Flat-bellied Jumping Spider, Ribbanded Jumping Spider
Metacyrba taeniola
Salticidae (Jumping Spiders), Order Araneae. Characterized by high-speed vision and hydraulic jumping ability.
Physical Description
A flattened, elongated jumping spider with a dorso-ventrally compressed body, allowing it to hide in narrow crevices. The cephalothorax is dark and robust, while the abdomen is oval and tapers slightly at the rear. The body appears smooth but is covered in fine, short hairs.
Size Estimate
Body length 4-7mm; leg span approximately 10-15mm. This specimen appears to be an adult female based on body proportions.
Coloration & Markings
Predominantly dark brown to black. It typically features two thin, light-colored longitudinal stripes or rows of spots running down the abdomen. Some specimens exhibit a reddish or orange hue on the front legs or pedipalps.
Web Type
Does not build a hunting web. As a jumping spider, it is an active hunter. It may spin small silken 'retreats' or 'thickest' in crevices for molting, sleeping, or guarding egg sacs.
Eye Arrangement
Standard Salticid pattern: 4 pairs of eyes. The two Anterior Median Eyes (AME) are extremely large and forward-facing, providing excellent binocular vision, flanked by two smaller Anterior Lateral Eyes.
Leg Characteristics
The first pair of legs is noticeably thicker and more robust than the others, used for grasping prey. Legs are relatively short and adapted for quick lunges rather than long-distance running.
Venom & Safety Information
Venom Information
Possesses a mild venom used to subdue small insect prey. The venom is not considered toxic to humans.
Medical Significance
Harmless to humans. A bite might cause minor localized redness or itching similar to a mosquito bite, but they are very reluctant to bite unless squeezed.
Safety Recommendations
No special safety measures required. If found indoors, they can be safely relocated using the cup-and-paper method. They are beneficial guests in gardens.
Habitat & Behavior
Habitat & Range
Found across North America, particularly in the United States and Mexico. They prefer dry habitats and are frequently found on tree bark, under stones, or on the walls of man-made structures.
Behavior & Temperament
Diurnal, active hunters with very high intelligence for arthropods. They are curious and alert, often turning to face observers. They are not aggressive toward humans and will usually jump away if threatened.
Diet & Prey
Primarily small insects and other spiders. They hunt by sight, stalking prey like a cat before delivering a precise, high-speed pounce.
Seasonal Activity
Most active from late spring through autumn. They may overwinter in silken sacs hidden under bark or in building eaves.
Description
The Flat-bellied Jumping Spider is a master of the vertical world. Its unique, compressed body shape allows it to vanish into the smallest cracks in bark or siding. Unlike many other spiders that wait for food to come to them, this species uses its incredible eyesight to track movements and plan complex routes to ambush its prey.
Key Features
Distinguished by its extremely flat body profile, dark coloration with light abdominal lines, and oversized front legs.
Similar Species
Platycryptus undatus (Tan Jumping Spider), which is larger, hairier, and has a distinct zig-zag pattern. Metacyrba punctata is also similar but has different abdominal spotting.
Life Cycle
Females lay eggs in silk retreats. Spiderlings emerge and look like miniature adults. They undergo several molts to reach maturity. Mating involve complex visual displays by the male.
Ecological Importance
Excellent biological pest control. They consume small gnats, flies, and agricultural pests that other spiders might miss.
Conservation Status
Not evaluated by the IUCN, but common and widespread. Not currently facing significant threats.
Interesting Facts
The genus name Metacyrba refers to their tendency to change direction frequently. They can jump up to 40 times their own body length using hydraulic pressure in their legs.
Photography Tips
Focus on the front of the cephalothorax to capture the large primary eyes. Use a macro lens and high shutter speed to freeze their sudden, jerky movements.
Identified: 2026-05-04T17:13:49.392827