17 research outputs found

    Effects of defoliation from an outbreak of the teak skeletoniser, Paliga damastesalis walker (Lepidoptera: Crambidae), on the growth of teak, Tectona grandis L.

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    The effects of defoliation by the teak skeletoniser Paliga damastesalis Walker (Lepidoptera: Crambidae) on a six-month old stand of teak Tectona grandis L. was evaluated on the subsequent year-long growth in the field. Defoliation did not exceed 10%. It had a transient negative effect on post-defoliation height increment and new leaf production of up to two and three months of growth. However, defoliation severity significantly affected collar diameter increment up to the seventh month. A peak in the mean monthly growth increments for new leaf production occurred in April, followed by collar diameter increment in June and height in July. In addition, a peak in one of these three growth parameters also corresponded with a trough in the other or both of the other parameters; as such, the height increment peaked with a concomitant trough in collar diameter increment a month later. As for the remaining period of the dry season after July, new leaf production remained at a constant low level, while increments for both the height and collar diameter were found to decrease. Tree recovery appeared rapid with regard to these growth parameters, thus the impact of defoliation was generally and relatively negligible on the growth parameters measured

    Evidence for a higher number of species of Odontotermes (Isoptera) than currently known from Peninsular Malaysia from mitochondrial DNA phylogenies

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    Termites of the genus Odontotermes are important decomposers in the Old World tropics and are sometimes important pests of crops, timber and trees. The species within the genus often have overlapping size ranges and are difficult to differentiate based on morphology. As a result, the taxonomy of Odontotermes in Peninsular Malaysia has not been adequately worked out. In this study, we examined the phylogeny of 40 samples of Odontotermes from Peninsular Malaysia using two mitochondrial DNA regions, that is, the 16S ribosomal RNA and cytochrome oxidase subunit I genes, to aid in elucidating the number of species in the peninsula. Phylogenies were reconstructed from the individual gene and combined gene data sets using parsimony and likelihood criteria. The phylogenies supported the presence of up to eleven species in Peninsular Malaysia, which were identified as O. escherichi, O. hainanensis, O. javanicus, O. longignathus, O. malaccensis, O. oblongatus, O. paraoblongatus, O. sarawakensis, and three possibly new species. Additionally, some of our taxa are thought to comprise a complex of two or more species. The number of species found in this study using DNA methods was more than the initial nine species thought to occur in Peninsular Malaysia. The support values for the clades and morphology of the soldiers provided further evidence for the existence of eleven or more species. Higher resolution genetic markers such as microsatellites would be required to confirm the presence of cryptic species in some taxa

    The economic importance and control of termite infestations in relation to plantation forestry and wood preservation in Peninsular Malaysia - an overview

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    Both the plantation forestry and wood preservation industries in the tropical and sub-tropical belts of the world, exemplified by the humid equatorial Peninsular Malaysia, regard termites as major destructive pests of standing trees, various timber products and building timber structures. This paper is a compilation of information on these economically important pests encountered in both plantation forestry and the wood preservation industry in Malaysia, particularly the peninsula, and describes on-going termite research activities to establish practical control strategies for tree and wood protection

    Trogonoptera brookiana mollumar d’Abrera, Doggett & Parker, 1976 (Lepidoptera: Papilionidae), a subspecies or a synonym?

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    The birdwing butterfly Trogonoptera brookiana (Wallace, 1855) is a well-known conservation icon, yet questions remain about the infraspecific status of regional populations. The eastern Peninsular Malaysian population has been described as the subspecies mollumar d’Abrera, Doggett & Parker, 1976, but its status as a subspecies distinguishable from the taxon trogon (Vollenhoven, 1860) in Sumatra has been disputed. Wing characters and measurements of specimens from the two regions were therefore examined quantitatively using discriminant function and correspondence analyses. Eastern Peninsular specimens differ on average from Sumatran specimens in having more extensive green, especially in the female. This is reflected in many of the measurements and characters analysed. Females from the Peninsula also have a characteristically blacker upperside ground colour in which the outer areas of both wings barely contrast with the black veins and forewing cell. The extent of these differences enables a reliable differentiation of the females of both regions. The magnitude and consistency of differences are comparable to that between other subspecies of undisputed status. Behavioural differences also exist. The name mollumar therefore merits subspecific status. In addition, we consider the male forms walshi Haugum & Low, 1982 and walshoides Haugum & Low, 1982 to be chemically discoloured specimens of trogon rather than biological forms

    Morphological and genetic analyses verify the occurrence of the butterfly Graphium chironides (Lepidoptera: Papilionidae) in Peninsular Malaysia and resolve the confusion on the validity of its subspecies malayanum Eliot, 1982

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    Graphium chironides malayanum Eliot, 1982 was described as a taxon occurring sympatrically with G. bathycles bathycloides in Peninsular Malaysia. However, the validity of the subspecies has been questioned in a recent publication that was based on a study of DNA and morphology, implying that G. c. malayanum is a synonym of G. b. bathycloides and G. chironides is absent from the Peninsula. A re-examination of male wing morphology, genitalia and DNA shows that G. c. malayanum is a valid taxon distinguished from G. b. bathycloides by wider discal markings, a less falcate forewing, distinct differences in the arms of the harpe in the male genitalia and clearly divergent mtDNA COI genes. In the DNA analysis, G. c. malayanum formed a monophyletic clade closely related to G. chironides from China, and both were well-separated from the G. b. bathycloides clade. An examination of characters used in the previous study showed that the conclusions reached were due to misinterpretation of diagnostic characters, misidentification of specimens and the absence of G. c. malayanum among the specimens examined. When these characters were correctly interpreted, each specimen was readily assigned to the correct taxon. Diagnostic morphological characters are reclarified based on the current data

    An overview of the economic importance and control of termites in plantation forestry and wood preservation in Peninsular Malaysia

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    Both the plantation forestry and wood preservation industries in the tropical and subtropical belts of the world, exemplified by the humid equatorial Peninsular Malaysia, regard termites as major destructive pests of standing trees, various timber products and building timber structures. This paper is a compilation of information on these economically important structural pests encountered in both plantation forestry and the wood preservation industry in Malaysia, particularly the peninsula, and describes ongoing termite research activities to establish practical control strategies for tree and wood protection

    Fluctuation in the population index of monthly birdwing counts over a period of two years.

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    <p>Data shown are mean daily counts at puddles, the standard error and range for each month.</p

    Puddling males of the Rajah Brooke’s Birdwings in Ulu Geroh.

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    <p>Puddling males of the Rajah Brooke’s Birdwings in Ulu Geroh.</p

    General linear model for counts of puddling birdwings in response to monitoring month, relative humidity and brightness (final model).

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    <p>General linear model for counts of puddling birdwings in response to monitoring month, relative humidity and brightness (final model).</p
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