The diversity and evolution of spider spinning organs

RAMIREZ, M.J,

Greifswald

Congreso; 33rd European Congress of Arachnology; 2022

The silk-spinning organs and associated glands are among the most diverse and biologically meaningful organ systems in spiders. The way of life, hunting strategies, web design and ancestry are reflected in the morphology of their spinning organs in a complex and rich way. We present an overview of the diversity of structures that comprise the spinning organs, including spinnerets, glands, spigots and associated setae. We mapped the origin, repeated evolution and losses of important structures over a large phylogenetic tree with more than 500 species based on genetic sequence data. Among the most remarkable findings are the many convergences to similar morphologies and functional solutions, such as the reduction in the number of major ampullate gland spigots, probably related to dragline performance, the multiple origins and diverse physical principles of silk stickiness, and the loss of many of these novelties after changes in life style.