Fact Check: Pic Genuinely Shows Bagworm Moth Caterpillar and Its 'Little Log Cabin'?

Claim:

A photograph genuinely showed a bagworm moth caterpillar and its "little log cabin" cocoon.

Rating:

True ( About this rating? )

In 2019, a photograph shared to Reddit was said to show a bagworm moth caterpillar — a small, seemingly whiskered insect — carrying several moss-covered sticks on its back, forming what looked like a "little log cabin."

"Bagworm moth" caterpillars make little log cabins for their cocoons from pieces of cut twigs
by u/eviepotato in interestingasfuck

Joe Rominiecki of the Entomological Society of America said bagworm moth caterpillars are genuine insects that "build covers over themselves out of sticks or other debris." Collectively, they are referred to as "case bearers."

Rominiecki sent Snopes a blog post published by the ESA in 2020 that featured the bagworm moth caterpillar, along with several other "costumed insects." According to the post, the insects "construct entire wooden houses to wear." The society wrote:

During the entirety of their larval development period, bagworm moth caterpillars reside within protective cases they build around themselves out of precisely placed twigs and thorns. (Some even resemble tiny log cabins!) These cases have made the study of bagworm moth larval growth rates difficult, as the caterpillars never fully emerge from the housing. While studying the relationship between case size and caterpillar size in Eumeta crameri bagworm moths, researchers discovered that the length of the largest stick in a case directly corresponded to the larva's developmental stage . Larval surface area roughly doubles at each instar, requiring bagworm moth caterpillars to expand their housing as they grow.

David Cheng , a researcher at the University of Florida's Department of Entomology and Nematology, said he did not believe any parts of the photo were exaggerated. The picture showed a "typical spiral type of bag," he said.

"In fact, there are more than six different types of these 'bags' that have been defined, and there could be even more," Cheng added, referring to the following photos taken at the Smithsonian National Museum of Natural History:

(Smithsonian National Museum of Natural History)

"As their name suggests, bagworms' larvae normally build bag-like cases from leaves, stems, and detritus, which they spin together with silk," Cheng wrote. "So far, the bagworm family (Lepidoptera: Psychidae) has been relatively poorly studied. However, for most of the known taxa, their life cycles are typically around one or two years."

Aside from the bugs' bags, Cheng said entomologists were particularly interested in their sexual dimorphism.

"In most taxa, males are winged, just like other moths, while adult females are wingless (over half of the known species). Females of some species are even less mobile, being vermiform [worm-like] into adulthood and lacking legs, wings, eyes, antennae, and mouthparts entirely… which is really weird, right?"

Given that two experts confirmed the authenticity of the image, we rated this claim as "True."