141 research outputs found

    First record and occurrence of Acraea terpsicore (linnaeus, 1758) (Lepidoptera: Nymphalidae) in Malaysian Borneo

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    The Tawny Coster, Acraea terpsicore (Linnaeus, 1758) (Lepidoptera: Nymphalidae) is recorded from Malaysian Borneo for the first time based on three specimens collected in Samarahan, southwestern Sarawak on 15th March 2013. Originally distributed in India and Sri Lanka, A. terpsicore is now known to have expanded its geographical range southwards to Southeast Asia and Australia over the last three decades. However, prior to 2013, there was no record of its occurrence on Borneo. Preliminary results of our field tracking and observations of the species in Malaysian Borneo within the last three years indicated that this species has recently become established in western Borneo and expanded its area of distribution from Samarahan 200 km northwards to Sri Aman. Field observations of this butterfly and distribution map of the species on Borneo based on field visits from 2013-2016 are presented. This common Oriental butterfly species may expand its range of distribution further northwards to North Borneo

    Effects of different coffee extracts on the egg fertility and lifespan of dengue vectors (Aedes albopictus and Aedes aegypti) (diptera: culicidae)

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    This study was conducted to examine the impacts of various extracts of coffee on the egg production aedes fertility and adult lifespan in two dengue vectors. Coffee is known for its chemical richness that is so far no resistance in insects was documented. For this purpose, two types of extracts (crude and used) from two types of coffee (fresh and roasted) of Coffea canephora (Robusta coffee) were used. We compared the effects of the extracts on the egg hatching responses and the longevity of dengue vectors; Aedes albopictus and Aedes aegypti. Overall, the roasted coffee extracts tend to have more negative impact than the fresh coffee extracts in reducing the hatching success. Crude extracts of both fresh/green and roasted coffee seems to exerts more chemicals and appears to be more acidic than the used extracts in which resulted in reduced rate of larval eclosion. Longevity statistically has no difference among coffee extracts However, based on the overall observation on the longevity of the adult and the difference in the longevity suggested that the exposure of the coffee to the dengue vectors during the embryogenesis does reduces the longevity of the survived adult by few days difference

    Classification of Aedes Adults Mosquitoes in Two Distinct Groups Based on Fisher Linear Discriminant Analysis and FZOARO Techniques

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    This paper describes the breeding, feeding and measurement of Aedes mosquitoes based on body size (wing length). Due to similarity in body size measurements, we were constrained on gender recognition. To reveal the gender identity of these mosquitoes, Fisher linear discriminant analysis and FZOARO classification models were considered suitable for prediction and classification.   We randomly selected 15 mosquitoes from each groups and categorize the body size as small and large and applied the classification procedures. Both classification techniques perform similar. The numerical simulation reveals that 86.67% were classified as male for group one and 80% were correctly classified as female in group two. Keywords: Fisher linear discriminant analysis; FZOARO; Classification

    Classification of Aedes Adults Mosquitoes in Two Distinct Groups Based on Fisher Linear Discriminant Analysis and FZOARO Techniques

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    This paper describes the breeding, feeding and measurement of Aedes mosquitoes based on body size (wing length). Due to similarity in body size measurements, we were constrained on gender recognition. To reveal the gender identity of these mosquitoes, Fisher linear discriminant analysis and FZOARO classification models were considered suitable for prediction and classification.   We randomly selected 15 mosquitoes from each groups and categorize the body size as small and large and applied the classification procedures. Both classification techniques perform similar. The numerical simulation reveals that 86.67% were classified as male for group one and 80% were correctly classified as female in group two.   Keywords: Fisher linear discriminant analysis; FZOARO; Classification

    The efficacy of insecticides (Fendona and Malathion) against larvae and adult stages of Musca domestica

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    Malathion and Fendona® (alphacypermethrin) insecticides were tested against larvae and adult stages of house flies, Musca domestica Linnaeus. The percentage mortality of House flies larvae range between 0% and 100%at different exposed dose rate of tested insecticide. Probit analysis was used to determine the LD50. The value LD50 for malathion without food medium was 0.833 -l/larvae and treatment with food medium was 0.895 -l/larvaerespectively. The LD50 for Fendona® without food medium was 0.545 -l/larvae and 0.870 -l/larvae for treatment with food medium. The LD50 values for Fendona® in both treatment was lowers compared with malathion, which meansthat alphacypermethrin is more toxic than malathion. Different with the test on adult house flies, the knockdown time values for alphacypermethrin at KT50 is 9.876 minutes and KT95 is 20.495 minutes against female adult house fliesand were significantly lower than malathion (KT50 is 75.17 minutes and KT95 is 103.38 minutes respectively). Result also showed that a total of 1.0-l of Fendona® is reacting more effective than 1.0-l of malathion. Therefore, we canconclude that Fendona® is the most effective insecticide towards larvae and adult stage of M. domestica. The effectiveness of both chemicals was affected when treated larvae was in the rearing mediu

    Life history effects of prey choice by copepods: implications for biocontrol of vector mosquitoes

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    Macrocyclops distinctus, Megacyclops viridis, and Mesocyclops pehpeiensis, which are common in rice fields during the summer season in Nagasaki, Japan, showed variable potentialities as biological control agents of larval Aedes albopictus, Culex tritaeniorhynchus, and Anopheles minimus in the laboratory. Macrocyclops distinctus and M. viridis, the largest copepod species, had fewer eggs within an egg clutch in nature than the smallest species, M. pehpeiensis, which also had a lower developmental time for sexual maturation (based on the appearance of the 1st clutch). Longevity as well as fecundity were influenced by nutritional conditions and varied significantly between the species. All species had shorter life spans when starved, but resistance to starvation was more pronounced in the larger species. All the species had lower clutch production when starved. Also, although the frequency of clutch production was high in M. pehpeiensis (M. pehpeiensis produced a clutch every 2 days, whereas M. distinctus and M. viridis took on average almost 3 days), total clutch production was far higher in the larger species. The copepods fed readily on mosquito larvae, with M. distinctus and M. viridis killing fewer Ae. albopictus than M. pehpeiensis, which, however, killed fewer An. minimus. These copepods exhibited a similar and limited predation against Cx. tritaeniorhynchus. Results of our study support the contention that these copepods have the potential to be used as biological control agents of immature mosquitoes. Also, our results give useful information on colony maintenance and field introduction. In particular, releasing copepods with Paramecium as food could increase their survival in the habitat of the targeted pest

    Lanthanide(III) complexes with tridentate Schiff base ligand, antioxidant activity and x-ray crystal structures of the Nd(III) and Sm(III) complexes

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    The tridentate N4-type Schiff base was synthesized from the condensation reaction of 2-hydrazinopyridine and pyridine-2-carbaldehyde. Neodymium and Samarium complexes were isolated when the corresponding nitrate salt was added to the solution of the ligand. The isolated compounds were characterized by elemental analyses, IR study, room temperature magnetic measurements and single X-ray crystal diffraction of the two crystals. Both complexes crystallize in the monoclinic system with space group P21/c. The cell parameters of the Nd complex are a=11.0927(8) Å, b=17.9926 (13) Å, c=11.9395(9)Å and β = 115.274(5) ° while the Sm complex shows parameters cell of a = 11.0477(8) Å, b = 17.9254(13) Å, c = 11.9149(8) Å and β =115.489(5) °. The X-ray study reveals isotopic Nd/Sm binuclear structures were each metal ion is nine-coordinated in the same fashion. Both metal centers have distorted tricapped trigonal prism geometry, with the Schiff base acting as tridentate ligand. The DPPH· radical scavenging effects of the Schiff base ligand and its Ln(III) complexes were screened. The Ln(III) complexes were significantly more efficient in quenching DPPH· than the free Schiff base ligand.Keywords: Lanthanide complexes, hydrazino, antioxidant activity, X-ray structur

    Larvicidal efficacy screening of Anacardaciae crude extracts on the dengue hemorrhagic vector, Aedes aegypti

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    Vector-borne diseases are still rife because of the re-emergence of diseases transmitted by mosquitoes. The objective of this paper is to evaluate the larvicidal efficacy of crude leaf extract of Mangifera indica, Gluta renghas, and Melanochyla fasciculiflora against vector of dengue hemorrhagic fever, Aedes aegypti. These plant species are endemic species and widely distributed in Malaysian forests. Leaves of Ma. indica, G. renghas and M. fascculiflora were collected from Teluk Bahang National Park, Penang Malaysia. Fractions of leaves were segregated, air-dried, powdered and extracted using Soxhlet with methanol. The solvent was removed by using rotary evaporator to obtain the crude extract. Using WHO standard larval bioassay test method, third instar larvae of Aedes aegypti were exposed to concentration ranging from 200- 4500 ppm of methanol extract for all plant species. Larval mortality was observed after 24 hours exposure. The highest susceptibility and toxicity was recorded by Mangifera indica with the lowest concentration at 800 ppm followed by M. fasciculiflora and G. renghas. This indicates that crude plant extract is very effective in killing Ae. aegypti mosquitoes. This finding may lead to new low cost alternative, environmentally friendly method for mosquito control programs. To our knowledge, this is the first report on larvicidal bioefficacy from endemic Malaysian plants

    Synthesis, physical studies and crystal structure determination of Y(III) and Er(III) complexes of 1-(pyridin-2-yl)-2-(pyridine-2-ylmethylene)hydrazine

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    Two isotype mononuclear yttrium(III) and erbium(III) complexes, {[Y(HL)(OAc)2(H2O)2]. (H2O)∙(NO3)} (1) and {[Er(HL) (OAc)2(H2O)2].(H2O)∙(NO3)} (2), where HL is the neutral Schiff base ligand 1-(pyridin-2-yl)-2-(pyridine-2-ylmethylene)hydrazine, and OAc is the acetate anion, have been synthesized and characterized by physicochemical methods and single crystal X-ray determination. Both complexes crystallizes in the triclinic space group Pī with unit cell dimensions for complex of Y(III) a = 7.909 (2) Å, b = 11.718 (4) Å, c = 12.497 (3) Å,    α = 78.907 (3)°, b = 73.840 (3)°, γ = 72.074 (3)°, V = 1051.26 (6) Å3, Z = 2, R1 = 0.051 and    wR2 = 0.112 and for complex of Er(III)a = 7.913 (1) Å, b = 11.719 (2) Å, c = 12.487 (2) Å,          α = 78.832 (1)°, α = 73.674 (1)°, γ = 72.012 (1)°, V = 1049.64 (3) Å3, Z = 2, R1 = 0.028, and   wR2 = 0.062. In both complexes, the coordination polyhedra around Ln(III) atoms are best described as a distorted tricapped trigonal prism. Antioxidant activities of the ligand and its Y(III) and Er(III) complexes are studied
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