Japan - December 29, 2025 Video footage has revealed the groundbreaking mating behavior of the jumping bristletail Petrobiellus akkesiensis, showing the first documented case of direct sperm transfer in apterygote insects. During mating, the male grasps the female’s ovipositor using a hook-shaped penis and specialized abdominal styli, allowing direct transfer of the spermatophore through genital coupling. This behavior represents a previously unknown reproductive strategy within Archaeognatha. “This study provides an important missing link in the evolution of mating strategies,” said Assistant Professor Shodo Mtow. “Petrobiellus is an important group for understanding the evolution of mating behavior; however, due to its rarity, very little biological research has been conducted to date.” Researchers collected a large number of specimens from the coast of Hokkaido, enabling detailed observations. The male’s highly developed genital structures make precise spermatophore transfer possible, a mechanism not previously seen in this lineage. Petrobiellinae species live on rocky coasts, suggesting adaptations to terrestrial life. The study compared P. akkesiensis with other Archaeognatha to assess its evolutionary significance, revealing a unique reproductive mode distinct from the three previously known spermatophore-transfer types. Published on December 10, 2025, in Arthropod Systematics & Phylogeny, the findings shed light on insect diversity, mating evolution, and coastal ecology. Researchers hope further studies will clarify the ancestral mechanisms leading to direct sperm transfer.