Why does building the stabilimentum represent a significant evolutionary trade-off for the writing spider?

Building the structure demands a considerable investment of silk protein, an essential and costly building block.

From an evolutionary standpoint, any trait requiring substantial resource allocation must yield a proportional benefit to be maintained across generations. The stabilimentum demands a considerable expenditure of silk protein, which is described as an essential and costly building material for the spider. Considering the immense volume of high-quality, sticky silk required just for the primary capture spiral of a mature female *Argiope aurantia*, diverting significant material to build a secondary structure like the stabilimentum implies that the payoff from that secondary structure—whether enhanced safety or increased, reliable throughput of large prey—must be exceptionally high to justify the energy expense.