Day 7: Birds, spiders and cockroaches.
A beautiful Tiger Marshmallow spider - Acusilas malaccensis
Woken up before dawn by the heaviest of rain showers thundering on the tarpaulin above us. Lying there in the cool grey light, jumper on and thin sleeping bag pulled up around me I wondered about the contrast between Tane’Olen and Sungai Wain forest in lowland Kalimantan. There it was so hot that if you didn’t have enough to drink before sleeping you woke up so delirious from lack of water that it took you a good half an hour to stop stumbling about and realise where you were. At dawn we were due to get up and listen for all the bird calls to see if we could work out how many species were present in the area. Turning over I seem to remember kicking Ted awake so I had someone to talk to until it was time to go.
Donning our respective ponchos (I had an excellent welsh tourist one) we slipped and fell up a very muddy path, droplets hanging off our noses. Reaching the top, we stood in a wet circle and began to listen. We listened in five minute intervals for an hour, recording any new bird calls we heard. We would later plot this data on a graph which would slowly level out to show a rough number of birds that were around the area. Some of the bird calls were especially beautiful, one sounding like the first few notes of Beethoven’s ‘Für Elise’, and it was quite magical standing listening to the sounds of the forest through the rain.
Back down in camp the river had swollen to such an extent that it would be impossible to carry out the original plan of going back to Base Camp. The rainforest gods had decided that we would stay at Waterfall for the next few days, something that I was very happy about. I didn’t much like Base Camp in comparison to Hornbill and Waterfall, I really love the sleeping without walls.
We spent the next couple of hours waiting for the rain to stop by drawing in our field notebooks and chatting. We also decided on what we should focus on for our mini research project. I thought back to the cockroach nymphs I had seen on the beach last night. They were Epilampra species and were coloured seemingly to match the colours of the beach’s rocks where they lived. They could be colour matching with their environment to camouflage themselves from daytime predators such as birds. If we could set up an arena with rock piles of colours representative of those found on the beach, would we see the cockroaches consistently hide under rocks that were a similar colour to them (a slate grey with touches of brown)? Even if they didn’t have a favoured colour, if they just hid under any rock then that would be interesting because then they are simply looking for a place to shelter and have no thought for camouflage. We decided to do this project which was good.
My poncho keeping touch with home.
Epilampra sp. our cockroach study species.
Finally it stopped raining and I grabbed my camera and went off spider hunting. Crossing the small stream at the back of camp Rhiannon and I started looking behind leaves for some of the more obscure spiders. The hunt started off very well with one of the strangest spiders I had ever seen revealing himself. He is a male Phoroncidia lygeana and seems to be the first one ever recorded in Indonesian Borneo which is exciting. He has a funny little nub where his eyes are clustered and the strangest of abdomens. Bright red with white spots and six long spines he has a strange projection underneath which juts out where his spinnerets are. To catch his food he has a very minimal web consisting of just a couple of strands, they are covered with a very sticky material which he lets slack if a small insect gets snared, increasing the likelihood of the prey being tangled. There is one paper that suggests that some species actively lure in specific fly prey with pheromones which is quite astonishing.
A spiny Phoroncidia - Phoroncidia lygeana
Phoroncidia lygeana showing his abdominal projection.
A small flat spider was sat in a fairly large web nearby. A lot of spiders have entertaining common names in Borneo and this was no exception: a common pizza Anepsion, Anepsion depressum. (I’m still holding out hope to see a four-nippled big head.) This Anepsion is an orb weaver and so spins a fairly typical spider’s web. It has a very pale middle to its abdomen, potentially involved in luring in pollinating insects (see day 2?).
The common pizza Anepsion - Anepsion depressum
Next was one of the spider groups that I absolutely love, the ant-mimics. Unlike the Mallinella sp. that I found a few days ago that is an ant predator, this one uses its ant-like characteristics to hide from predators! Ants are quite dangerous to many forest animals due to their sheer numbers and so mimicking them is a good idea. Most ant-mimics are jumping spiders (Salticidae) and this is no exception. It is an Argorius sp. and has a lot of amazing adaptations to make it more antlike. Coloured dark just like many ants, it doesn’t have a web and hunts insects by running after them, holds its front two legs high in the air just like antennae and its abdomen is tightly waisted to make it look like it has a head, thorax and abdomen, just like an ant!
The amazing Argorius sp. ant mimic. Look at how it holds its legs like antennae and its waisted abdomen!
The final couple of spiders were both lynx spiders in the Hamaduras genus. These pretty animals are quite colourful and have limbs covered in spiny hairs. They sit with their hind pair of legs facing backwards while all the rest point forward. Rather like crab spiders, these lynxes are ambush hunters and have good vision. However, they are not averse to running down any particularly athletic prey. The spiny hairs on their legs are thought to help prevent their unhappy prey from escaping. These spiders, if threatened, will rise up and wave their first pair of legs in the air to show their strength, however in reality they are not very brave and will run off if the perceived predator persists. The big orange thoraxed one here is the superb lynx (H. superba – I particularly like his green hat) while the smaller juvenile one gets its name from the letter ‘U’ on its abdomen – H. hieroglyphica.
Back in camp someone had found an extremely beautiful orb-weaving spider. She is called Acusillas malaccensis with the apt common name of the ‘Tiger Marshmallow spider’. She has black tipped feet, an orange thorax and a huge abdomen; encircled in orange with a pale middle, striped like a tiger. She particularly likes to spin her web fairly near the ground in moist areas, presumably as this is also the habitat of her preferred flying insect prey. You may think that this spider is quite bold with her brightly coloured clothing but in fact she seems quite timid. She has a curled leaf hung in the centre of her large web which she will hide in during the day. Her body colouration is therefore probably not involved in prey attraction and is instead to do with aposematism – colouring to ward off predators.
The beautiful Tiger Marshmallow spider - Acusilas malaccensis
On a nearby leaf a few very strange and tiny insects were sat. They had long spindly legs, a small, thin body and a long orange ‘nose’. They looked a little like what baby lantern bugs should look like (these are amazing animals, more on them tomorrow) but surely they are too small to be nymphs? The adults are many, many times their size but potentially these are the first instar versions of them. They are in the Hemipteran family (bugs) and so are hemimetabolous – there is no larval stage, the young are more or less small versions of the adults. Interesting little animals whatever they are.
Possibly lantern bug nymphs
As night fell, Ted set off on a night walk with a nose for new reptiles and amphibians while I stayed in camp, intent on finding some big beetle larvae with the local guides. We set about digging into a rotten log with sticks and, despite our best efforts, no beetle larvae were found. However, we did find some amazing animals – wood-eating cockroaches! These huge animals are Panesthia angustipennis and we found a really big male and a couple of juveniles/females. As their common name suggests these cockroaches eat rotting wood and must get through a lot given their size. The males have beautiful black wings which must be used primarily for flying to find females who are wingless. The cockroaches must have a good olfactory (smell) sense to be able to detect female pheromones across the jungle.
We also found one of the stranger looking cockroaches on a leaf above the riverbank – the black armoured cockroach Catara rugosicollis. Armoured for protection this cockroach emits a foul smell when threatened, something I experienced when I picked it up for a closer look.
Clockwise from top left: Panesthia angustipennis male, Panesthia angustipennis juvenile/female, Black armoured cockroach Catara rugosicollis
Headed back to camp just in time to see Ted bound in with a big smile on his face. He had found an animal he had been hoping to see ever since he knew he would be coming to Borneo. Luckily it was one that would still be there tomorrow…