The elusive Merope tuber and PCR methods for DNA analysis of aged museum specimens

DNA from dried insect specimens are generally not considered suitable for sequencing beyond 15 years of storage due to degradation. Therefore, vast resources of preserved museum specimens go largely untapped. The insect order Mectopera is closely related to the extinct Boreomerope antiqua Novokschonov from the Middle Jurassic period from Siberia and, currently, only three surviving species are known: Austromerope poultonii Killington from Australia, Austromerope brasiliensis Machado et al. from Brazil, and Merope tuber Newman, primarily found in eastern regions of North America. Collections of adult Merope are infrequent and no Meropeidae larvae have ever been collected. The ability to utilize the current museum specimens of Merope would be invaluable for molecular analysis. We tested several different DNA extraction parameters and multiple primer sets for their potential use on preserved Merope samples. These protocols were validated on 13 different museum insect species collected between 2001 and 2019 that were stored as dried specimens or in alcohol. Concentrations of DNA ranging from 3.3-51.9 ng/µl were successfully extracted from single insect legs. Primer sets were tested that targeted the cytochrome oxidase 1 (COI) gene. PCR amplification targeted either the entire COI gene or shorter overlapping regions to account for possible DNA degradation. Sequencing of PCR products was successful for five of the samples. We intend to increase the sensitivity of these methods and then proceed with testing the Merope specimens for further study into the biogeography of this elusory species.