A valuable resource, largely hidden from view
By researching variation among and within collection specimens, biologists have uncovered many ecological and evolutionary mysteries of the natural world. For instance, a recent study on bird specimens traced the increasing concentration of atmospheric black carbon and its role in climate change over more than a century. Scientists can collect ancient DNA from specimens and gather information about historical population levels and healthy genetic diversity for organisms that are now threatened and endangered.
My own research on global bat diversity used hundreds of museum specimens to conclude that tropical bats coexist more readily than many biologists expect. This finding fits with an overall pattern across much of the tree of life where tropical species outnumber their temperate cousins. It may also help explain why in many parts of Central and South America, bats are among the most abundant and diverse mammals, period.
However, research on these specimens often requires direct access, which can come at a steep price. Researchers must either travel to museums, or museums must ship their specimens en masse to researchers – both logistical and financial challenges. Museums are understandably wary of shipping many specimens that are truly irreplaceable – the last evidence that some organisms ever existed in our world. A museum’s budget and carbon footprint can quickly balloon with loans. And as physical specimens cannot be in more than one location at once, researchers may have to wait an indefinite amount of time while their materials are loaned to someone else.
CT scanning bat skulls
I have tried to tackle these issues of access with my collaborators Daniel Rabosky and Erin Westeen using micro-CT technology. Just like with medical CT scanning, micro-CT uses X-rays to digitize objects without damaging them – in our case, these scans occur at the fine scale of millionths of meters (micrometers). This means micro-CT scans are incredibly accurate at high resolutions. Even very tiny specimens and parts are preserved in vivid detail.