A groundbreaking discovery has emerged from Hawaii, where scientists have identified a unique lineage of caterpillar that employs a remarkable form of camouflage by adorning itself with the ‘bones’ of insects.
Researchers from the University of Hawaii at Manoa unveiled their findings in a recently published paper in Science.
Dubbed the “bone collector,” this rare caterpillar has developed an astonishing survival strategy by hiding within spider webs, allowing it to prey on small insects trapped in the silk. Despite its intriguing adaptations, the bone collector faces significant threats, primarily due to its limited habitat on a single mountain range on Oahu, one of Hawaii’s islands.
Caterpillars are typically the larval stage of butterflies and moths, part of the Lepidoptera order, known for their plant-based diets. In fact, less than 0.13% of caterpillar species are carnivorous, making the bone collector an unusual outlier in the insect world.
Lead researcher Daniel Rubinoff and his team have dedicated decades to studying Hawaii’s diverse insect population, particularly caterpillars and moths within the genus Hyposmocoma.
This genus is notable for containing over 350 species, including various caterpillar lineages distinguished by the cases they form to protect themselves during development. Yet, the researchers have only encountered one species belonging to the bone collector lineage thus far.
True to its name, the bone collector caterpillar ingeniously attaches insect remains—typically the remnants of spider meals and discarded spider skins—to the exterior of its silken casing.
This striking camouflage allows the caterpillar to remain concealed as it hunts for unwary insects ensnared in the web, which are usually situated in tree hollows and rock crevices.
Remarkably, the camouflage proves effective against the very spiders whose webs the caterpillars inhabit, with no evidence of predation on the caterpillars reported by the research team.
Rubinoff humorously likened the caterpillar’s existence to living in a lion’s den: “They’re hiding in Smaug’s lair, stealing his treasure. It’s a questionable life choice, but that’s the fun thing about evolution.”
He emphasized how Hawaii’s isolated environment has led to remarkable evolutionary adaptations that challenge conventional expectations of survival.
Rubinoff first discovered these extraordinary caterpillars in 2008, although further research has been hindered by inconsistent funding.
The team has since located the bone collectors within a mere 10-mile-long (16-kilometer) stretch of forest in the Waiʻanae mountain range on Oʻahu.
However, genetic analysis reveals that the lineage of these unique caterpillars dates back at least six million years, suggesting their ancestors were once more widespread across older islands before eventually arriving on Oʻahu.
Several factors may have contributed to the declining range of the caterpillars, including deforestation and other human-induced disruptions.
Yet the most significant threat appears to arise from the introduction of invasive species to the islands, which have drastically altered the ecological landscape.
Rubinoff explained, “What’s really killing us is that we have these forest reserves that are mostly invasive species now.”
He continued to describe how these forests have become biological deserts, overwhelmed by non-native plants, insects, and birds that adversely affect the survival of native Hawaiian species.
Despite these challenges, the caterpillars have shown some adaptability by coexisting with and deceiving non-native spider species.
However, their limited distribution raises concerns that the ancient lineage could be facing extinction, emphasizing Hawaii’s unfortunate reputation as the “extinction capital” of the world.
Rubinoff lamented, “This is the last sort of holdout for this entire lineage. It’s miraculous that they’re still hanging on, but we really do need to do more to save them.”
He expressed hope that the research team’s findings would catalyze enhanced funding and resources to protect and study these distinct insects.
Rubinoff stated, “We absolutely want to understand the genomic basis for how these caterpillars perceive the world.”
He noted that their ability to identify, isolate, and prepare the various body parts they utilize in their camouflage is a remarkable feat, implying a significant evolutionary transformation.
Additionally, the metabolic changes that enable them to endure a carnivorous diet would also be profound and likely rare.
As researchers continue to uncover the secrets behind this enigmatic caterpillar’s survival, the urgency to protect its remaining population and habitat grows, lest we lose yet another fascinating product of Hawaii’s unique evolutionary history.
image source from：https://gizmodo.com/new-caterpillar-found-in-hawaii-wears-dead-bugs-and-lives-with-spiders-2000593898
