The Tile Horned Prionus is a fascinating beetle that often goes unnoticed due to its nocturnal behavior and tendency to hide during the day. These robust and somewhat flat beetles have distinctive antennae that are about half the length of their bodies. In this article, you’ll get an up-close look at these amazing insects and learn everything you need to know about them.
You might come across these beetles around pecan, hickory, and oak trees, as they play a vital role in the ecosystem. The female Tile Horned Prionus lays eggs in the soil surrounding these trees, and the larvae feed on the tree roots. The development process takes around three to five years before they reach maturity and pupate.
Their large size, unique antennae, and fascinating life cycle set this beetle apart from others. As you read on, you’ll discover more intriguing details about the Tile Horned Prionus, including their significance in nature and interesting behaviors that make them a captivating subject to study.
What is a Tile Horned Prionus
Defining the Genus Prionus
The Tile Horned Prionus, scientifically known as Prionus imbricornis, is a member of the genus Prionus. This genus falls under the long-horned beetle family, Cerambycidae. These beetles, also known as longicorns, are known for their distinctively long antennae. The Tile Horned Prionus is native to eastern parts of the United States and is among the largest insects in the region1.
Key features of the Tile Horned Prionus:
- Robust and broad body
- Flattened blackish to reddish-brown coloration
- Antennae roughly half the length of body
Differentiating Between Prionus Species
Several Prionus species are similar in appearance, but each has unique characteristics to help distinguish them:
-
Tile Horned Prionus (P. imbricornis): Notable for its antennae with comb-like projections or “tiles”
-
Eastern Prionus (P. heroicus, previously P. laticollis): Known for its large size and broad flattened neck
-
Brown Prionid (P. californicus): Identified by its reddish-brown color, abundant in the western United States2
Comparison Table:
| Feature | Tile Horned Prionus | Eastern Prionus | Brown Prionid |
|---|---|---|---|
| Antennae | Comb-like “tiles” | Long | Long |
| Region | Eastern US | Eastern US | Western US |
| Color | Blackish to red-brown | Red-brown | Reddish-brown |
| Size (Adult) | Large | Very large | Large |
| Neck Shape | Normal | Broad, flattened | Normal |
By understanding the distinct characteristics of each species, you can better differentiate between the different Prionus beetles in the wild.
Physical Characteristics
Size
The Tile Horned Prionus (Prionus imbricornis) is a large beetle species. Its size can range from 1 to 3 inches in length. Generally, males are slightly smaller than females.
Color and Appearance
The color of this beetle varies from reddish-brown to black, making it easy to blend in with its surroundings. Its body is elongated and somewhat flattened. The exoskeleton is hard and shiny, with a smooth texture on its surface.
Features and Structures
- Bark: The Tile Horned Prionus is often found near decaying wood, where it feeds on the bark and underlying layers.
- Antennae: These beetles have long, impressive antennae with 12 to 20 segments. Each segment has serrated edges and overlaps the following one, resembling tiles – hence their name.
- Male antennae are more intricate and have a higher number of antennal segments, while female antennae are relatively simple with fewer segments.
- Serrated segments: The overlapping serrated segments of their antennae give them a highly sensitive sense of touch and smell, which they use for foraging and locating mates.
In conclusion, the Tile Horned Prionus has a number of distinct physical characteristics. Keep in mind that this beetle can vary in size and color, but its defining features like the antennae and serrated segments make it easily identifiable. Remember to consider these traits when observing this fascinating species.
Biology and Behavior
Life Cycle
The life cycle of the Tile Horned Prionus starts with eggs. The female lays these tiny eggs near the base of trees or in the soil. The larvae hatch within a few weeks and begin to feed on roots. They spend about three years underground, feeding and growing. After this period, they emerge as adults to start the process all over again.
Habitual Behavior
The Tile Horned Prionus is known for its nocturnal behavior, making it more active during the night. Attracted to light, males often come to lights when they’re seeking out a mate. They’re strongly attracted to lights, so you might notice them around outdoor lamps or other illuminated areas.
Feeding Behavior
These insects are considered root borers, meaning they feed on the roots of various plants. The larvae cause the most damage, as they tunnel through roots to feed, which can create significant problems for trees and other plants.
- Larvae feed on roots
- Tunneling through roots can harm plants
Reproductive Behavior
In their reproductive phase, both male and female Tile Horned Prionus display certain behaviors. Males are drawn to light sources, likely in search of a partner. Meanwhile, females seek out ideal spots near tree bases or in soil to lay their eggs. Once a mate is found, the female lays her eggs, beginning a new life cycle for this unique insect.
In summary, the Tile Horned Prionus has a three-year life cycle, starting as eggs and ending as adults. This nocturnal insect is attracted to light, particularly males in search of a mate. They’re known as root borers, with their larvae causing most damage to plants. Their reproductive behavior revolves around light attraction and egg-laying near tree bases or in soil. Remembering these characteristics will help you better understand the biology and behavior of this fascinating creature.
Habitat and Range
United States
The Tile-horned Prionus is widely distributed across the United States, with records from states such as North Carolina, Virginia, New York, Georgia, Texas, and Iowa. This eastern species is particularly active at night, and they tend to hide during the day.
In the United States, you can commonly find these beetles around various tree species:
- Pecan
- Hickory
- Oak
Natural Habitat
Tile-horned Prionus beetles are most commonly found in forests where their preferred trees grow. Their natural habitat is characterized by soil surrounding pecan, hickory, and oak trees. The larvae feed on tree roots, taking approximately three to five years to mature and pupate.
These nocturnal beetles prefer to stay hidden during the day, which helps them avoid predators. If you happen to come across one in the forest, it’s likely they were just taking a break from their nighttime activities.
Interactions with Humans
Local Pest
Tile Horned Prionus beetles, including species such as Prionus imbricornis and Prionus laticollis, can occasionally become local pests. These insects may cause damage to the roots of trees and other plants.
In Homes and Gardens
You may encounter these beetles near light sources, such as lights or lighted windows. This is because they’re attracted to artificial light at night. Although the beetles themselves don’t cause damage to your home, they can be a nuisance.
Identifying Insects
Correctly identifying insects in your environment is essential to understanding and appreciating the diverse natural world. For example, you might see a beetle resembling a Prionus imbricornis but end up realizing it’s an American cockroach, which is a completely different insect. To get accurate identification, try looking up pictures online or contacting your local extension office.
Dealing with Infestations
In case of infestations in your garden, take steps to deal with the issue without causing unnecessary carnage. Consulting expert professional advice can help you determine the most effective and least harmful methods of dealing with unwanted insects.
Sharing Accurate Information
It’s essential to share accurate information about insects like Tile Horned Prionus beetles. Websites such as BugGuide.net offer resources for both naturalists and amateurs to identify and learn more about these fascinating creatures. By seeking out expert advice and contributing to the sharing of accurate information, everyone can benefit from understanding the role these insects play in the ecosystem.
Classification and Taxonomy
Coleoptera
The tile-horned prionus beetle belongs to the order Coleoptera within the animal kingdom. This order contains a wide variety of beetles, making it the largest order in the class Insecta. Being part of the Arthropoda phylum, these beetles have a hard exoskeleton and jointed legs.
Some characteristics of Coleoptera include:
- Two pairs of wings
- Front wings, called elytra, are hard and protect the softer hind wings
- Mouthparts adapted for chewing
Cerambycidae
The tile-horned prionus beetle also belongs to the family Cerambycidae, commonly known as longhorn beetles. This family is part of the subfamily Prioninae and includes large beetles with long antennae.
Features of Cerambycidae include:
- Elongated bodies
- Often brightly colored or with intricate patterns
- Antennae that are at least half the length of their body
While there are numerous similarities, the features distinguishing the tile-horned prionus beetle from other beetles in the Cerambycidae family include their unique antennae and their mostly nocturnal behavior. These beetles are also known to lay their eggs in the soil surrounding trees such as pecan, hickory, and oak trees, with the larvae taking around three to five years to grow to maturity and pupate. You might be interested in knowing that tile-horned prionus beetles are not typically seen during the day, as they tend to be active at night and hide during daylight hours1.
Footnotes
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 – Unnecessary Carnage: Tile Horned Prionus
Subject: I think it’s a roach…
Location: Georgia, USA
June 3, 2012 8:50 am
I’m in Georgia, USA. I’m pretty familiar with most of the roaches that live around here. A couple nights ago when a storm hit I had three of the critters pictured scampering around. Unlike a normal cockroach, these guys were actively buzzing about and flying.
Also, unlike most pictures of cockroaches I could find in Google, these guys have beetle-like antenna; much larger and more pronounced than the ordinary cockroach.
However, the body structure and color doesn’t exactly match most of the common beetles Georgia is supposed to have. The body and color of these bugs is much closer to the American Cockroach.
So, I’m pretty sure these are roaches, but I think I’d rather know for sure.
Pictures are 3264×2448 resolution, 50% jpeg quality as saved through GIMP 2.6. If you need the source pictures, I can throw them up on Gdrive.
Signature: Liaison
Dear Liaison,
This magnificent beetle is a Tile Horned Prionus, Prionus imbricornis, and he is a male as evidenced by his incredible antennae. We hope that our response will serve to educate you on the importance of tolerance of the lower beasts since it appears that this Tile Horned Prionus is dead, presumably due to the intervention of humans which we determine to be Unnecessary Carnage. We understand that you mistook the Tile Horned Prionus for a Cockroach, but we hope that in the future, you will not react so quickly. Adult Tile Horned Prionus Beetles have very strong jaws and they could easily draw blood if carelessly handled, but they will not bite unless provoked. According to BugGuide: “Female lays 100-200 eggs around the base of various trees, vines, herbs. (These include oak, grape, pear, and maize.) Larvae feed on bark and roots. Larval stage lasts three years or more. Strongly attracted to lights.” The wet weather probably triggered an emergence and your lights most likely attracted the beetles to your home.
Letter 2 – Tile Horned Prionus
Large Beetle
Location: Norfolk, Virginia USA
June 6, 2011 10:31 am
This was on my front door lastnight, cant find a discription of any like it online. It was app. three inches long.
Signature: Bugman
This is a Root Borer in the genus Prionus. It is a male Tile Horned Prionus, Prionus imbricornis. BugGuide provides this identification information: “Huge longhorn, dark brown and shining. Antennae have 18-20 overlapping segments (male): Female has 16-18 serrated segments. Other eastern Prionus have 12-13 antennal segments.” BugGuide also provides this information which may explain this Tile Horned Prionus’s appearance on your porch if the light was left on: “On mid-summer nights, these hit lighted windows so hard at my house in Durham, North Carolina, that I fear the glass will break. Seems that mostly males come to lights.”
Letter 3 – Tile Horned Prionus
Big black beetle
Fri, Jun 12, 2009 at 7:45 AM
Dear Bugman,
I found this guy last night on my front porch during an intense thunderstorm. He was two to three inches long. I’ve never seen anything like this, can you identify it?
C. Conner
Central North Carolina
Dear C. Conner,
This magnificent specimen is a male Tile Horned Prionus, Prionus imbricornis. According to BugGuide: “On mid-summer nights, these hit lighted windows so hard at my house in Durham, North Carolina, that I fear the glass will break. Seems that mostly males come to lights. “
Letter 4 – Tile Horned Prionus
2 Large Unidentified Bugs, Possibly Beetles, With Large “Feathery” Antenna
July 18, 2009
Hi there! We found these two bugs yesterday floating in our cat’s water dish on the back porch. They appear of the same type, I assume they are male and female, who were attempting an ill-fated waterside rendezvous.
We are in the middle of South Carolina and it is currently the middle of the summer here… bug season for sure!
In the photo, the smaller and slightly lighter colored bug was impossible to keep flipped over. However, its back looked just like the other bug. Both have longish, almost “feathery” looking antenna, which we found unusual.
We’ve seen lots of beetles before, but none like these (if that is what they are). We would appreciate your help in identifying these two bugs! Thanks!
Rinella Family, SC
Southeastern US, Pelion, SC
Dear Rinella Family,
Each of your beetles is a male Tile Horned Prionus, Prionus imbricornis. There is a natural size range that has nothing to do with the sex of the beetles. The antennae distinguish the male from the female. We suspect your cat dish was near a light source since these beetles are often attracted to lights.
Letter 5 – probably Tile-Horned Prionus
Reaallly big bug in driveway!
Hi Bugman!
We found this guy parked in our driveway tonight. Not sure, but think it may be some kind of beetle. Can you help us identify? It’s actually quite attractive. Note the classic lines, body contours and attention to detail. The serrated curb feelers for parallel parking are a nice touch.
This is one of the Root Borers in the genus Prionus, probably the Tile-Horned Prionus, Prionus imbricornis. Global coordinates would have helped.
Letter 6 – Decapitated head of a Tiled Horned Prionus
Subject: What kind of bug is this?
Location: Virginia
June 17, 2016 1:38 pm
Hi,
Do you know what type of bug this is? I saw it on my sidewalk. Thank you!
Signature: Concerned
Dear Concerned,
This is the disembodied head of a Tile Horned Prionus, a large beetle with a very nutritious body. We suspect a bird or other predator ate the body and left the unappetizing head for you to discover on the sidewalk. Here is an image of an intact male Tile Horned Prionus.
Letter 7 – Male Tile Horned Prionus
Subject: Big beetle?
Location: Georgia
July 6, 2013 8:06 pm
I found this beetle in the breezeway of my apartment building at about 10pm tonight. It has been raining for the past few days and it’s the middle of the summer, so it’s hot and humid. I live in Georgia. The bug is at least two inches long with very big antennas.
Signature: Jackie
Hi Jackie,
This is a male Longhorned Borer Beetle in the genus Prionus. We believe it is a Tile Horned Prionus, Prionus imbricornis. See BugGuide for a matching photo.
Letter 8 – Male Tile Horned Prionus
Subject: Strange beetle with feather-like antennae.
Location: Tallahassee, FL
June 20, 2016 7:31 am
Hello,
My father ran across this beetle n June 19th is Tallahassee, FL and we were wondering what kind it might be.
Signature: David Robinson
Hi David,
Now that summer is upon us, we are beginning to receive submissions of Root Borers from the genus Prionus as well as other large Prionids. There are different species from different parts of the country, and your individual is a male Tile Horned Prionus, Prionus imbricornis. The species is described on BugGuide as: “Huge longhorn, dark brown and shining. Antennae have 18-20 overlapping segments (male): Female has 16-18 serrated segments. Other eastern Prionus have 12-13 antennal segments.” Earlier in the week we posted this arresting image of the decapitated head of a male Tile Horned Prionus.
Letter 9 – Male Tile Horned Prionus
Subject: Prionus Californicus in Tennessee?
Location: White County, Tennessee
June 20, 2016 11:10 am
I photographed this creature on my porch rail last night and posted it on IG in order to get feedback. Two people suggested it was a Prionus Californicus and gave me references. I’m pretty sure it IS one but what is it doing in Tennessee? With all of our nursery stock, I wonder if they’re plentiful here, have they been here a long while, how WE have come to have them, and are our nurserymen aware of them? I’m from Warren County, but this bug was found up at our river front property in Neighboring White County.
Thanks so much!
Signature: Peggy S Thompson
Dear Peggy,
This is indeed Prionus, but it is NOT P. californicus. In scientific nomenclature, the capitalized first word in the binomial name is the genus, and the second lower case word is the species. The members of the genus are closely related and often share physical attributes, and frequently they can be difficult to distinguish from one another. According to BugGuide, there are 16 North American species in the genus, and Prionus californicus is found as far east as Texas, according to BugGuide. Your relative is the Tile Horned Prionus, Prionus imbricornis, and its range is according to BugGuide, partially overlaps that of the California Root Borer, and includes Tennessee. The impressive antennae on your individual indicates he is a male. This is the third Tile Horned Prionus we have posted this week, though the first was a disembodied head.
Daniel,
Thanks so much for such a quick reply, ID, and also for posting my “Tile Horned Prionus” online for others to see. I had several people interested in him and his “Yosamitty Sam” antennas! Now WE know him…
Peggy T.
Letter 10 – Male Tile-Horned Prionus
Subject: Beetle
Geographic location of the bug: Morrow georgia
Date: 06/29/2018
Time: 10:05 PM EDT
Your letter to the bugman: Thought it was a Palo Verde but to far east.
How you want your letter signed: Just curious
Your case of mistaken identity is understandable. This male Tile-Horned Prionus is in the same tribe as the Palo Verde Root Borer. According to BugGuide: “Huge longhorn, dark brown and shining. Antennae have 18-20 overlapping segments (male).”
Letter 11 – Male Tile Horned Prionus
Subject: What is this? (flying beetle?)
Geographic location of the bug: Nashville, Tennessee
Date: 07/10/2021
Time: 07:53 AM EDT
Your letter to the bugman : Keep seeing about 5 or more of these things on my porch every night. Never seen them before. In one of the photos you can see in next to the door bell for size reference. It’s quite large.
How you want your letter signed: Max
Dear Max,
The male Tile Horned Prionus, which is pictured on BugGuide, Prionus imbricornis, is one impressive beetle. According to BugGuide: “larvae feed in living roots, primarily oak and chestnut, but also grape, pear, and corn.” BugGuide also includes this reader observation: “On mid-summer nights, these hit lighted windows so hard at my house in Durham, North Carolina, that I fear the glass will break. Seems that mostly males come to lights.”
Letter 12 – Tile Horned Prionus
Prionus somethingorothericus?
Here’s a photo of two very large beetles hanging around on my backyard window screen. I’m thinking it some type of woodboring beetle. Your help, as always, would be appreciated. By the way, they don’t appreciate being handled, as I could tell by the frantic little squeals they would make when I picked them up. Don’t worry, though, I never hurt my little buddies that I find, only photograph them.
Stefan Bowers
Fort Gordon, GA
Dear Stefan,
You are correct. These are Tile Horned Prionus beetles, Prionus imbricornus. It seems many species of Prionids are appearing across the nation.
Letter 13 – Tile-Horned Prionus
unknown critter
Hi:
I live in Glen Burnie, MD and saw this bug on my back porch. I am not sure what it is, so I thought I would ask you. So, what is it? He looks pretty scary. He was found at night. Thanks.
Erica
Hi Erica,
We are being besieged with images of Prionid Beetles in several genera from coast to coast. Your trophey male is one of the most spectacular, the Tile-Horned Prionus, Prionus imbricornis. You can see more on BugGuide. We especially love your head-on view of his magnificent antennae.
Letter 14 – Tile Horned Prionus
huge roach or beetle?
June 14, 2010
Found this very large thing on our front porch on a very hot day in Virginia. It’s seen here crawling on a clothespin. It is very active and fast. It flips on its back a lot and has trouble righting itself. I’d say it’s about 2″ long, not including the huge antennae. Sorry the image is blurry–this thing won’t stop moving.
LAB
Richmond, Virginia
Hi LAB,
This is one of the Root Borers in the genus Prionus, most likely the Tile Horned Prionus, Prionus imbricornis. We will be postdating your letter to post later in the week to cover our absence from the office.
Letter 15 – Tile Horned Prionus
Subject: Brown Beetle on my Screen porch
Location: Piedmont region, Apex, NC
July 18, 2017 7:53 pm
I found this beauty on my screen porch after a rain, it is about 1.5 inches long with the most interesting antennae. I cannot find a decent key that tells me more than that it is a beetle which I guesses. 71degrees F suburban piedmont NC Semi-wooded lot next to pasture land.
Signature: Debi
Dear Debi,
The spectacular antennae identify this as a male Tile Horned Prionus, and according to BugGuide: “Huge longhorn, dark brown and shining. Antennae have 18-20 overlapping segments (male). Female has 16-18 serrated segments. Other eastern Prionus have 12-13 antennal segments.” BugGuide also states: “On mid-summer nights, these hit lighted windows so hard at my house in Durham, North Carolina, that I fear the glass will break. Seems that mostly males come to lights.”
Letter 16 – Tile Horned Prionus
Subject: What is this Beetle?
Geographic location of the bug: Midlothian, Virginia, USA
Date: 08/18/2018
Time: 11:55 AM EDT
Your letter to the bugman: Can you tell me what this bug is ? It is about 1.5” long, black.
Thanks
How you want your letter signed: Dennis Shand
Dear Dennis,
This is an impressive Tile Horned Prionus, Prionus imbricornis, and according to BugGuide: “Huge longhorn, dark brown and shining. Antennae have 18-20 overlapping segments (male). Female has 16-18 serrated segments. Other eastern Prionus have 12-13 antennal segments.”
Letter 17 – Tile Horned Prionus from Virginia, In November!!!
Is this a Fire-colored beetle?
Location: Midlothian, Virginia
November 25, 2011 9:17 pm
Found this bug crawling across the carpet on night. It’s legs made a clicking sound as it walked. Not quite sure what it is. It’s about 1 inch long.
Signature: Grant
Hi Grant,
This is a Tile Horned Prionus, Prionus (Neopolyarthron) laticollis. These root borers are generally sighted in July and August, so a November sighting is unseasonably late, however, BugGuide indicates the season as “April to November (Northeast).” Perhaps it emerged from firewood that you brought indoors, which is often the case with the various insects that have wood boring larva because the warm indoor temperatures trigger an early emergence.
Letter 18 – Tile Horned Prionus swatted with fly swatter!!!
Subject: Large flying beetle
Location: Somerset Kentucky
July 27, 2012 11:57 pm
So my friend posts this picture of a beetle that was in hot pursuit of her and that she killed with a fly swatter. She said it made a busy noise and as you can see from the picture it has long feather like antennae and pincers. To me it looks like half moth half beetle. Identifying it would be a great help.
Signature: Egads!
Dear Egads!,
This magnificent beetle is a Tile Horned Prionus, a male judging by the antennae. The larvae feed on rotting wood, especially roots and males are frequently attracted to lights, which is most likely how this individual found itself indoors and the victim of Unnecessary Carnage. Alas, because of their large size, Tile Horned Prionus are frequently killed unnecessarily.
Letter 19 – What Killed the Tile Horned Prionus???
found this bug
Location: aberdeen, Mississippi
July 20, 2011 11:03 am
Hi there! I found tho bug on my moms farm in Aberdeen, Ms, on Monday. The ants were killing it at the time. I put it on a shelf outdoors for safe keeping…hope the ants didn’t find him! Do you have a four what this is. My cousin said it was a tick on steroids. Haha!
Signature: cindy christian
Hi Cindy,
We frequently receive photos of the decapitated heads of large beetles. This is a Tile Horned Prionus, and he is a male judging by the antennae. Birds will eat the beetles, but discard the hard head that hasn’t much nutritional value. The fat body contains all the calories needed by the bird. Here is a link to a complete beetle from our archives.
so obviously not a roach. sigh.
So I know the diet of the larvae consists of the roots of trees, but does anyone know what the diet is of the mature life stage? I’m assuming there is no difference in the diet between the male and female form. And how about the duration of each of the different life cycles. Any thoughts?
According to the Utah State University Integrated Pest Management site: “Adults emerge from pupae in the soil in July in northern Utah. The beetles fly at night in search of mates, and eggs are laid in the soil soon thereafter. Young larvae tunnel into the soil to seek out tree roots. Research in a Utah sweet cherry orchard suggests that the younger larvae begin feeding on smaller diameter roots and ultimately reach the tree crown as mature larvae as they move inward and upward along larger roots. The ‘crown’ refers to the region of the trunk (usually at or near the soil level) that represents the transition between below-ground (roots) and above-ground (trunk) growth. In cherries, a greater proportion of the larvae found at the crown were large, mature larvae, while most of the smaller, younger larvae were found in roots. Following 3 or more years of root and crown feeding and upward movement, the insect pupates close to the soil surface. The adults then emerge and seek out mates.” Nothing is said of the diet of adults. We would presume that if they eat at all, the adult Prionids would be attracted to sweet sticky things like sap. We will continue to research this matter.
We have 2. Of them is a yard
I found one today, looked it up… the beetle was about 3 inches long.
It was on its back, and I flipped it over thinking that it would help… but no… this afternoon I went back out to see if it was gone, and it was dead. I live in oregon, so I don’t see many beetles this big. at least now i know the name of this big beetle.
❤️ unnecessary carnage ❤️