Guardian Nature School Team Contact Blog Project Noah Facebook Project Noah Twitter

A worldwide community photographing and learning about wildlife

Join Project Noah!
nature school apple icon

Project Noah Nature School visit nature school

Spider fly symbiotics

Opisthoncus sp.


Symbiotic relationship between a jumping spider and a fly. The fly is probably a milichiid species.


Adjacent to a small stream. Altitude 1000m.


I have photographed three symbiotic relationships so far involving spiders. The most common being the relationship between the dewdrop spider and the host nephila spider, another between a nephila spider and a wasp, both involving kleptoparasitic stealing of food on the part of the intruder and acceptance of the intrusion by the host.

Symbiotic relationship implies that both parties get something out of the relationship. In the above two examples, the intruder gets an easy free meal, using the hosts web to catch its prey. The host nephila gets his web cleaned of all the small flies that can clog up the web.

The third, and by far the most interesting symbiotic example was between this jumping spider and a fly.

At first sight, I thought the spider was eating the fly, but on closer inspection, the spider was simply standing over the fly. When the spider moved, the fly moved with it. When the spider jumped to another leaf, the fly followed. As the fly re-approached the spider, the arachnid raised up like it was going to attack, it then relaxed and allowed the fly to run underneath once more.

Obviously symbiotic, but at the time, I could not figure out what the spider got out of the relationship. A few weeks after the shoot, I zoomed in and noticed that the fly appeared to be feeding off the spider. Further research revealed that nephila has been known to allow a fly to clean its fangs after feeding, then, it all fell into place. The fly was cleaning the fangs and around the mouth of the spider after a meal, as can be seen from the second and third images.

As far as I know, this particular relationship has not been documented and extensive searches did not bring up any images of such scenes as this, so I do believe these images are unique.

This set is for Karen, Yasser and Jakubko for making me really feel part of this community.

Species ID Suggestions

Sign in to suggest organism ID

59 Comments (1–25)

flyingfrogconcepts 8 years ago

How interesting!

SukanyaDatta 9 years ago


folicallychalled 10 years ago

Thanks very much Ash :)


Ashutosh Dudhatra
Ashutosh Dudhatra 10 years ago

Great discovery... !

folicallychalled 10 years ago



Scott Frazier
Scott Frazier 10 years ago

It was about biodiversity of Indonesia Dave and that certainly includes your spotting. But OK, I'll ask that it be removed.

folicallychalled 10 years ago

Scott - a well researched and written article, congratulations.

However, I do not see the relevance of my post about symbiosis. Neither the spider nor the fly in my post have positive identifications. I am flattered that you would choose to link my article, but would prefer if you removed it please.


Congrats Dave! :)

Scott Frazier
Scott Frazier 10 years ago

Hi folicallychalled. Your spotting is featured in the new PN blog post via a link! Cheers

folicallychalled 10 years ago

Obviously it is a rare sight. The best advice is to find a jumper that is eating and wait. Best take a stool, it could take an hour or two :)


Adarsha B S
Adarsha B S 10 years ago

Congratulations ! amazing information and hence the spot :)
Very special SOTD :)
I am getting curious to see one of those relationships in naked eye :)

folicallychalled 10 years ago

So kind Leanne, thanks.

Also thanks to everyone else who has left such wonderful comments :)


LeanneGardner 10 years ago

Belated congratulations Dave, on your SOTD & for all you contribute to P.N. :)

Josh Asel
Josh Asel 10 years ago

Incredible spotting congratulations!

AgnesAdiqueTalavera 10 years ago

Congrats Dave!

Gerardo Aizpuru
Gerardo Aizpuru 10 years ago

Congratulations wonderful spot and series

Great capture folicallychalled,congrats on the SOTD and thanks for sharing

TylerGraden 10 years ago

Amazing. That's a great observation, and great job documenting & researching it too.

The things we discover by observing, taking pictures and then sharing them here for others to see, it is Fantastic, thank you, PN members and folicallychalled.

Mandy Hollman
Mandy Hollman 10 years ago

Wow, that's amazing! Thanks for all the information.

Debbie Stewart
Debbie Stewart 10 years ago

Amazing macro series folically challed, fascinating symbiotic relationship between the two, congratulations on SOTD

Apple 10 years ago

Excellent spot! Symbiotic relationships is my favorite part of animal science.

Noel Buensuceso
Noel Buensuceso 10 years ago

Great spot, Dave! Congrats for this SOTD!

Mark Ridgway
Mark Ridgway 10 years ago

That's amazing. Congratulations Dave. Brilliant job.

Jacob Gorneau
Jacob Gorneau 10 years ago

Spectacular symbiosis, Dave!

Spotted by

Jawa Barat, Indonesia

Spotted on Apr 14, 2013
Submitted on Jul 3, 2013

Related Spottings

Opisthoncus mordax Opisthoncus parcedentatus Garden Jumping Spider Garden jumping spider

Nearby Spottings

Common Sun Skink Green Long legged Fly hoverfly Common Bushbrown


Noah Guardians
Noah Sponsors
join Project Noah Team

Join the Project Noah Team