My work focuses on the colour patterns on the wings of Bicyclus anynana butterflies to address key issues in Evolutionary Developmental Biology.
Butterfly wing patterns are ideally suited to study the reciprocal interactions between evolutionary and developmental processes (evo-devo) that shape morphological variation (Beldade & Brakefield 2002). They are visually compelling products of selection, often with a clear adaptive value, and are also amenable to a detailed developmental characterization at different levels, including genomics (Beldade et al. 2006, Beldade et al. 2009).
I am also interested in the Evolutionary Genetics and Genomics analysis in non-model systems (Beldade et al. 2008). The need to diversify study organisms has been repeatedly acknowledged and the generalization of genomic resources outside classical model systems is making it possible.
Genetic basis of morphological variation
Heritable phenotypic variation is the raw material of evolution by natural selection, and understanding its generation is a crucial issue in contemporary evolutionary biology (Beldade et al. 2005). What are the specific genes and gene regions (e.g. regulatory versus coding sequence) that contribute to evolutionarily relevant variation (Beldade et al. 2002)? Are the same genes that harbour loci of large effect making up for extreme "mutant" phenotypes those that harbour alleles of subtle effect that contribute to standing quantitative variation? Are the same genes that contribute to intra-specific variation those involved in inter-specific differences in phenotype?
In order to address these questions, we have started by identifying genes expressed in developing wings and DNA sequence polymorphisms in those genes (Beldade et al. 2006, Beldade et al. 2009), as well as the genomic sequence aound some of them (Conceição et al. 2011)
Origin of evolutionary novelties
The origin and diversification of evolutionary novelties is one of the key issues in evolutionary developmental biology, and butterfly wings provide exciting examples of such innovations. The colourful scales that cover butterfly wings and the specific pattern elements (such as eyespots) formed by their arranged distribution on the wing surface are adaptive innovations characteristic of lepidopterans. What are the genes and genetic pathways involved in producing these traits (Saenko et al. 2008, Saenko et al. 2010)? How have these pathways been changed in relation to the evolutionary diversification of novelties (Saenko et al. 2011)?
Evolutionary diversification of serial repeats
Much of morphological diversity results from the diversification of serially repeated structures like vertebrate teeth, insect body segments, and colour pattern elements on butterfly wings. What are the ecological, genetic, and developmental factors underlying this diversification (Beldade et al. 2002, Beldade et al. 2002)? How and to what extent have gene effects and different aspects of a trait's development become compartmentalized (Beldade et al. 2008)? How do correlations between serial repeats (Beldade et al. 2003) and the developmental basis of such correlations (Allen et al. 2008) impact possible evolutionary scenarios?
Adaptive developmental plasticity
More than just a filter of phenotypic variation during the trans-generational process of natural selection, the environment also plays a key role in generating variation during organismal development. Ecological developmental biology (eco-devo or eco-evo-devo) has started to bring the focus to how the external environment affects organismal development and how this impacts evolutionary change (Beldade et al. 2011).