Will Hawkes
E N T O M O L O G Y
Day 3: Ancient beetles, blue wasps and tarantulas
Waking to find that our sleeping bags hadn’t kept the mozzies off our legs, we sprang up for a new day. Diving into the swimming pool that was the jungle air, we both had cold showers before breakfast. Breakfast was good although somewhat disconcerting to have quite spicy chicken first thing in the morning.
Pulling on jungle boots we gazed around the dawn as we wandered along the path leading to the jungle. As soon as we got past the tiny village and we started on the trail along the reservoir’s edge, we began insect hunting. We were with the main guide Agus Din today and I think he was quite surprised as to how slow we were going! He must be quite used to people rushing into the jungle to try and see peacock pheasant, orang-utans, gibbons and the like. We could actually hear gibbons playing somewhere deep in the forest but our attentions were grabbed by a stunning wasp, similar in almost every way to our yellow and black Vespula species apart from the fact that she was bright blue and had large green eyes! Closer inspection revealed that she was likely one of the Bembix wasps, predatory creatures that prey on smaller insects.
A blue Bembix wasp.
Wandering over the wooden boardwalk we were standing on was a very sweet little yellow tortoise beetle. On a few of the leaves above sat its larval form. These larvae are dark, armoured caterpillar like creatures with a strange, fibrous projection from their back-ends. A bit of research found that this projection is actually their own poo and they use these ‘faecal shields’ for camouflage and also to make themselves seem bigger to ward off over-interested predators!
Yellow tortoise beetle and young.
Living in a small horizontal web about 30cm above head height was a spider with the most amazing jaws. Called Tetragnatha hassellti or the Red/Green long-jaw spider, the jaws are quite distinctive to his genus. Looking closer revealed two small spurs on the outside of his jaws, these he uses to lock into the jaws of the female during mating so he doesn’t get eaten.
Tetragnatha hassellti
A dark shape was spotted floundering about 3m offshore. Identifying it as a large beetle we proceeded to throw sticks past it in the hope that it would be washed back to shore (50% to save it and at least 50% for us to see what it was!). However this wasn’t working so we grabbed the longest palm frond we could find and, by leaning out over the bank (being held back by Ted) I eventually managed to get it onto the frond. Picking it off the palm the beetle was found to be a female Odontolabis castelnaudi stag beetle! Looking closer, we realised that the beetle had eyes separated by a line of exoskeleton so she could look both up and down! I’m not entirely sure as to what use this would be though, she may be a forest floor dweller and so she can look down for food and upwards to scan for predators at the same time?
Odontolabis castelnaudi stag beetle.
Flying past my ear just as you’d imagine a spider would if it had wings, was a small yellow and black creature. Alighting on a leaf it became an assassin bug, specifically Cosmolestes picticeps. Assassin bugs, as their name suggests, are predatory animals and will eat all manner of creatures (mostly smaller invertebrates). The young of species such as this are very clever creatures and have a preference for spiders. Crawling softly onto the webs of orb weavers which are smaller than the young assassin bug, the bug plucks the spider’s web in exactly the same way a struggling prey item would! This lures the spider unwittingly to its doom on the sharp end of the assassin bug’s mouth parts. If the spider is larger than the bug but the bug is still hungry however, it has a further trick. Research has suggested that the bug can mimic the movements of a soft breeze so as to camouflage itself. This allows the bug to move, unnoticed, towards the spider and get it with a sneak attack.
Cosmolestes picticeps
By this point almost an hour had past and we had barely moved 300m but at last we had reached the entrance to the jungle. The sheer humidity of the forest hit us again like a fist and our pace slowed further, in part to keep cool but mostly because there was so much to see. The dense canopy of competing trees meant that not much light made it to the forest floor so I had to keep the flash on my camera at all times.
A flash of red on the branch above us caught my eye, another bug – this time a nymph of Pycanum rubens with its amazing shield-like body of red and blue. The adult females of this species are actually very caring mothers, they will stand guard over the eggs and will even allow their young to cling on to their undersides to give them a better chance of survival!
Pycanum rubens
Resting on a leaf also was a butterfly in the Satyrinae family (I am no good at butterflies, especially in Asia, and can’t find a good ID guide) which had amazing eyespots underneath. Much research has been done into the function of these eyespots, whether they are mimicking birds or mammals to ward off predators or whether it is a startle effect and the general consensus seems to be the latter.
Satyrinae butterfly
Rounding a corner of the jungle path we emerged into a clearing with a large-ish human-made shelter where we sat for a much needed lunch. Suddenly, a crash through the branches above us and three red langur monkeys bounded along a branch! Too fast for me to get a photo as I was concentrating on something by my feet but still exciting to see a mammal!
The things by my feet were especially interesting however. The sandy soil underneath the shelter was covered in small craters maybe 3cm deep and 8cm wide. One side of the crater was vertical while the opposite was sloping. Occasionally small ants would fall in the crater and attempt to crawl out the sloping side. Suddenly, a pair of jaws would dart out and grab the ant back into the jaw’s lair, never to be seen again. Intrigued, I got out my knife and began to unearth the surreptitious predator. It was about 3cm long and soft, save for a head covered in hard exoskeleton and largeish jaws. Almost certainly a larval stage similar to an antlion but not sure at all what it is! Very clever to make the design of its pitfall trap just so the prey only has one perceived escape route which leads to its demise.
Pitfall trap insect and trap.
A call from Agus Din revealed one of the spiders I had been really hoping to see ever since I got the Bornean spider book a few months ago. There, in a web at least two metres across was a small spider barely 10mm wider with the most amazing spines. She is called Macracantha arcuata, the long-spined kite spider, and her spines projecting from her armoured abdomen arced up an almost touched about 4cm above her head! Nobody seems to know exactly why she has such elaborate spines but it can’t make her easy for birds to swallow! This spider is also amazingly beautiful. Our one was bright yellow tinged with red on her abdomen but there are many different colour morphs. The reason for these bright colours is thought to be that they act as a lure for pollinators. The colours exploit the pollinators visual preferences for bright hues and attract the flying pollinators into the spider’s web. Interestingly, the shade of colour the spider exhibits is fairly telling of its habitat. Our spider was found in a clearing where there as a lot of light and so was quite yellow to increase chromatic contrast (colour contrast) between it and the environment to stand out. In darker areas these kite spiders tend to be much whiter to increase achromatic contrast (shade contrast) because in dark situations it is easier to determine white from black rather than between colours.
Macracantha arcuata spider.
Leaving the clearing we continued through the jungle, trying to evade the clutching walls of humidity. Perched on a leaf was a tiny grasshopper with antennae four or five times its length! Some of the animals in the jungle have the most amazing sensory adaptations for life in the forest. Others have specialised markings to ward off predators like a tiny moth we found sat on a tree. It sat raised slightly so its underwings could be seen from above. On each side the moth had eyespots (these are fairly commonplace in jungle Lepidoptera – see above butterfly) to scare off predators from both above and below. One such predator was the Dracolis flying lizard, something we were desperate to see!
Long antennae cricket.
Suddenly an orange blur zipped across the path in front of me. Crashing through the jungle after it, the insect eventually settled on a leaf long enough for me to get a quick photo. She was a golden spider hunting wasp (something around the Pompilidae family) and was on the hunt for some large-ish spiders for her to paralyse, drag back to her nest, and feed to her young.
Orange Pompilid wasp.
Sat at the base of a tree nearby, watching all this crashing was one of the prettiest insects in the jungle- a lantern bug, specifically Pyrops whiteheadi gunjii. With dark edged wings giving way to a sun of yellow merging into the dark blue of space, mottled with white stars before an orange head and nose, culminating in a small galaxy of stars on a blue base. Despite its name this bug does not give off any sort of light and uses its impressive ‘nose’ (which is actually its rostrum (mouth)) to suck up sweet sap and fruit juice from trees. Interestingly, some moths have learnt to drink this bug’s urine as it is very sweet and so a good source of sugar!
Pyrops whiteheadi gunjii lantern bug.
Rounding a corner into a patch of light where a large tree had recently fallen naturally, Ted spotted one of the oddest insects in the forest, a trilobite beetle. This Platerodrilus sp. is one of a few Bornean species and is a female. When the beetles were discovered in the 1800s it took until 1925 for a male to be observed. A Swedish zoologist Eric Mjoberg discovered one only after many years of searching. He found that adult females look almost identical to their larval forms and the only difference being that the adults have working sex organs! Mjoberg enlisted the help of locals to find a male trilobite beetle and eventually he succeeded. According to an article in National Geographic (https://news.nationalgeographic.com/2016/10/rare-weird-insect-trilobite-beetle/) a local came up to him holding a pair of trilobite beetles wrapped in a banana leaf, copulating! The male was far, far smaller than the female, looked nothing like her and had wings! It is therefore likely that the females produce a pheromone which the smaller, winged males follow through the jungle when she is sexually mature. The reason why the female remains very similar to her larval form is likely to save energy for egg laying and to produce fat, healthy young.
Platerodrilus sp. of trilobite beetle.
Some of the mimicry different animals show is so interesting. One tiny fly on a leaf caught my eye as it seemed to be mimicking a beetle with rounded and darkened wings. Presumably mimicking a beetle makes it just that much harder for a predator to eat and so the fly which would ordinarily be quite an attractive food source has a little more protection. The diversity is just endless here!!
Beetle-mimic fly.
By this point we had been walking and hunting for things in the jungle for nearly nine hours and we were on the journey back to the base. When we arrived however, Agus Din showed us around the little patch of jungle neighbouring the lodge. He pointed out two holes in the bank and said they were tarantula burrows, something to look out for tonight! Stopping quickly, Agus Din grabbed a shiny rock which turned out to be a black marsh terrapin which was exciting to see!
Black marsh terrapin.
It was nearing five in the afternoon now and we were quite exhausted and so I decided to have a quick nap before tea. Waking very disorientated and dehydrated I had to douse myself in cold water before wolfing down some tea to make myself feel better.
Agus Din had gone off for the evening and so we were left alone to explore. We reasoned that we probably shouldn’t stray too far into the jungle and so went tarantula hunting nearish to the lodge.
Wandering straight towards one of the tarantula burrows we shone our torches in and just caught a glimpse of some furry feet retreating into the depths – we were going to have to be more sneaky if we wanted to get a good look. Resolving to try in a bit we headed downhill into droves of mosquitoes towards the boggy area near the bottom to look for reptiles and amphibians.
Sat on a trunk was a different species of spider: Pandercetes sp. a lichen huntsman. With her green thorax and spotted legs she is an attractive creature pretending to be some lichen.
Pandercetes sp. lichen huntsman.
A whispered call from Ted telling me to look up showed me what I would have otherwise missed; a sleeping rufous-backed kingfisher! It is good to have someone with you who is able to look at more than just insects, I so rarely look up when I’m hunting through the undergrowth. Although I did spot something familiar but very different, an earwig! So obviously related to our common species in the UK but much longer and with thicker thighs. This is a female because her cersi (pincers) are long and thin whereas the male’s form a circle.
Rufous-backed kingfisher and earwig.
We were nearing the boggier bits now and more herpetiles were appearing at our feet. This medium sized one is a crested toad. Its back markings make it well camouflaged during the day while at night it hops about looking for insects. Because of its thick skin, it loses less water than its thinner skinned cousins so can stray further from water bodies without worrying too much about dehydration.
Crested toad.
A dot of light caught my headtorch beam from a dead tree about ten metres away. Negotiating the swampiest areas I got closer to have a look and found a huge huntsman spider! It was likely a giant tree trunk huntsman (Heteropoda boiei) but a browner morph than the ones we were yet to see so I was a bit unsure! She was certainly sure of her size as when I waved my fingers in front of her to see what she would do, she absolutely went for them and it was only because I was concentrating that I could snatch them back in time!
This wasn’t the first time that we would encounter enthusiastic giant tree huntsmen.
Giant tree-trunk huntsman Heteropoda boiei
A flash of gold and a shout from Ted moved me away from the spider and, still eyeing the arachnid warily, I crashed over to see what he had found. A red bellied keelback snake! It had just eaten a fairly large meal and the bulge in its belly was golden where its scales were stretched. In addition to being flecked with gold, the snake has a darkened head and red eye with striking white collar markings. This was already the third snake we had seen and we’d been here just over 24 hours! Very excited for more to find!
On the way back we decided to take drastic action to see the tarantula. Finding a juicy looking cricket-type thing we caught it and carried it back to where the big spider lived. Placing our sacrificial insect nearby the hole, we waited with baited breath for the spider to pounce, camera poised. The cricket moved closer and closer, walking right into the entrance of the tunnel. My finger on the shutter ready to capture the moment the elusive spider revealed herself… but nothing. The cricket just walked on by unfazed, leaving me with just a photo of the spider’s hairy feet. Luckily, this was just enough to tentatively identify it as an orange-fringed tarantula.
Back in the lodge we looked at the geckos snaffling up unfortunate moths while we sat with our books identifying today’s finds from the back of my camera. Cooled off sufficiently, we clambered back to our room, pulled the single person mosquito net over our heads and fell sound asleep, dreaming of tomorrow.
Red bellied keelback.
Big cricket and the legs of an orange-fringed tarantula.