Where Do Bagworms Come From? Unraveling The Origins of These Pests

October 26, 2023October 10, 2023 by Daniel Marlos, Piyushi Dhir

Bagworms are caterpillar pests known for the unique protective cases they construct around themselves.

These cases, often referred to as “bags,” are made using silk and materials from the plants they feed on.

At a glance, these bags can resemble small pinecones or clusters of pine needles, making them easily mistaken for natural parts of the trees or shrubs they inhabit.

Inside these bags, one might find the developing larvae, eggs, or even the adult female bagworms preparing for the next generation.

Where Do Bagworms Come From — Bagworm Cocoon

As the larval form of the bagworm moth, these creatures play a significant role in their life cycle, transitioning from feeding larvae to reproductive adults.

In this article, let’s understand where these bagworms come from and how they can be a pest in your garden and home.

What Are Bagworms?

Bagworms are the larval stage of the bagworm moth, a species that has evolved a unique method of protection during its developmental phase

These larvae create and reside within bags, which serve both as a shield against predators and as a means of camouflage within their environment.

These bags are meticulously crafted using silk produced by the larvae, combined with bits of leaves, needles, and other plant materials from their host plants.

While the term “bagworm” might suggest a worm-like creature, it’s essential to understand that these are, in fact, caterpillars.

As they mature, they undergo a transformation within these bags.

Male bagworms eventually metamorphose into winged moths, leaving their bags to seek out females for mating.

In contrast, female bagworms remain wingless and largely resemble their larval form throughout their lives.

They stay within their bags, laying their eggs inside, which will hatch into the next generation of bagworms.

Where Do Bagworms Come From? Origin and Distribution

Bagworms, particularly the North American bagworm, have a widespread presence throughout the continental U.S. and southern Canada.

This species has counterparts that extend their range into Central and South America, reaching as far south as Argentina.

Where Do Plaster Bagworms Come From? – Origin and Distinguishing Features

Plaster bagworms are a species of moth known as Phereoeca Uterella. Their larvae form casings, which they live inside during their vulnerable period.

These casings are around half an inch in length and feature slits at both ends, allowing the larvae to move in and out.

The most distinguishing characteristic of plaster bagworms is their bag, which looks like a small cocoon.

This bag, resembling a watermelon or pumpkin seed in shape, is made up of silk fiber and other organic materials, such as lint, sand, or dry plaster debris.

The cocoon’s color is light gray and hangs discreetly on walls. Inside this protective casing, the larva, primarily white with a brown head, resides.

These pests are especially prevalent in humid environments, such as the Southeastern United States, with a significant presence in Florida.

Bagworm Life Cycle

Bagworms begin their life cycle with eggs laid by the female inside the protective bag.

This bag serves as a safeguard, shielding the eggs from cold temperatures throughout the late fall and winter months.

Depending on the location, these eggs typically hatch in the spring to early summer.

Feeding Habits

After hatching, the young caterpillars venture out to feed on the needles and leaves of their host tree.

Contrary to what one might assume, bagworms are not stationary creatures.

Young worms can transport their bags with them, moving around in search of food.

This mobility allows them to feed on various parts of the host plant, causing potential defoliation and other damage.

As the seasons progress, bagworms transition into the pupal stage by fall. During this phase, they transform into adults.

Female adults, being wingless, remain in their bags, while males leave their bags to locate females for mating.

Post-mating, the female lays over 300 eggs inside her bag, which will endure the winter and hatch the following spring, completing the life cycle.

Habitats and Host Plants

Bagworms have a preference for certain trees and plants, which serve as their primary habitats.

These insects are known to reside in a variety of trees such as willow, spruce, maple, oak, and pine.

Among these, arborvitae and juniper trees are their favorites. However, bagworms are adaptable creatures.

In the absence of their preferred trees, they can settle in decorative shrubs that provide a suitable food source.

Do Bagworms Come From the Ground?

A common misconception is that bagworms originate from the ground. In reality, bagworms do not come from the soil.

Instead, they begin their life cycle in the protective bags, usually attached to host trees or plants.

These bags shield the eggs during the colder months, and once hatched, the larvae feed on the foliage of their host plant.

The bags can sometimes be found on the exteriors of structures or other locations, but this is typically the result of caterpillars moving their bags to pupate rather than an indication of ground origin.

Signs of Bagworm Presence in Residential Areas

One of the most evident signs of bagworm presence in residential areas is the distinctive bag they create.

These bags can be easily spotted hanging from tree branches or leaves.

At first glance, a bagworm’s bag might resemble a small pine cone or a collection of pine needles stuck together.

When freshly constructed, these bags can range in color from green to light brown.

However, as they age, especially throughout the winter months, they fade to a grayish-brown hue.

If you notice a tree or shrub appearing as though it’s losing its foliage, it’s essential to inspect it closely to determine if bagworms are the cause.

Why Certain Trees and Bushes Are More Susceptible

Bagworms are not random in their choice of habitat. They specifically look for places that can also serve as food sources for themselves and their offspring.

While they can survive on a variety of trees, they have a particular preference for conifers.

The reason for this preference is that conifers do not produce a new crop of foliage every year, making them more vulnerable to the damage caused by bagworms.

Trees like evergreens, which retain their leaves or needles throughout the winter, are at a higher risk of severe damage or even death due to defoliation by bagworms.

On the other hand, deciduous trees can often survive a bagworm infestation, but it’s always better to address the issue before it escalates.

How Do You Prevent Bagworms?

Preventing bagworms involves a combination of regular monitoring, physical removal, and, if necessary, the use of specific treatments. Here are some steps to prevent bagworm infestations:

Regular Inspection: Regularly inspect trees and shrubs, especially those known to be preferred by bagworms such as juniper, arborvitae, spruce, and pine. Early detection is crucial to managing and preventing a full-blown infestation.
Physical Removal: If you spot bagworm bags on your trees or shrubs, especially during the winter months, physically remove them. This is effective because each bag can contain hundreds of eggs that will hatch the following spring. Use scissors or shears to snip off the bags and place them in a bucket of soapy water to kill the larvae, or seal them in a plastic bag and dispose of them.
Biological Control: Introduce natural predators like birds and beneficial insects that feed on bagworms. For instance, certain parasitic wasps can help control bagworm populations.
Biorational Insecticides: If you detect an infestation early, typically in May or June, you can use biorational insecticides like Bt (Bacillus thuringiensis), neem, or Spinosad. These are especially effective on younger bagworms.
Chemical Control: For more severe infestations or when bagworms are discovered later in the season, consider using synthetic insecticides like bifenthrin, sevin or carbaryl. However, always use chemical controls as a last resort and follow label directions carefully. It’s also essential to note that while these insecticides can reduce the number of bagworms, they might not eliminate the population entirely.

Maintain Tree Health: Healthy trees are more resilient to pests, including bagworms. Ensure your trees are well-watered, appropriately pruned, and receive the necessary nutrients.
Consult with Experts: If you’re unsure about the presence or severity of a bagworm infestation, consult with a local extension service or a professional arborist. They can provide guidance tailored to your specific situation.
Educate and Collaborate: Share information about bagworm prevention with neighbors. Collaborative efforts can be more effective in preventing the spread of bagworms across a larger area.

Remember, the key to preventing bagworms is early detection and intervention. Regularly inspecting your trees and shrubs and taking prompt action can help keep these pests at bay.

Health and Environmental Implications

Bagworms, despite their potential to cause significant damage to trees and shrubs, are not harmful to humans or animals.

If you happen to come into contact with a bagworm or its bag, there’s no cause for concern; they won’t harm you or cause any sickness.

However, it’s essential to note that while the bagworms themselves are harmless, the pesticides often used to treat bagworm-infested trees can be toxic.

These pesticides can pose risks to humans, animals, and even beneficial insects if not used correctly.

Therefore, while addressing a bagworm infestation, it’s crucial to be cautious and informed about the chemicals being used.

Frequently Asked Questions

How harmful are bagworms?

Bagworms are harmful primarily to trees and shrubs, causing defoliation which can lead to plant death, especially in evergreens. It’s advisable to manage bagworms to protect your plants. To get rid of bagworms, physically remove their bags from plants, drown them in soapy water, or use specific insecticides, ensuring early detection for effective control.

Should I kill bagworms?

Yes, if bagworms are infesting your plants, it’s advisable to manage and control them. Left unchecked, they can cause significant defoliation and potentially kill plants, especially evergreens. Early intervention can prevent extensive damage to your landscape.

How do I get rid of bagworms?

To get rid of bagworms, manually remove the bags from trees and drown them in soapy water. If infestations are caught early, use biorational insecticides like Bt (Bacillus thuringiensis), neem, or Spinosad. For older bagworms, synthetic insecticides like bifenthrin or carbaryl may be effective. Always consult with a pest control expert for severe infestations and follow label directions for any pesticide.

Conclusion

Bagworms, the larval form of the bagworm moth, are fascinating creatures with a unique life cycle.

Originating primarily from North America, they have spread to various parts of the world, with their distinctive bags serving as a protective home during their larval stage.

These bags, made from silk and materials from their host plants, are a clear sign of their presence in residential areas.

While they prefer certain trees, especially conifers, they are adaptable and can infest a range of trees and shrubs.

Though harmless to humans and animals, their potential to damage trees makes it essential to manage and control their populations effectively.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Bagworm from South Africa

Hi,
My dad just sent me this photo, he lives is Johannburg, south africa. We have never seen anything like it. Could it be the bagworm?
Thank you
Tracey

Hi Tracey,
We agree that this is a Bagworm.

Letter 2 – Bagworm Moth from New Zealand

Subject: Found a pair of these, metallic blue with orange and black Location: New Zealand March 12, 2013 6:57 pm Hi we found two of these on our deck, it’s summer over here at the moment. The bug looks like a form of ladybug with black and orange wings, and possibly a set of metallic blue wings over the top? The antenna has white tips, and the legs look black, The abdomen is the part that makes me think it’s not a ladybug…. We have never seen one before, and wondering what they are Thanks heaps Signature: Gizmo_RA2

Dear Gizmo_RA2, We believe this is a moth and that its wings haven’t fully expanded, but we have been unable to find a matching image online. Perhaps one of our readers will have better luck than we had. Chad provides an identification: Bagworm Moth Chad provided this link to a Bagworm Moth, Cebysa leucotelus. According to the Landcare Research Manaaki Whenua website: “Caterpillar forms an untidy bag to live in Found on rock walls and houses. Feeds on minute algae and lichen Adult female is often mistaken for a beetle. Adult female can fly, but only in short hops Male is fully winged”

Letter 3 – Flightless Bagworm Moth from New Zealand

Subject: “Australian” Bagworm Moth Location: Epsom, Auckland March 14, 2014 2:54 pm Never seen one before but I spotted and I think correctly identified an Australian Bag Moth yesterday 14 March 2014 in Epsom, Auckland Signature: Lindsay

Dear Lindsay, Thanks for submitting your photo of a flightless, female Bagworm Moth, Cebysa leucotelus. According to Nature Watch: “It is found in New Zealand and the southern half of Australia (Tasmania, Victoria and Western Australia). The adult female moth has black wings with yellow wingtips and patches, but they do not expand properly, so she is not able to fly. The male has a similar pattern and colouring, but has no iridescence. His wings are fully developed and adult males can fly normally. The larvae feed on lichen.”

Letter 4 – Flightless Female Bagworm Moth from Australia

Subject: BUG Location: SYDNEY AUSTRALIA October 19, 2013 2:11 pm I PHOTOGRAPHED THIS INSECT IN MY BACKYARD LAST SUMMER. CAN YOU PLEASE IDENTIFY THIS STRANGE AND BEAUTIFUL INSECT. I HAVE SEARCHED MANY SITES WITH NO RESULTS. ITS ONLY SMALL NO MORE THEN 2CM HAS SMALL COLORFUL WINGS AND APPEARS FLIGHTLESS ONLY CRAWLS AND HOPS. I HOPE YOU RECEIVE MY FILES Signature: WHAT BUG IS IT

This is a flightless female Bagworm Moth, Cebysa leucotelus. Your photos are excellent. You can find additional information on Butterfly House. We will be postdating your submission to go live in early November while we are out of the office.

Letter 5 – Bagworm from the Philippines

Subject: What kind of bug is this? Location: Cebu, Philippines July 17, 2015 6:01 am I don’t know what this bug is and I’m dying to find out. My curiosity is killing me. It’s a very tiny bug supporting a huge shell of some kind of wood shavings , if you will. Hoping for an answer!! Signature: What

This is a Bagworm, the caterpillar of a moth in the family Psychidae. Bagworms construct shelters from bits of plant that act as camouflage as well as protection.

Letter 6 – Bagworm from Singapore

Subject: Bug Location: Singapore August 24, 2012 1:07 am Dear Sir, I live in Singapore, and I found this but that look as carry pieces of wood on his back the size is +- 2-3cm crawling on the wall but have king of string connect as a spider. I gave him a name Xpus just sound cool 🙂 thanks in advance. Frank Signature: Bug

Hi Frank, This is a Bagworm in the family Psychidae. We located an Ecological Observations in Singapore Blog posting of Bagworms that has one image that somewhat resembles the head of your Bagworm. We cannot be sure they are the same species. Bagworms construct their bags from pieces of the plants they feed upon. The bags act as camouflage and protection.

Letter 7 – Flightless Female Bagworm Moth from Australia

What’s this funny insect? Location: Sydney, Australia April 13, 2011 7:03 am This creature was on the wall the other day. I have never seen anything like it. Any idea what it is? Is it dangerous? The spike on the back looks a bit scary! Signature: Carey

bagworm_moth_australia_carey — Bagworm Moth

Dear Carey, Just a few days ago, we had another identification request for this flightless female moth from Australia, and it was identified as a Bagworm Moth, Cebysa leucotelus. Only the females are flightless. We suspect that is an ovipositor protruding from her abdomen.

bagworm_moth_australia_carey_2 — Female Bagworm Moth

Dear Daniel, Thank you for that! I hope she laid her eggs outside first. Carey

Letter 8 – Bagworm from Greece

Subject: Bug that carries its home with it Geographic location of the bug: Larisa, Greece Date: 04/04/2018 Time: 07:56 AM EDT Your letter to the bugman: I find this one bug occasionally in my garden and I believe its always the same one I see (I’ve never spotted two or more together). It doesn’t seem harmful but I’m scared to touch it and I don’t want to bother it. It always carries something on its back as you can see in the photo. Sometimes I find it immobile with it being entirely inside the thing on its back. It has six legs from what I can see. I’d really like to identify it. How you want your letter signed: EntomologistWannaBe

Dear EntomologistWannaBe, This is a Bagworm, the caterpillar of a moth in the family Psychidae. We located a beautiful poster on Etsy with images of the Hairy Sweep, Canephora unicolor/Canephora hirsuta, which is described as “a moth of the family Psychidae. It is found in Europe. The female has no wings. The wingspan of the male is 20–25 mm. The moth flies in one generation from May to July. The larvae feed on shrubs, deciduous trees and herbaceous plants.” There are also images on Papillon en Macro, Project Noah and BioLib. Bagworms construct a bag from bits of plants that they drag around and use for protection, eventually pupating inside the bag.

Letter 9 – Mystery Caterpillar from Costa Rica similar to Bagworm

mysterious large cocoon with a caterpillar inside. April 5, 2010 I found him on the ground in my yard in Costa Rica. I brought it inside to hatch, but he just comes partially out to eat and poops round pellets out of the bottom, and spends most of his time inside. I have had him for about 5 days now. He has moved about to different locations, until i found a place he likes with leaves he likes to eat. He attached himself to a branch i provided with a small silk thread, and has remained there. Is it normal for a caterpillar to continue to eat after spinning a cocoon, or is this his protective living space? Will it eventually pupate? Jan Betts Costa Rica, Central America 3000 feet altitude.

Dear Jan, We intended to post your photo two days ago, but we got distracted. The number of letters that are arriving each day has drastically risen since the first of April, and it is becoming impossible to even respond to a small fraction. Your submission is so unusual, and we are hoping one of our readers, perhaps Karl who just returned from Costa Rica, will be able to assist with this creature. Normally, we would think that a caterpillar of this kind would be a Bagworm, but we don’t believe that is the case here because Bagworms generally incorporate plant material in their bags.

Do you know the plant it is feeding upon?

Daniel: I initially thought this might be a Sack-bearer Moth (Mimallonidae) but the caterpillar itself just doesn’t look right. I am therefore going back to the Psychidae (Bagworm Moths), some of which look very similar to the caterpillar in Jan’s first photo. I can’t be certain about a more specific identification but I think the genus may be Oiketicus, possibly O. kirbyi which is widespread throughout the tropical Americas and Caribbean. Assuming that it is O. kirbyi, the caterpillars do incorporate plant material into their bags as you indicated, but in this case the silk that binds the material together often envelopes the bag entirely. The result is a “lumpy” looking bag, much like the one in Jan’s photos. Females in the genus never leave their bags (except to die) and don’t develop wings, so Jan may be disappointed if she is expecting a winged moth to eventually emerge (unless it is a male). Oiketicus kirbyi has caused some problems in Costa Rica and other places as an agricultural pest. Regards. Karl

Letter 10 – Bagworm from India

Please tell me wtb
Dear sirs
I am Ibrahim from Kerala, India. I would like to know full details on this bag moth larvae (as I presume) which saw on the way side plant urena lobate. Please help me
Regards
Ibrahim

Hi Ibrahim,
We cannot tell you a species or even a genus as we are not that savvy with Asian insects. We do agree is is the larval form of one of the Bagworm moths.

Letter 11 – Bagworm from New Guinea

Bagworm in Papua New Guinea April 30, 2010 Dear Bugman, Last week we found this “thing” on the ground, presumably having fallen out of a tree. We took it home and laid it on a shelf outside our house. The next day, it had attached itself to this jar. We have, thanks to your site, identified it (her?) as a bagworm, but as her “bag” is a good eight inches (8″) long, we thought you might like to see her! As for the season, well, it’s just about always the same here. But it is just now transitioning from rainy season to dry season here. Thanks for helping us identify her! She’s a beauty! We are curious, too, about the grub in picture three. The coin is about the size of a quarter, so it’s a big one. Any idea what it becomes? Thanks! Sharon Papua New Guinea

Hi again Sharon, What a gorgeous Bagworm. We will try to identify the species. The grub is a Scarab Grub, probably a May Beetle.

Letter 12 – Bagworm from Mexico

Metamorphosizing Bug in Puerto Vallarta, Mexico? Location: Puerto Vallarta, Mexico September 12, 2010 3:23 am Hi Bugman! First and foremost, I wanted to say that I think what you’re doing here as an educational (or shall we say, ”ent”ucational!) service is awesome! I truly hope that you achieve the dream of meeting up with Martha one day and I’m pulling for you! Secondly, I was hoping you could identify this bug which was sighted by my twin sister during her brave, charitable, summer journey via bicycle from Arizona all the way to Panama. It was found metamorphosizing or perhaps laying eggs, as it remains unclear to the layman viewer what exactly is happening, although I suppose one would think as a ”layman”, I could at least identifying egg laying properly. Please excuse the bad pun, and I hope that doesn’t hurt my chances of getting this enigma identified! So, in your expertise, what is going on in this picture, and by which kind of bug? Your knowledge and eagerly anticipated response is greatly appreciated! Thank you! Signature: Paco and Brunilda

bagworm_oiketicus_paco_brunilda — Bagworm

Urgent ID priority escalation! Re: Identification Request: Metamorphosizing Bug in Puerto Vallarta, Mexico? September 20, 2010 11:50 AM Hello again Bugman! Perhaps it was the letter riddled with awful puns the first time or just the mere fact that you are a staff of single digits fielding an onslaught of mail from the masses on a daily basis, however, I have yet to receive a response from my original inquiry below, and in light of this, I wanted to provide an update regarding the request. In the event that the puns were the turn-off in the first place, I hesitate to apologize for “bugging” you, as this will certainly not help my chances of getting some closure on this insect any time soon, but I am sorry for disturbing you, as you are a busy guy, especially with the release of the new book which I can’t wait to get my hands on! (No, honestly, I mean that, and this was not said in hopes of getting my question answered sooner, I promise. But does it help?) Okay so to make a long story short, although it looks as if we’re too late for that, the identification of this bug is the subject of a heated bet, in turn, escalating the urgency of this request, as it’s not just any bet…it’s a bet with a guy who always has to be the one to know it all. He cannot stand being wrong, and no matter what, he insists on being right, and the most unfortunate part for the rest of us is that he IS RIGHT most of the time. He claims that the insect appearing in our photo is a queen termite laying her eggs, however, to be quite honest, we’re not so sure about that, and think we may have finally entrapped Mr. Trivia into admitting he is human and fallible! He wanted me to assert what I thought it was, however, I have held him at bay merely by telling him that it’s NOT THAT. I’m running out of time, however, in committing to an actual answer, as he keeps probing for a more definite response. Now, of course, if you do indeed identify it as being a queen termite laying eggs, then I will quietly thank you, and hope that he doesn’t stumble upon “What’s That Bug” for more ego stroking satisfaction that we certainly don’t need to see! Though, should our bug turn out to be something NOT of the termite family, then we can consider this a win-win, as I revel in proving him wrong, and you would shortly receive an incredible spike in web traffic, as there are legions of us who would like to see that just once, Mr. Trivia hiccuped with an answer! Just to be clear, the bet is a friendly one of no material value made between rivals, and there is no money being changed hands here, nor is someone going to lose a house, car, or spouse as a result of high stakes betting. So, the pressure is off, Bugman, in terms of being responsible for someone’s life going down the tubes in response to a bug identification, however, let us not underestimate the value of being able to reference this slip up on his part, basking in eternal glory from the point of a non-termite identification, on! Thank you again for your consideration to elevate the priority of this review! Sincerely, Paco and Brunilda Dear Paco and Brunilda, Collect your debt. This is no termite, queen or otherwise. It is a Caterpillar, more specifically a Bagworm in the family Psychidae. Bagworms are known for constructing bags from silk and bits of plant material from their food plants, like leaves, stems and conifer needles. We were not familiar with any Bagworms that make strictly silken bags, so we turned to BugGuide and found an example from Arizona in the genus Oiketicus that looks very similar to your Bagworm. Since insects do not respect international borders, it may be the same genus as your example. Sorry for the delay, but we can only answer so much mail. Hi Daniel! Thank you so much for taking the time to identify the little border crossing Bagworm who I suppose didn’t want to stick around to see what ultimately would come of the Arizona SB 1070 Immigration Laws (SB standing for Suspicious Bagworm, of course), if he/she was on the run (or as much as this little critter can try, anyway)! We cannot tell you how liberating it feels to finally conquer Mr. Trivia in what, at times, became a rather bugly battle of aggressive words, and thanks to you, the win was literally in the BAG! I’ll stop with the “pun”ishment now, I promise. Thanks again, and best of luck in the future with all your endeavors! Paco and Brunilda

Letter 13 – Bagworm from Brazil

Inseto estranho Location: Rerião norte do Brasil, Amazônia. October 23, 2010 4:56 pm Encontrei este inseto sob a copa de um pé de carambola. Estou na Amazônia, município de Ananindeua, estado do Pará, Brasil. Mês de outubro, verão amazônico. As fotos não estão muito boas. Minha camera, cannon Power Shot A460 está com um problema, com excesso de luz. Signature: Paulo araujo

Ed Note: Translation by Google Strange insect Location: Rerião northern Brazil, the Amazon. October 23, 2010 4:56 pm I found this insect under the canopy of a foot carom. I’m in the Amazon city of Anand, Pará state, Brazil. October, Amazon summer. The photos are not very good. My camera, Cannon Power Shot A460 has a problem with excessive light. Signature: Paul araujo Hello Paulo, This is a Bagworm, the caterpillar of a moth in the family Psychidae. Muito obrigado pela resposta. Abraços. Translation by Google Thank you for the reply. Hugs.

Letter 14 – Bagworm from Israel

Bagworm or boxworm? Location: Wadi Og, Israel January 23, 2011 6:22 am Hi WTB, On my hiking trip this past weekend I came across this bagworm, Amicta quadrangularis, in Wadi Og, just south of Jericho. I think ’Boxworm’ is a more appropriate name, don’t you? Signature: Ben, from Israel

Hi Ben, Thanks so much for sending us your photo as well as identifying this unusual Bagworm.

Letter 15 – Bagworm from Zambia

Possibly bagworm, from Zambia Location: Kasanka National Park, Zambia December 11, 2011 10:52 am Hello, This creature was photographed in Kasanka National Park, Zambia. It was crawling on the hood of a stationary car, possibly fell down from an overhanging bush. Date: May 10, 2011. Any idea, at least to genus? I’d be grateful. Thanks. Signature: Monika Forner

Dear Monika, That is sure one crazy looking Bagworm with its grassy bag. Bagworms generally create their bags from the foliage of the plants they feed upon. If you are able to identify the plant species it is feeding upon, it will facilitate a species identification for the Bagworm.

Letter 16 – Bagworm from Indonesia

Strange moving pile of sticks Location: Menjangan, Bali, Indonesia May 13, 2012 5:11 pm This photo was taken in Bali in March 2012. I noticed a very strange pile of regularly stacked sticks moving on a balustrade. I only managed to get one photo with the wrong kind of lens for the job. My first thought was that it was something that was being moved slowly by an ant from underneath. Another possibility is some kind of bizarre snail. The sticks that this ’shell’ is made from look far too regular. Have you ever seen anything like this before? Signature: Miles

Unidentified matchstick insect — Bagworm

Hello Miles, This appears to be a Bagworm, the larva of a family of moths that are characterized by building shelters from various types of plant material. Here is a photo from FlickR that we believe is from Indonesia and looks similar.

Letter 17 – BEST INSECT ACCESSORY: Giant Silkmoth from Malawi is Gonimbrasia rectilinea. Also a Bagworm worth 500 kwacha!!!

Subject: Bug in a hut and some sort of sphinx moth Location: Nkhotakota, Malawi, Africa September 14, 2012 10:34 pm Well, since you folks were so great about getting that sun spider identified, I have two more mystery insects for you, from my sister in the Peace Corps in Malawi. The first one we assume is some sort of (gorgeous) sphinx moth. The second one she says she sees everywhere, and can never seem to get to hatch out to its final stage, whatever that may be. 500 kwacha have been offered to whoever can identify it. Signature: Catherine

gonimbrasia_malawi_catherine — Insect Accessory: Gonimbrasia dione

Dear Catherine, Several months ago, more to amuse our editorial staff than for any other reason, we ran a contest to find the loveliest insect accessory photo, and though this photo of a Giant Silk Moth (not a Sphinx Moth) has arrived considerably later, it is by far the comeliest insect accessory photo we have ever received. We searched through species on the World’s Largest Saturniidae website and we have identified this moth as a member of the genus Gonimbrasia, probably Gonimbrasia dione. The photos on Encyclopedia of Life tend to support that identification, but we will copy Bill Oehlke on our response to see if he is able to verify that identification. The other insect is a Bagworm, and we have no idea what 500 kwacha might be, but we are thrilled to claim the prize. Bagworms are caterpillars in the family Psychidae that create a protective habitat from the plants upon which they feed. Bagworms spend their entire caterpillar period within the bag which they enlarge over time to accommodate their growth, and they eventually pupate within the bag. Catherine replies Congratulations, you won $1.50! Thanks, folks, I love this website.

bagworm_malawi_catherine — Bagworm identification worth 500 kwacha!!!

Correction courtesy of Bill Oehlke: Hi Daniel, The very clear basal area of forewing is more suggestive, to me, of Gonimbrasia rectilinea Large hindwing ocellus is also more typical of rectilinear Hi Catherine, See note above to Daniel. Nice photo. Is it possible to send me a larger version of image for my Saturniidae data base? Thanks Bill. We always appreciate your assistance. Daniel Hi Catherine, We are so excited about our prize. We would greatly appreciate if you are able to send the photo to Bill Oehlke who runs a wonderful website that we use for reference all the time. Many species of Giant Silk Moths are only represented online by mounted specimens, so individuals photographed in the wild are always appreciated. Update: We got 500 Kwacha!!!!! October 26, 2012 We were surprised to find an hand addressed envelope from Colorado in our mailbox amidst the political propaganda, and upon opening it, we found a lovely thank you note with our 500 Kwacha. What a wonderful way to end a long and difficult day.

Letter 18 – Bagworm from Uruguay

Subject: Bagworm in Uruguay? Location: Bella Vista, Maldonado, Uruguay February 5, 2013 5:24 am Hi, my name is Tadeo, i am 10 years old and i discovered this strange cocoon in a just planted tree. After a while i saw that the cocoon was at a different place as the previous watch…so i started to pay more attention to it. Just tonight i found out that inside the cocoon lives a big worm…but i was not sure it was a SilkWorm….I have HD pictures…Can you please help me identify it… Thanks a lot Signature: Tadeo

Hi Tadeo, This Bagwormis most likely in the family Psychidae and it will eventually pupate within its bag when it will become a stationary cocoon. Your photos are of a beautiful quality and they are a nice addition to our website. We are sorry we cannot identify your Bagworm to the species level. We don’t receive many submissions from Uruguay to our site, so thank you for sending your sighting.

Hi Daniel, thank you very much for your reply…. if you can…i have some other questions…. I want to know if this will be a buterfly…I want to know also how much time can take that so i can see and take pictures from all the process. Unfortunatelly the tree where it was at the beginning broke and now we put some tree leaves near him to eat…but maybe we can generate a better place….. Thank you very much… i am really very interested and your website is very very cool. tadeo Hi again Tadeo, Bagworms are actually moth caterpillars and they are not especially showy. Interestingly, female Bagworms are wingless and they do not venture far from the bag when they eclose or emerge from the cocoon. Once she has mated, the female Bagworm lays eggs inside her bag for the next generation.

Letter 19 – Bagworm from Portugal

Subject: Strange bug – what is it? Location: Setubal, Portugal February 10, 2013 7:20 am Dear WTB, Would you tell me what this bug is? I found it while strolling in a local park. It was slowly dragging itself along the pavement. I tried poking it with a stick to see if it would come out of that ”shell”, but some kind of orange-ish blood poured out! Signature: Luis M.

Dear Luis, We believe this is a Bagworm, the caterpillar of a moth in the family Psychidae. Bagworms construct mobile homes for themselves from the plant parts that they feed upon.

Letter 20 – Bagworm from Guatemala

Subject: psychidae oiketicus Location: Guatemala city October 4, 2014 1:21 pm After a large amount of picture comparisons and forum searching, I think I have this one pegged as a basket bug. I sent an identification request this morning still thinking it was hornetsnest of some kind. Signature: ithinki’ve got it

We agree with your identification. Moths in the family Psychidae are commonly called Bagworms because the larva construct “bags” from silk and plant parts that they live inside as a means of protection.

Letter 21 – Bagworm from Cyprus

Subject: Strange debris covered creature Geographic location of the bug: Cyprus Date: 06/19/2019 Time: 04:13 AM EDT Your letter to the bugman: Saw this moving across my shoe. It stops when prodded. I’d love to know what it is. How you want your letter signed: Jelvis

Dear Jelvis, We cannot make out any details in the creature that is hiding in this shelter, but we suspect it is a Bagworm, the larva of a moth in the family Psychidae. According to BugGuide, a North American website: “Larvae (bagworms) construct elaborate little cases around themselves of plant debris and other organic matter.” This particular individual appears to have constructed its bag from pink flower petals. Was there a plant with similar looking blossoms nearby? Based on this FlickR image, there are Bagworms on Cyprus. Hi Daniel Thank you for your reply. Yes there is a Bougainvillea nearby so his cocoon was quite colourful. He poked his head out and it looks like the Bagworm. Thanks again. Jelvis

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.