Imagine having a costume so well-made that it allows you to blend in with another species’ family. Now, here’s a little body horror for your Halloween: Imagine that costume being a bloated part of your body, and you end up looking like another species’ nymph.
This isn’t a creature out of a horror film; it’s an actual species of Beetle! In 2023, Bruno Zilberman and Carlos Pires-Silva of the Universidade de São Paulo described a new Beetle species, Austrospirachtha carrijoi, the latest for the rare genus. Notably, A. carrijoi has a distinctly bloated abdomen that looks peculiarly like a Termite nymph’s.
Like their sisters in the Austrospirachtha genus, this Beetle has been challenging to study, especially as they are hard to find. For reference, their sister species Austrospirachtha mimetes is based on just two Beetles found in an old Termite mound.
SPECIES HIDING IN STORAGE
According to Zilberman, the original Austrospirachtha Beetle was donated by Tiago Carrijo, a Termite specialist, to the Museu de Zoologia da Universidade de São Paulo way back in 2014.
It wasn’t until Zilberman worked with the Beetle in 2023 as part of his PhD that he identified the Beetle as A. carrijoi. Despite having worked with Termite Symbionts for ten years, he vividly remembers them as one of the most impressive creatures in his career.
SNEAKY TACTICS FOR FREE FOOD
Being an inquiline means deliberately integrating into the complex social lives of insects, such as Bees, Ants, or in this case, Termites. Christopher Taylor, an entomologist and taxonomist based in Perth, explains this phenomena well in his article.
Austrospirachtha Beetles are a type of Staphylinid Beetle, many of whom are described as inquilines. “Inquiline” may not sound like a friendly word, but these Beetles are friendly to Insects that they both adapt their lifestyles to each other.
Some Beetles are even quite particular about whom they live with. For example, Staphylinid Beetles, like those in the Coroticini Tribe, have learned to live specifically with Nasutitermitinae Termites.
WHAT THE PHYSOGASTRY!
Physogastry refers to the phenomenon of abdominal distention in arthropods. In the case of Austrospirachtha Beetles, their abdomens enlarge and develop into a shape identical to those of Termites.
This incredible Termite-like costume allows them to blend in with Termite nymphs and trick worker Termites to feed and care for them. Don’t be fooled: These Beetles are not at all in their larval stage and are already fully-formed adults.
Austrospirachtha Beetles have abdomens that enlarge and develop into a shape identical to those of Termites.
TOO FEW TO STUDY
There’s a triple whammy to making Austrospirachtha Beetles challenging to study. In the first place, they’re difficult to find, and there are few specimens stored in museum collections. Secondly, they are tiny. They’re typically 2.5 to 3 millimeters, but some barely reach 1 millimeter in length.
Lastly – and this is the trickiest challenge – identifying Beetle species requires researchers to dissect and preserve their mouthparts. Identifying them is delicate work as mistakes can damage crucial specimens.
It even took Zilberman years of practice to build up the confidence to work with the rare A. carrijoi specimens. Nowadays though, he’s extremely skilled at it.
A PUZZLE PIECE IN THE GREAT TREE OF LIFE
Just like with many invertebrates, it can be a bit hard to wrap your head around how important such a small and rare Beetle is compared to many other species.
Zilberman’s passion for this unique insect and his enthusiastic pursuit of knowledge makes discoveries like this scientifically and philosophically valuable. He shares, “The extremely derived and unique morphology points to a social parasite fully integrated into [T]ermite colonies. It is not just a taxonomic oddity — it serves as a window into broader questions about the evolution of symbiosis and significantly expands our understanding of how far natural selection can go to achieve mimicry.”
It just goes to show that no matter how small and rare or how hidden they are in a Termite nursery, every being is precious.
