Web structure and building behavior in Sennin tanikawai sp. nov. (A–G) and Theridiosoma epeiroides (H) A orb web, frontal view B orb web, illustrated C open hub, frontal view D orb web, lateral view E spider holding tension line with forelegs F process of weaving sticky spirals by S. tanikawai sp. nov. G radial elongation behavior in S. tanikawai sp. nov. H web building processes of Theridiosoma epeiroides. Blue lines indicate elongated portion of radii. Abbreviations: HL hub loops OH open hub RD radii SS sticky spiral TL tension line TS temporary spiral.