This beautiful Argiope protensa spider is also known as the Long-tailed St. Andrew’s Cross Spider. It is part of the Infraorder Araneomorphae, that are spiders with opposing fangs. It is also part of the family Araneidae, that are Orb Weavers with over 232 named species in Australia.
The web of Argiope protensa is a fragile almost circular shape, that is strung between stems of small shrubs and even tall grasses. The pictured web structure here is strung across the stems of a rosemary bush.
There is often a visible stabilimentum, which in some webs may be absent, although this is not in the form of the X shape like other St Andrew’s Cross spiders.
A stabilimentum is the decorative web structure within the webs of some species of orb-web spiders. Often a distinctive zig-zag pattern, whilst those of most Saint Andrew’s Cross spiders have a distinctive X shape, there are other shapes, including a zig-zag line (as with Argiope protensa), but with broken in the centre, where the spider sits.
The egg sac of the Argiope protensa resembles a small cup with a lid, although there is some slight variations, as pictured.
Long-tailed St Andrew’s Cross Spider, Elongated St. Andrews Cross Spider, Longtailed Orb-weaving Spider, Tear Drop Spider, Tailed Forest Spider.
Many thanks to Narelle Murphy for ID of this species, member of the Australian spider identification page on Facebook.
- Scientific classification
- Kingdom: Animalia
- Phylum: Arthropoda
- Subphylum: Chelicerata
- Class: Arachnida
- Order: Araneae
- Infraorder: Araneomorphae
- Family: Araneidae
- Genus: Argiope
- Species: Argiope protensa
Footnote & References
- Argiope protensa, Atlas of Living Australia, https://bie.ala.org.au/species/urn:lsid:biodiversity.org.au:afd.taxon:f607fc3a-4348-424e-80a7-f71c78489d1e
- Argiope protensa (L. Koch, 1872) Long-tailed Argiope, Arachne.org.au, A Field Guide to the Spiders of Australia, by Robert Whyte, and Greg Anderson, http://www.arachne.org.au/01_cms/details.asp?ID=2103
- Do stabilimenta in orb webs attract prey or defend spiders?, by Todd A. Blackledge, John W. Wenzel, Behavioral Ecology, https://academic.oup.com/beheco/article/10/4/372/2252323
- Australian spider identification page, https://www.facebook.com/groups/australianspidereducation