Spider that mimics a frog in our Rio Zunac Reserve. Photo: Lou Jost/EcoMinga.
I’ve been away again, this time gone for almost three weeks with a great group of students from Stanford University led by Dr Margaret (Minx) Fuller. We spent most of our time in the Amazonian lowland rainforest, but I also took them to EcoMinga’s Rio Zunac and Rio Anzu Reserves. Throughout the trip we found amazing examples of mimicry. The most unusual mimic was this spider, which was found by students Dylan Moore and Natalia Espinoza on our Rio Zunac trip. At first they thought it was a frog. It holds its forelegs in a position reminiscent of the hind legs of a frog, and its abdomen mimics a frog head, complete with eyes. I imagine that small birds or insects that would catch a spider might not want to waste energy or risk their lives trying to catch a frog.This spider seems to be related to the famous “bird poop spiders” but I don’t really know. If an arachnologist reads this, perhaps he or she could add some information about this?
Above and below: Spider that mimics a frog in our Rio Zunac Reserve. Click to enlarge. Photo: Lou Jost/EcoMinga.
Note added July 26 2017: Andreas Kay in nearby Puyo reports that he has also found this spider twice, and thinks it is in the genus Stephanopis; see his picture here:
It is always a pleasure to browse his site, Ecuador Megadiverso.
I found another exquisite mimic in our Rio Anzu Reserve the next day. This leaf-mimic katydid would have passed unnoticed except that when we walked past, it went into its hiding pose and moved its two antennae together so that they appeared as one. That motion caught my attention, but it still took me a minute to see the katydid.
A leaf-mimic katydid in our Rio Anzu Reserve. Click to enlarge. Photo: Lou Jost/EcoMinga.
The best way to see exotic katydids, grasshoppers, and crickets is to walk in the forest at night. Here are some others we found in the eastern lowlands on this trip.
Dead-leaf katydid in the Amazon. Click to enlarge. Photo: Lou Jost/EcoMnga.
Grasshopper in the Amazon. Click to enlarge. Photo: Lou Jost/EcoMinga.
Amazonian nymph katydid. Click to enlarge. Photo: Lou Jost/EcoMimnga.
Mimicry is not limited to insects and arachnids, though. Birds can can also disguise themselves. The hardest birds to spot in these forests are the potoos, which look like dead stubs on tree branches. When some species of potoo sense danger, they even lift their heads to point straight up, enhancing the illusion. They sit all day on their chosen perch, and only hunt at night, sallying for large flying insects. The females lay their single egg carefully balanced on the broken-off tip of a branch, and the baby grows up looking just like an extension of the branch.
Great Potoo. Click to enlarge. Photo: Lou Jost/EcoMinga.
Common Potoo. Click to enlarge. Photo: Lou Jost/EcoMinga.
Thanks for looking,
Lou Jost, EcoMinga Foundation.
Fundacion EcoMinga 
Fascinating and beautifully photographed. The frog-mimicking spider is particularly interesting in it’s imperfections. It’s like the spider hasn’t quite finished evolving ‘the frog look’ yet. Good timing, well caught 🙂
Thanks for looking, Steve. Coming from you, that is high praise! Yes, evolution still has some work to do here. While “perfect” examples of mimicry get most of the attention, the more abstract precursors are all around us and are equally fascinating.