Blue and Black and Weevil

By Rachel Ewing

Do you see blue and black here? The insect pictured above is a weevil from the genus Eupholus, a specimen in the entomology collection of the Academy of Natural Sciences of Drexel University.

You’re looking at this blue and black (and partly iridescent green) weevil today because we’re making a shameless ploy for attention on the coattails of a dress photo whose coloring proved very controversial: Some of us correctly perceive the dress as blue and black, but many more people insist it is white and gold. (Lots of outlets have weighed in on the science of this phenomenon. See Vox for one explanation.)

But the weevil is more than just a ploy for your attention. It’s also a symbol of an important lesson from #TheDress: It’s really important to be able to observe the object itself, not just a photograph of it, to make informed judgments about its physical characteristics. In the case of the dress, additional photos and the retail product listing clarified that the original garment was indeed blue.

In the case of natural history specimens, the same principle applies. The need to measure and observe physical objects, in new ways and in different lights, is one reason why museums, including the Academy of Natural Sciences of Drexel University, maintain natural history collections of plant and animal specimens like this weevil—and not just their photographs. It’s especially important in the case of samples taken from natural environments that are rapidly disappearing due to climate change and habitat loss.

In a coincidence of timing, this is the crux of the argument in an op-ed in today’s New York Times, co-authored by Academy ichthyology postdoc Nathan Lujan, with Larry Page of the Florida Museum of Natural History.  They write:

There is no substitute for collecting and curating specimens for long-term study — not just for scientists studying biodiversity today, but also for future generations, whose need for clues to the spectacular breadth and complexity of unaltered ecosystems will be even greater than our own.

Lujan and Page point out that digital copies are not an adequate replacement for real, natural specimens. But many natural history museums are facing severe cuts and are in need of support.

The Eupholus weevil is just one of many blue and black insects preserved in the Academy’s entomology collection. And scientists don’t know exactly why it has that coloring.

According to Academy collections manager Jason Weintraub, “I am not sure what the adaptive significance of the coloration is in the case of this weevil. We simply don’t know enough about the biology of these insects to venture a guess!  In at least some other insect species with iridescent blue/black coloration, the species in question use visual cues and color signals for intraspecific communication during courtship or during territorial encounters between competing males.”

Perhaps future scientific study will shed further light on the reasons behind this insect’s coloring.

As for the dress? I’m obviously #TeamBlueandBlack.

 

This post first appeared on the Drexel News Blog on Feb. 27.

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