A staging scheme for the development of the scuttle fly Megaselia abdita

This is the final version of the article. Available from the publisher via the DOI in this record.Model organisms, such as Drosophila melanogaster, provide powerful experimental tools for the study of development. However, approaches using model systems need to be complemented by comparative studies for us to gain a deeper understanding of the functional properties and evolution of developmental processes. New model organisms need to be established to enable such comparative work. The establishment of new model system requires a detailed description of its life cycle and development. The resulting staging scheme is essential for providing morphological context for molecular studies, and allows us to homologise developmental processes between species. In this paper, we provide a staging scheme and morphological characterisation of the life cycle for an emerging non-drosophilid dipteran model system: the scuttle fly Megaselia abdita. We pay particular attention to early embryogenesis (cleavage and blastoderm stages up to gastrulation), the formation and retraction of extraembryonic tissues, and the determination and formation of germ (pole) cells. Despite the large evolutionary distance between the two species (approximately 150 million years), we find that M. abdita development is remarkably similar to D. melanogaster in terms of developmental landmarks and their relative timing.Funding: The laboratory of Johannes Jaeger and this study in particular was funded by the MEC-EMBL agreement for the EMBL/CRG Research Unit in Systems Biology, by SGR grant 406 from the Catalan funding agency AGAUR, by grants BFU2009-10184 & BFU2012-33775 from the Spanish Ministry of Science (MICINN, now called MINECO), and by ERANet: ERASysBio+ grant EUI2009-04045 (MODHEART). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript