Drosophila willistoni group is a Neotropical model for evolutionary studies and has been explored since the latter half of the past century. The willistoni group encompasses 24 species divided into alagitans, bocainensis and willistoni subgroups. This group has a very interesting evolutionary and taxonomic history, characterized by the different speciation levels of its species – some seem to be in the process of speciation whereas others already have completed it. Despite the amount of studies on this group, there is a lack of morphological studies, especially concerning the pre-adult stages of development. Thus, the objective of this study was to characterize the external morphology of the eggs, larvae and pupae of the Drosophila willistoni species group based on Scanning Electron Microscopy. We verified that the morphology of these immature stages are very similar between the analyzed species. The respiratory filaments of the eggs, however, present variation even among the semispecies of the D. paulistorum complex. This morphological similarity is compatible with the relatively recent process of speciation and the pattern of substrate exploration.
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