Weaver ants (Oecophylla spp.) are often found on plants with insect symbionts (trophobionts), but the extent of such associations is not known. Examination of literature records of weaver ant host plants from 1900 to 2006 revealed that Oecophylla smaragdina, native to Asia, was recorded on 175 plant species in 46 families, with 28 associated trophobiont species in 7 families. Oecophylla longinoda, native to Africa, was recorded on 66 plant species in 34 families with 17 associated trophobiont species in 6 families. Both Oecophylla spp. shared host records on 17 economically important plant species. Such host plants could be used to augment establishment of weaver ants, facilitating their role as deterrents of phytophagous insect pests of economically important plants. O. smaragdina-tended trophobionts were recorded associating with the ants on several crops but rarely considered to be pests. Thus, the risk of trophobionts associated with Oecophylla ants being pests is considered minimal.
Citridiol is an extract of the leaves of Corymbia citriodora (Myrtaceae), the lemon eucalyptus, and mostly consists of p-menthane-3,8-diol isomers. The effectiveness of this extract as a repellent against land leeches of the genus Haemadipsa (Haemadipsidae), primarily H. sylvestris, was tested in the laboratory and field, in Peninsular Malaysia. The formulation tested, Mosi-guard Natural spray, contained 40% (w/w) Citridiol in a base of ethanol, water and isopropanol. In the laboratory test, specimens of H. sylvestris that were placed within moist, untreated arenas enclosed by treated paper rings made numerous attempts to cross the rings but were prevented or delayed from crossing over, in a dose-dependent manner. Mortality was high among the leeches that attempted to cross over the paper rings that had been sprayed to saturation point but low among the leeches that attempted to cross over paper rings that had only been partially treated, with a droplet-spray. The field study was carried out using indices that were formulated to reflect the severity of leech attack and the degree of repellency. Heavy or moderate spraying of footwear and trouser legs (tucked into socks) not only gave complete protection against bites by H. sylvestris and H. picta but also provided high enough repellency to keep the treated footwear virtually free of leeches. Even a light spray greatly reduced the numbers of leeches on footwear and delayed their progression toward biting the test subjects, although it failed to prevent bites completely. There was no decline in the repellency of the Citridiol when hourly assessments were made over a 6-h test period in the field. The results of the study show that Citridiol is highly repellent as well as toxic to leeches, and can be effectively used to prevent leech bites in the field.
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.
Abstract. 1. The ability of bioluminescent organisms to produce light provides opportunities for remote, non-destructive sampling through imaging. A case study of its use in monitoring populations is described for fireflies that congregate on riverbank trees in an ecotourism destination in Kuala Selangor, Malaysia.2. Digital images were captured from set locations at a standardised moon phase and time of night, at distances of 60-270 m across the riverbank.3. Counts of bright spots by trained, cross-calibrated operators were used as an index of abundance, and could often be predicted by regression equations for a subsample of particle analysis counts generated by image analysis software.4. In tests of the sustainability of the technique, prediction of counts from an upgrade camera could be achieved by multiple linear regressions incorporating camera-subject distance, particle size, and particle intensity characteristics. Multiple linear regressions could also be used to refine prediction of manual counts from particle analysis counts in this camera.5. Sampling light emissions enabled a much larger area of habitat to be monitored than would have been possible with other methods. In total, 1.6 km of the river margin could be imaged in just three nights from 20:30 to 23:30 hours. The technique can also be adapted to monitor populations of other aggregating, light producing organisms and to study group display behaviour.
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