Bioactivity of Azadirachta Excelsa Jack. Extractives on Selected Insects

Azadirachta excelsa Jack. is a fast growing timber species that has been newly chosen as a potential forest plantation species to overcome timber deficit for domestic consumption in future. This species like Azadirachta indica is suspected to contain biologically active compounds that is detrimental on insects. Many studies have been done on the A. indica, a relative species to A. excelsa, however, studies on A. excelsa are still in preliminary stages. Therefore, the aim of this study was to evaluate the effect of A.excelsa crude extractives towards three selected insect pests, (i.e. Spodoptera Iitura, Callosobruchus chinensis and Coptotermes curvignathus). A preliminary test to evaluate the susceptibility of A. excelsa wood towards termites, compared to Koompasia malaccensis, Hevea brasiliensis and Pinus caribaea was also conducted. In the first part of the study, the A.excelsa plant extracts were extracted from different plant parts (i.e. leaf, bark, trunk, twigs and branch) using a range of polar to non-polar solvents, namely hexane, petroleum ether, toluene, ethyl acetate and methanol. The plant extractives were sampled and analysed through Thin Layer Chromatography (TLC) and Infrared Spectrocopy (IR). In the second part of the study, bioassay tests were conducted on the selected insects. The insects were exposed to the plant extractives prepared at three concentration levels (i.e. 250 ppm, 500 ppm and 1000 ppm) and the solvents (0 ppm) as the control, by feeding the insects with treated food source. The S. litura larvae were fed with castor leaf discs soaked in the respective extractives. The C. chinensis adults were exposed to mungbean seeds that had been soaked in the plant extrctives while the C. curvignathus were fed with treated filter paper. In the last part of this study, the A. excelsa wood together with the other three wood species mentioned earlier, were exposed to the termites both in the laboratory and field

The distribution and species diversity of black flies (Diptera: Simuliidae) in selected areas in Ranau, Sabah

Blackfly play an important role in the freshwater ecosystem as a biological indicator, as the blackfly prefers clean water area to breed. Certain blackfly species are categorized as vector as it can transmit disease known as Onchocerciasis (river blindness).This study is an entomology research which focuses on the species diversity of blackfly (Diptera: Simuliidae) in Ranau District of Sabah. Eight sampling stations located the highlands and lowlands were chosen. Larvae and pupae were manually collected directly from the substrate in the streams and river. A total of 12 data sets were collected over a period of six months, which started from August 2015 to January 2016. The data collection was done once every forth night. A preliminary result from this study has so far recorded fourteen species of blackfly. Among the fourteen species recorded, Simulium (Gomphostilbia) alienigenum was the first specimen recorded in Malaysia especially in Sabah. All the fourteen species of black flies recorded in this study belongs to three subgenus which are; Simulium, Nevermania and Gomphostilbia. The highest individual being recorded comes from the subgenus of Simulium. The diversity indices result shows a ranged from 1.13 to 1.58, and this indicates low diversity in the eight sampling stations

The relationship between water quality and black fly (Diptera: Simuliidae) abundance in Tambunan District, Sabah

Black flies (Diptera : Simuliidae) have been extensively studied almost worldwide (Hamada & Grillet, 2001). This is because blackflies are among the best-known aquatic insects and globally distributed (Adler et al., 2004). Black flies in Malaysia are less known and research about this aquatic insect is still scarce especially in Borneo region. Most of the earlier studies on black flies in Sabah were related to taxonomy (Takaoka, 2001). However, studies on ecology and the role of black flies as bio-indicator has so far not been well reported yet. The aim of this study is to determine the relationship of water quality against the abundance of black flies pupa (Simuliidae). Regression test shows that relationship between dissolve oxygen (r2=0.57, p=0.02), total dissolve substance (TDS) (r2=0.18,p=0.04) and conductivity (r2=0.14, p=0.04) appeared significant to the abundance of black flies pupae. All the study sites (6 rivers) were classified into Class 1 based on Water Quality Index Classification (DOE, 2006)

A trait-based plant economic framework can help increase the value of reforestation for conservation

While reforestation is gaining momentum to moderate climate change via carbon sequestration, there is also an opportunity to use tree planting to confront declining global biodiversity. Where tree species vary in support of diversity, selecting appropriate species for planting could increase conservation effectiveness. We used a common garden experiment in Borneo using 24 native tree species to examine how variation among tree species in their support of beetle diversity is predicted by plant traits associated with "acquisitive" and "conservative" resource acquisition strategies. We evaluate three hypotheses: (1) beetle communities show fidelity to host identity as indicated by variation in abundance and diversity among tree species, (2) the leaf economic spectrum partially explains this variation as shown by beetle preferences for plant species that are predicted by plant traits, and (3) a small number of selected tree species can capture higher beetle species richness than a random tree species community. We found high variation among tree species in supporting three highly intercorrelated metrics of beetle communities: abundance, richness, and Shannon diversity. Variation in support of beetle communities was predicted by plant traits and varied by plant functional groups; within the dipterocarp family, high beetle diversity was predicted by conservative traits such as high wood density and slow growth, and in non-dipterocarps by the acquisitive traits of high foliar K and rapid growth. Using species accumulation curves and extrapolation to twice the original sample size, we show that 48 tree species were not enough to reach asymptote levels of beetle richness. Nevertheless, species accumulation curves of the six tree species with the highest richness had steeper slopes and supported 33% higher richness than a random community of tree species. Reforestation projects concerned about conservation can benefit by identifying tree species with a disproportional capacity to support biodiversity based on plant traits

The Distribution and Species Diversity of Black Flies (Diptera: Simuliidae) In Selected Areas in Ranau, Sabah

Blackfly play an important role in the freshwater ecosystem as a biological indicator, as the blackfly prefers clean water area to breed. Certain blackfly species are categorized as vector as it can transmit disease known as Onchocerciasis (river blindness).This study is an entomology research which focuses on the species diversity of blackfly (Diptera: Simuliidae) in Ranau District of Sabah. Eight sampling stations located the highlands and lowlands were chosen. Larvae and pupae were manually collected directly from the substrate in the streams and river. A total of 12 data sets were collected over a period of six months, which started from August 2015 to January 2016. The data collection was done once every forth night. A preliminary result from this study has so far recorded fourteen species of blackfly. Among the fourteen species recorded, Simulium (Gomphostilbia) alienigenum was the first specimen recorded in Malaysia especially in Sabah. All the fourteen species of black flies recorded in this study belongs to three subgenus which are; Simulium, Nevermania and Gomphostilbia. The highest individual being recorded comes from the subgenus of Simulium. The diversity indices result shows a ranged from 1.13 to 1.58, and this indicates low diversity in the eight sampling stations

Relationship between water quality & black flies (Diptera: simuliidae) abundance in Tambunan district, Sabah

A study to investigate the relationship between black flies (Simuliidae) pupa abundance and physio-chemical parameters such as velocity, water temperature, pH, dissolved oxygen, conductivity and total dissolved solid was conducted at Tambunan district, Sabah. A total of six rivers were selected as sampling stations. Five sampling points located at a distance of 5-10 meters were established in each sampling station. Sampling was conducted every fortnight for a duration of six months from October 2015 until March 2017. Samples of black flies’ larvae and pupae were manually collected from substrates consisting of grasses, plant roots and plastics which were found stuck in between the rocks with running water area. Water quality parameters that were measured during every sampling, include water temperature, velocity, pH, dissolved oxygen, conductivity and total dissolve solids (TDS). Results from this study showed that The Principal Component Analysis (PCA) revealed two PC’s which had eigenvalues >1.0 and together accounted for 78% total variability of the physio-chemical parameters. PC-1 which accounted 56% of variability defined a normal temperature (23-250C), high water velocity, high dissolved oxygen, low conductivity and low total dissolved solid. While PC-2 explained 22% of the variability was related to water pH. Pearson’s correlation result shows that only velocity had a significant relationship with the abundance of black flies (r=0.512, p<0.01), while other parameters did not show any significant relationship with its abundance. In conclusion, results from this study revealed that only water velocity had a significant relationship with the abundance of black flies

Temephos resistance in field Aedes (Stegomyia) albopictus (Skuse) from Selangor, Malaysia

Larvae of Aedes albopictus obtained from dengue endemic areas in Selangor, Malaysia were evaluated for their susceptibility to operational dosage of temephos (1 mg/L). Larval bioassays were carried out in accordance to modified WHO standard methods. Biochemical microassay of enzymes in Ae. albopictus was conducted to detect the emergence of insecticide resistance and to define the mechanisms involved in temephos resistance. The 50% mortality lethal time (LT50) for Ae. albopictus tested against temephos ranged between 58.65 to 112.50 minutes, with resistance ratio ranging from 0.75 – 1.45. This study addressed the fluctuation of time-related susceptibility status of Ae. albopictus towards insecticide. Significant difference on the weekly enzyme levels of non-specific esterase’s, mixed function oxidases and glutathione S-transferases was detected (p 0.05). Only glutathione Stransferases displayed high level of activity, indicating that Ae. albopictus may be resistant to other groups of insecticide. The insensitive acetylcholinesterase was detected in some field collected Ae. albopictus populations, indicating the possibility of emergence of carbamate or other organophosphate resistance in the field populations. Continuous resistance monitoring should be conducted regularly to confirm the efficacy of insecticides for dengue control

Diversity And Abundance of Canopy Beetles in A Forest Restoration Site in Luasong, Tawau, Sabah, Malaysia

A study on the canopy beetle’s diversity was conducted at Species Demo Plot in Luasong, Tawau, Sabah, Malaysia. This is a part of a forest restoration project under the Innoprise-IKEA (INIKEA) Forest Rehabilitation Program managed by Yayasan Sabah. This study focused on the beetle diversity on the canopy of 11-year-old trees. The objectives of this study were to compare the diversity of canopy beetles between the Dipterocarps and non-Dipterocarp trees and to compare the abundance of canopy beetles between the two group of trees. Fogging method using handheld pyrethrum insecticide was performed to sample the canopy arthropods. The trees that were sampled were Dipterocarpus conformis, Dryobalanops lanceolata and Hopea ferruginea from the Dipterocarp group, and Diospyros sp., Pentace laxiflora and Mangifera odorata from the non-Dipterocarp group. Results showed that the Shannon-Wiener Diversity Index, H’ for the canopy beetles for Dipterocarp tree was 3.5827 while for nonDipterocarp was 3.2986 which indicates a high diversity of canopy beetles of both tree groups. Study showed that there is no significant difference between the Shannon-Wiener Diversity Index between two groups (T-test, t=1.237, df=22, P>0.05). In addition, there is no significant difference in the abundance of beetles between the Dipterocarp and non-Dipterocarp group (Ttest, t=0.958, df=18, P>0.05) and between the tree species (ANOVA, F=1.098, df=22, P>0.05). The outcome of this study can be used as appropriate guidelines to manage restoration projects, by using canopy beetle diversity and abundance on various tree species as indicator of biodiversity recovery. In the future, studies should be conducted by comparing the beetle composition across multiple stages of restoration projects which varies in forest condition and structures

Defoliation symptoms on trees planted at a restoration site in Sabah, Malaysia

A study on defoliation of selected tree species was conducted at a forest restoration site located at Species Demo Plot in Luasong, Tawau Sabah. The study site is part of the INIKEA Forest Rehabilitation Project managed by Yayasan Sabah. The objective of this study was to determine the type and variation of defoliation symptoms observed on the foliage of eight to ten years old trees of Dipterocarpus conformis (KBK), Diospyros sp. (KMLM), Dryobalanops lanceolata (KPJ), Pentace laxiflora (TDH), Pentace adenophora (TDB) and Hopea ferruginea (SMKU) that were planted by line planting method. Sampling was conducted in July 2017 for a period of one week. Four replicates for each tree species was sampled. Defoliation symptoms were assessed on the crown of the trees. The mean defoliation symptom occurrence was calculated to represent each tree species. The mean defoliation symptoms among the six tree species were tested by using the Chi-square statistical analysis. Defoliation symptom occurrence across the six species of trees was categorized as herbivory, egg cases, leaf miners, leaf rollers, and galls. The highest percentage of defoliation symptom was herbivory (44.71%), followed by both egg cases and leaf miners (24.71% respectively), and only 1.18% of galls, which was the lowest. The highest mean defoliation symptom occurrence was recorded on D. lanceolata, with a mean of 4.75 occurrence, while the lowest mean defoliation symptom occurrence of 3.00 was recorded on both Diospyros sp. and H. ferruginea. Results of the Chi-square analysis indicated no significant difference (p>0.05) in the mean occurrence of defoliation symptoms across the six species of trees

Dimorphic male scutal patterns and uppereye facets of Simulium mirum n. sp. (Diptera: Simuliidae) from Malaysia

Background: A species of Simulium in the Simulium melanopus species-group of the subgenus Simulium (formerly misidentified as S. laterale Edwards from Sabah and Sarawak, Malaysia) is suspected to have dimorphic male scutal color patterns linked with different numbers of upper-eye facets. This study aimed to confirm whether or not these two forms of adult males represent a single species. Methods: DNA sequences generated from four genetic loci, the mitochondrial-encoded COI, COII, 12S rRNA and 16S rRNA genes, of both forms of Simulium sp. males were compared with each other and also with those of the females and larvae of the same species. Four other related Simulium spp. were also used for comparison. Results: Both the concatenated dataset and single-locus phylogenetic analyses indicate that the two distinct morphological males of Simulium sp. are indeed conspecific, and represent, together with their associated females and larvae, a distinct species. Conclusions: Based on DNA analyses, Simulium sp. is proven to show dimorphism in males and is herein described as a new species, Simulium mirum Takaoka, Sofian-Azirun & Low. This is the first report of such a novel species among the family Simuliidae