In a bizarre adaptation, the bone collector caterpillar dons the body parts of insect prey to camouflage itself in spider webs, stalking trapped bugs for survival on Hawaii’s Oahu island.
The Bone Collector Caterpillar: A Master of Disguise
A newly discovered caterpillar species has been found to wear the body parts of insect prey onto a protective case, acting as camouflage while it stalks spider webs for trapped bugs. Dubbed the ‘bone collector,’ this caterpillar sports remains of prey as a unique adaptation to its environment.
A caterpillar is the larval stage of a butterfly or moth.
It undergoes complete metamorphosis, starting as an egg and molting four times before forming a chrysalis.
During this stage, it eats constantly to store energy for transformation into a pupa.
The number of instars (stages) varies between species, but most caterpillars have around 4-5 instars.
After the final molt, the caterpillar transforms into a pupa and eventually emerges as an adult butterfly or moth.
The Hunting Grounds of Spider Webs
The Bone Collector caterpillar is found on the Hawaiian island of Oahu and is the first known species to live in spider hunting grounds. It belongs to the Hyposmocoma genus, also called Hawaiian fancy case caterpillars, endemic to the islands. These caterpillars are relatively few in number, with about 300 carnivorous varieties out of nearly 200,000 documented moth and butterfly species.
The Bone Collector Caterpillar (Caligo idomeneus) is a species of butterfly in the family Nymphalidae.
Native to Central and South America, this rare and fascinating insect has distinctive bone-white markings on its wings.
The caterpillars feed on Cecropia trees, which are their primary host plant.
Adult butterflies have a striking appearance with dark brown wings featuring white spots and lines, resembling bones.
They play a vital role in pollination and seed dispersal, contributing to the ecosystem's health.
A Macabre Coat of Arms
Each caterpillar takes up residence in a spider web enclosed in a tree, log or rock cavity. The caterpillar lurks, waiting to prey on insects stuck in the web while masking its scent and texture with leftovers from the spider’s meals and skin shed by its eight-legged landlord. This ‘decorate or die‘ situation is crucial for the caterpillar’s survival, as a plain protective case might not be enough to stop the spider from trying to puncture the case and eat the caterpillar.
A Decorative Process
When curating its collection, a caterpillar carefully probes and rotates bodily remains. The carnivorous critter nibbles large pieces down to size before weaving them onto its silken case. After a few months of gluttony, the caterpillar seals off the end of its case — now a cocoon — to transform into a moth.
The caterpillar stage is a vital part of an insect's life cycle, characterized by rapid growth and development.
During this stage, caterpillars undergo significant physical changes to prepare for metamorphosis into pupae and eventually adult butterflies or moths.
Key adaptations include the development of specialized organs, such as silk glands and prolegs, which enable caterpillars to feed, move, and protect themselves from predators.
According to a study by the University of California, caterpillar growth rates can reach up to 10 times their original size in just a few weeks.
Ancient Origins
Genetic analysis revealed that the Bone Collector caterpillar’s lineage is at least 6 million years old, far more ancient than Oahu, so an ancestor probably traveled there from a different island. However, while other Hyposmocoma lineages are represented by multiple species on several of the Hawaiian Islands, the Bone Collector is the only species in its lineage.
A Rare Discovery
Entomologist Dan Rubinoff and his colleagues first spotted the bone collector caterpillar over 20 years ago, while walking in the Waianae Mountains. They initially dismissed it as a curious coincidence but eventually kept crossing paths with more weird larvae. In all, they spotted 62 bone collector caterpillars over two decades, but only within a 15-square-kilometer range.
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- sciencenews.org | This caterpillar wears the body parts of insect prey
