Complete skeletons and individual bones are an integral part of the exhibitions and collections in natural history museums and also play an important role in research. However, removing the bones from an animal carcass cleanly and undamaged, while maintaining the skeletons’ natural anatomical shape, is not at all easy. In order to prevent decay and to ensure the bones can be preserved in the long term, all organic soft tissue – such as cartilage, flesh, tendons, etc. – must first be completely removed. Common methods, such as breaking down the organic material using enzymes or chemicals, are often associated with lengthy processing times or the release of hazardous substances, and can cause damage to fragile bones. Another common method involves using dermestid beetles (e.g. Dermestes maculatus) to clean the skeletons. While this method is gentler on the bones and much more environment-friendly, it comes with a considerable risk: Even just one escaped beetle can wreak havoc upon any museum collection or exhibition, voraciously eating through any organic material it can find.
An international team of scientists, in cooperation with Dr Niloofar Alaei Kakhki from the Stuttgart Museum of Natural History, has now found a method for the effective, low-cost and low-risk skeleton cleaning of animal carcasses using larvae of the darkling beetle Zophobas morio, also called “superworms”.
The adult darkling beetle can grow up to 3 cm long and originates from Central and South America. Its mealworm-like larvae can even reach up to 6 cm in length and are bred and sold worldwide as a protein-rich food for small animals and even for human consumption.
The research team “tested” the superworms on carcasses of different sizes (from house mouse to wolf) and established the optimal ratio between the number of larvae and the weight of the carcasses. Depending on the weight, the skeleton cleaning process took from just a few hours up to several days.
The superworms have several advantages over the commonly used dermestid beetles. Their strong mandibles as well as a longer larval stage make them faster and more efficient at cleaning flesh from bones. The risk of an infestation of collections is also lower, as adult darkling beetles are less mobile than dermestid beetles and rarely eat skin, fur, feathers or other organic materials commonly found in taxidermies. Moreover, when kept in large groups, the superworms’ pupation is inhibited, so very few adult beetles develop. This makes rearing and using the larvae simple, cost-effective and safe.
The article was published in the scientific journal PLOS One.