The peacock spider, a member of the jumping spider family and genus Maratus, is renowned for its courtship ritual. These arachnids, typically measuring only a few millimeters in length, are found primarily across Australia. The male of the species possesses iridescent coloration, which is the central feature of their famous “dance.” The display is a multi-sensory performance that serves as a prelude to mating.
The Purpose of the Peacock Spider Dance
The function of the male peacock spider’s elaborate dance is sexual selection, compelling the female to choose him as a mate. For the male, the performance is an audition to prove his suitability. The choreography and visual spectacle act as an honest signal of his genetic quality and physical fitness. Females use the complexity and persistence of the display to gauge the male’s health and vigor.
The duration and flawless execution of the performance often predict a male’s success in mating. A strong display communicates to the female that the male possesses superior genes, which could be beneficial for their offspring. This selective pressure exerted by the females has driven the evolution of the males’ spectacular colors and intricate movements over generations. The species-specific nature of the dance helps the female confirm that the male belongs to the correct species, preventing unproductive hybridization.
Visual Displays and Vibrational Signals
The peacock spider’s courtship is a multi-modal display, combining visual flair with vibrational communication. The visual component begins with the male elevating his abdomen and unfurling his opisthosomal flaps, often called a fan or shield. These flaps are covered in microscopic, modified hairs that produce the stunning, often iridescent, patterns of red, blue, and orange. The coloration is achieved through both pigments and structural engineering that manipulate light to create vibrant effects, including areas of “super black” that intensify the surrounding colors.
The male waves his third pair of legs, which are often elongated and tipped with white or black tufts of hair. As he approaches the female, he adds substrate-borne vibrations, which are tremors transmitted through the ground or leaf litter. These vibrations are produced by rapid abdominal movements and serve multiple purposes. Initial signals, sometimes described as “rumble-rumps,” are used to draw the female’s attention and confirm his presence before the full visual display begins.
The High Stakes of Courtship
The peacock spider’s dance is not a harmless show, but a ritual where the male’s life hangs in the balance. If the female judges the male’s performance as inadequate, she will reject his advances. Rejection is swift and carries the ultimate penalty for the male performer.
If the male fails to impress, the female may perceive him as prey rather than a suitable mate, leading to sexual cannibalism. Females signal their displeasure with an aggressive abdominal shake, which serves as a warning for the male to retreat immediately. The male must be prepared for a rapid escape, using his jumping ability, to avoid being killed and consumed by the much larger female. This constant risk ensures that only males capable of the most compelling and energetic displays are successful, reinforcing the strong evolutionary pressure on the dance.