DNA amplification from pin-mounted bumble bees (Bombus) in a museum collection: effects of fragment size and specimen age on successful PCR

Abstract

Historic data in the form of pinned specimens in entomological collections offer the potential to determine trends in genetic diversity of bumble bees (Bombus). We screened eight microsatellite loci in pinned bumble bee specimens from the U. S. National Pollinating Insects Collection. We tested three species (Bombus appositus, Bombus huntii and Bombus occidentalis) representing three subgenera of bumble bees (Subterraneobombus, Pyrobombus and Bombus sensu stricto) respectively. Bombus occidentalis is a species of particular concern for conservation biologists. Single mid-legs of ninety-six individuals from each species were assayed to determine microsatellite amplification success rates of historic material in a museum collection. Microsatellite alleles amplified in specimens up to 101 years old, but the rate of amplification success was significantly lower in material over 60 years of age. Loci with shorter allele sizes amplified more frequently than relatively longer alleles in samples from all age classes. We correlate the age of specimens to the age at which loci fail to amplify and discuss potential impacts of using certain markers for population genetic studies of museum specimens.