Abstracts (first author)

Talk 

Phylogenetic patterns of diversification and community structure reveal the role of ecological factors in generating and shaping Neotropical mimetic butterfly diversity

Author(s): Chazot N, Willmott KR, Jiggins CD, Freitas AVL, Elias M

Summary:

The Neotropic is the most diverse region in the world. Identifying the causes underlying the observed diversity and spatial structure and unraveling how different factors interact remain outstanding questions. Addressing these questions in the Neotropics provides a unique opportunity to understand the processes that shape the structure of ecosystems. Recent advances in molecular phylogenetics, such as novel tests for diversification scenarios or community ecology phylogenetics, provide new insights into biodiversity questions. The Ithomiini tribe is a species-rich group of Neotropical butterflies, which consists of ca. 380 species widely distributed from the lowlands to 3000 m in the Andes. All species are involved in Müllerian mimicry, whereby different species protected by chemical defenses converge to share the same warning color patterns (mutualistic interactions). Here we combine phylogenetic, trait and species assemblage (community) data to investigate the effects of color patterns and adaptation to altitude in generating and shaping the diversity of Ithomiini.Comprehensive phylogenetic and trait analyses of several genera show that shifts in altitude and color patterns are both involved in diversification. In parallel, phylogenetic analyses of 15 communities along an altitudinal gradient show that both adaptation to altitude and mimetic interactions act as ecological filters and contribute in shaping species assemblages. Moreover, we find that both factors are not independent, and species that share color patterns also share altitudinal niche more often than predicted by phylogeny alone. The two approaches undertaken here are complementary and provide support for a similar scenario, whereby ecological factors, especially positive interactions, have been instrumental in generating and shaping biodiversity. Taking other types of positive interactions into consideration may shed light on why some groups have diversified dramatically, and why others have not.


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Abstracts (coauthor)

Summary:

Mimicry as a defensive strategy is one of the most compelling example of adaptation. Mimicry communities often involve numerous species, and both mutualistic (Müllerian) and deceptive (Batesian) mimics coexist. In deceptive mimicry, palatable prey mimic unprofitable species (e.g. chemically defended prey which predators avoid) with a negative impact on avoidance learning by predators. In mutualistic mimicry, appearances of defended prey converge on a similar warning signal, thereby reinforcing it and decreasing the per-capita cost of training predators. Theoretical and experimental studies on mimicry phenotypes abound, but studies empirically testing their predictions in real mimicry communities remain scarce. Indeed, the quantitative distribution of phenotypes within and among mimicry complexes is largely unknown, and how phenotypic variations are influenced by the type of mimicry, selection intensity, and/or phylogeny remains unaddressed. We first developed a novel framework that enables for the automatic and precise quantification and comparison of colour pattern. We then used this tool on over 2000 specimens, consisting of 130 butterfly species, collected from distinct Neotropical butterfly communities in the Peruvian Amazon. We quantified the distribution of phenotypes and their structure into a number of separate mimicry optima, using a morphological space encompassing the variation and frequencies of all coexisting colours patterns. We analysed this structure to extract the ecological and phylogenetic patterns underlying the coexistence of multiple mimicry groups within a given locality. We then demonstrated the influence of deceptive vs. mutualistic mimics on phenotypic variability around a mimicry optimum in order to address the effective impact of deception on mimicry.

Contacts

Chairman: Octávio S. Paulo
Tel: 00 351 217500614 direct
Tel: 00 351 217500000 ext22359
Fax: 00 351 217500028
email: mail@eseb2013.com

Address

XIV Congress of the European Society for Evolutionary Biology

Organization Team
Department of Animal Biology (DBA)
Faculty of Sciences of the University of Lisbon
P-1749-016 Lisbon
Portugal

Website

Computational Biology & Population Genomics Group 
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