Morphology and behaviour: functional links in development and evolution

Abstract

Development and evolution of animal behaviour and morphology are frequently addressed independently, as reflected in the dichotomy of disciplines dedicated to their study distinguishing object of study (morphology versus behaviour) and perspective (ultimate versus proximate). Although traits are known to develop and evolve semi-independently, they are matched together in development and evolution to produce a unique functional phenotype. Here I highlight similarities shared by both traits, such as the decisive role played by the environment for their ontogeny. Considering the widespread developmental and functional entanglement between both traits, many cases of adaptive evolution are better understood when proximate and ultimate explanations are integrated. A field integrating these perspectives is evolutionary developmental biology (evo-devo), which studies the developmental basis of phenotypic diversity. Ultimate aspects in evo-devo studieswhich have mostly focused on morphological traits-could become more apparent when behaviour, 'the integrator of form and function', is integrated into the same framework of analysis. Integrating a trait such as behaviour at a different level in the biological hierarchy will help to better understand not only how behavioural diversity is produced, but also how levels are connected to produce functional phenotypes and how these evolve. A possible framework to accommodate and compare form and function at different levels of the biological hierarchy is outlined. At the end, some methodological issues are discussed.

Neuroanatomical and Morphological Trait Clusters in the Ant Genus <b><i>Pheidole:</i></b> Evidence for Modularity and Integration in Brain Structure

“…Identifying evolutionary and ecological patterns of morphological and behavioral variation is critical to understanding the nature of diversification [Bertossa, 2011;Parsons et al, 2012;Weber et al, 2013]. Morphological, behavioral, and neuroanatomical differentiation are predicted to be coupled, with brain organization enabling adaptive responses to ecological challenges [Dukas, 1998;Farris and Roberts, 2005;Striedter, 2005;Tsuboi et al, 2014].…”

Homology across inheritance systems

“…Behaviour, which is often evolutionarily conserved, is also a proper subject of homology relations and can be used in phylogenetic reconstruction (Rendall and Di Fiore 2007;Bertossa 2011;Hall 2013). Although behavior is developmentally labile, dependent on environmental input, and realized via disparate ontogenetic pathways, the same holds true of morphology, and thus these properties do not preclude its 'homologization'.…”

“…Similarly, control could be handed over from genetic programs to epigenetic or cultural determinants, or vice versa. Unfortunately for this neat account, the picture of genes as the locus of special causal agency in development is mistaken (Oyama 2000;Griffiths 2001;Robert 2004;Pigliucci 2010;Bertossa 2011). Genes are one amongst many causal factors that make a contingent difference to organismic development (Oyama 2000).…”

Grand challenges in evolutionary developmental biology

“…To be sure, precise predictions about the future of evo-devo are impossible (Hall, 2012), but the possibility, and in consequence the responsibility, is to an extent in our hands to steer the boat toward intellectually rewarding paths. We are already witnessing our discipline expanding its scope by exploring its boundaries toward other disciplines, ecology in particular (eco-evodevo, e.g., Hall, 2003;Gilbert and Epel, 2008; also evo-devo vs. niche construction, e.g., Laland et al, 2008), but also ethology (e.g., Bertossa, 2011) and the sciences of language (e.g., Hoang et al, 2011;Hall, 2013). Future advances in all these directions are welcome, but I expect that much more progress will come from the impact that evo-devo will eventually have on the foundations and the research agendas of its parent disciplines.…”