Argyrodes argentatus is a kleptoparasitic spider.
In Singapore, it is often seen in webs of Nephila antipodiana.
On Guam it can often be found hanging in webs of the much larger spider Argiope appensa: while A. appensa can reach a total length of about 7 cm, A. argentatus females reach only 3mm, and males 2mm at the most.
Like in rats, following copulation the male seals the female's epigyne with a mating plug, preventing the female from further mating.
It has been found in China, Japan, Guam, Thailand, Burma, Vietnam, Sri Lanka, the East Indies (Singapore, New Guinea), and Hawaii.
The species name argentatus means "silvery" in Latin.