Malaria, the most widespread mosquito-borne disease, affects 350-500 million people each year. Eco-friendly control tools against malaria vectors are urgently needed. This research proposed a novel method of plant-mediated synthesis of silver nanoparticles (AgNP) using a cheap seaweed extract of Ulva lactuca, acting as a reducing and capping agent. AgNP were characterized by UV-vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The U. lactuca extract and the green-synthesized AgNP were tested against larvae and pupae of the malaria vector Anopheles stephensi. In mosquitocidal assays, LC50 values of U. lactuca extract against A. stephensi larvae and pupae were 18.365 ppm (I instar), 23.948 ppm (II), 29.701 ppm (III), 37.517 ppm (IV), and 43.012 ppm (pupae). LC50 values of AgNP against A. stephensi were 2.111 ppm (I), 3.090 ppm (II), 4.629 ppm (III), 5.261 ppm (IV), and 6.860 ppm (pupae). Smoke toxicity experiments conducted against mosquito adults showed that U. lactuca coils evoked mortality rates comparable to the permethrin-based positive control (66, 51, and 41%, respectively). Furthermore, the antiplasmodial activity of U. lactuca extract and U. lactuca-synthesized AgNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. Fifty percent inhibitory concentration (IC50) values of U. lactuca were 57.26 μg/ml (CQ-s) and 66.36 μg/ml (CQ-r); U. lactuca-synthesized AgNP IC50 values were 76.33 μg/ml (CQ-s) and 79.13 μg/ml (CQ-r). Overall, our results highlighted out that U. lactuca-synthesized AgNP may be employed to develop newer and safer agents for malaria control.
Sexually anomalous individuals, typically intersexes or gynandromorphs, bear a mixture of male and female traits. Twelve sexually anomalous individuals of the black fly Simulium (Gomphostilbia) trangense Jitklang, Kuvangkadilok, Baimai, Takaoka & Adler were discovered among 49 adults reared from pupae. All 12 sexually anomalous adults were parasitized by mermithid nematodes, although five additional parasitized adults had no overt external anomalies. Sequence analysis of the 18S rRNA gene revealed that the mermithids, possibly representing a new species, are related to Mesomermis spp., with genetic distances of 5.09-6.87%. All 12 anomalous individuals had female phenotypical traits on the head, thorax, forelegs, midlegs, and claws, but male features on the left and right hind basitarsi. One individual had mixed male and female genitalia. The findings are in accord with the trend that mermithid infections are associated with sexually anomalous adult black flies.
A great variety of parasites and parasitoids exploit ant societies. Among them are the Mesostigmata mites, a particularly common and diverse group of ant-associated arthropods. While parasitism is ubiquitous in Mesostigmata, parasitoidism has only been described in the genus Macrodinychus. Yet information about the basic biology of most Macrodinychus species is lacking. Out of 24 formally described species, information about basic life-history traits is only available for three species. Here we formally describe two new Macrodinychus species, i.e. Macrodinychus hilpertae and Macrodinychus derbyensis. In both species, immature stages developed as ecto-parasitoids on ant pupae of the South-East Asian army ant Leptogenys distinguenda. By piercing the developing ant with their chelicera, the mites apparently suck ant hemolymph, ultimately killing host individuals. We compare infection rates among all studied Macrodinychus species and discuss possible host countermeasures against parasitoidism. The cryptic lifestyle of living inside ant nests has certainly hampered the scientific discovery of Macrodinychus mites and we expect that many more macrodinychid species await scientific discovery and description.
The fall armyworm (Spodoptera frugiperda) is a major economic pest in the United States and has recently become a significant concern in African and Asian countries. Due to its increased resistance to current management strategies, including pesticides and transgenic corn, alternative management techniques have become more necessary. Currently, silicon (Si) is being used in many pest control systems due to its ability to increase plant resistance to biotic and abiotic factors and promote plant growth. The current experiments were carried out at the College of Plant Protection, Gansu Agricultural University, Lanzhou, China, to test the effect of Si on lifetable parameters and lipase activity of fall armyworm and vegetative and physiological parameters of maize plants. Two sources of Si (silicon dioxide: SiO2 and potassium silicate: K2SiO3) were applied on maize plants with two application methods (foliar application and soil drenching). The experiment results revealed that foliar applications of SiO2 and K2SiO3 significantly (P≤0.05) increased mortality percentage and developmental period and decreased larval and pupal biomass of fall armyworm. Similarly, both Si sources significantly (P≤0.05) reduced lipase activity of larvae, and fecundity of adults, whereas prolonged longevity of adults. Among plant parameters, a significant increase in fresh and dry weight of shoot, stem length, chlorophyll content, and antioxidant activity was observed with foliar applications of Si. Root fresh and dry weight was significantly (P ≤ 0.05) higher in plants treated with soil drenching of SiO2 and K2SiO3. Moreover, SiO2 performed better for all parameters as compared to K2SiO3 and control treatment. The study conclusively demonstrated a significant negative effect on various biological parameters of fall armyworm when plants were treated with Si, so it can be a promising strategy to control this pest.
Paracyrba wanlessi is a southeast Asian jumping spider (Salticidae) that lives in the hollow internodes of fallen bamboo and preys on the larvae, pupae and adults of mosquitoes. In contrast to Evarcha culicivora, an East African salticid that is also known for actively targeting mosquitoes as preferred prey, there was no evidence of P. wanlessi choosing mosquitoes on the basis of species, sex or diet. However, our findings show that P. wanlessi chooses mosquitoes significantly more often than a variety of other prey types, regardless of whether the prey are in or away from water, and regardless of whether the mosquitoes are adults or juveniles. Moreover, a preference for mosquito larvae, pupae and adults is expressed regardless of whether test spiders are maintained on a diet of terrestrial or aquatic prey and regardless of whether the diet includes or excludes mosquitoes. Congruence of an environmental factor (in water versus away from water) with prey type (aquatic versus terrestrial mosquitoes) appeared to be important and yet, even when the prey were in the incongruent environment, P. wanlessi continued to choose mosquitoes more often than other prey.
Bemisia tabaci (Gennadius) merupakan spesies lalat putih utama dan berbahaya kepada pertanian. Kajian telah dijalankan di Stesen MARDI Jalan Kebun, Klang, Selangor dari 9 September 2006 hingga 11 November 2007. Objektif kajian ini adalah untuk menilai kesan populasi lalat putih terhadap tanaman cili yang diberi kadar nitrogen yang berbeza (0, 33, 43, 53 g/pokok). Keputusan kajian menunjukkan pokok cili yang dibaja dengan kadar nitrogen yang tinggi menyebabkan peningkatan yang bererti (P<0.05) kepada populasi B. tabaci peringkat belum matang berbanding pada pokok cili yang dibajakan nitrogen pada kadar rendah. Min bilangan B. tabaci pada peringkat belum matang per aras kanopi adalah berbeza secara signifikan (P<0.05) antara aras kanopi dan antara perlakuan. Secara amnya, min bilangan telur dan larva B. tabaci adalah lebih tinggi secara bererti (P<0.05) pada aras kanopi atas berbanding tengah dan bawah. Walau bagaimanapun, min bilangan pupa B. tabaci adalah tinggi secara signifikan (P<0.05) pada aras kanopi bawah berbanding aras kanopi atas dan tengah. Min bilangan B. tabaci pada peringkat belum matang adalah berbeza secara bererti (P<0,05) mengikut minggu selepas pokok cili ditanam pada semua perlakuan. Secara amnya, populasi B. tabaci lebih tinggi semasa awal musim penanaman dan menurun selepasnya hingga ke akhir musim kecuali pada minggu ketiga dan ketujuh selepas pokok cili di tanam.
Kajian mengenai taburan dan kelimpahan parasitoid lalat rumah (Musa domestica) telah dijalankan di ladang ternakan ayam di beberapa negeri di Semenanjung Malaysia. Didapati bahawa spesies parasitoid yang memparasit pupa lalat di ladang ternakan ayam di Semenanjung Malaysia adalah Splangia endius, Splangia cameroni, Dirhinus himalayanus
dan Pachycrepoideus vindemiae. Taburan populasi S. endius dan D. himalayanus adalah menyeluruh iaitu terdapat di semua negeri berbanding P. vindemiae. Namun, kelimpahan (bilangan individu) S. endius adalah tinggi secara signifikan (p<0.05) berbanding lain-lain spesies parasitoid. Kelimpahan D. himalayanus, S. cameroni dan P. vindemiae adalah tidak berbeza secara signifikan antara negeri. Ini menunjukkan S. endius adalah berpotensi untuk dijadikan agen kawalan biologi lalat rumah di ladang ternakan ayam di Malaysia. Kelimpahan parasitoid adalah tinggi secara signifikan (p<0.05) di ladang ayam telur berbanding ladang ayam daging. Secara keseluruhannya, terdapat perbezaan yang tinggi dan signifikan tentang populasi parasitoid di Johor berbanding Kelantan tetapi tidak (p<0.05) di antara negeri Johor, Selangor, Pulau Pinang dan Pahang. Perbezaan yang tidak signifikan juga direkodkan antara kelimpahan pupa lalat rumah dan parasitoid di sepanjang tempoh kajian dan antara lokasi di Malaysia. Kesan suhu dan jumlah hujan
didapati tidak mempengaruhi perbezaan kelimpahan parasitoid di ladang ayam. Potensi S. endius dan D. himalayanus untuk dikomersialkan pengeluarannya juga dibincangkan.
The larval growth of Liosarcophaga dux Thompson (Diptera: Sarcophagidae) was studied under varying indoor room temperatures in Malaysia. Five replicates were established. The immature growth of this species from first instar until adult emergence was 307.0+/-3.0 hours. The mean larval length measured for second instar, third instar, post-feeding stage and puparia were 6.5+/-0.5 mm (n=10), 11.8+/-3.7 mm (n=31), 12.7+/-0.8 mm (n=16), and 9.5+/-0.5 mm (n=15), respectively.
The efficacy of the larvicidal and pupicidal agent (Agnique) MMF was evaluated against larvae of An. arabiensis and Culex (Diptera: Culicidae) under field conditions in Bahary Locality, Khartoum, Sudan. At an applied dosage of 0.25 ml/m2, MMF resulted in 89.4, 79.8 and 88.2% reductions in L3-L4 instars An. arabiensis and 63.5% in Culex larvae (all stages) 24 to 72 hours post-treatment. Pupae were completely eliminated (100%) within 24 hours posttreatment. The earlier instars (L1-L2) of An. arabiensis were more tolerant with a 62.5% reduction at 72 hours post-treatment compared to (L3-L4) instars and pupae. At 7-days post-treatment Agnique gave a 57.5% reduction in L1-L2 and 92.6% in L3-L4 instar larvae of An. arabiensis and 57.3% and 86.4% in Culex larvae and pupae, respectively. We conclude that Agnique can perform effectively against L3-L4 instars and pupae of An. arabiensis for only 1 week, and 3 to 4 days against L1-L2 instars of Culex spp.
Successful colonization of Mansonia dives, the principal vector of subperiodic Brugia malayi was established in a field insectary. Mean egg clusters laid on Eichhornia crassipes, Pistia stratiotes, Homalomena cordata and polystyrofoam strips were 12.0, 10.4, 9.5 and 13.7 respectively. However, the mean number of first instar larvae hatched from each egg cluster laid by females on the three plant substrates (range 51.1 to 58.6) was higher than that laid on the polystyrofoam strips (41.8). There were no significant differences in the success pupation and adult emergence rates among the three host plants used as attachment substrates. Adult emergence occurred at a mean of 10.8 days. The first adult emergence was observed at the 25th day after hatching and continued till the 50th day. The 50% mortality rates for the adults were estimated as 8 days for the males and 14 days for the females. The mean gonotrophic cycle ranged from 3.8 to 4.3 days with a mean of 4.04 days. 63.6% of Ma. dives females oviposited in a medium of rat dung and water. The mean incubation period of eggs ranged from 5.2 to 6.5 days with a mean of 5.7 days. The biology of Ma. dives and Ma. bonneae is briefly compared.
The male, pupa and mature larva of Simulium (Asiosimulium) wanchaii Takaoka & Choochote, one of the four species of the small Oriental black fly subgenus Asiosimulium, are described for the first time based on samples collected from Thailand. The male S. (A.) wanchaii is characterized based on the enlarged hind basitarsus and the ventral plate which is much wider than long. The pupa and larva are characterized by the gill with 19 filaments and the deep postgenal cleft, respectively. Keys are provided to identify all the four species of the subgenus Asiosimulium for females, males, pupae and mature larvae.
Simulium (Nevermannia) chomthongense sp. nov. is described from female, male, pupal and larval specimens collected from Doi Inthanon National Park and Doi Phahompok National Park, Chiang Mai, Thailand. This new species, first reported as S. (Eusimulium) sp. A, and later regarded as S. (N.) caudisclerum Takaoka & Davies, described from peninsular Malaysia, is distinguished from S. (N.) caudisclerum in the male by the number of enlarged upper-eye facets and the relative size of the hind basitarsus against the hind tibia and femur, and in the pupa by the relative length of the stalks of paired filaments against the common basal stalk and the color of the dorsal surface of abdominal segments 1- 3 (or 4). Taxonomic and molecular notes are provided to separate this new species from four other known species of the vernum species-group, which share an accessory sclerite on the larval abdomen, a rare characteristic in this species-group.
Simulium (Gomphostilbia) sofiani sp. nov. is described on the basis of reared adult female, male, pupal and larval specimens collected from Cameron Highlands, Pahang state, Malaysia. This new species is placed in the ceylonicum species-group within the subgenus Gomphostilbia and is easily distinguished from all the related known species by the combination of the following characteristics: an elongate sensory vesicle and yellow hair tuft on the stem vein of the wing in the female, the greater number of large upper-eye facets (15 or 16 vertical columns and 15 or 16 horizontal rows) and almost entirely darkened hind basitarsus in the male, and the gill bearing a long common basal stalk and 8 filaments arranged as [(1+2)+(1+2)] +2 filaments from dorsal to ventral in the pupa.
A forensic entomological study was conducted using monkey carcasses (Macaca fascicularis Raffles) that were placed in either an outdoor or indoor environment at a coastal area in Tanjung Sepat, Selangor, Malaysia during May until August 2008. We collected pupae of Chrysomya rufifacies (Marquart) from the carcasses and kept them individually. The emergence of 13 parasitic microhymenopteran, from one of the pupae occurring within a week were identified as Exoristobia philippinensis Ashmead (Hymenoptera: Encyrtidae). Another observation was made whereby a pupa of C. rufifacies was predated by a muscid larva, Ophyra spinigera (Stein). The larva squeezed into the pupa and consumed the contents. This paper report C. rufifacies as a new host record for E. philippinensis in Malaysia and highlighted the predatory behavior of O. spinigera larva in natural environment.
The pupae of Desmometopa sp. (Diptera: Milichiidae) were collected from a human corpse found indoor in active decay stage together with the larvae of Sarcophagidae, Synthesiomyia nudiseta (Wulp), Chrysomya megacephala (Fabricius) and Chrysomya rufifacies (Macquart). This research note is the first report of the Desmometopa sp. recovered from a human corpse in Malaysia.
Megaselia scalaris (Loew) is a cosmopolitan polyphagous small fly with the ability of exploiting variety of ecological niches. Different life history stages act as detritivore, parasite, and parasitoid of wider spectrum of plant and animal matter under natural and laboratory conditions. Here, for the first time we present the opportunistic parasitism of M. scalaris on Otobius megnini, which act as a vector of Q fever and is capable of causing paralysis, toxic conditions, otoacariasis and otitis in humans and other animals. Tick samples from the ear canals of 14 thoroughbred horses were brought to the laboratory and several days later, larvae of M. scalaris were found feeding on immature stages of O. megnini. When the development was completed pupae were found attached to adult ticks and all nymphs were found dead. This context reveals the capability of M. scalaris surviving on O. megnini and the risk of their invading ear canals of horses.
Simulium chayamaritae Takaoka and Srisuka from Thailand belongs to the Simulium darjeelingense species-group of Simulium (Simulium) (Diptera: Simuliidae). The female of this species is described for the first time based on a female reared from a pupa collected from Chiang Mai, Thailand. It is characterized by the sensory vesicle elongate and the inner margins of the arms of the genital fork divergent, then convergent apically. It is similar to the female of S. eshimai Takaoka and Adler of the same speciesgroup from Vietnam. Taxonomic notes are given to separate it from two other species of the S. darjeelingense species-group from India and Malaysia, and 28 of 31 other species of the subgenus Gomphostilbia recorded from Thailand.
Simulium (Gomphostilbia) dhangi sp. nov., S. (G.) sumbaense sp. nov. and S. (Nevermannia) wayani sp. nov. are described from the Lesser Sunda Archipelago, Indonesia. Simulium (G.) sumbaense sp. nov. is placed in the S. varicorne species-group and is characterized by the pupal gill with eight filaments arranged as (1+1+1+1+2)+2 from dorsal to ventral, while S. (G.) dhangi sp. nov., unplaced to group, is characterized by the pupal gill composed of two inflated trunks and four slender filaments all arising basally, and the short larval antenna as long as the stem of the labral fan. Simulium (N.) wayani sp. nov. belongs to the S. ruficorne species-group and is characterized by the female spermatheca with an unsclerotized neck, and pupal gill with four inflated filaments. The number of species of black flies from the archipelago increases from 19 to 22.
Simulium (Simulium) contractum Takaoka from Sulawesi, Indonesia was known only as the pupa. Its female, male and mature larva are described for the first time. The tentative assignment of this species in the Simulium dumogaense species-group is confirmed by the adult characters including the female and male genitalia. The female and male of this species are similar to those of Simulium (Simulium) tumpaense Takaoka and Roberts but are distinguished by the yellowish femora.