Trip Date: 2024-05-29
Vivarium is a small cave with two entrances. The 'back' entrance is via a boulder choke, and the 'front' entrance is a largish opening into the main chamber of the cave. The opening is large enough to allow a lot of light (and wind) into the chamber. A stream flows from the dark part of the cave into the main chamber. This configuration means you often find animals from 'the dark zone' in a relatively well lit zone.
This trip was confined to the boulder choke entrance and the dark, 'up-stream' part of the cave.
The top of the boulder choke is outside the cave, and bottom is well into the darkest part of the twilight/transition zone. The boulder choke was full of the usual suspects:
- Cave crickets
- Bristletails
- Cave daddy-long legs spiders
Just inside the entrance of the cave was a crane-fly like creature.
At the deepest part of boulder choke, where the dark part of the twilight zone becomes complete darkness, there were two bristletails, a few cave crickets, and a centipede. The centipede hid in a rock crevice before I could photograph it.
Bristletails
Bristletails seem to prefer being in the darkest part of the twilight zone of the cave. They are usually found inside the crevices between boulders in the twilight zone. Out side of the boulder pile, indirect light may be visible to the human eye, but 1m into the boulder pile, only dimly reflected, indirect, indirect would be present, and it appears to be completely dark to the human eye.
Spiders
A Metellina spider had its web across a gap in the boulders, but the wind coming out of the cave was buffeting the web quite violently, and the spider decided to hide in a crevice next to its web.
There were lots of Spermophora of all sizes in the twilight zone and in the gaps between the boulders.
Aquatic
I saw some quite large (18mm?) Paramelita and a lot of Spelaeogriphus lepidops in the upstream section of the cave.
A visit to the main chamber is still needed.