On the weekend I had the privilege of taking a caving trip of 3 visiting Brazilian cave biologists and local entomologist Ian Millar to two caves in Takaka to look for troglobites. Finding troglobites (species exclusive to caves) can be tricky business at the best of times. Having never properly looked for them before I was unsure if we’d find anything interesting at all.
The day started off checking out some aquatic fauna I had photographed on a previous trip in Commentary Cave. Without much effort we found the isopod and amphipod in the small stream way – it seems likely they are un-described species. Just as Ian was telling us this is the exact kind of habitat that the carabid beetle was found in we spotted one about 30cm away on a small shelf – perfect timing.
After a quick drink and pie stop in Takaka we were off to Motupipi to check out Council Cave. Although it seems relatively small and insignificant Council Cave is actually considered the most important cave in New Zealand for cave fauna. Sadly Council Cave has had an extensive history of vandalism since the late 1800’s, making a locked gate necessary to stop the damage.
Armed with my macro lens I was ready to photograph the rare cave dwellers. Not far past the gate we found a lovely Nelson Cave Spider (Spelungula cavernicola) with a freshly shed skin nearby – something I hadn’t seen before. Next up was a harvestman (Opiliones) that appeared to be specially adapted to the cave environment. The adaptations that usually signify a cave dweller are things like reduced eyes (or complete lack of them), reduced pigmentation and elongated legs and antenna. Not long after that one of the Brazilians found a centipede that may well turn out to be a new species – not a bad start!
Although the harvestman and centipede were cool we were really there to find three specific species – a plant hopper, a dipluran and a carabid beetle. The first of the three we found was the beetle – any hopes of a good photo vanished when I saw it – talk about a speed demon. The little guy was constantly moving at high speed, oblivious to my efforts to photograph it.
While this was happening Gabrielle had found a tiny transparent spider on the cave floor. Surprisingly only two species of cave spider are currently described in New Zealand. Surely there must be a whole bunch more out there waiting for a observant caver to notice them!
Perhaps the strangest of all the cave species we saw was the dipluran – it looks like an earwig but they are completely unrelated. This species is known only from Council Cave and as far as diplurans go is a monster. Although like the beetle it was constantly on the move it was slow enough to allow a few good photos to be taken.
That left the smallest and most elusive of the three species to find. I had pretty much given up when I heard a shout that a hopper had been found. To me it looked like a smaller verison of the common vine hopper, but when I looked at it through my macro lens I noticed it had no eyes. With all hands carefully guarding it to prevent it hopping away I snapped a few photos. Fortunately the only time it did hop it landed on the top of my gumboot and was easily seen. The hopper feeds on the roots of trees that are able to penetrate the cave, and may even feed only on certain species roots. Currently its known from two small caves in Takaka.
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