Walking With Wallace – Insects and Invertebrates

Posted by on November 27, 2013 in Borneo Notes, Featured, Thoughts | 0 comments

WalkingWithWallace2

All etchings and the photo of Alfred Russel Wallace from papuaweb.org. All photographs by Martin S Pribble.

Our decision to go to Borneo was made quickly. By “we” I mean my partner Hayley and I, and her sister Charmaine. By “quickly” I mean we had it planned, booked and paid for only 3 weeks before we were set to leave. But in that time, we managed to organise to hike up Mount Kinabalu, accommodation in Kota Kinabalu and near Kudat, and a one day layover in Kuala Lumpur on our return trip.

01 Kinabalu-from-Mountain-Centre

To say it was a whirlwind would be an understatement. I now realise that I cold have easily spent several months in Borneo and still only seen a fraction of what that island has to offer. So, what’s so special about Borneo?

Borneo is the largest island in Asia, situated in the Malay archipelago, and is home to some of the world’s strangest and most wonderful plants and animals. It is shared between 3 countries; Indonesia, which takes up the largest portion of the island, Malaysia, with the two states of Sabah and Sarawak along the north and west coasts, and Brunei, a small but extremely rich country which is ranked 5th in the world by gross domestic product per capita. Our trip was confined to the northern region, in the Malaysian state of Sabah.

02 Alfred-Russel-Wallace-c1895

In 1854, Alfred Russel Wallace (known to have developed the theory of evolution independently from, and slightly later than, his more famous contemporary Charles Darwin) travelled to the Malay archipelago on a journey that would rival Darwin’s journey to The Galapagos. During Wallace’s travels in the archipelago, he collected thousands of bird, plant, mammal, mollusc and insect samples, many of which were completely new to the world of science. His book “The Malay Archepelago” is still seen as one of the most celebrated of travel writings in the region. Much of my journey, especially that taken to the summit of Mount Kinabalu, can be compared to parallel writings within this book by Wallace. The elation I felt simply being in an environment like this as an amateur naturalist was intense, and I can only imagine the excitement that Wallace, as a professional biologist, would have felt to be the first to document so many wonderful and unique forms of life.

As noted by Wallace, each of the islands and peninsulas which make up the Malay archipelago are unique unto themselves in terms of plant and animal species because of the fractured nature of the many islands. From the aforementioned book:

“We have indications of a vast continent, with a peculiar fauna and flora having been gradually and irregularly broken up; the island of Celebes probably marking its furthest westward extension, beyond which was a wide ocean… From this outline of the subject, it will be evident how important an adjunct Natural History is to Geology; not only in interpreting the fragments of extinct animals found in the earth’s crust, but in determining past changes in the surface which have left no geological record. It is certainly a wonderful and unexpected fact that an accurate knowledge of the distribution of birds and insects should enable us to map out lands and continents which disappeared beneath the ocean long before the earliest traditions of the human race.”

This is precisely what makes the Borneo region and the Malay archipelago unique on this planet. It is a veritable jewel-box of treasures and surprises, with many animals endemic to the region.

The insect life in Borneo is astounding. We saw butterflies, crickets, grasshoppers, weevils, wasps, bees, ants, cockroaches, and the obligatory flies and mosquitoes. The fireflies kept us company on the still nights, and I was moved to wax lyrical about them on my blog. Occasionally huge beetles would fly past, making a sound like a tiny helicopter, and flying in what can only be described as “barely in control”, banging into trees and walls, one even landing on my hat! Wallace collected hundreds of individual species of beetle on Borneo alone. On beetles, Wallace wrote:

“On one day I collected 76 different kinds, of which 34 were new to me. By the end of April I had more than a thousand species, and they then went on increasing at a slower rate, so that I obtained altogether in Borneo about two thousand distinct kinds, of which all but about a hundred were collected at this place, and on scarcely more than a square mile of ground.”

03 Beetles

This kind of astounding diversity is something we experienced over and over whilst in Borneo, and something I could never tire of. We saw many species of beetle, including some longhorn beetles as in Wallace’s plate above, but to my mind the most spectacular among the beetles was the rhinoceros beetle we discovered at the villa in far north Borneo. It was a dead specimen, possibly killed by the fumigation in the villa the previous week, but it was huge, at least 3 times the size of similar beetles back home in Melbourne.

04-Beetle

Another beetle species I saw was on the hike up Mount Kinabalu, what is known as a “trilobite beetle”, or Duliticola, after a nearby mountain Mount Dulit. The females stay in the larval form for their entire lives, and the can grow up to 8cm long. This one was about 6cm. The males, by contrast are rather unremarkable and only 6-8mm long.

05 TrilobiteBeetle

The butterflies on Borneo are a huge and varied family. Sometimes what appears to be a leaf falling from a tree turns out to be a butterfly, with many species adapting to looking, and acting, like inanimate falling leaves from the trees. It wasn’t until the falling leaf started flying upward again that it was obviously alive and flying. On leaf imitating butterflies, Wallace wrote that the butterfly’s markings are:

“…so as to imitate more exactly the venation of a leaf. The tint of the undersurface varies much, but it is always some ashy brown or reddish colour, which matches with those of dead leaves. The habit of the species is always to rest on a twig and among dead or dry leaves, and in this position with the wings closely pressed together, their outline is exactly that of a moderately-sized leaf, slightly curved or shrivelled.”

06 butterfly

Other butterflies we saw occasionally flitting through the forests and jungles were the birdwing butterflies. The more common one we encountered is called Trogonoptera brookiana, named by Alfred Wallace after James Brooke, the Rajah of Sarawak. Butterflies are notoriously difficult to photograph in the wild, but I did manage to get a great shot of one at the Kuala Lumpur butterfly park, seen here against a trellis. The wingspan on these butterflies was a whopping 15-17 cm, and the colour varies from a bright yellow, through iridescent green, to iridescent blue, depending on the angle you view them from.

07-butterfly

Also spotted in the wild, but unable to be photographed was the common birdwing butterfly, Troides helena. Only slightly smaller than the brookiana, it was no less spectacular. This was also photographed at the Kuala Lumpur butterfly park.

08-butterfly

Aside from insects, we also saw a very interesting millipede, a giant tractor millipede (genus Barydesmus), making its way slowly and meticulously along the edge of the pool at our villa. At first we thought it was a centipede, but upon further investigation (and counting the legs per segment on the creature), we were sure it was a millipede, and quite harmless. This one was about 16cm long (7inches).

09-Tractor-Millipede

This is but a small taste of what we saw in Borneo, and I intend to follow this post up with more, on reptiles, primates and birds. But it does show just a slice of the breadth and variety of species contained on the island of Borneo. Even more interestingly, we did not set out to find any of these creatures; rather, they found us.

Wallace noted, on the variance of species from island to island, and on the sheer diversity within Borneo, that the geology of the area was particularly suited for the emergence of different species over time.

“Any geologist who knows how strata have been contorted and tilted up, and how elevations and depressions must often have occurred alternately, not once or twice only, but scores and even hundreds of times… is a matter of much interest, both to the geologist and to the philosophic naturalist, to be able to form some conception of the order of those changes, and to understand how they may have resulted in the actual distribution of animal life in these countries; a distribution which often presents phenomena so strange and contradictory, that without taking such changes into consideration we are unable even to imagine how they could have been brought about.”

Wallace’s travels in Borneo helped us understand the way specific geological movements and physical barriers isolate species and lead to new and unique speciation. Given that we only saw a small sliver of what Borneo has to offer, and that there are specific animals we would need to go farther afield to see, we will definitely be returning to this magical land.

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