Will Hawkes
E N T O M O L O G Y
Day 5: Long Millipedes, Rockstar Bugs and the Onset of Illness...
Ted and Lintar heading into the jungle.
Peeling ourselves off the camping mattresses we showered from a bucket and went into the lodge to find out today’s plans. Lintar would be today’s guide and he met us over breakfast and said we would be heading into the forest behind the lodge this morning, where Ted and I had been hunting most nights.
Pulling on wet jungle clothes, hopefully washed the evening before, we walked into the forest listening to singing gibbons in the distance. Such is the speed of decomposition in the hot and humid environment that any log on the ground is likely to be soft with rot. The one at our feet was no different and as I pulled it over, one reason for its rottenness was revealed: a large wood-eating beetle larvae. These soft undulating creatures are without any type of defence and stay hidden deep within the logs until they develop into the harder adults. Their legs are short and only serve to pull them through the wood tunnels of their own creation. Their head is the only part that is hard and consists mostly of large strong mandibles. Because these creatures eat solely wood, they take a long time to develop. In the UK large beetles such as stag beetles can take many years but, such is the perfection of the habitat for decomposers here in the jungle, I dare say these beetle larvae will become adults much faster.
Wood-eating beetle grub.
On a few of the thick jungle leaves tiny dark ants trailed industriously. There are so many ant species here that because I know so little about them, many faded into the background of just ‘another ant’. These ones, however, were far more distinguishable on account of their golden saddle. These ants are called Crematogasta inflata and they live in cracks in branches or trunks of trees. Their golden yellow saddle is more than just a warning to predators, it contains an enlarged metapleural gland filled with a liquid that the ant releases when threatened! I thought it was just a pattern when I took the photo so cannot comment on the pungent nature of this defence but I imagine it is quite effective!
Crematogaster inflata ant.
Some things in the jungle are just thrown out of proportion to what British students are used to. A leaf I picked up off the floor was not much shorter or narrower than my torso and was amusingly described as a ‘Ladyboy leaf’ by our guide, Lintar, who proceeded to mince down the path a few steps, holding the leaf as a parasol.
Big 'ladyboy' leaf.
Crawling up a nearby tree, legs moving in a slow, smooth wave was the largest millipede we had ever seen. Luckily it was just within grabbing distance and so I reached up and had a closer look. About 25cm long with a black shiny top and undulating waves of red legs it was an attractive creature. A bit worried about being picked up this Trigoniulus species had emitted a strong smell which wasn’t entirely distasteful but not massively pleasant. An understandable reaction to being picked up by a large omnivorous mammal. After letting it crawl across my hand and watching for a little while it was released back into its tree.
Trigoniulus millipede feat. expedition watch.
Groundhoppers which are members of the order containing grasshoppers and crickets and are in the family Tetrigidae, are masters of camouflage. We saw a few on our walk but there must have been many more that we missed. They ranged from more arboreal ones mimicking the smooth brown bark of trees to the more intricate lichen mimics. Interestingly, we consistently found the groundhoppers on the substrate that they were camouflaged to look like. This is obviously an advantage to the creature but it is certainly impressive that they know what they look like well enough to stay in that area and not wander into a location less suited, easy to do in such a varied jungle environment!
Camouflaged groundhoppers.
More beautiful lantern bugs were spotted along the way. The same galaxy coloured Pyrops whiteheadi gunjii as found on day 2. We could hear them singing like a cicada throughout the forest. There was a vast array of insect noise around us and most prominent were the cicadas. There were may different types. Some had that classic electrical buzz, others a high pitched whine but some were quite distinct. There was one point in which we stopped and heard an eerie siren gusting through the air giving the forest an ominous feel. Another sounding just like an iPhone’s alarm and some sounding almost exactly like a long, drawn out ‘yeh-boiiiiiiiiii’ which was greatly entertaining! However, what all the noise had in common was that it was much higher pitched than all of the bird song. This was because the insects arrived before birds in evolutionary time and are too stubborn to change. Like the insects, birds sing to be noticed and because the insects are so loud, they struggle to make themselves heard. To counter this, many jungle birds have evolved to sing at lower frequencies (and to hear lower frequencies too) so they can find a mate despite the incessant background noise of the insects!
Pyrops whiteheadi gunjii lantern bug.
These thoughts were interrupted by Ted spotting a racket-tailed Drongo in the middle distance and me completely failing to see it for the next five minutes or so. Certainly much more used to spotting smaller things, my prey-image rarely includes birds.
To continue with the wonders of bird calls, however, there are many many species in the jungle and the vast majority call to make themselves heard. They sing at a lower frequency to avoid competition with the insects but how do they avoid drowning each other out? Adaptive timing seems to be the answer. There seems to be a fairly complex inter-specific timing mechanism in place where birds in an assemblage have their own specific time slot in which to sing, cued by the previous species finishing their song. Species with more subtle voices and less persistent singing behaviour may rely more on timing as a noise-coping strategy than loud and dominant singers!
Back to the insects and sitting on the next leaf was another mimic. A small fly with darkened rounded wings, and quite a spherical body overall. It was trying its best to mimic a beetle which are usually distasteful in the jungle and at the very least hard to eat on account of their hardened bodies. Below this an individual of the stereotypical mimics lay, a stick insect. This one not only accurately mimicked the shape of a twig but also the texture and colouration of lichen on its bark-like exoskeleton!
Beetle-mimicking fly.
Camouflaged stick.
A black Mutillid wasp (or velvet ant) was nearby. This one is a mimic to avoid being eaten but only the males are copiers, mimicking the females. This is because the males lack stings and so cannot defend themselves. The females, on the other hand, are renowned for having powerful stings and so many animals avoid them. To further fuel the idea that the male is dangerous, he will mime ‘stinging’ the predator (me in this case as I was holding it gently in my fingers) to put it off. With Mutillidae, it is easy to discern males from females and only the males have wings so he can fly long distances in the jungle to find his female.
Male Mutillid wasp.
We had wandered to the edge of a river at this point and there always seemed to be more diversity in the brighter, less densely vegetated areas, although this may be just because it was easier to spot things. Our next point of interest did not take much spotting though. It was about 5cm long and bright yellow and, what’s more, it had a large face seemingly painted on its wing cases! This was an animal which we had been hoping for but never expected to see; a Catacanthus incarnatus, a shieldbug that has an uncanny resemblance to Elvis Presley! It is, however, fairly unlikely that this shieldbug has heard much Elvis (although with our guide, Lintar, around, Westlife is a possibility – see Day 2) and so its colouring is far more likely to be just a striking contrast to scare off predators.
Elvis Presley shieldbug - Catacanthus incarnatus.
Almost unnoticed beneath the showy insect was an understatedly attractive creature, a Ricaniidae plant hopper with intricate wings part of which were completely transparent. Sharing its plant was a tiny Cosmophasis species of jumping spider. Interestingly, when UV light is shone on these spiders the males reflect the light very strongly while the females and juveniles do not reflect the UV light at all. This suggests that the spiders not only can detect UV light far better than humans but also use it in sexual signalling. The more reflective the male, the higher fitness it has for example.
Ricaniidae plant hopper.
Cosmophasis jumping spider.
We were still wandering next to the slow moving brown water channel and the banks were high with reeds. Darting between them were myriad dragonflies. One understatedly beautiful one landed close to me so I could admire its golden sheen. It was a good predator, hunting for smaller insects near the river. There were quite a few predators about actually, one especially hairy robberfly was sat on a leaf nearby. I don’t know what use its extra hair was, maybe it was just aesthetic.
Beautiful dragonfly.
Hairy robberfly.
As we were so focussed on animal searching, we weren’t paying attention to our direction and it was a surprise when we suddenly emerged onto the reservoir that we had come to know. We were nearing the end of our walk but there was still a lot to see on the short trail back to the lodge. Three menacing creatures lay in wait. First a large assassin bug on a leaf, then a fairly cross-looking ant with a huge head patrolled the edge of a concrete bridge while another with 180˚ jaws wandered down at the bottom of the steps.
Bird poo assassin bug.
Bulldog ant.
Wide-jawed ant.
As is so often the case in the jungle, you have to keep your eyes peeled until the very end unless you want to miss something. Just as we were leaving the vegetation bordering the reservoir to quicken our pace while walking through the small village, we spotted one of the best insects of the day. It was a small dark moth, one of the clearwings, with a small line of crimson around the shoulders. Its legs, however, were by no means subtle and adorned with long red hair-like scales on their lower edge. The little moth when threatened would line its legs up with the edges of its wings, making itself seem bigger and scaring off any predators with its bright contrasting colours.
A fiery-legged clearwing moth.
After a bit of lunch, poor Ted began to feel ill. Taking it very slowly we spent the rest of the afternoon in the lodge sheltering from the sun and keeping hydrated, working on field notebooks and playing daft football games on our phones. Ted felt worse and worse as the day progressed and was beginning to get a little worried about staying here for another few days. After he had tried to eat his food (and I had helpfully finished off the rest) we decided to call it a night. Feeling especially kind, I read poor ill Ted a couple of chapters of Harry Potter to help him sleep before tomorrow.