A bug commonly sold at pet stores is helping scientists with a vexing task

Superworms Offer a Gentle Solution for Museum Specimen Cleaning

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At a natural history museum connected to Ferdowsi University in Mashhad, a city located in northeastern Iran, researchers receive a constant stream of donations. These include injured birds and animals that have been struck by vehicles on local roads. The influx of specimens quickly created a storage crisis for the research team.

"We don't have enough freezers to put these dead animals," explains Niloofar Alaei Kakhki, a bioinformatician who has both studied and worked at the institution. "We have to find a way to clean them," she adds, emphasizing the need to prepare these animals' skeletons for both study and public exhibition.

While scientists employ various methods to remove flesh from organisms, each approach carries certain limitations. In a paper released this month within PLOS One, Alaei and her fellow researchers present an innovative alternative: utilizing a collection of superworms. These substantial beetle larvae demonstrate remarkable ability to clean a diverse range of animal skeletons.

"The worms work fast, yet they're 'super gentle,'" Alaei notes regarding their cleaning capabilities.

Chemical treatment represents one established technique for removing tissue from specimens, though this method often proves harmful to the environment and may weaken skeletal structures. Boiling offers another possibility, but Alaei points out that this process requires considerable time and can harm "tiny, delicate bones."

Another insect-based approach involves dermestid beetles, which rapidly consume flesh. However, Alaei warns that if these beetles escape their containment, "it could be really dangerous for the museum collection." This risk exists because dermestid beetles tend to destroy preserved specimens by chewing through feathers and dried skin.

Several years ago, Alaei's Iranian colleagues began investigating Zophobas morio—commonly known as the superworm. Originally native to South and Central America, each superworm measures nearly the length of a human finger and possesses large chewing mandibles. These larvae are readily available as animal feed at numerous pet stores. While superworms typically serve as food for other creatures, Alaei and her team wondered whether they might instead perform the eating, consuming flesh to clean valuable specimens.

"You can reuse the same larvae for almost six months," she explains.

Superworms develop into adult beetles exclusively when separated from one another, Alaei clarifies. Consequently, maintaining them in groups keeps them permanently in their larval phase, preventing them from causing damage throughout the museum.

The researchers tested superworms on dead animals spanning various sizes, from mice, fish, and small birds to wolves and wild cats. After slightly pre-cleaning the specimens and softening them in hot water for several minutes, the team introduced the superworms to begin their work.

Alaei reports that the larvae performed exceptionally well without any noticeable negative effects, even managing to clean "the ribs of the fish, which is super, super tiny."

Through experimentation, the researchers determined that 10 to 15 larvae provide optimal results. This quantity enables efficient progress while protecting fragile bones from damage.

Alaei, currently stationed at the State Museum of Natural History in Stuttgart, Germany, believes the superworm's effectiveness alongside their commercial availability could benefit numerous institutions, including smaller facilities with limited resources.

"This study is adding one more possibility when you need to clean something," observes Damien Charabidze, a forensic entomologist at the University of Lille in France who participated in no aspect of the research.

Charabidze suggests that superworms might prove simpler to manage than dermestid beetles, yet he cautions that their powerful mandibles could accidentally break small bones. Additionally, while superworms consume both plant and animal matter, they favor vegetation. Therefore, cadavers represent "not their usual food," potentially making them more selective eaters.

Marna Sakalem, an anatomist at the State University of Londrina in Brazil who also contributed nothing to the study, expressed comparable concerns. She further notes that during her five years working with dermestid beetles, neither she nor her colleagues witnessed any escapees—meaning she remains reluctant to dismiss conventional methods entirely.