Carnivorous \u2018Bone Collector\u2019 Caterpillars Wear Corpses as Camouflage<\/p>\n
Nicknamed the \u201cbone collector,\u201d this newly confirmed caterpillar in Hawaii secretly scrounges off a spider landlord by covering itself with dead insect body parts<\/p>\n<\/div>\n
By Gayoung Lee<\/a> edited by Sarah Lewin Frasier<\/a><\/span><\/p>\n Caterpillars nicknamed the “bone collector” create protective shelling out of dead insect bones and body parts.<\/p>\n<\/div>\n Rubinoff lab, Entomology Section, University of Hawaii, Manoa<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/div>\n Caterpillars are known for their fuzzy exterior and sometimes weird behavior. Some vibrate aggressively<\/a> to scare predators; others create their own antifreeze<\/a> to survive the cold. But a newly identified member of the offbeat caterpillar club might be the weirdest of all. Nicknamed the \u201cbone collector,\u201d it builds a disguise from insect cadavers it scrounges from a spiderweb, covering its body with these spider-meal leftovers\u2014and occasionally engaging in cannibalism<\/a>.<\/p>\n It took researchers almost 17 years to convince themselves that this behavior was not some kind of anomaly among a couple of individuals. After meticulous observations and fieldwork, they finally confirmed that bone collector caterpillars, with all their macabre eccentricity, are the larvae of a new species<\/a> that is native to the Hawaiian island of Oahu. The finding was published on Thursday in Science<\/i>.<\/p>\n Bone collector larva in web.<\/p>\n<\/div>\n Rubinoff lab, Entomology Section, University of Hawaii, Manoa<\/p>\n<\/div>\n<\/figcaption><\/figure>\n If you’re enjoying this article, consider supporting our award-winning journalism by subscribing<\/a>. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.<\/p>\n \u201cI just couldn\u2019t believe it. The first couple of times you find that, you think it\u2019s got to be a one-off\u2014it\u2019s got to be a mistake,\u201d says the study\u2019s lead author Daniel Rubinoff<\/a>, an entomologist at the University of Hawai\u2019i at Manoa. \u201cI\u2019ve been looking at it for over a decade, and it still<\/i> blows my mind.\u201d<\/p>\n So how exactly did these caterpillars take on this hardcore habit? The answer is probably evolutionary, Rubinoff says. Bone collector caterpillars grow up to be moths, like most caterpillars do, but these moths tend to lay their eggs in a spiderweb\u2019s nooks and crannies. A newly hatched caterpillar then collects bones to \u201ccamouflage itself from the spider landlord,\u201d Rubinoff says. \u201cThe only chance they have of making a living in this situation is to decorate or die; they live for fashion.\u201d<\/p>\n Adult \u201cbone collector\u201d moths lay their eggs in spiderwebs.<\/p>\n<\/div>\n Rubinoff lab, Entomology Section, University of Hawaii, Manoa<\/p>\n<\/div>\n<\/figcaption><\/figure>\n Setting aside the threat of becoming spider food, for a bone collector caterpillar, a web is actually a great place to snack on the arachnid\u2019s leftovers, such as a beetle\u2019s wings or a fly\u2019s soft tissue. The web is thus an \u201cunexploited niche\u201d of food and protection from other predators, Rubinoff says. Harder bits get added to its protective casing.<\/p>\n These bone collectors are not quite parasitic, nor are they considered symbiotic with spiders. They\u2019re more like a scavenger in the way they pick from meals that a spider might have otherwise finished. Plus, Rubinoff notes, they\u2019re cannibalistic. \u201cThat just gives you a sense of how they go after food\u2014and recognize that there\u2019s food inside things that maybe don\u2019t look like food,\u201d he says.<\/p>\n Video of a Hawaiian “bone collector” caterpillar camouflaged in insect prey\u2019s body parts crawling on black fabric at 2X speed.<\/p>\n<\/div>\n Rubinoff lab, Entomology Section, University of Hawaii, Manoa<\/p>\n<\/div>\n<\/figcaption><\/figure>\n And these critters are far from the only strange, funky caterpillars roaming Hawaii. The bone collector belongs to a native genus of moths called Hyposmocoma,<\/i> whose larvae are commonly referred to as Hawaiian fancy case caterpillars. They have lived in these islands for millions of years, says Akito Kawahara<\/a>, who is director of the McGuire Center for Lepidoptera and Biodiversity at the Florida Museum and was not involved in the new work. \u201cThey\u2019ve adapted to the environment because the conditions of Hawaii are very different from other places around the world,\u201d he explains.<\/p>\n Some of these adaptations have resulted in \u201cbizarre morphology and life history,\u201d says Cornell University entomologist Patrick M. O\u2019Grady<\/a>, who was also not involved in the study. Several Hyposmocoma<\/i> species are known to be carnivorous. Others are aquatic and live under Hawaii\u2019s streams.<\/p>\n \u201cInsects do everything,\u201d Kawahara adds. \u201cThey\u2019re amazing. In some ways, I was not surprised [by the bone collectors] because I know insects do some really crazy things.\u201d<\/p>\n For Rubinoff, who has studied insects for more than two decades, species like the bone collector are a constant reminder of \u201chow little we know about insect diversity\u2014even in places [where] we should know it pretty well\u201d such as Hawaii, which is comparatively easy to access. \u201cWe\u2019re finding stuff that we didn\u2019t even imagine was out there,\u201d he adds. \u201cIt wasn\u2019t something that was even on our radar. But it shows how interesting evolution can be. It really is\u2014I don\u2019t want to say magic\u2014but it\u2019s incredible.\u201d<\/p>\n<\/div>\n![\"Six](\"https:\/\/static.scientificamerican.com\/dam\/m\/24837fa0f09a6ac5\/original\/carnivorous_hawaiian_bone_collector_caterpillar_cases_on_white.jpg?m=1745503434.797&w=600\")
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