After 140 years, scientists have unraveled the enigma surrounding the care of giant Antarctic sea spider eggs. Unlike their counterparts that transport eggs on their backs, male giant Antarctic sea spiders, such as Colossendeis megalonyx, dedicate two days to affixing their thousands of tiny eggs to the rocky seafloor, according to a recent study.
Sea spiders, marine arthropods found across oceans worldwide, possess eight elongated legs, resembling terrestrial daddy longlegs spiders despite lacking any biological relation. While many sea spiders reach only an inch in length, those inhabiting polar regions, like C. megalonyx, exhibit “polar gigantism,” boasting leg spans up to 20 inches.
Among marine arthropods, sea spiders stand out as the males take exclusive responsibility for offspring care. Despite a long history of research into sea spider reproductive strategies, the brooding behavior of certain families, including Colossendeidae to which C. megalonyx belongs, remained unobserved for 140 years.
To unveil the mystery of their parental care, divers ventured into the frigid waters of McMurdo Sound in Antarctica, collecting mating pairs of C. megalonyx. These specimens were then transported to McMurdo Station for observation in tanks. Interestingly, rather than carrying their eggs, as typical in sea spiders, one parent, likely the male, meticulously attached the egg brood to the tank floor over two days.
After several weeks, the eggs became obscured by algae growth, potentially providing natural camouflage against the seafloor. Ming Wei Aaron Toh, a co-author of the study and a doctoral student at the University of Hawai’i, expressed gratitude for the opportunity to study these remarkable creatures directly in their Antarctic habitat, highlighting the unprecedented insights gained from this research endeavor.
