| comparative genetic analyses of historical and contemporary collections highlight contrasting demographic histories for the bumble bees bombus pensylvanicus and b. impatiens in illinois. | direct comparison of genetic patterns between museum specimens and contemporary collections can be a powerful approach for detecting recent demographic changes. using microsatellite markers, we examined historical and contemporary genetic variation from an apparently declining bumble bee species, bombus pensylvanicus, and from a stable species, bombus impatiens, in central illinois. for each species, we genotyped specimens from the illinois natural history survey collected from three populations ... | 2009 | 19344350 |