authors: US Geological Survey, Western Ecological Research Centre, 160 N. Stephanie St, Henderson, NV 89074, USA.
authors: Todd C
authors: TC
authors: Esque
authors: Department of Biology, University of Idaho, Moscow, ID 83844, USA.
authors: Olle
authors: O
authors: Pellmyr
mesh_terms: D000818:Animals; D044822:Biodiversity; D002980:Climate; D005843:Geography; D008954:Models, Biological; D009036:Moths / Q000502:physiology; D012372:ROC Curve; D013559:Symbiosis / Q000502:physiology*; D027623:Yucca / Q000502:physiology