Red-shouldered Bug, Goldenrain Tree Bug
Jadera haematoloma
Rhopalidae (Scentless Plant Bugs), Order Hemiptera
Physical Description
NOTE: This is not a spider, but a true bug. It has an elongated oval body, a distinct triangular scutellum (shield on the back), and long, segmented antennae. They possess piercing-sucking mouthparts (a rostrum) tucked under the head.
Size Estimate
Adults are approximately 9-14 mm (0.35-0.55 inches) in length. Based on the photo, this appears to be a mature adult specimen.
Coloration & Markings
Primarily slate-black to brownish-black with striking crimson or bright red 'shoulders' (the sides of the pronotum) and red eyes. The abdomen is often reddish underneath, visible at the margins.
Web Type
None. As a true bug rather than a spider, it does not produce silk or spin webs. It is highly mobile on legs and capable of flight.
Eye Arrangement
Two prominent lateral compound eyes, typically bright red in this species, located on the sides of the head. Being insects, they do not have the 8-eye pattern of spiders.
Leg Characteristics
Six long, slender black legs. Unlike spiders which have eight legs, this insect has three pairs. The legs are designed for walking and climbing through foliage.
Venom & Safety Information
Venom Information
None. They do not possess venom glands or fangs. They are completely harmless to humans and pets.
Medical Significance
Harmless. They do not bite humans or transmit diseases. Their only defense is walking away or occasionally emitting a mild scent common to 'scentless' plant bugs when crushed.
Safety Recommendations
No safety measures needed. They can be safely handled or gently brushed away. If they enter a home, they can be vacuumed or picked up with a tissue and released outside.
Habitat & Behavior
Habitat & Range
Common throughout the southern United States (Florida to California), Mexico, Central America, and the Caribbean. Frequently found on or near Goldenrain trees (Sapindaceae family).
Behavior & Temperament
Non-aggressive and docile. They are often gregarious, forming large clusters on tree trunks or walls during sunny days. They are fast runners and can fly when disturbed.
Diet & Prey
Herbivorous. They feed on the seeds of plants in the soapberry family (Sapindaceae), particularly Goldenrain trees and western soapberry. They use their beak to pierce seed pods and suck out nutrients.
Seasonal Activity
Most active in spring and autumn. In warmer climates, they may be seen year-round. They often aggregate on buildings in the fall to find warmth.
Description
The Red-shouldered bug is a vibrant, harmless insect often mistaken for a spider by those only seeing the long legs at a distance. With its charcoal-colored wings and fiery red accents, it is a common sight in suburban landscapes where host trees are present. They are often seen sunning themselves in large groups on light-colored surfaces like the footwear shown in the photo.
Key Features
Six legs, long antennae, bright red eyes, red margins on the pronotum (shoulders), and a slate-black body with overlapping wings forming an 'X' shape on the back.
Similar Species
Boxelder Bug (Boisea trivittata) - distinguished by red veins on the wings; Flamecrest Bug; and various species of 'Assassin Bugs' which have a curved rostrum and can bite.
Life Cycle
Hemimetabolous (simple metamorphosis). Females lay eggs in soil or leaf litter; nymphs emerge looking like small, bright red versions of adults without wings. They go through five molts before reaching maturity.
Ecological Importance
They act as specialized seed predators, helping to control the spread of certain trees. They serve as a food source for birds, lizards, and predatory insects.
Conservation Status
Not evaluated, but abundant and locally common throughout their range. They are considered a minor nuisance pest but not ecologically threatened.
Interesting Facts
These bugs have evolved rapidly; in regions where invasive Goldenrain trees were introduced, these bugs developed shorter mouthparts to better exploit the seeds of the new host plant compared to their ancestors.
Photography Tips
Focus on the head to capture the red eyes and the 'shoulders' for identification. Top-down shots are best to show the wing arrangement and the number of legs (6) to distinguish from spiders (8).
Identified: 2026-04-27T16:11:07.905368