This is Mr Bob. Or maybe not. He's a little on the small side, probably not more than a metre and a half, and so is probably Bob's cousin, Bub. But with luck (and lots of monkeys to chow on) he should some day reach his species' maximum length of six metres and graduate to eating larger land-based tetrapods. Ducks and crocs are natural enemies so I took the reasonable precaution of bringing along a sacrificial monkey to distract the toothy one should he deem my duck a delightful dessert.
Despite the downpour, Sungei Buloh Wetland Reserve was fairly busy today, with plenty of people braving the woebegone weather for a meander through the mangroves. Unfortunately, for some tender folk, the uncivil chatter of bulbuls and shrill songs of cicadas were too much to bear and they sought the pounding solace of handphones which have as much beat and boom as the ghetto-blasters of old. I am certain the device achieved its designed purpose of driving away all wildlife, fowl and fair. Later, my duck was further distressed when he passed by a boy who pointed to a bird in the bushes and exclaimed, "Duck! Duck!" Something is sorely and surely lacking in biology classes if a skulking little water hen can be misidentified as a proudly, erect duck! Oh the indignity of being mistaken for an aquatic chicken! Other than that, my outing to Sungei Buloh was full of crab.
Public Talk on 2 August
The climbing fern Lygodium microphyllum is invading Florida's natural environment. In its native range the fern is an attractive and relatively common part of the environment. In Florida, L. microphyllum covers tens of thousands of hectares, blanketing and killing trees, shrubs and entire natural plant communities, and increasing the intensity and spread of fires. Control by physical or chemical means is not feasible, leaving biological control as the key to long-term management of the weed.
The US Department of Agriculture - Agricultural Research Service (USDA-ARS) is searching the native distribution of L. microphyllum for potential biological control agents. Much of the exploratory work is based at CSIRO Entomology laboratories in Brisbane, and a vital part of the research occurs in Singapore with the cooperation of National Parks Board personnel.
Of the insects being studied as potential biological control agents, this talk centres on just three. First is a leaf-feeding sawfly (Neostromboceros albicomus), whose type specimen was collected in Singapore in 1909 but apparently it no longer survives here. Next are two small stem-boring moths. One species (Siamusotima aranea) from forest areas around Chiang Mai appears to be happily maintaining good populations on a related climbing fern, Lygodium flexuosum. The other stem-boring moth, an undescribed species from Singapore, seems to be grimly holding on in low numbers at a few field sites around the island.
Speaker: Mr Tony Wright
(A biologist with CSIRO Entomology)
Venue: Peirce Road
Multi-purpose Hall Peirce Road Depot
Biodiversity Centre, National Parks Board
Date: Wednesday 2nd August
I wasn't able to attend the talk but found a paper co-authored by the speaker with John A. Goolsby and Robert W. Pemberton in the journal Biological Control on "Exploratory surveys in Australia and Asia for natural enemies of Old World climbing fern, Lygodium microphyllum: Lygodiaceae", which is summarised below.
The authors conducted surveys from 1997-2002 in Australia and the Asia Pacific to look for natural enemies of this pteridophyte pest in its natural range, with the idea of using host-specific species to combat the fern, which is running rampant in Florida's swamps. The fern's climbing habit causes it to spread across tree canopies, increasing the damage caused by wildfires which would otherwise be limited by the swamp water around the trees.
Southeast Asia and Australia were chosen as the exploration sites due to their climatic similarility to Florida and the fact that the fern is common but not regarded as weedy in these regions. The Floridan fern populations were also genotypically closer to populations in East Asia than conspecifics in Africa. The genus Lygodium is also most speciose in East Asia and Australia, which harbour 15 of out 26 known species, increasing the probability that specialist herbivores would have evolved to feed on the genus.
The authors found L. microphyllum in a broad range of habitats throughout the region, from peaty soils and coastal wetlands to wet, lateritic clay soils and the edges of perennial creeks. But in its natural range, the plant was never found to be more than a few metres tall and did not dominate its plant community. In Florida, nothing appears to prevent the fern from forming dense mats a metre thick above the soil and twining fronds up to 30 metres long.
Twenty insects and two mite species were found to feed on L. microphyllum or related species. The most common and widespread herbivore was the eriophyid mite Floracarus perrepae, followed by the pyralid moth Neomusotima conspuractalis. The authors report that all species that feed on L. microphyllum occured in low field densities except for the eriophyid, which they also regard as having the greatest promise for biological control of the fern in its host specificity and ability to ceate a 'steady state' equilibrium whereby mite-induced damage and tissue death equals the rate of new growth. However, mites from Queensland, Australia performed poorly on the Florida form of L. microphyllum, pointing to a need to find a race that can tackle the invasive ferns effectively, assuming this population still exists.
The leaf-feeding sawfly (Neostromboceros albicomus) was another candidate considered by the authors. Sawflies are not flies (Diptera) but belong as to the same order as ants, wasps and bees. However, they lack the thin waist that characterises most Hymenopteran and do not sting. The common name comes from the female sawfly's ovipositor, which 'saws' a slit in plant leaves for egg-laying. N. albicomus is believed to be extinct in Singapore but still survives in Thailand and Indochina. The adult flies are black and sluggish, laying eggs on new fern growth. The caterpillar-like larvae then pupate in the soil. The authors note that local populations of the sawfly can reach fairly high densities and defoliate patches of L. microphyllum and L. flexuosum. "The apparently narrow host range of this insect and its unique biology as a sawfly make it a good candidate agent for biological control," they conclude.
A recently described moth (Siamusotima aranea) also holds promise as it is the first stem-boring moth in Asia known to be a fern feeder. The moth's caterpillars were found in the stems of L. flexuosum and being tested on L. microphyllum to determine their biological control ability. This moth is also interesting for other reasons; its caterpillars have armoured backsides that resemble those on beetle larvae and the adult moth has markings that appear to mimic a spider (hence the specific name aranea). The other stem-boring moth, which I gather to be an undescribed Ambia sp. found in Singapore, which is very rare but noted to be potentially very effective against L. microphyllum.
Biological control of L. microphyllum in Florida is reckoned feasible as the fern has no close relatives in the Neotropics and a number of host specific herbivores are in the experimental pipeline. For many other species, however, no easy solution seems possible. So for now, Burmese pythons, African walking catfish, Asian swamp eels and Chinese clams are conquering the Everglades even as cane toads hop their way through Australia, foxes prowl in Tasmania and Asia is enriched with Neo-tropical and African cichlids; South American loricariid catfish and livebearers; and North American sliders and bullfrogs unleashed in the name of good intentions and wilful ignorance. Biogeography is sooo screwed.
A couple of 'uncles' join our table for breakfast.
"So this is your son ah! And he's working in Singapore, you say. What does he do?"
"He does... office work..."
"Oh my son is in Singapore too! He works for a big American company dealing in electronics!"
"[budak] travels quite a lot for his work..."
"That's good! My son travels everywhere for work too! Has your boy ever been to China?"
"No lah.... not China. But he goes to Germany quite often."
"Is that so? I have been to Germany too! And France! And Holland! Also Mei Guo! Canada! Australia! ..... does your son go to Jakarta? Bangkok?"
".... Good! Good! But must go to China you know... now very important!"
"[budak] doesn't have business in China..."
"Where does he stay in Singapore?"
"Oh, Ang Mo Kio."
"Good, good..... got a place so you can go visit him often.... my daughter is also in Singapore you know!"
"I think it's time for me to catch my bus..."
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I hate this bloody game of one-upmanship that you people play, where your children's achievements, matrimonial progeny and manifestations of material piety are brandished like trophies at your peers. Why should I answer your smiling queries on how much I earn, what bonuses and raises have I received, or how much my wife makes? I refuse to join in your charade of care and concern for the well-being for our family good, scorn your earnest enquiries on this household's successes, and wish my parents had the will and wherewithal to disclaim this dance of egos. For in their ardent partaking of such parries, I have not the heart to be honest about my accomplishments and my failures, my dreams and denials, hearing as I do hopes that may not withstand the deadness of truth and parsimony of modest ambitions.
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Sometimes blood is so much thicker than water that it smothers and stifles the life out of relationships, preferring to seal with superficial clots wounds that should be left to bleed dry.
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Besides SGH, where else can I get a seminal analysis done? And in a conducive environment – I doubt handing me a sterile jar at 7.30 am and telling me to go to the nearest toilet cubicle will help my duck produce the necessary sample.
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I missed the stupid bus back to my hometown on Thursday, despite arriving at the terminal early. Ten minutes after the scheduled departure time, there was no sign of the bus, and I found out that it had already left. The next bus would leave only in six hours, so I had to hop into a cab to rush to the checkpoint where I joined the daytrippers on SBS 170 to arrive at that hellhole of crime and grime known as Larkin Bus Terminal. It was a weekday so I could get a bus that departed in half an hour.
If it were a weekend or Friday evening, there would be little chance of getting such immediate seats. Assuming I arrive at the terminal at, say, 10 am, I would be lucky to get a bus that leaves in the mid-afternoon, as most tickets would have been purchased earlier in the week by local folk who commute between the towns on a weekly basis. So, I could well (and have done just that in the past) spend something like 8-9 hours on the road, much of it rotting at the bus terminal while fending off beggars and extortioners, before reaching home – a journey that takes a 'mere' three hours by car. And they still wonder why I don't take the opportunity to rush home every other weekend or public holiday....
NParks hosted a double-bill talk today centred around monkeys – specifically the macaques of Singapore and South Asia. Before the talk, my sweaty duck sat outside the visitor centre at the Bukit Timah Nature Reserve and observed the two extant species of local primates. Both taxa were out in full force, with many bringing out their offspring for an evening stroll. The mother macaques held on to their babies tightly, while the hominids were somewhat less bright, some letting their newly-weaned young wander a mere metre away from nervous macaques on the verge of baring their defensive fangs.
The second of the talks was titled: Considering Human to Primate Transmission of Measles Virus Through the Prism of Risk Analysis. Speaker Lisa-Jones Engel of the University of Washington (State) is a primatologist who has conducted epidemiological research in both Singapore and Kathmandu, Nepal to determine the risk factors for diseases such as measles that afflict both man and monkey, with the goal of develop management strategies and communication plans to minimise inter-species transmission of these diseases.
The same virus that causes measles in man affects other primates, and Dr. Engel revealed that the regions that suffer 90% of measles-related deaths are also where non-human primates are widely distributed, i.e. Sub-Saharan Africa, South and Southeast Asia. The measles virus is highly contagious, being easily transmitted via airborne secretions from the respiratory systems of infected individuals as well as via fomites, the term used for inanimate objects (tissue paper, food, clothes) that can harbour and transmit the virus. Currently, despite the existence of an effective vaccine, measles continues to affect 30-40 million people each year.
The measles virus also makes life miserable for monkeys. The disease results in variable morbidity and mortality, with certain species keeling quickly, while others put up more of a fight. Secondary problems also result, such as bacterial infections, encephalitis and spontaneous abortion in females. Survival, however, confers lifetime immunity.
In Kathmandu, there is an ancient stupa called Swayambhu, a World Heritage Site with a thirteen tiered golden spire. About 400 free-ranging rheseus monkeys (Macaca mulatta) dwell in its grounds and the animals, which are deemed sacred, rely largely on the favour of residents and visitors for food. Blood samples from these monkeys were collected and compared with samples obtained from long-tailed macaques (Macaca fascicularis) in Singapore, which also live in proximity to human populations.
ELISA tests to detect antibodies for measles revealed than 0% seropositivity in Singaporean monkeys, indicating that the population has had no recent exposure to measles at all. In contrast, 100% of the samples from Swayambhu were measles seropositive.
Why were the Singaporean monkeys free from measles, unlike their Nepalese cousins? What role did differences in human behavioural variables between the two locations such as feeding of monkeys, teasing and other risky acts, culture and local regulations play in fostering measles transmission? On the part of the monkeys, factors to be considered include their habituation level with humans, aggression levels and intra- and interspecies group behaviour. Questions remain about possible genetic, physiological and immunological factors. Might M. mulatta have a greater susceptibility to measles than M. fascicularis?
In Kathmandu, it was observed that the monkeys enjoy a greater level of physical contact with humans, being almost entirely reliant on man for food in a tree-less urban habitat. Public sanitation and waste disposal systems are also relatively primitive, increasing the number of potential fomites in disease transmission. Nepal also suffers a much higher measles incidence rate compared to Singapore.
The data gathered pointed to the need for a risk management strategy that encompasses a high benchmark vaccination rate (94%), regulation of potentially infectious individuals (e.g. keeping sick children at home), public education on the bidirectional tranmission of diseases as well as enforcement of laws with regard to animal feeding, garbage disposal and general hygiene. The ultimate goals would be to facilitate human-primate commensalism while reducing disease risks to both humans and non-human primates, a multi-disciplinary task that is likely to prove herculean given the ineffectiveness of fact-based communication to both monkeys and men.
The other half of the session was about the "Morphology and Somatometric Growth of Long-tailed Macaques in Singapore." Michael Schillaci of the University of Toronto has surveyed populations of the macaque in Singapore and Thailand and believes there are significant differences to designate the island's monkeys as a new subspecies. His data covered variables including animal weight, body length, tail length, cranial length, cranial breadth, relative testicular volume (this is said to be important in sexual selection) and pelage (fur) characterisctics.
Summarising his presentation, Singapoean macaques of both genders are said to be significantly lighter as well as shorter than their Thai counterparts. Cranial size differences are evident at at early age, but what local monkeys lack in brainpower, they make up for it by having a greater relative testicular size than the Thais, indicating that a greater selective pressure may be at work. Singaporean monkeys also exhibit greater facial melanism, with visibly darker rostrums as well as more pronounced facial whiskers.
Clouding the question however is the existence of viable hybrids and backcrosses between M. fascicularis and M. mulatta in Thailand. This hybridisation is absent south of the Isthmus of Kra, suggesting that this narrow strip of land serves as a biogeographical bottleneck that separates the monkey populations. To shed more light, molecular analysis of mitochrondial markers from the two populations as well as further examination of historical specimens from Peninsular Malaysia are planned. But whether or not the monkeys are accorded their own sub-species status, it's not likely to further endear them with those human residents of this island who find the notion of interspecies coexistence intolerable.
Death from the hands that fed them. A casualty at the public carpark at Upper Seletar Reservoir Park last week, where the monkeys have become accustomed to food handouts from people in vehicles. Photo by angelkitty.