UNDERSTANDING AND PREDICTING SPECIES ADAPTATION TO ENVIRONMENTAL CHANGES IN INSECTS – SPHINX

Global changes are affecting biodiversity on unprecedented rate and scale with some forecasts suggesting that half of all species could go extinct by 2050. Yet it remains unclear if we can reliably predict the impact of global changes on biodiversity because we lack sufficient understanding of the potential of species to adapt to new environmental conditions. Our objective is to provide the theoretical and empirical foundation to derive species adaptive potential from macroevolutionary patterns.

Recent studies using vertebrates and plants as model organisms have revealed that this potential is constrained by their evolutionary history. However, the bulk of Earth’s diversity is invertebrates, among which insects are the most diversified terrestrial organisms; they encompass a considerable variety of forms and life histories and they account for many ecosystem services and disservices. Yet, their evolution – occurring under different constraints than plants or vertebrates – is at best only partly understood. In particular, the spatial and temporal understanding of the diversification in diverse and globally distributed insect groups is conspicuously absent.

We have identified a group of phytophagous insects – Saturniidae and Sphingidae, two sister families of moths – that represent an unparalleled insect model for the study of diversification and for the prediction of adaptive potential. This group is unique among insects in being thoroughly documented worldwide and offers an unprecedented opportunity to consider diversity and distribution patterns, as well as macroevolutionary processes, on global scale for all species. Our project proposes: (1) to build a comprehensive species-level phylogeny for the ~4500 species of moths and to conduct the first diversification analysis at global scale in insects accounting for the role of biotic (e.g. dispersal capacity, hostplant range) and abiotic factors (e.g. climate and geological changes); (2) to analyse the evolutionary dynamics of ecological niches and extend existing macroevolutionary models combining phylogenetic, biogeographical, ecological and paleogeological/climatic information; and (3) to test experimentally the ability of these models to predict species responses to environmental changes by analysing in the field species communities of these moths in pristine and human-impacted habitats on three different continents.

Our project is designed to bring both empirical and theoretical foundations to the study of species adaptive potential, and it will not only address this topic for the first time on a global scale in a group of invertebrates, but it will also establish, in a more general way and through experimental tests, if and how the evolutionary history of species can be used to forecast species’ responses to contemporaneous environmental changes. This understanding of species fates in the face of global changes is of primary importance at a time when biodiversity loss is recognized as a major societal concern jeopardizing the sustainability of Earth’s eco- and agro-systems in the short term. This study will then contribute to a more rationale formulation of conservation strategies and management in the context of environmental changes.