Red-Shouldered Bug Demystified: Identification and Intriguing Facts

folder_openHemiptera, Insecta
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The red-shouldered bug, also known as the golden rain tree bug or Jadera haematoloma, is a common insect found in various parts of the United States. These bugs are known for their distinctive red markings, which can be seen on their eyes, back, wings, and along the sides of their thorax. Red-shouldered bugs are typically between 3/8 to 5/8 inches long and have a somewhat flattened appearance. They can be found in wooded areas, gardens, and sometimes even homes when seeking shelter during colder months.

Being considered a scentless plant bug, the red-shouldered bug doesn’t emit any particular odor, making it less bothersome for homeowners compared to other insect pests. These bugs mainly feed on seeds of certain plants, such as golden rain trees and boxelders, which can lead to small infestations in areas where these plants are abundant. In general, red-shouldered bugs are not considered harmful to plants or humans, but may become a nuisance if they gather indoors or in large numbers.

One important distinction between red-shouldered bugs and their close relative, the boxelder bug, is the pattern of red markings on their bodies. Boxelder bugs typically have three red stripes running lengthwise behind their head, while red-shouldered bugs have only two red stripes in the same area. This difference can serve as a helpful guide for identification when dealing with these insects in your home or garden.

Red-Shouldered Bug Overview

Classification

The red-shouldered bug, scientifically known as Jadera haematoloma, belongs to the family Hemiptera, also known as the “true bugs.” These insects are often found in gardens and landscapes, feeding on various plants.

Identification

Red-shouldered bugs can be identified by their unique appearance, which includes:

  • Flattened body
  • About 1/2-inch long and 1/3-inch wide
  • Brownish-gray to black color
  • Distinctive red eyes
  • Red markings on the pronotum (segment behind the head)
  • Three red lines running lengthwise on the pronotum

Nymphs vs. Adults

Red-shouldered bug life stages can be differentiated as follows:

Nymphs:

  • Bright red color
  • Black legs and antennae
  • Develop black markings and wing pads as they grow

Adults:

  • Red eyes
  • Red markings on the pronotum
  • Red “shoulders” or lines on the sides of the thorax

Here’s a comparison of red-shouldered bugs’ key features:

Feature Nymphs Adults
Size Smaller About 1/2-inch long
Color Bright red Brownish-gray to black
Legs & Antennae Black Same as nymphs
Red Markings Develop as they grow Pronotum & “shoulders”
Life Stage Immature Mature

Remember, when identifying red-shouldered bugs, pay close attention to the distinctive red markings on their body and the red eyes. This will help you differentiate them from other similar insects.

Natural Habitat and Range

United States Distribution

The red-shouldered bug (Jadera haematoloma) can be found in various regions of the United States. They are commonly encountered in:

  • Florida: The red-shouldered bug has a strong presence in this southern state. 1
  • Texas: This state also provides a suitable habitat for this bug. 2
  • California and Colorado: They can be found in these western states as well. 3

Central and South America Distribution

The red-shouldered bug also inhabits countries in Central and South America. Some of these locations include:

  • Mexico: This bug has been reported in certain areas of Mexico. 4
  • Central America: They can be found in countries such as Guatemala and Belize. 5
  • South America: Red-shouldered bugs have been spotted in Venezuela and Colombia. 6
  • West Indies: The bug is also present in the Caribbean region, including Puerto Rico. 7

Feeding Habits and Diet

The Red-shouldered bug mainly feeds on seeds and sap. They can also consume dead insects, flowers, and buds. These bugs are often confused with Boxelder bugs due to their similar appearance and diet.

  • Nymphs and adults have similar diets
  • Prefer boxelder trees and western soapberry (soapberry bug)

Their diet also includes fruit trees like:

  • Apple
  • Peach
  • Grape
  • Plum
  • Cherry

Red-shouldered bugs can also feed on other trees such as:

  • Chinaberry
  • Ash
  • Maple

Here’s a table comparing Red-shouldered bugs and Boxelder bugs:

Feature Red-shouldered Bug Boxelder Bug
Appearance Red-shouldered, black Black, red markings
Diet Seeds, sap, dead insects Seeds, sap, tree buds
Common Hosts Boxelder, soapberry Boxelder, maple trees

In conclusion, the Red-shouldered bug is a resilient and adaptive insect with diverse feeding habits. This versatility allows them to thrive in various environments, though they remain partial to boxelder trees and western soapberries.

Life Cycle and Reproduction

Eggs and Nymph Stages

Red-shouldered bugs start their life as eggs. Females lay light yellow eggs that soon darken to rusty red. Nymphs emerge from these eggs, starting their life cycle.

  • Nymphs are bright red.
  • Older nymphs have dark gray wing pads.
  • Head, legs, and antennae are gray.

Nymphs go through several instars, or stages of development, before reaching adulthood. They develop black markings and wing pads as they grow.

Adult Stage

In the adult stage, red-shouldered bugs are:

  • Flattened, about 1/2-inch long.
  • 1/3-inch wide.
  • Brownish-gray to black.
  • Characteristic red eyes, back (pronotum), and wing markings.

Adult red-shouldered bugs don’t have a central red stripe on the pronotum of the thorax. Instead, they have a distinctive red line on both sides of the thorax or ‘shoulder’ (source).

During winter months, adult red-shouldered bugs overwinter or hibernate. They find shelter in dry, protected places to survive the cold weather. After overwintering, adults emerge to lay eggs, starting the life cycle once again.

Physical Features and Identification

Size and Body Structure

The red-shouldered bug is a small insect with a size of about 1/2 inch long and a width of 3 to 4 mm. Its body is somewhat flattened, making it easy to identify. Key physical features include:

  • Small size
  • Flattened body
  • Distinct thorax

Color Patterns

These bugs have unique color patterns for easy identification. The most notable features are their red eyes and pronotum with red markings. Other color features include:

  • Red eyes
  • Red markings on the thorax
  • Red edges on the wings

A comparison between the red-shouldered bug and a similar insect, the boxelder bug, might help with identification:

Feature Red-Shouldered Bug Boxelder Bug
Size 1/2 inch long 1/2 inch long
Body Structure Flattened Flattened
Eyes Red Red
Pronotum Two red stripes Three red stripes
Wings Red edges Red lines on outer edges and back edge

In summary, the red-shouldered bug has distinctive physical features making it easy to identify, such as its small size, flattened body, and unique color patterns with red eyes, markings on the thorax, and red edges on the wings.

Interactions with Humans and the Environment

Nuisance in Homes and Gardens

Red-shouldered bugs can become a nuisance in homes and gardens due to their presence around vegetation. They are most commonly found around:

  • Homes with gardens or lawns
  • Yards with trees that leak sap

These bugs are also known as scentless plant bugs and tend to congregate in large numbers, which can be bothersome for homeowners.

Impact on Gardens and Lawns

Red-shouldered bugs have both positive and negative impacts on gardens and lawns.

Positive aspects:

  • They feed on leaking tree sap, reducing sticky residue on foliage
  • They prey on harmful pests that can damage plants and vegetation

Negative aspects:

  • When present in large numbers, they can become a nuisance
  • Some people might find them aesthetically displeasing

Here’s a comparison of red-shouldered bugs’ impact on gardens and lawns:

Pros Cons
Red-Shouldered Bugs Feed on sap and harmful pests Can be a nuisance in large numbers

It’s essential to keep your garden and lawn in balance, as red-shouldered bugs can become a problem if their population grows too large. But in moderate numbers, they can be helpful in controlling other pests and maintaining a healthy environment for your plants.

Control and Prevention Methods

Mechanical and Behavioral Controls

To control and prevent red-shouldered bugs, try the following:

  • Vacuum: Use a vacuum to remove bugs from indoor spaces, then promptly seal and dispose of the vacuum bag.
  • Seal cracks and crevices: Inspect your home’s exterior for cracks and crevices where these bugs can enter, and seal them up to prevent invasions.
  • Contact your extension office: If the problem persists, seek advice from your local extension office.

For a quick comparison with a similar bug:

Red-Shouldered Bug Boxelder Bug
Appearance Red markings on thorax Red markings on wings
Size 3/8 to 5/8 inches long Similar size
Control methods Vacuum, sealing cracks, extension office Similar methods

Chemical Controls

  • Limited chemical use: Chemical controls are not generally recommended for red-shouldered bug control, as populations usually don’t reach damaging levels. However, if the situation demands, consult with a professional.

Remember, it’s essential to avoid making exaggerated claims about the effectiveness of any particular control method. Consistency and diligence in prevention efforts will ultimately yield the best results.

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 – Aggregation of Red Shouldered Bugs

 

Subject: What is this red bug?
Location: At the gulf coast in Corpus Christi, TX
March 1, 2014 5:17 pm
I recently saw this bugs in the side of my garage. I was afraid to get closer but I will say they are about 1/8 of an inch long to perhaps 1/4. I started feeling a rash so I left right after taking the pics
Signature: Liz Ramirez

Aggregation of Red Shouldered Bugs
Aggregation of Red Shouldered Bugs

Dear Liz,
This is an aggregation of Red Shouldered Bugs,
Jadera haematoloma, including mating adults as well as immature nymphs of various instars or stages of development.  We believe your rash was triggered by an emotional reaction, however, we have no qualifications to diagnose psychological syndromes.  To the best of our knowledge, Red Shouldered Bugs are perfectly harmless, though they may create a nuisance if they are numerous. 

Letter 2 – Red Shoulder Bug Threeway

 

screen door “love” bugs…
hey wtb!
i read your site at least twice a week (often enjoying the archives when theres nothing new) but i’ve never had anything to send y’all. here are a couple of pictures of bugs mating on our screen. i have no idea what they are and i’m positive they’re already on your site as they seem pretty common. i’m not that concerned with what they are. they don’t seem to bite and i usually just brush them away when i want to go outside. anyway, these were some pretty clear pictures of the bug threesome lol. hope you enjoy!
amanda

Hi Amanda,
We are trying to go through some old mail to see if there is anything interesting to post, and lo and behold, we spotted your photograph. This is a new species for our site, the Red Shouldered Bug, Jadera haematoloma. It is a widespread southern species. Sorry for the delay but we are happy to be able to post your image.

Letter 3 – Aggregation of Red Shouldered Bugs

 

Subject: Hundreds of these red guys!!!
Location: Sand Springs,OK
September 30, 2013 3:20 pm
I am really curious to know what these red/ black bugs are. They came back again this year in the same spot. Hundreds of them out by out mailbox.
Signature: The Browns

Red Shoulder Bug Aggregation
Red Shoulder Bug Aggregation

Dear The Browns,
This is an aggregation of Red Shouldered Bugs,
Jadera haematoloma.  The nymphs have the red bodies and the adults are the black winged individuals with red shoulder patches.  According to BugGuide, they are found in:  “Yards, gardens, riparian areas, and other areas in association with hostplants. Often found in large aggregations feeding on leaking tree sap, dead insects, or seeds that have fallen from trees overhead. Also forms aggregations in winter to hibernate, often in association with human residences.” 

Aggregation of Red Shouldered Bugs
Aggregation of Red Shouldered Bugs

Letter 4 – Countdown 15 more postings to the 20,000 mark: Red Shouldered Bug

 

Subject: What’s this bug?
Location: Santa Barbara California
March 27, 2015 6:42 pm
My backyard has been completely over run by thousands of these bugs over last 6 months. What are they?
Signature: Jeff

Red Shouldered Bug
Red Shouldered Bug

Dear Jeff,
This is a Red Shouldered Bug,
Jadera haematoloma, and according to BugGuide, the habitat is:  “Yards, gardens, riparian areas, and other areas in association with hostplants. Often found in large aggregations feeding on leaking tree sap, dead insects, or seeds that have fallen from trees overhead. Also forms aggregations in winter to hibernate, often in association with human residences.”  BugGuide has a list of host plants, and eliminating the food source should help to control the numbers of Red Shouldered Bugs in your yard.

Letter 5 – Mating Red Shouldered Bugs

 

Another bug in love
Hi, Bugman!
I am finding lots of these beetles in the redwood bark in my front garden. What are they? I’m assuming these are more candidates for the “bugs in love” page? They have wild looking red eyes, which I didn’t even notice until I took a picture to send to you. Many thanks,
Joan
Goleta, CA (near Santa Barbara, on the southern CA coast)

Hi Joan,
Your mating insects are Red Shouldered Bugs, Jadera haematoloma. They are probably feeding on seeds that have fallen from your trees into the redwood bark. One of their favorite food plants is the Golden Rain Tree and they are sometimes called Golden Rain Tree Bugs.

Authors

  • 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.

    View all posts
  • 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.

    View all posts
Tags: Red Shouldered Bugs

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3 Comments. Leave new

  • Today is 1-18-14 I was sitting outside in my back yard and knowticed a bunch of these Red Shouldered Bugs! They’ve never been around my house before, but now they are. I’m wondering how can I keep them away from my house lol! And I’m also wondering if they bite, I’m not a big fan of biting bugs . If anyone has any ideas on how to repel them please let me know. Thanks for your time.
    ~Sarah~

    Reply
  • Hello,
    What an incredible site. I am in San Diego, and saw this unusual bug crawling in my driveway.
    And yes, it looked like to bugs stuck together at the rear. I did a quick search on the net, and it popped right up with a picture of the insect. (red Shoulder bug)
    Thank you,
    Nate

    Reply
  • Nicholas Matroni
    June 15, 2016 11:57 am

    How do I get rid of these guys without harming them? They have taken over every plant .. I mean thousands of them…. please help

    Reply

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