[Seminar Blog] DNA on Display: The use of museum specimens in unlocking genomic data and understanding history from insects

written by Harriet Harris

Dr. Stephania Sandoval Arango is an entomologist and evolutionary biologist working at the USDA Bee Lab in Beltsville, Maryland. In addition to expanding on what we know about bees, she focuses on who gets to ask these questions in the first place. As a queer, Colombian scientist working in the U.S., her perspective brings richness and diversity to evolutionary biology, one that reflects the intersectional reality of science today.

Dr. Sandoval Arango does not focus on honey bees, but rather the weird and wild ones: bees that sneak into other bees’ nests, , bees that mimic other non-bee species, and bees that look native to the habitats they’re in but are actually invaders. While her first love was orchid bees, her work has expanded as she now studies Mason bees (Osmia), orchid bees (Eulaema) ,Cuckoo bees (Triepeolus), and more.
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Like the cuckoo bees she studies, Dr. Sandoval Arango is resourceful, able to make magic with the finite resources that have at times been presented. While completing her PhD at Penn State University as a Fulbright scholar, Dr. Sandoval Arango was navigating the world of scientific research during a global pandemic. Realizing her dreams of conducting field work were shuddering to a halt, she found she had to adapt quickly to finish her degree. Her revised project was reminiscent of anthropologists studying ancient artifacts. She used bees from museum collections, successfully extracting usable DNA from them to unlock many mysteries in the world of bees. Dr. Sandoval Arango then continued to wow the world of entomology when she was awarded a Smithsonian Institution Fellowship.

Using phylogenetic methods, Dr. Sandoval Arango was able to explore whether orchid bees with different coloration and band markings indeed represented different species or, rather, simply different evolutionary lineages with varying phenotypical traits. It was revealed that the latter was more likely the case. Within the species, Dr. Sandoval Arango identified geographic lineages and regions (e.g., the Atlantic Forest of Brazil) where color differences are more closely associated to genetic differences. 
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While listening to Dr. Sandoval Arango talk about her research, it was impossible not to see the parallels between the natural world and the one in which many scientists live and work today. These bees serve as a reminder that, like many of us in STEM in marginalized groups, nature does not always follow our rules or care about neat labels; it adapts to continue to thrive. And maybe with time, patience, and care, we can all realize we are more closely related than we thought, just like the Eulaema bees. 

Her work does not stop here, though. Dr. Sandoval Arango worked on tracking a cuckoo bee, Triepeolus remigatus. Triepeolus, a kleptoparasitic bee, is a silent intruder, laying eggs in the nests of squash bees (Xenoglossa spp) and disappearing, leaving the parenting up to the unsuspecting squash bees. Dr. Sandoval Arango worked to track this bee across North America using live-trapped bees and museum specimens. She explored not what it does, but why its methods of kleptoparasitism are so effective. Sandoval Arango analyzed the behaviors of these bees, how they entered nests, how long they stayed, and the host reactions to their presence. What she found was that most of the time, the squash bees were unaware of their presence, or simply not bothered by it, leaving their nests unattended and undefended. When looking at these cuckoo bees, she noticed phenotypic variation among them and felt the same nagging questions from her earlier research on orchid bees. Using similar methods to her prior work, she identified genetic differences in T. remigatus populations across their range, indicating that populations may indeed be evolving into different species.
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What both of these projects ultimately point to is the fact that you cannot judge a bee by its stripes alone. Rather, genetic variations can be hidden among similar-looking bees and not present in bees that look very different from each other. This challenges the way we have relied on bodily characteristics to identify bee species for decades. It also highlights the importance of using historical data, like specimens from years past in museum collections, to help draw conclusions on present-day species.

If new species are hiding in plain sight and blending into other species, then our decisions regarding conservation need to change with it. As our landscapes evolve, museum specimens persist. They provide a window through time and provide insight into places we may not always be able to travel. By turning dead bees into living data, Dr. Sandoval Arango resolved a picture of how species change over space and time. While we may look at museums as relics that are nice to visit every now and then, this research highlights how they act as critical infrastructure. As museums continue to face funding cuts, we risk losing the very tools that enable discoveries like those of Dr. Sandoval Arango.

If you are interested in reading more about Dr. Sandoval Arango’s work mentioned in this blog you can check out her papers on Eulema bees and Triepeolus bees at the hyperlinks! This blog was written by Harriet Harris, a graduate student in the van Engelsdorp lab studying honey bees and how our rapidly changing world impacts their health. 

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