Going collecting in a collection

Museum collections are a truly unique source of data. Some important recent work has demonstrated the catastrophic impact the fungal disease Batrachochytrium has had on amphibian populations The conclusion that Batrachochytrium appearance was coincident with dramatic population decline was made possible by the ability to examine specimens from decades ago, preserved in museum collections.

A single field trip can only take a snapshot of a population, and laboratory culture of specimens necessarily removes organisms from their natural environment. Museum collections typically consist of a number of specimens collected by different people at different times and from different place. In one single room, we can have an overview of the total diversity of a population, a species, even entire orders of organisms through both time and space.

Traditionally, this diversity was analysed in terms of morphological data, principally the presence or absence of certain characters, and was studied to shed light on the relationships between different groups, the adaptation of species to their environment and the changes in appearance of organisms over time and space (when you have specimens from across the range of a species in a single drawer, the differences are much easier to see).

Now, museum collections are increasingly seen as a source of molecular data too. One part of my PhD involves extracting DNA from preserved museum specimens of butterflies, some collected over 90 years ago. These specimens offer me the chance to sample the entire range of one species in one go (the alternative would be a MAJOR field trip covering most of sub-Saharan Africa). It also includes members of populations which are now extinct - without the Natural History Museum collections, it would be impossible to study these populations and I would not have as much power to resolve the questions I am researching. Techniques for making use of preserved material are really only in their infancy: as we gain more experience and as DNA sequencing technology becomes ever more sophisticated, the amount of information we can get from previously collected (and studied) material will be pushed ever higher.