The nature of the froth which surrounds spittlebug nymphs during development was studied with topochemical methods, light and electron microscopies, and gel electrophoresis. The composition and structure of the froth were found to be complex, at least ten polypeptides (most of them glycopeptides), acid proteoglycans and calcium being detected. Sinuous filamentary elements of a possibly structural glycoprotein nature were found ultrastructurally. The distribution of an acid proteoglycan-glycoprotein complex at the ultrastructural level resembles that of vertebrate extracellular matrices and of some vertebrate and invertebrate muci reported in the literature. The stereo-arrangement of the proteins in the froth endows it with anisotropic properties, such as birefringence and linear dichroism. The froth of spittlebugs in its whole structure and composition is not properly comparable to salivary and Malpighian tubule silks of other insect groups. This certainly provides it with special properties adequate to the performance of its functions. Ver menos

The nature of the froth which surrounds spittlebug nymphs during development was studied with topochemical methods, light and electron microscopies, and gel electrophoresis. The composition and structure of the froth were found to be complex, at least ten polypeptides (most of them glycopeptides), acid proteoglycans and calcium being detected. Sinuous filamentary elements of a possibly structural glycoprotein nature were found ultrastructurally. The distribution of an acid proteoglycan-glycoprotein complex at the ultrastructural level resembles that of vertebrate extracellular matrices and of some vertebrate and invertebrate muci reported in the literature. The stereo-arrangement of the proteins in the froth endows it with anisotropic properties, such as birefringence and linear dichroism. The froth of spittlebugs in its whole structure and composition is not properly comparable to salivary and Malpighian tubule silks of other insect groups. This certainly provides it with special properties adequate to the performance of its functions. Ver menos