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Mosquitoes

From Munshipedia, the MBRAS digital historical encyclopedia

Mosquitoes

Mosquitoes in the Malay Region: Biological Control, Folklore, and Entomological Observation

Mosquitoes have long occupied a central place in the public health, ecological, and cultural landscape of the Malay Peninsula and Borneo, their presence shaping both administrative policy and local oral tradition. The colonial-era literature of the Straits Branch of the Royal Asiatic Society documents mosquitoes as vectors of malaria, as objects of biological control experiments, as subjects of indigenous folklore, and as specimens of unusual entomological behaviour. The records span from the 1880s to the 1910s, reflecting a progression from anecdotal and mythological accounts to systematic field investigation under the auspices of government public health policy.

Folklore and Cultural Memory

The earliest recorded reference to mosquitoes in the Society’s literature is a brief miscellaneous note by D.F.A. Hervey, published in 1883, which preserves a local legend associated with Batu Kodok (The Frog Rock), a rock formation situated between Changi and the eastern end of Pulau Ubin in the old Straits of Singapore [1, p. 167]. At low tide, the rock resembles a squatting frog, and the local account explains that in an age when mosquitoes were as large as fowls, frogs were proportionally enormous; the living original of the rock attempted to swim across the straits but was turned to stone by the arrival of daylight before reaching land [1, p. 167].

Hervey’s note elaborates on the legend of the Raja Nyamok (King of Mosquitos), who periodically devoured maidens until one of them, by burning rubbish and using the smoke to repel him, discovered the means of keeping mosquitoes at bay—after which they “declined in the scale of creation” [1, p. 167]. The Malay term nyamok for mosquito is thus embedded in a narrative that encodes practical knowledge of smoke as a repellent within a mythological framework of cosmic diminishment.

Biological Control: The Fish Experiment

The most substantial treatment of mosquitoes in the archival record is a government-commissioned report by Dr. R. Hanitsch, Director of the Raffles Museum and Library in Singapore, published in 1912 [2]. The study was undertaken at the direct request of the colonial Government (minute H.C. 2/3042/3 of 21 March 1912) and investigated whether indigenous freshwater fish could serve as a biological control agent against mosquito larvae and malaria, in the same manner as the “Millions” fish (Girardinus poeciloides) was believed to do in Barbados [2, p. 26].

The Barbados precedent was as follows: the island enjoyed a remarkable immunity from fever, and when the reason was attributed to the presence in enormous numbers of a small fish that fed on mosquito larvae, the Colonial Office decided to distribute that fish among various tropical colonies to ascertain whether it might check malaria elsewhere [2, p. 26]. The “Millions” fish, so called on account of its extraordinary abundance in Barbados, is only about 1½ inches in length and belongs to the family Cyprinodontidae, which according to Gunther includes the smallest fish known [2, p. 26]. The Zoological Society of London, together with the Agricultural Department of Barbados, declared itself willing to assist in the experiment and distribution, though some scepticism existed as to whether it would succeed [2, p. 26].

Since a closely allied species, Haplochilus panchax—the Ikan mata lalat of the Malays—occurs in the Malay region, it was thought advisable to ascertain whether this indigenous fish might be as effective before introducing the Barbados species [2, p. 26]. Hanitsch accordingly conducted field surveys of fish populations in Singapore’s ditches and pools, supplemented by direct feeding experiments to assess which species consumed mosquito larvae and to what degree [2, p. 27].

The results were varied. Haplochilus panchax, the species originally under investigation, was found to be the most common small fish in Singapore’s ditches, growing to only about 2 inches in length, of slow-moving habits, and generally keeping close to the surface of the water [2, p. 27]. It ate mosquito larvae, but not greedily [2, p. 27]. A more promising candidate emerged in the Fighting Fish, Betta pugnax (the Ikan pelaga), which grows to about 3½ inches and is a great favourite among sporting natives [2, p. 27]. This species ate mosquito larvae greedily within a few seconds of their being offered, making it the most effective larvivorous species identified in the study [2, p. 27].

Other species showed intermediate or negative results. Hemirhamphus fluviatilis (the Ikan jolong jolong), an ally of the Gar-Pike and Flying fish, was confirmed as herbivorous, living on algae and waterweeds, and did not eat mosquito larvae [2, p. 27]. The Ikan sepat (Osphromenus trichopterus) showed that young specimens ate mosquito larvae, though not ravenously, whilst full-grown specimens seemed to despise them [2, p. 28]. The Ikan betok (Climbing Perch, Anabas scandens) and the Ikan aruan (Ophiocephalus striatus) both had young that ate mosquito larvae greedily [2, pp. 28–29].

Field observations provided compelling natural evidence for the efficacy of fish as larval predators. In the Teluk Blangah swamps—the most malarial region in Singapore—Anopheles larvae were found only in dense masses of waterweed and in empty tins, sites where no fish could operate, while the open and clean stretches of water in the same pool, containing six species of fish, were free of larvae [2, p. 29]. A pair of adjacent pools off Gaylang Road provided what amounted to a natural experiment: one pool was “thick and black with mosquito larvæ (Culex)” and contained no fish, while another pool, only about a yard away, was free from larvae and contained Ikan mata lalat [2, p. 29].

Hanitsch concluded that the introduction of the Barbados “Millions” fish was doubtful in its prospects, as it might not be able to hold its own against the several species of fish indigenous to Singapore Island, and in Barbados it was the only freshwater fish known [2, p. 29]. He recommended instead that large pools near the town be filled up or cleaned of surplus vegetation, and that small species of fish known to feed on mosquito larvae—particularly the Ikan mata lalat and the Ikan pelaga—be introduced [2, p. 30]. He cautioned, however, that in a crowded town like Singapore, many localities where Anopheles and other mosquitoes bred were quite inaccessible to fish, and that an attempt to exterminate malaria by means of fish in the central districts would be “utterly hopeless,” though the experiment might be of use in the outskirts [2, p. 30].

Entomological Observation: Unusual Oviposition Behaviour

A separate line of investigation into mosquito biology is represented by a short note by C. Strickland, Travelling Medical Entomologist of the Federated Malay States, published in 1917 [3]. Strickland recorded an unusual oviposition behaviour observed in Chaetomyia (Leicesteria) flava at the Gap on the Selangor-Pahang boundary, at an elevation of 2,800 feet [3, p. 39]. He observed a female of this species carrying an ova-mass attached to a hind-leg, from which young larvae were already emerging [3, p. 39]. When the mosquito was placed in a bottle of water, it dipped its leg into the water and the larvae immediately hatched and swam away [3, p. 39]. Strickland observed the phenomenon on two occasions and once caught a specimen whose leg still bore the empty ova-mass [3, p. 39].

He concluded that the mosquito oviposits on its own leg as a device for depositing larvae in water collections inaccessible by ordinary means—such as bamboo joints or leaf axils of plants like kladi or pig-lily—or possibly to protect the eggs from danger on the water surface [3, p. 39]. This observation, though brief, represents a notable contribution to the understanding of mosquito reproductive ecology in the highland forests of the Malay Peninsula.

Research and Documentation

The Society’s literature on mosquitoes reveals a clear trajectory from cultural and anecdotal recording to systematic scientific investigation. Hervey’s 1883 note [1] preserves indigenous folklore and practical knowledge of smoke as a repellent, situating mosquitoes within the mythological and ecological imagination of the local population. By 1912, Hanitsch’s report [2] represents a fully institutionalised public health inquiry, commissioned by the colonial Government, combining field ecology with controlled feeding experiments, and engaging with international comparative entomology through the Barbados precedent. The 1917 note by Strickland [3] extends the scope to highland species and unusual reproductive behaviour, reflecting the expanding geographical and taxonomic reach of medical entomology in the region.

The shifting priorities are evident: from the preservation of local knowledge, to the application of biological control within a malaria-eradication framework, to the documentation of species-specific adaptations. The Hanitsch report in particular illustrates the tension between the promise of biological control and its practical limitations in an urban environment, a debate that would continue to occupy public health administrators throughout the colonial period.

MBRAS Sources

References

  1. D.F.A. Hervey (1883). Batu Kodok (The Frog Rock JSBRAS 11: 167.
  2. Hanitsch R (1912). Mosquito larvae and freshwater fish JSBRAS 62: 26–30. Read on JSTOR
  3. C. Strickland (1917). A curious adaptation of habit to environment of a Malayan mosquito JSBRAS 75: 39. Read on JSTOR