What Do Caddisflies Eat? Unveiling their Surprising Diet

Caddisflies are fascinating creatures with unique feeding habits. They come from a diverse group of insects called Trichoptera and have a strong presence in various aquatic ecosystems.

Understanding their diet is essential, as it sheds light on their role within these environments.

As a caddisfly larva, you primarily reside on the bottom surface of streams, munching on a variety of organic materials.

This can range from algae to detritus, depending on your species and availability of food sources. Your ability to adapt to various conditions makes you a key player in the aquatic food chain.

As you metamorphose into an adult caddisfly, your diet shifts mainly towards plant-based matter, such as nectar or even pollen.

This change not only supports your growth and reproduction but also contributes to the dispersal of plant species within your ecosystem.

What Do Caddisflies Eat

What Are Caddisflies

Caddisflies, scientifically known as Trichoptera, are a group of insects that are closely related to moths. They have a few key features that make them unique:

  • Wings: Caddisflies have two pairs of wings, with their forewings being hairy and their hindwings often clear. They hold their wings rooflike over their backs, giving them a mothlike appearance.

  • Antennae: These insects possess long, threadlike, and many-segmented antennae. Their antennae are usually as long as the rest of their body.

There are over 14,000 species of caddisflies belonging to different genera. While their physical appearances may vary slightly, their overall characteristics remain the same.

Caddisfly larvae are aquatic and play a crucial role in their ecosystem. They construct protective cases around their soft bodies, using materials like plant debris or small stones.

For example, the Giant Casemaker Caddisfly is known for its large size and the portable cases it builds. To create these cases, caddisfly larvae produce silk from a gland in their lower lip which acts as a natural glue.

These insects are an essential part of the food chain, with many fish species, such as trout, feeding on caddisfly larvae. Additionally, adult caddisflies play a vital role in the diet of birds, bats, and other insectivorous animals.

Life Cycle of Caddisflies

Caddisflies go through a complete metamorphosis during their life cycle. This means that they hatch from eggs and grow through several stages, including larvae, pupa, and finally, adult caddisflies.

In the egg stage, caddisflies can be found clinging to rocks or plants in or near water. After hatching, the larvae live underwater for several months to years, depending on the species1.

As larvae, they’re known for building protective cases from twigs, leaf fragments, and sand, which they use while feeding2.

During their larval stage:

  • They can be up to 1 1/2″ long1.
  • They are aquatic and slender.
  • They play a vital role in maintaining the nutrient and energy cycle in streams3.

Caddisflies undergo several instars, or growth stages, as they grow. Once the larvae reach their final instar, they find a hiding place to pupate.

During the pupal stage, they undergo a transformation and develop into winged adult caddisflies.

Adult caddisflies:

  • Can be up to 1″ in length1.
  • Have long, threadlike antennae4.
  • Hold their wings roof-like over their backs4.
  • Are often dark and drab in color4.

In summary, the life cycle of caddisflies involves hatching from eggs, growing through larval instars, undergoing metamorphosis during the pupal stage, and finally emerging as winged adults.

Caddisfly Habitats

Caddisflies are an order of insects that spend most of their life in aquatic environments.

As caddisfly larvae, they can be found in various freshwater habitats such as lakes, rivers, and streams, where they play a vital role in maintaining these ecosystems’ health.

In their larval stage, caddisflies require habitats with a diverse range of microhabitats, such as gravel, rocks, and plant material.

This variety allows them to find suitable places to build their cases or nets, which are critical for their survival and growth. Some examples of these habitats include:

  • Fast-flowing streams with coarse substrate, ideal for case-building caddisflies that use stones and other materials for constructing their protective cases
  • Slow-moving waters with abundant aquatic vegetation, where net-spinning caddisflies can attach their silk nets to plants for filter-feeding

One of the key factors affecting caddisfly habitat is the quality of the water.

Caddisflies generally prefer clean, well-oxygenated water, making them excellent indicators of the overall health of aquatic ecosystems.

In polluted or oxygen-depleted waters, you are less likely to find thriving caddisfly populations.

What Do Caddisflies Eat?

Diet of Caddisfly Larvae

Caddisfly larvae are aquatic creatures that construct a portable protective case for themselves.

The cases are made from tiny pieces of plants, sand grains, or other detritus adhered or spun together into a tube or cone-like structure to provide shelter and camouflage against predators.

Their diet mainly consists of organic materials found in their aquatic environment. There are two primary feeding types among caddisfly larvae: shredders and scrapers 2.

Shredders feed on a variety of organic materials, including dead leaves, twigs, and decomposing plant matter.

They play an essential role in breaking down these materials into smaller particles, allowing other aquatic organisms to access the nutrients 3.

On the other hand, scrapers feed on algae and aquatic plants, scraping them off surfaces. They are essential for maintaining a balanced ecosystem as they help control the algae and plant populations 4.

To give you an idea of their dietary variation, here’s a comparison table:

Feeding TypeShreddersScrapers
Food SourceDead leaves, twigs, plant matterAlgae, aquatic plants
Role in EcosystemDecompose organic materialControls algae and plant population

It’s fascinating to see how the diet of caddisfly larvae contributes to maintaining a healthy and balanced aquatic ecosystem.

Diet of Adult Caddisflies

Unlike their larvae, which are aquatic and consume a variety of organic materials in their underwater environment, adult caddisflies mainly feed on nectar.

This sugary liquid provides them with their main source of energy, which helps them in their search for mates and carrying out their crucial role in the ecosystem as pollinators.

You’ll often find adult caddisflies attracted to light sources at night, as they become active after sunset. Like other nocturnal insects, they use the light to navigate and find food sources.

While feeding on nectar, they also inadvertently transfer pollen from one blossom to another, contributing to the pollination of various plant species.

With their moth-like appearance and drab colors, adult caddisflies might not appear as glamorous as some other pollinators.

However, they are an essential part of the ecosystem, and their nighttime feeding habits make them a valuable asset to the plant life that relies on their pollination services.

Protection and Survival Tactics

Caddisfly larvae are known for their unique way of protecting themselves and surviving in their aquatic environment.

One of their main tactics is to build protective cases around their bodies. These portable cases offer various benefits for the caddisfly larvae.

Caddisfly larvae use silk to construct their cases. They excrete the silk from special glands and use their mouthparts to manipulate it. Silk provides a strong and flexible material that allows them to create a sturdy case.

The larvae use several materials to build their portable cases. They often collect tiny pieces of plants, sand grains, or other detritus from their surroundings.

These materials are then adhered or spun together using silk, forming a tube or cone shape.

Ecological Importance

Caddisflies play a crucial role in their environment. They are an essential part of the food chain, providing sustenance for various species, and their presence is an indicator of water quality.

As inhabitants of freshwater habitats, caddisflies contribute to the natural balance of the ecosystem.

Their food sources include detritus, algae, and small invertebrates, making them essential for breaking down organic matter and recycling nutrients.

In turn, they become prey for other aquatic species, such as trout and larger invertebrates.

In addition to their importance in aquatic ecosystems, caddisflies also serve as a food source for birds and bats.

When the caddisfly larvae transform into adults, they fly out of the water and take to the air. This makes them an easy target for predators such as swallows and bats.

The presence of caddisflies in a body of water can also be viewed as an indicator of good water quality.

As they thrive mainly in clean water with a low level of pollutants, their existence in a specific habitat reflects the overall health of that ecosystem.

Here is a comparison table to explain caddisflies’ ecological importance:

Ecological RoleImpact on Ecosystem
Food SourceSupports a variety of aquatic and terrestrial predators
Water Quality IndicatorIndicates a clean, healthy ecosystem
Nutrient CyclingBreaks down and recycles organic matter
Caddisfly

Classes of Caddisflies

Caddisflies are fascinating insects that belong to the order Trichoptera. They can be classified into three major groups: Integripalpia, Annulipalpia, and Spicipalpia.

Let’s take a closer look at each of these classes and their distinct features.

Integripalpia

Integripalpia is the largest group of caddisflies. Some common features of this group include:

  • Larvae construct portable cases
  • Aquatic habitat
  • Filter feeding

An interesting example of an Integripalpia species is the Giant Casemaker Caddisfly. Their larvae are known to live in cold water and build cases using plant materials.

Annulipalpia

The Annulipalpia group consists of caddisflies with the following characteristics:

  • Larvae build fixed retreats
  • Aquatic habitat
  • Predatory feeding habits

One notable example of an Annulipalpia species is the Hydropsyche. This species creates a fixed retreat out of silk and small particles. They use their retreat to capture passing prey.

Spicipalpia

Spicipalpia is the smallest group of caddisflies. Some notable features of this group include:

  • Larvae build portable and quite diverse cases
  • Aquatic habitat
  • Omnivorous feeding habits

A unique example of a Spicipalpia species is the Rhyacophila, which builds its case from various materials like twigs, leaf fragments, and sand. They are versatile and adaptive in their feeding habits.

Caddisfly

Caddisflies are closely related to the Amphiesmenoptera, a superorder which includes both caddisflies (Trichoptera) and moths/butterflies (Lepidoptera).

This relationship is primarily based on the similarities in their wing structures and larvae development stages.

Overall, understanding the different classes of caddisflies sheds light on the diversity and versatility of these insects in their habitats.

Interesting Caddisfly Species

Caddisflies are fascinating insects with a variety of species worth exploring. For example, the Hydroptilidae, also known as microcaddisflies, are tiny and often overlooked. Let’s take a deeper look at what makes these species unique:

Hydroptilidae:

  • Smallest family of caddisflies
  • Build unique cases using silk and plant materials
  • Usually found in clean, flowing water

Leptoceridae:

The Leptoceridae family, also known as long-horned caddisflies, are well-known for their long antennae. Here are some of their characteristics:

  • Longer antennae than other caddisflies
  • Larvae known for building cases from plant materials
  • Commonly found near the edges of lakes, streams, and rivers

Enoicyla pusilla

Another interesting caddisfly species is the Enoicyla pusilla which is unique because it doesn’t require water during the larval stage. This is what sets them apart:

  • Larvae live on land rather than in water
  • Feed on decaying plant matter called detritus
  • Build cases out of leaf fragments and silk

To make it easier to compare these three fascinating caddisfly species, here’s a comparison table:

SpeciesSizeNotable FeaturesHabitat
HydroptilidaeSmallUnique case building using silk and plant materialsClean, flowing water
LeptoceridaeVariesLong antennae, cases from plant materialsEdges of lakes, streams, and rivers
Enoicyla pusillaVariesLarvae live on land, feed on detritus, leaf-based casesMoist terrestrial environment

In conclusion, caddisflies display a great diversity in size and behavior, making them an exciting topic for further exploration.

Conclusion

Caddisflies are fascinating aquatic insects that play a vital role in freshwater ecosystems. As larvae, they consume various types of organic matter found in their surroundings, including:

  • Algae
  • Leaves
  • Microbes
  • Small invertebrates

By doing so, they help maintain a healthy balance by breaking down and recycling nutrients within the aquatic environment. In turn, they become an essential food source for larger organisms, such as fish and birds.

When caddisflies transition to their terrestrial adult stage, their diet changes. They mainly feed on nectar and other liquids, using their long, threadlike antennae to navigate their surroundings.

So, let’s appreciate the role that these tiny creatures play in keeping our freshwater systems thriving.

Footnotes

  1. Caddisflies of Kentucky 2 3 4

  2. Caddisfly larvae feeding 2

  3. Aquatic Insects 2

  4. Caddisflies 2 3 4

Reader Emails

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

Letter 1 – Black Dancer Caddisfly

Subject: ID help
Location: Stamford, CT
May 22, 2015 7:47 am
Walking along a small river with a thin line of trees/shrubs on both sides in Stamford, CT on May 22, 2014, I saw this insect repeatedly on various tree and shrub leaves. There was no sign of leaf damage in the area of the insect. I was amazed by the length of the antennae – almost 2 times the body length.
Your help on ID would be appreciated!!
Signature: Patty

Black Winged Flying Insect
Black Dancer Caddisfly

Dear Patty,
We do not recognize your insect, but it looks to us like it might have an aquatic nymph.  We have contacted Eric Eaton for input and we will begun researching this after we finish cooking.

What's That Bug?  Caddisfly perhaps???
Black Dancer Caddisfly

Hi, Daniel:
This is a caddisfly called the “Black Dancer,” Mystacides sepulchralis.  The thick, leg-like things in front are actually the palps, part of its mouthparts.  They do not bite or anything, though.
Eric
author, Kaufman Field Guide to Insects of North America
http://bugeric.blogspot.com/

Thanks Eric,
We thought it was probably a Caddisfly, but didn’t have the time to research it before requesting assistance.  According to BugGuide:  “Only two species of
Mystacides occur in the east and the other one has brownish wings. … Males have red eyes.”

Letter 2 – Mystery Insect from Thailand: Beetle, Moth, Caddisfly or other????? Solved: A Fairy Moth

Funny Looking Bug or Beetle?
Location:  n.e. thailand
August 27, 2010 10:36 pm
this wonderful character was found in n.e. thailand. looks like 17th century french noble going to ball. im guessing it maybe a net wing beetle Lycidae if not that then im hoping if some recognizes this insect to help me ID it. the feathery antenna seem iridescent and the legs have feathered boots. THANK YOU, GARY HEIDEN
gary heiden

Mystery Insect from Thailand

Hi Gary,
Our first thought is that this must be a Moth, though your photos do not really show the mouthparts well enough to be able to say for certain.  Fairy Moths in the family Adelidae (see BugGuide) often have weirdly exaggerated antennae.  We cannot really find a match on the Thai Microlepidoptera page.  Netwing Beetles mimic moths, and another possibility might be a Caddisfly or even a Hemipteran.  We hope one of our readers can supply an identification.  This Thai Bugs website seems like a good place to start, though we had no luck.

hi daniel,  thank you for the tip.   now that you mention it it does look like it could be very fancy moth.   I think I have seen those feathery legs on moths.   I will go thru the moths before I rule them out.   when I track it down I will send it in w proper ID.

Thanks Gary,
It would be awesome if you let us know in the event that you manage to identify this critter.  You might also want to provide a comment on the posting of your letter, because six months from now, someone might write in to us with an identification and then you will also be notified.

Update from Karl
September 8, 2010
Mystery Insect from Thailand
Hi Daniel and Gary:
I think your first hunch was the best, Daniel. The metallic sheen and position of the wings, and overall first impression do suggest a Fairy Moth in the family Adelidae. Those antennae are quite amazing and very similar looking ones appear in several species of the Old World genus Nemophora (compare to N. issikii and N. aurifera, for example). Although I couldn’t find any images that looked the same as this one, I did find an intriguing description in a report abstract titled “Nemophora maxine: a remarkable new species of Oriental fairy-moth (Lepidoptera, Adelidae)” by Kozlov and Gaden (1996; Malayan Nature Journal; v. 50(1) p. 21-25). Describing two specimens from Thailand and Brunei they state: “The species is distinctive, with plain, coppery-brown forewings; it is the only Old World tropical adelid with uniformly coloured forewings. The female antenna is remarkable, the proximal region resembling a bottle-brush, with whorls of erect scales.” Obviously I can’t make a definitive identification for this one, but I have a feeling this might be it. This may be a rare find, or at least a rare photo – microlepidoptera often go unnoticed. If you are really curious, Gary, you can download the report (for a fee) or try contacting the authors for a confirmation. Regards.  Karl

Letter 3 – Not Owlfly, but Caddisfly from UK

Identification help please.
Location: Yateley, Berkshire
January 27, 2011 12:33 pm
Hi bugman,
I have tried to identify this off my own back but I’m stumped. I thought it is like a Mayfly but it doesn’t have long tail extensions.
Kind Regards
Signature: Matthew Harvey

Caddisfly

Dear Matthew,
We believe that because of the structure of the head and antennae, that this is an Owlfly in the Neuropteran family Ascalaphidae, but we are not certain.  We had no luck finding any matching images on the internet.  BugGuide describes Owlflies as:  “Bizarre creatures that look like a cross between a dragonfly and a butterfly. The body resembles that of other neuropterans, more-or-less, but the prominent antennae are clubbed like those of butterflies. Key characters:  Medium to large size  Clubbed antennae  Eyes large and bulge out from head  may rest in cryptic posture with abdomen projecting from perch, resembling a twig
.”  The way that the individual in your photograph holds its wings seems quite different from any other images of Owlflies we have seen.

Identification thanks to Eric Eaton
Hi, Daniel:
Thanks to the Facebook post, I can help you out with this one.  Nice shot of a caddisfly, order Trichoptera.  Seems obvious to me.  Owlflies have huge eyes, clubbed antennae, and wings like dragonflies.  Granted, caddisflies normally don’t have their wings up like this one does….
Eric

Thanks for the assistance Eric.  That makes so much sense because Caddisflies are mothlike, and we thought that the head looked somewhat Lepidopteran.  According to BugGuide:  “Adults resemble moths, but wings are hairy instead of scaly.  Forewings usually dark, sturdy, sometimes with striking color patterns, held tightly together roof-like over the abdomen when at rest.  Hindwings often clear, relatively delicate, and hidden under forewings when at rest.  Antennae usually very long, threadlike, with many segments.  Chewing mouthparts with prominent palpi.  Tarsi have five segments.  Ocelli (simple eyes) present in some families.

Hi Daniel,
Thanks for trying.
I found one image of an owlfly with a similar wing pose but I can see your point.
http://www.treknature.com/gallery/Asia/photo187343.htm
Have seen none from the UK either.
Kind Regards
Matt

Result!
Please thank Eric on my behalf.
Still can’t find an image of one with it’s wings in that position but I have to concur with Eric that he’s got it right.
Cheers
Matt

Letter 4 – Swarming Caddisflies, we believe

Teeming
Location: Davenport, Iowa
June 14, 2011 3:12 pm
Please help me identify these insects. They swarm to the security light outside of the house by the thousands. They make their way into the home and vehicles parked outside. I sprayed an insecticide directly into a cloud of these bugs on our home. They fell to the ground and within seconds, there were just as many swarming the light again. They also seem to die on their own because they literally carpet a portion of a walkway every morning. It has been happening nightly since about June 10th. It was suggested these are Mayflies however they do not resemble the photos I’ve seen online.They seem to be mounting their assault from the trees in our yard.
Signature: Puzzled.

Swarming Caddisflies

Dear Puzzled,
Your photo documents an amazing population explosion, but we wish you had a nice closeup of a single individual.   We believe these light seeking insects are Caddisflies in the order Trichoptera, and BugGuide indicates:  “Species most diverse in well-aerated streams, but also occur in lakes, ponds, and marshes. Adults rest on nearby vegetion during the day; flight activity begins at dusk. Adults are attracted – sometimes in great numbers – to artificial light.”

Caddisflies Swarming, we believe

Letter 5 – Northern Caddisfly or Snow Sedge

Subject: Insect/Bug, Sitka Alaska
Location: Sitka, Alaska
March 18, 2013 9:15 pm
I actually found this bug inside our home. I thought it was a piece of plastic that came off of our grocery’s that we brought home. It looked shiny. I thought it was a sliver of plastic until I scooped it up and it moved in my closed hand. I kinda screamed and dropped it fast. Mind you I am a 50 year old Tlingit woman who was born and raised in Alaska. My husband calls me an ”urban indian.”
After I washed my hands in both the kitchen and bathroom sink, I composed myself and decided to rescue the insect by trapping it with a mason jar and piece of paper. It crawled on the paper and I put the mason jar over it and took it outside. I placed it on the wood deck and watched it for a long time. It only crawled around and stood still for most of the time.
It is about 2 inches long.
It has black beady eyes.
Long antennae’s.
Long skinny shiny brown and white spotted wings that hug its body at the side.
I’ve seen the wing colors in all various shades of brown and even orange. Like fish egg orange.
Sometimes spotted and not. Their wings look shiny too.
I’ve seen them with their legs and wings tucked in, so they look ultra skinny, hard to spot.
I think they like to hang around the Alaskan wet woods.
I’ve occasionally seen them and wondered what kind of bug is it.
My twin sister in Juneau said they never see that kind there.
Thank you very much!
Signature: Scared of insects, but fascinated with them

Snow Sedge
Snow Sedge

Dear Scared of insects, but fascinated with them,
We hope our response will prompt additional curiosity and not fear and loathing.  This is a Northern Caddisfly and previous research unearthed the common name Snow Sedge.  Please see our previous posting on the Snow Sedge for more information and links to our research.  Caddisflies cannot survive in polluted waters, so their presence is an indication of the purity of your local streams and ponds.

Letter 6 – Zebra Caddisfly

Subject: Unknoown Bugs
Location: Charlotte area (Ft. Mill, SC)
August 15, 2014 11:19 am
Hi. I know your busy, but I have two bugs I just can identify.
Image #1 is a brown turtle-shaped bug. Found at the edge of a pond. It is about nickel size.
Image #2 is a bug that was attracted to a naight light.
Both were photographed in the Jul-Aug period this year in the Charlotte (NC) area.
Thanks. No rush in geting an answer.
Signature: Dr. Danny O. Crew

Zebra Caddisfly
Zebra Caddisfly

Dear Dr. Crew,
Your first bug is some species of Stink Bug, and we will attempt to be more specific in the future, but your second image has us very excited.  We did not know how to begin to classify this winged insect with such extremely long antennae, but diligent searching eventually led us to the Zebra Caddisfly,
Macrostemum zebratum, on BugGuide.  Caddisfly larvae are aquatic, and the adults are not strong fliers, so they are generally found near water.  As you indicated, adult Zebra Caddisflies are attracted to light.  This is a new species for our site.

Thanks. I do live on a large pond.  As for the stink bug?, that was my first thought; however, it looked more like a beetle/turtle and was thick with a very round shell. I’ve never seen a stink bug like that. Also it was larger than most I’ve seen. I’ll await your research.

Letter 7 – Caddisfly or Barklouse from Puerto Rico

Subject: Help identifying flying insect
Location: San Juan, Puerto Rico
September 29, 2015 8:37 pm
Hi,
I’m from Puerto Rico and there are some fun bugs down here in the Caribbean. We recently found this guy in the bedroom and as I reasoned with my wife not to swat it we lost it. What is it? I am including a photo.
Signature: Antonio Rodríguez, bug apologist

What's That Bug???
What’s That Bug???  A Barklouse Perhaps

Dear Antonio,
This has us a bit stumped, and we haven’t much time to research this morning, though we did quickly look at the Insects of Puerto Rico site.  Our initial thought is that it reminds us of a member of the order Mecoptera (see BugGuide) which includes Scorpionflies and Hangingflies, but we might be way off the mark.  Perhaps one of our readers will be able to supply some information.

Update:  Barklouse perhaps
Lepidopterist Julian Donahue wrote in a comment indicating perhaps Psocoptera, and we located a similar looking Peruvian Barklouse on Alamy.

Update:  November 10, 2018
We just approved a comment with a link that indicates this might be a Caddisfly.

Letter 8 – Scorpionfly or Caddisfly???

Subject: Help!
Location: Central Texas
March 26, 2016 4:48 pm
Can you please help us identify this bug?
Signature: Abby

Possibly Scorpionfly
Possibly Scorpionfly

Dear Abby,
We believe this is a Scorpionfly in the order Mecoptera, but we cannot find any images of individuals with black wings and an orange body on BugGuide other than
Panorpa lugubris, which is definitely not your species.  We are requesting assistance from Eric Eaton.  If possible, can you send additional images showing the insect from a lateral view that would show details of the head and mouthparts?  Thanks.

Eric Eaton poses another possibility
Daniel:
I am thinking this is a caddisfly of some kind.
Eric

Letter 9 – Stonefly Exuvia and Caddisfly Naiads

Subject: Aquatic bug?!
Location: Glacial river, base of mt Rainier
July 31, 2017 8:24 pm
Hello! We were out playing in a very cold glacial river at the base of Mt Rainier in Washington state and came across these guys today. There were hundreds of them on rocks in the water, but only a few this sprawled out and large outside the water.
Signature: Alexa

Stonefly Exuvia

Dear Alexa,
Your images document two different, unrelated aquatic insects.  The image of the one “sprawled out and large outside the water” is actually the exuvia or cast-off exoskeleton of a Stonefly, and the “hundreds of them on rocks in the water” are Caseworms, the larvae or naiads of Caddisflies.  Larval Caddisflies are known as Caseworms and according to BugGuide:  “Most species live in a mobile case constructed from plant material, algae, grains of sand, pieces of snail shells, or entirely of silk. The case is held together with strands of silk secreted by the larva. In some species the case is attached to a rock, log, or other underwater surface; a few species have no case and are free-living.”  The cases on your individuals appear to be constructed using grains of sand or small pebbles.

Caseworms: Caddisfly Naiads
Caseworms: Caddisfly Naiads

Letter 10 – Zebra Caddisfly

Subject:  Need Help to Identify this Insect
Geographic location of the bug:  Lanark County, Ontario, Canada
Date: 01/13/2019
Time: 01:58 PM EDT
Your letter to the bugman:  Hello,
I have been unable to find any insect anywhere on the internet that looks like the one that I photographed in Lanark County, Ontario, Canada, in June of 2018. It is on the leaf of a Sumac tree, if that helps to determine approximate size.
Appreciate any assistance you can provide in identifying this insect.
Thank you.
How you want your letter signed:  Stu

Zebra Caddisfly

Dear Stu,
This is a Caddisfly in the order Trichoptera, a group of mostly drab, mothlike insects with aquatic larvae, meaning they are generally found near a source of water where the nymphs are able to develop.  Your individual is very brightly colored, and we quickly identified it on BugGuide as a Zebra Caddisfly,
Macrostemum zebratum.  According to BugGuide:  “adults Jun-Jul”, so your sighting was right on schedule.

Zebra Caddisfly

Hi Daniel,
Thank you for the quick identification. It is amazing that, once you have the identity, how many images you can now find on the internet, but beforehand, I couldn’t find any!
Your note that they are generally found close to a source of water was spot on… the Sumac trees were within twenty-five yards of the Mississippi River.
Thanks again,
Stu

Letter 11 – Do Caddisflies have a bad odor?

Subject:  Identify Bug Please
Geographic location of the bug:  Keene, NH USA
Date: 11/06/2019
Time: 04:13 PM EDT
Your letter to the bugman:  All I know is it gives off an awfule scent. What kind of bug is it and where is the scent coming from?
How you want your letter signed:  Frank F

Caddisfly

Dear Frank,
This is a Caddisfly, an insect with an aquatic nymph, so Caddisflies are generally found near a source of water.  We cannot ever recall any scent when we have encountered Caddisflies, nor can we recall reading about strong smells associated with Caddisflies, so we tried to research the matter.  There is no mention of an odor emanating from the insects in the Central Arizona Project page on Caddisflies nor is there a mention of an odor on the Encyclopaedia Britannica page.

Authors

    by
  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

16 thoughts on “What Do Caddisflies Eat? Unveiling their Surprising Diet”

  1. Hi Karl & Everyone at What’s That Bug. I contacted Prof. Kozlov one of the authors of the sited article as follow up. He stated that there are many species in fairy moth families that need dysection to make proper ID. He did state that species in my photo was probably closely related moth that is new species in same family and is as yet undiscribed to science or there is a chance it is indeed (Nemophora maxinae) note the spelling correction. It seems there are no properly ID N maxinae on line at present and my pictures maybe as close as it comes as leading expert couldnt tell for sure even though he said my pictures were excellent. The size of the moth is crucial in helping to determine species and N. maxinae doesnt get larger then approx. 6mm My moth may have been slightly larger. yes these pics seem very rare indeed. thanks so much, gh.

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  2. I found something very similar in Ceiba, Puerto Rico, a year ago. I have a picture of the profile of the insect and to me it does look like a Scorpionfly. I don’t know how to post a picture here, but the picture has been posted on iNaturalist so I put the link to the observation under Website.

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  3. I think they do:
    https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-7998.1914.tb07050.x
    https://www.biodiversitylibrary.org/part/56894#/summary

    On page 686 here: https://www.mapress.com/zootaxa/2007f/zt01668p698.pdf
    “The primary food source is leaf litter detritus. Males of many species have modified antennal scapes with scent scales or scent glands, eversible glands on the face, or mask-like maxillary palps,
    or a combination of these.”

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