The geographic distribution and habitat association of most mammalian polymorphic phenotypes are still poorly known, hampering assessments of their adaptive significance. Even in the case of the black panther, an iconic melanistic variant of the leopard (Panthera pardus), no map exists describing its distribution. We constructed a large database of verified records sampled across the species' range, and used it to map the geographic occurrence of melanism. We then estimated the potential distribution of melanistic and non-melanistic leopards using niche-modeling algorithms. The overall frequency of melanism was ca. 11%, with a significantly non-random spatial distribution. Distinct habitat types presented significantly different frequencies of melanism, which increased in Asian moist forests and approached zero across most open/dry biomes. Niche modeling indicated that the potential distributions of the two phenotypes were distinct, with significant differences in habitat suitability and rejection of niche equivalency between them. We conclude that melanism in leopards is strongly affected by natural selection, likely driven by efficacy of camouflage and/or thermoregulation in different habitats, along with an effect of moisture that goes beyond its influence on vegetation type. Our results support classical hypotheses of adaptive coloration in animals (e.g. Gloger's rule), and open up new avenues for in-depth evolutionary analyses of melanism in mammals.
Despite considered a non-consumptive use of the marine environment, diving-related activities can cause damages to coral reefs. It is imminent to assess the maximum numbers of divers that can be accommodated by a diving site before it is subject to irreversible deterioration. This study aimed to assess the ecological carrying capacity of a diving site in Mabul Island, Malaysia. Photo-quadrat line transect method was used in the benthic survey. The ecological carrying capacity was assessed based on the relationship between the number of divers and the proportion of diver damaged hard corals in Mabul Island. The results indicated that the proportion of diver damaged hard corals occurred exponentially with increasing use. The ecological carrying capacity of Mabul Island is 15,600-16,800 divers per diving site per year at current levels of diver education and training with a quarterly threshold of 3900-4200 per site. Our calculation shows that management intervention (e.g. limiting diving) is justified at 8-14% of hard coral damage. In addition, the use of coral reef dominated diving sites should be managed according to their sensitivity to diver damage and the depth of the reefs.
Thrips (Thysanoptera) are common pests on legume plants, yet little is known about their ecology or diversity in Peninsular
Malaysia. In legumes, thrips are typically found in flowers, where their feeding activity causes malformations that
eventually lead to crop damage. In this study, we examined the diversity of thrips species, particularly Megalurothrips
usitatus, in three selected legume farms around Peninsular Malaysia (Janda Baik, Pahang; Bestari Jaya, Selangor; and
Jelebu, Negeri Sembilan). Each month from April 2013 to May 2014, depending on growing season, legume flowers were
inspected for thrips in five random plots from each farm. Sampling was performed six times in Bestari Jaya and Jelebu
and twelve times in Janda Baik. The most abundant thrips species on legumes was M. usitatus (89.97%) followed by
Thrips parvispinus (9.77%), T. hawaiiensis (0.13%) and Ceratothripoides brunneus (0.12%). The abundance of M. usitatus
was not different between long bean, French bean and winged bean which equally distributed among different arbitrary
strata on legume plants. Temperature and light intensity were found to be positively correlated with the abundance of
M. usitatus, but relative humidity showed a negative relationship. M. usitatus was found in large numbers during hot
and dry months, but in lower numbers during raining season. This study suggested that wet season may help to regulate
the populations of M. usitatus on legume plants.
Hantaviruses are etiological agents of zoonotic diseases and certain other dis-
eases, which pose a serious threat to human health. When rodent and predator popula-
tions share in an ecology, the competitive force of the populations can lead to a reduction
or elimination of a hantavirus outbreak. The effect of the predator eliminating rodents
and predator populations that tends to reduce or eliminate hantavirus infection is investi-
gated. The existence of several equilibrium points of the model is identified and local and
global stabilities of the model at these equilibrium points are analysed in detail. Numerical
simulations are carried out to illustrate our model results.
Clostridium bifermentans serovar malaysia (C.b.m.) is highly toxic to mosquito larvae. In this study, the following aquatic nontarget invertebrates were treated with high C.b.m. concentrations (up to 1,600-fold the toxic concentration for Anopheles stephensi) to study their susceptibility towards the bacterial toxin: Planorbis planorbis (Pulmonata); Asellus aquaticus (Isopoda); Daphnia pulex (Cladocera); Cloeon dipterum (Ephemeroptera); Plea leachi (Heteroptera); and Eristalis sp., Chaoborus crystallinus, Chironomus thummi, and Psychoda alternata (Diptera). In addition, bioassays were performed with mosquito larvae (Aedes aegypti, Anopheles stephensi, and Culex pipiens). Psychoda alternata larvae were very susceptible, with LC50/LC90 values comparable to those of mosquito larvae (about 10(3)-10(5) spores/ml). The tests with Chaoborus crystallinus larvae showed significant mortality rates at high concentrations, but generally not before 4 or 5 days after treatment. The remaining nontarget organisms did not show any susceptibility. The investigation confirms the specificity of C.b.m. to nematocerous Diptera.
Five formulations of Bacillus sphaericus (strain 2362) including aqueous suspension BSP 1, BSP 2, technical powder ABG 6184, corncob granules ABG 6185 (potencies 2 x 10(10), 2 x 10(7), 9.5 x 10(10), 5 x 10(10), 5 x 10(10) spore/g, respectively) and wettable powder ABG 6232 (1,000 BS ITU/mg) were tested against laboratory-cultured late third/early fourth instar larvae of Mansonia uniformis in floating screened cages in small plots at swampy ditches on Penang Island, Malaysia. Mean dosage/response values at 90% mortality levels were 6.93, 95.32, 1.45, 11.92 and 2.86 liters or kg per ha, respectively, for the formulations tested. There were practically no residual effects for the formulations tested with larvae introduced at 48, 96, and 168 h post-treatment. In trials of BSP 1, ABG 6184 and ABG 6185 (1 liter or 1 kg per ha) against immature Mansonia spp. in impounded paddy field ditches, improved efficacy and residual effects were obtained with mean reductions of 93.1, 91.9 and 80.4% at days 3, 7 and 14 posttreatment, respectively.
An ovitrap survey was carried out in April and May of 1975 at twenty-one locations scattered throughout Penang Island excluding the City of Georgetown. The results showed the ubiquitous presence of Ae. albopictus. Ae. aegypti was recorded only in Tanjung Tokong Lama, an area adjacent to the City of Georgetown. In the survey, Ae. albopictus females were found to prefer the outdoor ovitraps than indoor ones. The effectiveness of ovitrap in Aedes survey was discussed.
To investigate the breeding habitat preference of black flies, a comprehensive black fly survey was conducted for the first time in Peninsular Malaysia. Preimaginal black flies (pupae and larvae) were collected manually from 180 stream points encompassing northern, southern, central and east coast of the Peninsular Malaysia. A total of 47 black fly species were recorded in this study. The predominant species were Simulium trangense (36.7%) and Simulium angulistylum (33.3%). Relatively common species were Simulium cheongi (29.4%), Simulium tani (25.6%), Simulium nobile (16.2%), Simulium sheilae (14.5%) and Simulium bishopi (10.6%). Principal Component Analysis (PCA) of all stream variables revealed four PCs that accounted for 69.3% of the total intersite variance. Regression analysis revealed that high species richness is associated with larger, deeper, faster and higher discharge streams with larger streambed particles, more riparian vegetation and low pH (F=22.7, d.f.=1, 173; P<0.001). Relationship between species occurrence of seven common species (present in >10% of the sampling sites) was assessed. Forward logistic regression analysis indicated that four species were significantly related to the stream variables. S. nobile and S. tani prefer large, fast flowing streams with higher pH, large streambed particles and riparian trees. S. bishopi was commonly found at high elevation with cooler stream, low conductivity, higher conductivity and more riparian trees. In contrast, S. sheilae was negatively correlated with PC-2, thus, this species commonly found at low elevation, warmer stream with low conductivity and less riparian trees. The results of this study are consistent with previous studies from other geographic regions, which indicated that both physical and chemical stream conditions are the key factors for black fly ecology.
The continued depletion of tropical rainforests and fragmentation of natural habitats has led to significant ecological changes which place most top carnivores under heavy pressure. Various methods have been used to determine the status of top carnivore populations in rainforest habitats, most of which are costly in terms of equipment and time. In this study we utilized, for the first time, a rigorous track classification method to estimate population size and density of clouded leopards (Neofelis nebulosa) in Tabin Wildlife Reserve in north-eastern Borneo (Sabah). Additionally, we extrapolated our local-scale results to the regional landscape level to estimate clouded leopard population size and density in all of Sabah's reserves, taking into account the reserves' conservation status (totally protected or commercial forest reserves), their size and presence or absence of clouded leopards.
Pesticides are of great concern because of their existence in ecosystems at trace concentrations. Worldwide pesticide use and its ecological impacts (i.e., altered environmental distribution and toxicity of pesticides) have increased over time. Exposure and toxicity studies are vital for reducing the extent of pesticide exposure and risk to the environment and humans. Regional regulatory actions may be less relevant in some regions because the contamination and distribution of pesticides vary across regions and countries. The risk quotient (RQ) method was applied to assess the potential risk of organophosphorus pesticides (OPPs), primarily focusing on riverine ecosystems. Using the available ecotoxicity data, aquatic risks from OPPs (diazinon and chlorpyrifos) in the surface water of the Langat River, Selangor, Malaysia were evaluated based on general (RQm) and worst-case (RQex) scenarios. Since the ecotoxicity of quinalphos has not been well established, quinalphos was excluded from the risk assessment. The calculated RQs indicate medium risk (RQm = 0.17 and RQex = 0.66; 0.1 ≤ RQ 1 (high risk) was observed for both the general and worst cases of chlorpyrifos, but only for the worst cases of diazinon at all sites from downstream to upstream regions. Thus, chlorpyrifos posed a higher risk than diazinon along the Langat River, suggesting that organisms and humans could be exposed to potentially high levels of OPPs.
A well-known planting medium in soilless culture is a coconut based material famously known in Malaysia as cocopeat.
It is a viable ecologically friendly peat soil substitute for containerized crop production. The multipurpose growing media
had received much interest particularly in commercial applications. This study focused on the physical and hydraulic
characteristics of cocopeat perlite mixture as a growing media in containerized plant production. Perlite was added to
cocopeat at a ratio of 3 cocopeat: 1 perlite. Bulk density, particle density, porosity, particle size distribution, water holding
capacity, wettability and hydraulic conductivity of the media were evaluated. About 82.93% of the total particles were
in the range between 0.425 and 4 mm in diameter at a bulk density of 0.09 g/cm3
. Total porosity (79%) and wettability
improved with the incorporation of perlite to cocopeat. This study showed that water holding capacity was very high at
912.54% whereas the saturated hydraulic conductivity was low at 0.1 cm/s. The results showed that adding perlite to
cocopeat had improved the physical and hydraulic characteristics of the media.
Climatic records for Danum for 1985-1998, elsewhere in Sabah since 1879, and long monthly rainfall series from other rainforest locations are used to place the climate, and particularly the dry period climatology, of Danum into a world rainforest context. The magnitude frequency and seasonality of dry periods are shown to vary greatly within the world's rainforest zone. The climate of Danum, which is aseasonal but subject, as in 1997-1998, to occasional drought, is intermediate between less drought-prone north-western Borneo and the more drought-prone east coast. Changes through time in drought magnitude frequency in Sabah and rainforest locations elsewhere in South-East Asia and in the Neotropics are compared. The 1997-1998 ENSO-related drought event in Sabah is placed into a historical context. The effects of drought on tree growth and mortality in the tropics are assessed and a model relating intensity and frequency of drought disturbance to forest structure and composition is discussed.
CDC Light traps were used to study the attractant effect of CO2 and 1-octen-3-ol on trap catches of mosquito populations at three different locations in Malaysia. There was a significant increase in the number of mosquitos caught in traps baited with CO2 and CO2 with 1-octen-3-ol. The number of mosquitos caught in the CDC light trap and in the CDC light trap baited with 1-octen-3-ol alone were very few. 1-octen-3-ol and CO2 acted synergistically in attracting significantly greater numbers of Culex tritaeniorhynchus. However Anopheles sp. were not very attracted to light traps even with attractants added to them.