Ovitrap surveillance was conducted in a selected urban area and suburban area, ie. Taman Permai Indah(TPI) and Kampung Pasir Gebu (KPG) in Penang for 14 months. It was found that Aedes albopictus was the most abundant Aedes species in both study areas, even though a small percentage of Aedes aegypti and Culex quinquefasciatus were found to breed simultaneously in the same ovitrap. This study indicated that the main dengue vector was Ae. albopictus. A strong correlation was found between rainfall and egg population in both of the study sites (r = 0.982 and r = 0.918).
In a case control study, 70 children consecutively hospitalized for acute ingestion of poisons were compared with 140 other hospitalized children matched for age. Children aged less than 3 years and boys were most often the victims. Univariate analysis identified Indian race, having a parent younger than 21 years, residing at present address for less than 1 year and living in a household with more than five occupants as significant risk factors. Experience of a recent stressful event in the family barely failed to reach the level of significance. Logistic regression analysis confirmed that Indian race, having a parent younger than 21 years and residing less than 1 year at the present address were independent predictors of acute poisoning. Positive interactions were noted between Indian race and duration of residence and between parental age and duration of residence. Knowledge of risk factors and their interactions may be useful in planning preventive measures against childhood poisoning.
Insect seed predators of 24 dipterocarp species (including the genera ot Dipterocarpus, Dryobalanops and Shorea) and five species belonging to the Moraceae, Myrtaceae, Celastraceae and Sapotaceae were investigated. In a tropical lowland dipterocarp forest in Sarawak, Malaysia, these trees produces seeds irregularly by intensely during general flowering and seeding events in 1996 and/or 1998. Dipterocarp seeds were preyed on by 51 insect species (11 families), which were roughly classified into three taxonomic groups: smaller moths (Trotricidae, Pyralidae, Crambidae, Immidae, Sesiidae, and Cosmopterigidae), scolytids (Scolydae) and weevils (Curdulionidae, Apionidae, Anthribidae, and Attelabidae). Although the host-specificity of invertebrate seed predators has been assumed to be high in tropical forests, it was found that the diet ranges of some insect predators were relatively wide and overlapped one another. Most seed predators that were collected in both study years changes their diets between general flowering and seeding events. The results of cluster analyses based on the number of adult of each predator species that emerged from 100 seeds of each tree species, suggested that the dominant species was not consistent, alternating between the two years.
The relationships between vertebrate pests and crop damage are often complex and difficult to study. In palm oil plantations rodents remain the major pests, causing substantial monetary losses. The present study examined the numerical and functional responses of rodents to changes in the availability of oil palm fruit and the damage associated with that response. For the study, 200 traps were set in pairs on a 10 × 10 trapping grid for 3 consecutive nights in each of 6 study plots at 8-week intervals in a 2569 ha oil palm plantation at Labu, Negeri Sembilan state in Peninsular Malaysia over 14 months. A total of 1292 individual rats were captured over 25 200 trap-nights. Animals were identified, aged, sexed, weighed and measured. An index of the relative abundance of rats was calculated based on trapping success. Damage to infructescences was assessed at each trap point. Regardless of the age of palms, there were positive and significant relationships between the relative abundance of rats and numbers of infructescences. The levels of damage to infructescences were significantly correlated with the relative abundance of rats. A steep increase in damage was observed with an increase in mature infructescences, indicating a feeding preference of rats for mature infructescences. For both males and females of all rat species, there were weak and non-significant correlations between body condition and infructescence numbers. These results indicated that there was a numerical and a functional response by rats to the availability of palm fruit and a resulting increase in depredation of oil palm fruits. The ways in which this information might aid in future pest control are discussed.
The aging population is a common problem faced by most countries in the world. This study uses 18 years (from 2002 to 2019) of panel data from 31 regions in China (excluding Hong Kong, Macao, and Taiwan Province), and establishes a panel threshold regression model to study the non-linear impact of the aging population on economic development. It is different from traditional research in that this paper divides 31 regions in China into three regions: Eastern, Central, and Western according to the classification standard of the National Bureau of Statistics of China and compares the different impacts of the aging population on economic development in the three regions. Although this study finds that the aging population promotes the economy of China's eastern, central, and western regions, different threshold variables have dramatically different influences. When the sum of export and import is the threshold variable, the impact of the aging population on the eastern and the central region of China is significantly larger than that of the western region of China. However, when the unemployment rate is the threshold variable, the impact of the aging population on the western region of China is dramatically higher than the other regions' impact. Thus, one of the contributions of this study is that if the local government wants to increase the positive impact of the aging population on the per capita GDP of China, the local governments of different regions should advocate more policies that align with their economic situation rather than always emulating policies from other regions.
A key driver of rain forest degradation is rampant commercial logging. Reduced-impact logging (RIL) techniques dramatically reduce residual damage to vegetation and soils, and they enhance the long-term economic viability of timber operations when compared to conventionally managed logging enterprises. Consequently, the application of RIL is increasing across the tropics, yet our knowledge of the potential for RIL also to reduce the negative impacts of logging on biodiversity is minimal. We compare the impacts of RIL on birds, leaf-litter ants, and dung beetles during a second logging rotation in Sabah, Borneo, with the impacts of conventional logging (CL) as well as with primary (unlogged) forest. Our study took place 1-8 years after the cessation of logging. The species richness and composition of RIL vs. CL forests were very similar for each taxonomic group. Both RIL and CL differed significantly from unlogged forests in terms of bird and ant species composition (although both retained a large number of the species found in unlogged forests), whereas the composition of dung beetle communities did not differ significantly among forest types. Our results show little difference in biodiversity between RIL and CL over the short-term. However, biodiversity benefits from RIL may accrue over longer time periods after the cessation of logging. We highlight a severe lack of studies investigating this possibility. Moreover, if RIL increases the economic value of selectively logged forests (e.g., via REDD+, a United Nations program: Reducing Emissions from Deforestation and Forest Degradation in Developing Countries), it could help prevent them from being converted to agricultural plantations, which results in a tremendous loss of biodiversity.
Recruitment constraints on Singapore's dwindling fluted giant clam, Tridacna squamosa, population were studied by modelling fertilisation, larval transport, and settlement using real-time hydrodynamic forcing combined with knowledge of spawning characteristics, larval development, behaviour, and settlement cues. Larval transport was simulated using a finite-volume advection-diffusion model coupled to a three-dimensional hydrodynamic model. Three recruitment constraint hypotheses were tested: 1) there is limited connectivity between Singapore's reefs and other reefs in the region, 2) there is limited exchange within Singapore's Southern Islands, and 3) there exist low-density constraints to fertilisation efficacy (component Allee effects). Results showed that connectivity among giant clam populations was primarily determined by residual hydrodynamic flows and spawning time, with greatest chances of successful settlement occurring when spawning and subsequent larval dispersal coincided with the period of lowest residual flow. Simulations suggested poor larval transport from reefs located along the Peninsular Malaysia to Singapore, probably due to strong surface currents between the Andaman Sea and South China Sea combined with a major land barrier disrupting larval movement among reefs. The model, however, predicted offshore coral reefs to the southeast of Singapore (Bintan and Batam) may represent a significant source of larvae. Larval exchange within Singapore's Southern Islands varied substantially depending on the locations of source and sink reefs as well as spawning time; but all simulations resulted in low settler densities (2.1-68.6 settled individuals per 10,000 m(2)). Poor fertilisation rates predicted by the model indicate that the low density and scattered distribution of the remaining T. squamosa in Singapore are likely to significantly inhibit any natural recovery of local stocks.
PIP: At the Population and Natural Resources Workshop of the World Conservation Union (IUCN) General Assembly in Perth, Australia, December 1990, population and quality of life issues were stressed as one of the central items to be placed on the 1992 Agenda of the UN Conference on Environment. The pace of environmental degradation is quickening, the causes are becoming more entrenched, and indecision will narrow our options. Poverty and population growth are making development unsustainable. Technological miracles will not appear to restore balance. Deforestation, soil erosion, decertification and loss of water resources are fueling urbanization. Therefore the World Commission on Environment and Development, known as the Brundtland Commission, ranks human resources development as a top priority in sustainable development and quality of life. Human resources can be improved by providing maternal and child care, family planning and improving the status of women. Successful family planning programs as seen in Thailand and Malaysia can show results very quickly once national population policies, institutions and capacity are in place.
A survey of the infestation rate of colonies of Macrotermes gilvus (Hagen) (Termitidae: Macrotermitinae) with the koinobiont endoparasitoid Misotermes mindeni Disney & Neoh (Diptera: Phoridae) was conducted in Malaysia from September 2009 to January 2011 in the states of Kedah, Penang, Perak, Selangor, Kuala Lumpur, Johor, Terengganu, and Sarawak. Of the 1,125 M. gilvus mounds surveyed, 12.4% contained termites parasitized by M. mindeni and these mounds occurred only in the states of Penang and Perak. High frequencies of mounds containing parasitized termites were found at sites in Penang: Bayan Lepas (21.1%), Minden Campus of Universiti Sains Malaysia ([USM]; 24.5%), Teluk Bahang (28.0%), and Bukit Mertajam (35.0%); the lowest frequency (4.0%) was recorded from Gelugor. The parasitized colonies at all sites were classified as healthy, with exception of several from the Minden Campus of USM (96.4% healthy) and Ayer Itam (87.5% healthy). Most parasitized colonies (71.2%) had a low level of M. mindeni infestation. Only 16.7 and 12.1% of the infested colonies had moderate or high parasite infestation levels, respectively. The height of infected mounds was significantly higher than that of the healthy mounds, but there was no difference between the mound diameters of infested and uninfested mounds. Parasite infestation level was not significantly correlated with mound height or mound diameter. The ambient light intensity at sites with infested mounds was significantly lower than that of uninfested mounds. There was also a significant negative relationship between light intensity and degree of parasitism.
Rapid sea-level rise between the Last Glacial Maximum (LGM) and the mid-Holocene transformed the Southeast Asian coastal landscape, but the impact on human demography remains unclear. Here, we create a paleogeographic map, focusing on sea-level changes during the period spanning the LGM to the present-day and infer the human population history in Southeast and South Asia using 763 high-coverage whole-genome sequencing datasets from 59 ethnic groups. We show that sea-level rise, in particular meltwater pulses 1 A (MWP1A, ~14,500-14,000 years ago) and 1B (MWP1B, ~11,500-11,000 years ago), reduced land area by over 50% since the LGM, resulting in segregation of local human populations. Following periods of rapid sea-level rises, population pressure drove the migration of Malaysian Negritos into South Asia. Integrated paleogeographic and population genomic analysis demonstrates the earliest documented instance of forced human migration driven by sea-level rise.
PIP: The initial results of a study conducted to develop guidelines for the clinical management of family planning acceptors with regard to return of fertility following contraceptive use, are presented. 193 parous women attending an urban family planning clinic were interviewed regarding their last pregnancy conceived after stopping a method of contraception. The average interval to pregnancy was 3.9, 2.8 and 1.8 months for ex-users of oral pills, intrauterine devices and conventional methods of contraception, respectively, with median delays to conception of 1.9, 1 and within the 1st month for the 3 categories. In comparison, 149 women who had not used any method at all took 7.3 months before becoming pregnant. Selected variables including age and parity, duration of use and problems encountered, and outcome of pregnancy are further analysed. Follow-up investigations and treatment are recommended 12 months after stopping oral pills and 6 months after removal of intrauterine device for those who have not yet conceived.
One of the available tools for mapping the geographical distribution and potential suitable habitats is species distribution models. These techniques are very helpful for finding poorly known distributions of species in poorly sampled areas, such as the tropics. Maximum Entropy (MaxEnt) is a recently developed modeling method that can be successfully calibrated using a relatively small number of records. In this research, the MaxEnt model was applied to describe the distribution and identify the key factors shaping the potential distribution of the vulnerable Malayan Sun Bear (Helarctos malayanus) in one of the main remaining habitats in Peninsular Malaysia. MaxEnt results showed that even though Malaysian sun bear habitat is tied with tropical evergreen forests, it lives in a marginal threshold of bio-climatic variables. On the other hand, current protected area networks within Peninsular Malaysia do not cover most of the sun bears potential suitable habitats. Assuming that the predicted suitability map covers sun bears actual distribution, future climate change, forest degradation and illegal hunting could potentially severely affect the sun bear's population.
Unsustainable hunting is emptying forests of large animals around the world, but current understanding of how human foraging spreads across landscapes has been stymied by data deficiencies and cryptic hunter behaviour. Unlike other global threats to biodiversity like deforestation, climate change and overfishing, maps of wild meat hunters' movements-often based on forest accessibility-typically cover small scales and are rarely validated with real-world observations. Using camera trapping data from rainforests across Malaysian Borneo, we show that while hunter movements are strongly correlated with the accessibility of different parts of the landscape, accessibility measures are most informative when they integrate fine-scale habitat features like topography and land cover. Measures of accessibility naive to fine-scale habitat complexity, like distance to the nearest road or settlement, generate poor approximations of hunters' movements. In comparison, accessibility as measured by high-resolution movement models based on circuit theory provides vastly better reflections of real-world foraging movements. Our results highlight that simple models incorporating fine-scale landscape heterogeneity can be powerful tools for understanding and predicting widespread threats to biodiversity.
Ancient DNA has significantly improved our understanding of the evolution and population history of extinct megafauna. However, few studies have used complete ancient genomes to examine species responses to climate change prior to extinction. The woolly rhinoceros (Coelodonta antiquitatis) was a cold-adapted megaherbivore widely distributed across northern Eurasia during the Late Pleistocene and became extinct approximately 14 thousand years before present (ka BP). While humans and climate change have been proposed as potential causes of extinction [1-3], knowledge is limited on how the woolly rhinoceros was impacted by human arrival and climatic fluctuations [2]. Here, we use one complete nuclear genome and 14 mitogenomes to investigate the demographic history of woolly rhinoceros leading up to its extinction. Unlike other northern megafauna, the effective population size of woolly rhinoceros likely increased at 29.7 ka BP and subsequently remained stable until close to the species' extinction. Analysis of the nuclear genome from a ∼18.5-ka-old specimen did not indicate any increased inbreeding or reduced genetic diversity, suggesting that the population size remained steady for more than 13 ka following the arrival of humans [4]. The population contraction leading to extinction of the woolly rhinoceros may have thus been sudden and mostly driven by rapid warming in the Bølling-Allerød interstadial. Furthermore, we identify woolly rhinoceros-specific adaptations to arctic climate, similar to those of the woolly mammoth. This study highlights how species respond differently to climatic fluctuations and further illustrates the potential of palaeogenomics to study the evolutionary history of extinct species.