This study was conducted to clarify the development of free neuromasts with growth of the barramundi, Lates calcarifer. A pair of free neuromasts was observed behind the unpigmented eyes in newly hatched eleutheroembryos with a mean total length of 1.93 mm, and two-hour-old eleuthero-embryos could respond to an approaching pipette. At 2 days after hatching, the egg yolk sac was mostly consumed, the eyes were pigmented, and the larvae commenced feeding on rotifers. Free neuromasts increased in number with growth and commenced developing into canal neuromasts in barramundi 15 days old with a mean total length of 8.07 mm. The average length of the major axis of the trunk free neuromasts attained approximately 12.9-15.5 microm, and the number of sensory cells was 15.4-17.5 at 15-20 days old. Developed cupulae of free neuromasts were observed in 1-day-old eleutheroembryos. The direction of maximum sensitivity of free neuromasts, determined from the polarity of the sensory cells, coincided with the minor axis of the lozenge-shaped outline of the apical surface of the free neuromasts. The polarity of trunk neuromasts was usually oriented along the antero-posterior axis of the fish body, but a few had a dorso-ventral direction. On the head, free neuromasts were oriented on lines tangential to concentric circles around the eye.
The current study assessed the implications of substituting fish meal (FM) with black soldier fly larvae meal (BSFLM) on sustainable African catfish (Clarius gariepinus) production. Five isocaloric experimental diets were formulated and 168-days feeding trials were performed with 1400 improved strains of African catfish. Fish fed with 50% BSFLM expressed the lowest and highest feed conversion ratio, and daily weight gain and specific growth rate. Fillets from fish fed diet with 50 and 75% BSFLM inclusion expressed higher lauric (11.4-16.7%) and linoleic acids. Omega-6 fatty acid was 19-fold higher in fillets from fish fed diet with 75%BSFLM. There was 5-8% and 9-11% higher crude protein in fillet from fish fed diet with 50 and 75% BSFLM, respectively. Essential amino acids in the fillets, particularly lysine [11 - 18g/kg] and methionine [11 - 27g/kg] values were significantly higher in catfish fed diet with BSFLM diets than with FM. Diet integrated with 50% BSFLM showed the best return on investment (105.2%) and cost-benefit ratio (1.05). Integration of 50-75% BSFLM into African catfish diet offers a sustainable and cost-effective alternative to conventional fish feed, with promising long-term nutritional and health benefits for the aquaculture industry.
New synthesized bis-imidazolium salts that are linked by xylyl derivatives moiety, 1-4 was reacted with Ag2O to facilitate the formation of dinuclear Ag(I)-N-heterocyclic carbene (NHC) complexes, 5-8, respectively. All the synthesized ligand salts and complexes were characterized by1H and13C NMR, FTIR spectroscopy and elemental analysis. Molecular structures of compounds 3, 5, and 7 were elucidated by single crystal X-ray diffraction analyses. Larvicidal studies against the Aedes aegypti and Culex quinquefasciatus were carried out on all synthesized compounds following the World Health Organization standard larval susceptibility test. All the imidazolium salts were found inactive while the activity of the dinuclear Ag(I)-NHC complexes on mosquito larvae are varies with the nature of the ligands. Complex 7 has high activity on Ae. aegypti and Cx. quinquefasciatus, emphasising its potential as a larvicidal compound.
After two years' use of hexachlorocyclohexane (BHC) as a larvicide in Georgetown, on Penang Island, control of Culex fatigans breeding became unsatisfactory. Two laboratory colonies of fatigans were established, one from Georgetown, and one from Kuala Lumpur where no insecticides had been used; tests were then made to determine the median lethal concentrations (MLC) of BHC, dieldrin, and DDT for the larvae of the two strains. The Georgetown strain was found to have acquired a tenfold resistance to BHC, and also to dieldrin to which it had not been exposed, but it showed no significant increase of resistance to DDT, to which it had also not been exposed. A year later, when both strains had passed through some ten generations in the laboratory without exposure to insecticides, the Georgetown strain was found to have lost much of its resistance to BHC, although the MLC was still twice that of the non-resistant Kuala Lumpur strain.
Innovative solutions are needed to limit environmental effect and optimise resource use as food waste generation rises worldwide. This study investigates the potential of upcycling food waste from fresh markets using Black Soldier Fly (Hermetia illucens) larvae (BSFL) as a sustainable approach. This study explored four fresh market food waste substrates for BSFL bioconversion: discarded fish waste (FI), slaughtered chicken waste (CHI), vegetable waste (VEG), and a 1:1:1 combination of all three (MIX). Soybean curd residue (SCR) was treated as the control substrate. The effects on larval growth, nutritional content, and waste bioconversion rates were examined. The larvae growth rate was strongly impacted by waste type, with BSF-fed CHI and MIX gaining 18.0 and 16.7 mg/d, respectively, followed by BSF-fed with SCR (12.2 mg/d), FI (8.9 mg/d) and VEG (7.6 mg/d). The waste type did not substantially alter BSFL length. The survival rate of the BSFL fed with the food waste studied ranges from 95 to 98.47%, with SCR being the highest. Our findings indicated that BSFL can effectively convert a variety of fresh market food waste into valuable biomass. CHI waste produced the highest larval biomass and bioconversion rate followed by MIX, SCR, FI and VEG. The different waste stream has a major influence on BSFL biomass nutrition. BSFL nutritional composition is independent of the substrate's nutritional content, indicating no direct correlation between substrate and BSFL biomass nutritional composition. SCR waste produced the highest protein content of BSFL (50.49%), followed by VEG (32.61%), MIX (32.57%), FI (31.03%) and CHI (29.06%). SCR waste also produced BSFL biomass with lowest lipid content (26.55%) compared to other waste which resulted into BSFL with lipid levels ranging from 42.92% to 53.72%. BSFL-fed with SCR is the most suitable to be used as an alternative animal's feed based on the protein and lipid levels, while defatting procedure is necessary for the other waste-fed BSFL to render it suitability as animal feed alternatives. Based on bioconversion rate, BSFL growth, and lipid content, the MIX and CHI waste might be viable substrates for future research.
Simulium (Asiosimulium) khongchiamense sp. nov. is described based on females, males, pupae, and mature larvae collected from Khong Chiam District, Ubon Ratchathani Province, northeastern Thailand. It is characterized in the female by the medium-long sensory vesicle, scutum with 3 dark longitudinal vittae and elongate cercus; in the male by the number of upper-eye (large) facets in 17 or 18 vertical rows and 18 or 19 horizontal rows, hind basitarsus moderately enlarged and ventral plate with the posterior margin moderately concave medially; in the pupa by the head and thoracic integument sparsely covered with tubercles and gill of arborescent type with 32 or 33 filaments; and in the larva by the postgenal cleft deep, reaching the posterior margin of the hypostoma and sheath of the subesophageal ganglion dark pigmented. DNA analysis based on COI gene of all known species of the subgenus Asiosimulium, except for S. shanense and S. suchitrae, indicated that this new species can be clearly differentiated from all other related species (S. phurueaense, S. oblongum, S. saeungae, S. furvum, and S. wanchaii) with interspecific genetic distances ranging between 4.79% and 19.18%. This is the eighth species of the subgenus Asiosimulium. Taxonomic notes are given to distinguish this new species from the 7 known species members in its same subgenus. Additionally, keys to species of all members in the subgenus Asiosimulium are provided.
Galleria mellonella larvae have been increasingly used in research, including microbial infection studies. They act as suitable preliminary infection models to study host-pathogen interactions due to their advantages, such as the ability to survive at 37°C mimicking human body temperature, their immune system shares similarities with mammalian immune systems, and their short life cycle allowing large-scale studies. Here, we present a protocol for simple rearing and maintenance of G. mellonella without requiring special instruments and specialized training. This allows the continuous supply of healthy G. mellonella for research purposes. Besides, this protocol also provides detailed procedures on the (i) G. mellonella infection assays (killing assay and bacterial burden assay) for virulence studies and (ii) bacterial cell harvesting from infected larvae and RNA extraction for bacterial gene expression studies during infection. Our protocol could not only be used in the studies of A. baumannii virulence but can also be modified according to different bacterial strains.
Simulium (Gomphostilbia) okinawense Takaoka and S. (G.) tokarense Takaoka, both from the Nansei Islands, Japan, were morphologically reexamined and genetically analysed by using the COI gene sequences. The female, male, pupa and mature larva of the two species are redescribed. Morphological reexamination shows that both species are more similar to species in the S. asakoae species-group than to those in the S. ceylonicum species-group, by having a medium-long female sensory vesicle, yellow tuft hairs (S. (G.) okinawense) or yellow tuft hairs mixed with a few to several dark hairs (S. (G.) tokarense) at the base of the radial vein in the female and male, and medium-long larval postgenal cleft. However, the body of the male ventral plate (viewed ventrally) is parallel-sided (S. (G.) okinawense) or parallelsided or slightly narrowed (S. (G.) tokarense) and not emarginated basally, differing from those of most species in the S. asakoae species-group. Our genetic analysis shows that S. (G.) tokarense is in the S. asakoae species-group, and S. (G.) okinawense formed a separate sister clade with other members of the S. asakoae species-group with high bootstrap support. From the results of morphological and genetic analysis combined, S. (G.) okinawense and S. (G.) tokarense are transferred from the S. ceylonicum species-group to the S. asakoae species-group.
Our previous study demonstrated that among different habitat sites (mangrove, estuary, river, seagrass and Open Sea) in Johor Strait, Malaysia, seagrass showed highest family diversity and abundance of larval fish. However, it is unclear whether this was due to difference in habitat complexity or water quality parameters.? To test this, larval fish were collected by using a bongo net equipped with a flow meter by subsurface horizontal towing from different habitats in Johor Strait between October 2007 and September 2008.? Various physico-chemical parameters were measured and then examined for any relationship to fish larvae diversity and abundance. Among the 24 families identified from the sites, seven families (Blenniidae, Clupeidae, Mullidae, Nemipteridae, Syngnathidae, Terapontidae and Uranoscopeidae) were significantly correlated with the tested waters quality parameters.? Salinity showed a positive and negative significant correlation with Clupeidae (p < 0.01) and Uranoscopeidae (p < 0.05), respectively. Terapontidae was significantly correlated with dissolved oxygen (p < 0.01), while both Mullidae and Syngnathidae were significantly correlated with pH (p < 0.05). However, a canonical correspondence analysis test indicated weak overall correlation (36.4%) between larval assemblage and in the seagrass-mangrove ecosystem of Johor Strait, Malaysia. This likely indicates that habitat structure was more important in determining larval abundance (highest in the seagrass habitat) as compared to water quality at the tested sites. This study emphasizes the need to conserve seagrass beds as important nursery grounds for various fish larvae to ensure adequate recruitment and ultimately sustainable fisheries management. ?
A large scale study was conducted to elucidate the true relationship among entomological, epidemiological and environmental factors that contributed to dengue outbreak in Malaysia. Two large areas (Selayang and Bandar Baru Bangi) were selected in this study based on five consecutive years of high dengue cases. Entomological data were collected using ovitraps where the number of larvae was used to reflect Aedes mosquito population size; followed by RT-PCR screening to detect and serotype dengue virus in mosquitoes. Notified cases, date of disease onset, and number and type of the interventions were used as epidemiological endpoint, while rainfall, temperature, relative humidity and air pollution index (API) were indicators for environmental data. The field study was conducted during 81 weeks of data collection. Correlation and Autoregressive Distributed Lag Model were used to determine the relationship. The study showed that, notified cases were indirectly related with the environmental data, but shifted one week, i.e. last 3 weeks positive PCR; last 4 weeks rainfall; last 3 weeks maximum relative humidity; last 3 weeks minimum and maximum temperature; and last 4 weeks air pollution index (API), respectively. Notified cases were also related with next week intervention, while conventional intervention only happened 4 weeks after larvae were found, indicating ample time for dengue transmission. Based on a significant relationship among the three factors (epidemiological, entomological and environmental), estimated Autoregressive Distributed Lag (ADL) model for both locations produced high accuracy 84.9% for Selayang and 84.1% for Bandar Baru Bangi in predicting the actual notified cases. Hence, such model can be used in forestalling dengue outbreak and acts as an early warning system. The existence of relationships among the entomological, epidemiological and environmental factors can be used to build an early warning system for the prediction of dengue outbreak so that preventive interventions can be taken early to avert the outbreaks.
A new species of black fly, Simulium (Gomphostilbia) rampae, is described, based on adult male, its pupal exuviae and mature larvae collected from Doi Inthanon National Park, northern Thailand. This new species is placed in the Simulium asakoae species-group, and is characterized in the male by the high number of upper-eye facets in 17 vertical columns and 18 horizontal rows, in the pupa by the gill with a long common basal stalk, cone-shaped terminal hook, and cocoon with an anterodorsal projection, and in the larva by the medium-long postgenal cleft. A DNA analysis using COI gene supported its assignment to the S. asakoae species-group and showed its close relationship to S. (G.) udomi Takaoka & Choochote and S. (G.) chiangdaoense Takaoka & Srisuka. This is the fourth member of the S. asakoae species-group recorded from Thailand.
In recent decades, the numbers of cryptic taxa have increased significantly with current progress in DNA barcoding, yet, most of these cryptic taxa have not been formally named and recognized as valid species. To address this issue, we provide a guide for applying the procedure of describing new cryptic species in the family Simuliidae. Simulium (Simulium) vanluni from Pahang, Peninsular Malaysia, previously treated as S. nobile De Meijere, is described as a new species by using an integrated morpho-taxonomical and genetic approach. This new species is morphologically identical to S. nobile from Java and S. kiuliense Smart & Clifford from Borneo, but their distinctiveness is supported by an expanded multigene phylogeny analysis.
The final instar larva of Acrogomphus jubilaris Lieftinck, 1964, is described and figured for the first time based on exuviae from four male and one female larvae collected in Sarawak, Malaysian Borneo. The adults of A. jubilaris are very rarely encountered. The larvae, however, are surprisingly common in forest streams in Borneo. It is compared with A. malayanus Laidlaw, 1925 and A. walshae Lieftinck, 1935, and notes on behavior, distribution and habitat are included. A map including all known records of A. jubilaris is provided.
To better understand the population dynamics and dispersal ability of insect species, it is often helpful to derive a life table containing fundamental demographic data. The aim of this study was to determine a life table for the predatory necrophagous species Synthesiomyia nudiseta (van der Wulp, 1883) on a pig liver diet and under controlled laboratory conditions (29.5 ± 2. 5°C, RH 50 ± 15%, and a photoperiod of 12:12). This species has medical and veterinary importance and its distribution extends in tropical and subtropical areas and now it has been established in the southwestern of Europe. The mean adult longevity was 36. 18 ± 2. 06 d and the net reproduction rate, R, was 27.65 offspring/female, the mean generation time, T, was 22. 09 d, the finite rate of increase, λ, was 1. 16 d-1, and the intrinsic rate of increase, r, was 0. 15 d-1. These results indicate that S. nudiseta cannot be considered an r-strategist as the most common synanthropic necrophagous blowflies due to its predatory behavior; however, its invasive and colonist abilities are discussed. This is the first life table study of this species from Palearctic region to analyze the effect of its dispersal ability.
Two new species of black flies, Simulium (Comphostilbia) terengganuense sp. nov. and Simulium (Gomphostilbia) aziruni sp. nov. (Diptera: Simuliidae), are described on the basis of reared adult, pupal, and larval specimens collected from Peninsular Malaysia. Both species are placed in the batoense species-group within the subgenus Gomphostilbia, one of two dominant subgenera of the genus Simulium in Peninsular Malaysia as well as in the Oriental Region. Strikingly, three morphological characteristics that rarely occur in the subgenus Gomphostilbia are found in these two new species: the very narrow female frons and the mushroom-like pupal terminal hooks in S. (G.) terengganuense sp. nov. and the pupal gill composed of an inflated horn-like structure and eight slender filaments in S. (G.) aziruni sp. nov.
Simulium (Comphostilbia) izuae sp. nov. is described from female, male, pupal, and larval specimens collected from Cameron's Highlands, Peninsular Malaysia. This new species is placed in the asakoae species-group of the subgenus Gomphostilbia. The pupa of this new species is characterized by the gill with eight long filaments arranged as (3 + 3) + 2 filaments, of which the ventral pair of filaments is borne on a stalk that is always shorter than the common basal stalk. Taxonomic notes to distinguish this new species from five other Malaysian species and 12 other species of the asakoae species-group from other countries are given. Keys to identify all 18 species of the asakoae species-group are also provided for females, males, pupae, and mature larvae.