Comparative analysis of different fixative solutions on insect preservation for molecular studies

In order to define a convenient and reliable method for DNA preservation that can be applied both during field collection and archival maintenance of Coleoptera, a comparative analysis of different fixative solutions has been performed. In the present paper both quality and quantity of DNA extracted by insects stored for different periods of time have been compared. In particular, we used the yellow mealworm beetle, Tenebrio molitor (Coleoptera: Tenebrionidae, Linnaeus, 1758), as an experimental model comparing the results obtained with this species with those available in literature for other insects. As a whole, acetone preservation proved to be cost-effective and widely applicable making acetone an excellent storage medium not only during field surveys, but also to obtain efficient and low-cost storage of Coleoptera in museum collections for biomolecular studies. Furthermore, the morphological characters of acetone-preserved insects have been examined by scanning electron microscope analysis, showing that acetone can preserve also fragile structures, such as sensilla, strengthening our suggestion of acetone as an optimal fixative for insect archival maintenance.