Red-Shoulder Bugs, are a common sight in gardens and landscapes. These insects have an elliptical shape and are dark gray in color, with bright red lines on their thorax. Their eyes are also a striking red color, making them easily identifiable.
Red-Shouldered Bugs are often confused with Boxelder bugs, another type of insect with similar red markings. To distinguish between the two species, it’s important to note that Boxelder bugs have three red stripes on their thorax, while Red-Shouldered Bugs have only two. Additionally, Boxelder bugs exhibit red outlines on their wings, which are not present in Red-Shouldered Bugs url.
These bugs are commonly found feeding on a variety of plants, including the Golden Rain Tree and other plants found in gardens. They generally do not cause significant damage to the plants they feed on, but may become a nuisance in large numbers. To manage their population in your garden, it’s essential to maintain a healthy habitat and implement natural pest control measures when necessary.
Identifying Red-Shouldered Bugs
Appearance and Size
Red-shouldered bugs, also known as Jadera haematoloma, belong to the Hemiptera order of insects. They have a dark gray or black body with distinctive red markings. These bugs are somewhat flattened and have an elongated, elliptical shape. The adults can measure between 3/8 to 5/8 inches in length (Kansas State University).
Red Markings and Wings
The red-shouldered bug’s main identifying feature is its bright red markings. The bug has:
- Red eyes
- Red antennae
- Red lines on both sides of the thorax or ‘shoulder’
- Leathery wings outlined in red (NC State Extension)
Host Trees and Habitat
Red-shouldered bugs can commonly be found on host trees such as the golden rain tree and the boxelder tree. These bugs may be confused with the similar-looking boxelder bug (Boisea trivittata), which also has red stripes on the thorax but also has red markings on the wings, unlike the red-shouldered bug (NC State Extension).
Comparison Table: Red-Shouldered Bug vs Boxelder Bug
| Red-Shouldered Bug | Boxelder Bug | |
|---|---|---|
| Size | 3/8 to 5/8 inches | About 1/2 inch long |
| Color | Dark gray to black | Dark gray to black |
| Red markings | Both sides of thorax | Three red stripes on thorax |
| No red on wings | Red markings on the wings |
By identifying the distinctive features and understanding their preferred habitats, one can easily differentiate red-shouldered bugs from other similar species.
Life Cycle and Behavior
Nymphs
Boxelder bugs, also known as red-shouldered bugs, have a life cycle that begins with eggs laid by females. The eggs, initially light yellow, soon darken to rusty red. After this, the nymph stage begins, during which they are small and wingless. Nymphs are about 1/2 inch long and resemble adults in color and shape, but their wings are not yet fully developed.
Adults
The final stage of the boxelder bug life cycle occurs when the nymphs transform into adult bugs. Adults have a dark gray to black color, with red stripes on their thorax and outlines on their wings. Their eyes are also red, giving them their distinct appearance.
Seasonal Changes
Boxelder bugs experience various seasonal changes in their behavior:
- Spring: As temperatures rise, nymphs and adult bugs become more active, feeding on trees and plants.
- Summer: During warmer months, they continue feeding and breeding, while nymphs grow and develop into adults.
- Fall: As temperatures drop, boxelder bugs search for shelter in homes or other protected areas to overwinter.
- Overwinter: Red-shouldered bugs remain in a state of dormancy until temperatures start to rise again in the spring.
Behavior:
- Red-shouldered bugs are social insects, often found in groups.
- Their primary food source is boxelder tree seeds or sap, but they may also feed on other plants.
- They are considered a nuisance to homeowners due to their habit of entering homes in large numbers during the fall and winter months.
Comparison of Nymphs and Adults:
| Characteristic | Nymphs | Adults |
|---|---|---|
| Size | 1/2 inch long | About 1/2 inch long |
| Color | Similar to adults | Dark gray to black with red details |
| Wings | Not fully developed | Fully developed wings with red outlines |
In summary, boxelder bugs, or red-shouldered bugs, go through a life cycle that includes egg, nymph, and adult stages. Their behavior and appearance change throughout the seasons, with various impacts on their surroundings.
Feeding Habits
Diet and Preferred Plants
Boxelder bugs, also known as Red Shoulder Bugs, feed mainly on:
- Leaves
- Seeds
- Host trees: boxelder, maple, goldenrain tree
They prefer to target plants like lilies and grass, but also consume seeds of boxelder and maple trees. To better understand their feeding habits, let’s compare boxelder bugs with goldenrain tree bugs:
| Feature | Boxelder Bug | Goldenrain Tree Bug |
|---|---|---|
| Main diet | Seeds of boxelder and maple trees | Seeds of goldenrain trees |
| Other plants | Lilies, grass, and other flowers | Lilies, grass, and other flowers |
Impact on Trees and Gardens
Boxelder bugs and goldenrain tree bugs can cause damage to:
- Leaves: Feeding on leaves can produce noticeable scarring along the edges and sides.
- Flowers: Eating the flowers may reduce the plant’s ability to propagate and attract pollinators.
However, they are generally not considered severe pests as their impact on trees and gardens is usually minimal.
Prevention and Control
Natural Predators
Several natural predators can help control the population of black bugs with red bottoms, such as the red shoulder bug (Boisea trivittata). Beneficial insects, like the milkweed assassin bug (Zelus longipes) and native ladybugs, are excellent predators that feed on these nuisance pests. Gardeners can encourage their presence by:
- Planting diverse and native plants
- Providing shelter and water for insects
Pesticides
Pesticides can be an option to control black bugs with red bottoms. However, it’s essential to weigh the pros and cons of using them:
Pros
- Effective in controlling bug populations
- Can prevent infestations
Cons
- May harm beneficial insects
- Potential risk to pets and the environment
It’s important to follow the pesticide label instructions carefully and use them as a last resort.
Removal
Manual removal of these pests is also an option. Some common techniques include:
- Vacuuming: Use a vacuum cleaner to remove bugs from walls and other surfaces. Remember to empty the vacuum bag or container to prevent the bugs from escaping.
- Washing: A hose or pressurized water can be used to flush bugs off surfaces outdoors.
Remember to inspect your home regularly, seal cracks and crevices to prevent bug entry, and maintain a clean environment.
| Prevention Methods | Pros | Cons |
|---|---|---|
| Natural Predators | Eco-friendly, supports biodiversity | Takes time to establish |
| Pesticides | Effective control, prevents infestation | Risks to beneficial insects, pets, and the environment |
| Removal | Non-toxic, immediate results | Requires ongoing effort |
Other Similar Bugs and Species
Commonly Mistaken Insects
- Boxelder bugs (Boisea trivittatus): These bugs are dark gray to black with red stripes on the thorax and red outlines on the leathery parts of the wings. Their eyes are also red. Young boxelder bugs have red stripes on a dark red body. Boxelder bugs are commonly found on and around ash trees, warm days, and are known for staining surfaces when crushed. More information
- Soapberry bugs: These bugs resemble boxelder bugs but are associated with plants like soapberry, goldenrain tree, and chinaberry. They have similar black and red color patterns and are true bugs.
- Scentless plant bugs (Jadera spp.): Scentless plant bugs are basically brownish-salmon in color, with a reddish abdomen and darker red spots. They have a length of 7.5 to 11mm and width 2.5 to 4.0mm. Found across the Caribbean, Central America, and the U.S, Jadera bugs are most abundant in warm climates and do not emit any scent. More information
- Milkweed bugs: These bugs include the small milkweed bug and milkweed assassin bug. Milkweed bugs are primarily black with reddish-orange patches and feed on milkweed plants. Milkweed assassin bugs are predatory insects that feed on other insects and are often found in gardens.
- Scarlet lily leaf beetle (Lilioceris lilii): This European beetle can on occasion be mistaken for similar red and black bugs. However, they are not true bugs, and have a shiny, bright red body as adults. They are best known for feeding on the leaves of lilies and causing damages to the plants.
Here is a comparison table of these insects:
| Bug Name | Color Pattern | Size Range | Habitat | Associated Plants/Hosts |
|---|---|---|---|---|
| Boxelder Bug | Black with red | 12 – 15mm | North America | Ash trees, Boxelder trees |
| Soapberry Bug | Black with red | 12 – 14mm | Warm climates | Soapberry, Goldenrain tree |
| Scentless Plant Bug | Brownish-salmon | 7.5 – 11mm | Caribbean, U.S | Milkweed, warm days |
| Small Milkweed Bug | Black & reddish-orange | ~10mm | North America | Milkweed plants |
| Milkweed Assassin Bug | Red, black, orange | 16-18mm | North America | Gartens, Pollinators |
| Scarlet Lily Beetle | Bright red | 8-10 mm | Europe, Canada | Lilies |
