Bird Dropping spiders and the 'Transparent Organ Pulsation Superpowers

[Gogyeng]

Is the common name bird-dropping spider appropriate?

Cyrtarachne is a genus of EastAfrican/ Australasian orb-weaver spiders with a very wide distribution (Cameroon, Sri-Lanka, Australia, China, Philippines, Korea, Japan). They are commonly denominated bird-dropping spiders for their appearance. Interestingly the adult females have a bilobular ocela and semi-transparent abdomens that show internal organs/digestive processes, which characterizes them as 'pulsating'. It is plausible that these animals could be mimicking some other species of arthropoda but who?

 

[pannaking22]

I'd say that's a good common name, but it's one I've heard applied to other groups (various bolas spiders mimic bird droppings as well).

I'm not sure what other arthropod they could be mimicking. Perhaps one of the slug moth caterpillars? I don't know what species occur within the range of Cyrtarachne, but there should be at least some species.

 

[RezonantVoid]

I've seen some bolas spiders before, they often get call bird dropping spiders here in Aus

 

[The Snark]

I've seen a lot of orb weavers around here that resemble bird droppings. Eriovixia is probably the most common. There is also an orb weaver that leaves glops of web and debris in the web as a distraction/camouflage. I get bewildered pretty easily: 'Ooo! Pretty (weird) spider!'
Thai's refer to them as keenok maam moom, poop+bird spider.

 

[Gogyeng]

I've just read that these spiders actually fluoresce under uv light. Maybe more insights about their function?
https://www.wired.com/2013/11/arthropods-are-having-a-secret-rave/