Stinkbugs Farm Fungi on Their Legs
▼ Summary
– Female Dinidoridae stinkbugs were long thought to have tympanal hearing organs on their hind legs, similar to other insects like grasshoppers.
– Researchers discovered these structures are not tympanal organs but are actually mobile fungal nurseries, a unique finding.
– The organs lack a tympanal membrane and sensory neurons, confirming they have no role in hearing.
– They contain thousands of pores filled with benign filamentous fungi connected to nutrient-secreting cells.
– This finding corrects a long-standing misconception and reveals a novel symbiotic relationship in these stinkbugs.
For decades, scientists believed female stinkbugs from the Dinidoridae family possessed a unique hearing system, with tympanal organs located on their hind legs rather than the front. This assumption, based on anatomical similarities to other insects like crickets, went largely unchallenged until a recent Japanese study uncovered a far more astonishing reality. These structures are not auditory organs at all, but rather sophisticated, portable fungal gardens, a biological phenomenon never before documented in the animal kingdom.
The investigation began with the goal of understanding how this unusual leg placement affected the bugs’ hearing. Researchers, including evolutionary biologist Takema Fukatsu, examined the species Megymenum gracilicorne, a Dinidoridae stinkbug native to Japan. The team quickly realized their initial premise was incorrect. A detailed analysis revealed the so-called organs lacked the essential components for detecting sound. “We found no tympanal membrane and no sensory neurons, so the enlarged parts on the hind legs had nothing to do with hearing,” Fukatsu stated. The case of the hind leg organs, once considered closed, was suddenly wide open.
What they discovered instead was a complex, symbiotic structure dedicated to farming. The enlarged sections of the leg are covered in thousands of tiny pores, each one packed with harmless filamentous fungi. These pores connect directly to specialized secretory cells nestled within the leg. The researchers hypothesize that these cells release nutrient-rich substances, effectively fertilizing the fungal crops and promoting their growth. This turns the stinkbug’s leg into a mobile agricultural plot, a survival strategy that provides a constant, cultivated food source.
This finding completely redefines our understanding of this insect group. The Dinidoridae family is relatively small and has not been studied as extensively as its more common relatives, with prior research focusing mainly on taxonomy and physical description. The revelation of fungal farming highlights how much remains unknown about insect biology and the intricate, mutualistic relationships they can form with microbes. This stinkbug doesn’t use its hind legs to listen for a mate; it uses them to tend its own personal garden, a remarkable adaptation for life in the wilds of Asia.
(Source: Ars Technica)
