The unique ribbon morphology of the major ampullate silk of spiders from the genus Loxosceles (recluse spiders).

The morphology of silk produced by recluse spiders (Loxosceles arizonica) was investigated by scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. This silk consisted entirely of very long, thin ribbons of width 2-4 microm and thicknesses of no more than 40 nm. The correspondence in shape and dimension between the silk ribbons and the elongated aperture of the major ampullate spigot indicated that these ribbons were major ampullate silk.