Argiope appensa in Guam: Banana Spider

bugman

January 4th, 2007 at 1:00 am

Categories

Spiders

Spiders in Guam
I live in Guam and have these wonderful spiders living in my carport. I would like to know if the spider is male or female. Also, is the little one the offspring, rather than simply caught in the web? I hope these photos are clear enough. I’ve enjoyed watching two of these spiders grow from tiny to this size (approx 3.5 inches in span) in the course of five months, but others never seem to make it past infancy (or what I presume is infancy due to their size). Regards,
June Ameika

Hi June,
This is a pair of Argiope Spiders. The female is the larger of the two and the male shares her web. We did a google search of “Argiope Guam” and were led to a Wikipedia page describing and picturing Argiope appensa. Argiope appensa is one of at least three unrelated spiders commonly called Banana Spiders. According to Wikipedia: “Females reach a body length of up to 7cm and are strikingly black and yellow, while the brown males reach only about 2cm. [1] On Guam, where A. appensa is ubiquitous, it is frequently visited by Argyrodes argentatus. Locals there refer to A. appensa as banana spiders. Following the introduction of the brown tree snake and the subsequent extinction or near-extinction of many of the island’s small birds, spider populations on Guam exploded decreasing predation and competition. A. appensa is almost certainly one of the large species which were encountered there in vast numbers, much to his horror, by nature writer David Quammen (who is extremely arachnophobic) during his trip doing background research for the book The Song of the Dodo, as he vividly recalls therein.”