Housefly Larvae Research Articles

Nutritional evaluation of dried larvae and pupae meal of the housefly (Musca domestica) using chemical- and broiler-based biological assays

The nutritional composition of common housefly (Musca domestica) larvae and pupae meal is reported in terms of proximate analysis, amino acid profile, fatty acid composition, apparent metabolisable energy and total tract digestibility (TTD) of nutrients. Proximate analysis and TTD of meal showed larvae and pupae meal to contain, on a DM basis, a gross energy value of 20.10 MJ/kg and 20.42 MJ/kg, respectively, and an apparent metabolisable energy value of 14.23 MJ/kg and 15.15 MJ/kg, respectively. Crude protein content was 60.38% and 76.23%, with TTDs of 69% and 79%, respectively, with similarly high values reported for individual amino acids. Amino acid analysis revealed a favourable amino acid composition with high lysine concentrations but marginally low methionine concentrations. Arginine : lysine ratios of larvae and pupae meal were 0.67 and 0.91, respectively, and isoleucine : leucine ratios were 0.68 and 0.64, respectively. Crude fat contents were 14.08% and 14.39%, with TTDs of 94% and 98%, respectively, and crude fibre contents were 8.59% and 15.71%, with TTDs of 62% and 58%. Housefly larvae meal had crude protein TTD of 69%, whereas that of pupae meal was 79%. Both larvae and pupae meal had high amino acid TTDs. The TTD values of the crude fat and crude fibre were determined at 94% and 62%, respectively, for the housefly larvae, and at 98% and 58%, respectively, for the housefly pupae. M. domestica larvae meal can therefore be regarded as a good-quality protein source suitable for animal feeding.

Housefly larvae hydrolysate: orthogonal optimization of hydrolysis, antioxidant activity, amino acid composition and functional properties

BackgroundAntioxidant, one of the most important food additives, is widely used in food industry. At present, antioxidant is mostly produced by chemical synthesis, which would accumulate to be pathogenic. Therefore, a great interest has been developed to identify and use natural antioxidants. It was showed that there are a lot of antioxidative peptides in protein hydrolysates, possessing strong capacity of inhibiting peroxidation of macro-biomolecular and scavenging free redicals in vivo. Enzymatic hydrolysis used for preparation of antioxidative peptides is a new hot-spot in the field of natural antioxidants. It reacts under mild conditions, with accurate site-specific degradation, good repeatability and few damages to biological activity of protein. Substrates for enzymatic hydrolysis are usually plants and aqua-animals. Insects are also gaining attention because of their rich protein and resource. Antioxidative peptides are potential to be exploited as new natural antioxidant and functional food. There is a huge potential market in medical and cosmetic field as well.ResultProtein hydrolysate with antioxidant activity was prepared from housefly larvae, by a two-step hydrolysis. Through orthogonal optimization of the hydrolysis conditions, the degree of hydrolysis was determined to be approximately 60%. Fractionated hydrolysate at 25 mg/mL, 2.5 mg/mL and 1 mg/mL exhibited approximately 50%, 60% and 50% of scavenging capacity on superoxide radicals, 1, 1-Diphenyl-2-picrylhydrazyl radicals and hydroxyl radicals, respectively. Hydrolysate did not exhibit substantial ion chelation. Using a linoneic peroxidation system, the inhibition activity of hydrolysate at 20 mg/mL was close to that of 20 μg/mL tertiary butylhydroquinone, suggesting a potential application of hydrolysate in the oil industry as an efficient antioxidant. The lyophilized hydrolysate presented almost 100% solubility at pH 3-pH 9, and maintained nearly 100% activity at pH 5-pH 8 at 0°C- 4°C and room temperature during the first 6 months of storage. Essential amino acids in the hydrolysate accounted for 43% of the total amino acids.ConclusionsThe results suggesting that hydrolysate could be added to food oils as an efficient antioxidant. It might be useful for food additives, diet nutrients and pharmaceutical agents.

A full-scale house fly (Diptera: Muscidae) larvae bioconversion system for value-added swine manure reduction

Manure produced from confined animal farms can threaten public and environmental health if not managed properly. Herein, a full-scale commercial bioconversion operation in DeQing County, China for value-added swine manure reduction using house fly, Musca domestica L., larvae is reported. The greenhouse-assisted larvae bioreactor had a maximum daily treatment capacity of 35 m(3) fresh raw manure per day. The bioconversion process produced a fresh larvae yield of 95-120 kg m(3) fresh raw manure. This process provided an alternative animal foodstuff (having 56.9 and 23.8% protein and total fat as dry matter, respectively), as well as captured nutrients for agricultural re-utilization. Bioconversion reduced odour emission (characterized by 3-methylindole) and the Escherichia coli (E. coli) index by 94.5 and 92.0%, respectively, and reductions in total weight, moisture and total Kjeldahl nitrogen in solids were over 67.2, 80.0 and 76.0%, respectively. Yearly profit under this trial period ranged from US$33.4-46.1 per m(3). It is concluded that swine manure larvae bioconversion technology with subsequent production of value-added bio-products can be a promising avenue when considering a programme to reduce waste products in an intensive animal production system.

Evaluation of replacing various levels of dried broiler manure reared in cages containing house fly larvae in diet of local ducks 2- some physiological characters and gut measurements

Evaluation of replacing various levels of dried broiler manure reared in cages containing house fly larvae in diet of local ducks 2- some physiological characters and gut measurements

Inflammatory Regulation Effect and Action Mechanism of Anti-Inflammatory Effective Parts of Housefly (Musca domestica) Larvae on Atherosclerosis

The protein-enriched extracts of housefly larvae were segregated by gel-filtration chromatography (GFC) and then anti-inflammatory activity screening in RAW264.7 (induced by LPS) was carried out. After acquire the anti-inflammatory effective parts, its anti-atherosclerotic properties in vivo were then evaluated. Results showed that the anti-inflammatory effective parts of housefly larvae were low-molecular-weight parts. After treated with the effective parts oral gavaged for 4 weeks, the atherosclerotic lesions of the mouse were significantly decreased. The inflammatory and lipid parameters were also reduced (except HDL which was increased). Western blot analysis demonstrated that the effective parts exerted potent inhibitory effect on expression of p65 in nucleus and cytoplasm. The results of immunofluorescence microscopy analysis also showed that the expressions of p65 both in cytoplasm and nucleus were significantly reduced. The hypothesis that the anti-inflammatory effective parts of housefly larvae possessed anti-atherosclerosis activity in mouse and the possible mechanism could be associated with the inhibition of expression and nuclear transfer of NF-κB p65 could be derived.

Improvement of survival of the house fly (Musca domestica L.) larvae under mass-rearing conditions

Two new approaches were examined, aimed at increasing survival of the house fly (Musca domestica L.) larvae under mass-rearing conditions of a biodegradation facility: modification of the larval substrate and dispersal of the eggs during inoculation. The two types of pig manure used in this study (manure with sawdust and manure without sawdust) differed in terms of larval survival and nutritional value for the house fly larvae. Larval survival in manure without sawdust in the control treatment was low (46.8±2.1%) and its nutritional value for the larvae were high. Addition of 5.7% of previously biodegraded manure did not significantly affect larval survival (52.3±1.9%), but larval development was faster and the pupae were significantly smaller (14.28±0.4mg) compared to the control (16.29±0.5mg). Using alternative substrate for incubation of eggs and first-instar larvae significantly increased larval survival (63.3±3.3%) and decreased the mean weight of produced pupae (14.39±0.71mg). Overall, the weight of recovered biomass in the alternative substrate treatment increased by 14.3kg ton-1 of manure compared to the control. Larval survival in manure with sawdust was generally higher than 70%, but its nutritional value for the larvae was lower than in manure without sawdust. Dispersal of eggs over the surface of manure with sawdust significantly affected larval survival and mean weight of pupae. Larval survival was significantly lower (59.2±4.0%) and pupae were significantly heavier (18.45±0.8mg) when eggs were applied to a small area on the manure surface (spot treatment), as compared to diagonal, Z-line and multiple zig-zag dispersal (72.5±2.4 to 74.6±3.0% and 14.76±0.6 to 15.97±0.6mg, respectively). No significant differences were observed in larval survival or mean weight of pupae when comparing the diagonal, Z-line and multiple zig-zag dispersal patterns. Implementation of the techniques which improve larval survival and increase the weight of produced fly biomass may decrease demand for production of house fly eggs and, therefore, reduce the maintenance costs of adult colony, as well as increase the revenue earned by selling the products.

Preparation and characterization of Mentha × piperita oil emulsion for housefly (Musca domestica L.) control

Emulsified concentrate (EC) formulation of Mentha×piperita oil was prepared by taking (w/w) 40% oil, 45% aeromax, 3% butanol-1 and 12% surfactant (CABS-70 and NP-20 in variable ratio). Three ECs (designated as A, B and C) were screened amongst prepared ECs on the basis of physical criteria. Emulsions were assessed for their stability through creaming volume, particle size and zeta potential determination. Particle size of emulsions varied between 536.7 and 1133.6nm, while zeta potential value (−45.9 to −47.3mV) was strongly negative suggesting stability. Characterization of emulsion for its pH (≈6.6–7.5) and flash point analysis (≈90–92°C) indicated a stable formulation, which was safe to handle and transport. Prepared emulsions were stable at various temperatures (4–60°C), and showed a thin creaming layer at the upper surface without any phase separation, when subjected to centrifugation. Freeze/thaw cycles showed no visible change in appearance in EC ‘A’ and ‘B’, while EC ‘C’ showed tendency to rupture, i.e. dispersion of oil droplets in emulsion, after 6 cycles. Bioefficacy of EC ‘B’, adjudged as most stable emulsion, against adults of housefly (Musca domestica) showed 70–88% repellency with freshly prepared EC. The repellency decreased to 34–72% after 12 months storage at room temperature. Assay against housefly larvae showed an LC50 value of 0.08μL/cm2 (emulsion from freshly prepared EC) and 0.34μL/cm2 (emulsion from stored EC).

Housefly (Musca domestica L.) control potential of Cymbopogon citratus Stapf. (Poales: Poaceae) essential oil and monoterpenes (citral and 1,8-cineole)

In spite of being a major vector for several domestic, medical, and veterinary pests, the control aspect of the common housefly, Musca domestica L. (Diptera: Muscidae) is often neglected. In the present study, the essential oil of Cymbopogon citratus and its major components were evaluated for control of housefly. The chemical composition analysis of C. citratus oil by gas chromatographic mass spectrometry (GC-MS) revealed citral (47%) and 1,8-cineole (7.5%) as principal components. The analysis of oil vapor by solid phase microextraction (SPME/GC-MS) showed increase in citral (74.9%) and 1,8-cineole (8.6%) content. Assay of oil against housefly larvae and pupae through contact toxicity assay showed lethal concentration (LC)(50) value of 0.41μl/cm(2) and of percentage inhibition rate (PIR) of 77.3%, respectively. Fumigation assay was comparatively more effective with LC(50) of 48.6μl/L against housefly larvae, and a PIR value of 100% against housefly pupae. The monoterpenes, citral, and 1,8-cineole, when assessed for their insecticidal activity against housefly larvae, showed LC(50) of 0.002 and 0.01μl/cm(2) (contact toxicity assay) and LC(50) of 3.3 and 2.4μl/L (fumigation assay). For pupicidal assay, both citral and 1,8-cineole had a PIR value of 100%. High efficacy of citral and 1,8-cineole against housefly, established them to be an active insecticidal agent of C. citratus oil. The study demonstrates potentiality of C. citratus oil as an excellent insecticide for housefly control, and the results open up the opportunity of oil/monoterpenes being developed into an eco-friendly, economical, and acceptable product.

Effect of light regime on biochemical parameters of development of stress-reactions of Musca domestica L. Lines with different lifespan

The paper presents results obtained at recording under conditions of stresses of different character of activities of enzymes (tyrosinase, DOPA-oxidase, acetylcholinesterase) and level of the catecholamine content in tissues of head and fat body of imago and larvae of housefly from lines with different lifespan. A suggestion is put forward about different mechanisms mediating photoperiodic regulation of metabolism in individuals with different intensity of metabolism.

Observations on house fly larvae midgut ultrastructure after Brevibacillus laterosporus ingestion

The pathological and histopathological course caused by Brevibacillus laterosporus on house fly larvae has been investigated conducting observations on insect behavior and midgut ultrastructure. After dissection and fixation, gut tissues were analyzed under transmission electron microscopy (TEM) in order to compare in vivo-treated and non-treated (control) fly specimens. Treated larvae showed extensively reduced feeding and growth rate, then became sluggish and died within 72h. A progressive midgut epithelium deterioration was observed in treated larvae, compared to the control. Ultrastructural changes consisted of microvilli disruption, cytoplasm vacuolization and general disorganization, endoplasmic reticulum deformation, mitochondria alteration. Deterioration became progressively more dramatic until the infected cells released their content into the gut lumen. Disruption was associated also with midgut muscular sheath and connective tissue. These ultrastructural changes are similar to those widely described for other entomopathogenic bacteria, such as Bacillus thuringiensis, against different insect species.The rapid disruption of cellular fine structure supports a hypothesis based on an interaction of toxins with the epithelial cell membranes reminiscent of the specific B. thuringiensis δ-endotoxins mechanism of action on other insect targets.

Comparative evaluation of five Beauveria isolates for housefly (Musca domestica L.) control and growth optimization of selected strain

Pathogenic potential of five native Beauveria isolates was assessed against housefly adult and larvae in laboratory bioassays. Beauveria isolate Beauveria bassiana HQ917687 showed highest virulence with 72.3 and 100 % mortality of larvae and adults of Musca domestica, respectively. Other Beauveria isolates caused 36-52 % housefly larval mortality while the adult mortalities varied between 72 and 82 %. B. bassiana HQ917687 also showed the fastest killing activity with LT(50) of 4 days (for larvae) and 3 days (for adults). This isolate showing highest virulence was selected for its growth optimization in terms of biomass and spore production using response surface methodology. The optimum value of temperature, yeast extract, and pH for maximum biomass and spore production was predicted as 27 °C, 5.00 g/l, and 6.75, respectively. Temperature was found to be the most critical factor influencing biomass and spore yield of the fungus and even nullified the effects of other factors at sufficiently higher value. The results obtained in this study depict the significance of appropriate strain selection and process parameter optimization in order to facilitate mass production of biocontrol agents.

Molecular cloning and expression patterns of copper/zinc superoxide dismutase and manganese superoxide dismutase in Musca domestica

Superoxide dismutases (SODs) are metalloenzymes that represent one important line of defense against reactive oxygen species (ROS). In this paper, two novel SOD genes, MdSOD1 and MdSOD2, which putatively encode 261 and 214 amino acid residues respectively were identified and characterized from the housefly Musca domestica. The high similarity of MdSOD1 and MdSOD2 with SODs from other organisms indicated that they should be two new members of the SOD family. qPCR exhibited a universal expression of MdSOD1 and MdSOD2 detected in various tissues of housefly larva, including the fat body, gut, hemocyte and epidermis. Expression profiling reveals that MdSOD1 and MdSOD2 can be induced significantly via not only heat shock and cadmium (Cd) stress but also Escherichia coli and Staphylococcus aureus challenge. The two genes were cloned into the prokaryotic expression vector pET-28a to obtain the fusion proteins rMdSOD1 and rMdSOD2. Between them, the activity of rMdSOD2 was found by visual assay methods. ESI-LC–MS/MS analysis showed that three peptide fragments of the protein rMdSOD2 were identical to the corresponding sequence of M. domestica MdSOD2. MdSOD1 and MdSOD2 in housefly larvae were abrogated by feeding bacteria expressing dsRNA. High mortalities were observed in the larvae treated with dsRNA of SODs at heat shock, Cd stress and bacterial invasion. This phenomenon indicated that MdSOD1 and MdSOD2 are related to the survival of M. domestica under stress. This may provide new insights into the role of the two SOD genes in protecting M. domestica against both stress and bacterial invasion.

Swine manure vermicomposting via housefly larvae (Musca domestica): The dynamics of biochemical and microbial features

Improper handling of animal manure generated from concentrated swine operations greatly deteriorates water ecosystems. In this study, a full-scale vermireactor using housefly larvae (Musca domestica) was designed to investigate the effectiveness and efficiency of swine manure reduction, and to explore the associated biochemical–biological mechanisms. The one-week larvae vermireactor resulted in a total weight reduction rate of 106±17kg/(m3d) and moisture reduction of 80.2%. Microbial activities in manure decreased by 45% after vermicomposting, while the activities of cellulose, proteases, and phosphatases in the vermicompost were significantly 69 times, 48%, and 82% lower than those in raw manure, respectively. The vermicompost was exclusively dominated by Entomoplasma somnilux, Proteobacterium, and Clostridiaceae bacterium where the microbial diversity was decreased from 2.57 in raw manure to 1.77. Correlation coefficients statistic showed that organic C might be a key indicator of the biochemical features and microbial functions of the larvae vermireactor.

Adulticidal activity of some botanical extracts, commercial insecticides and their binary mixtures against the housefly, Musca domestica L.

Following preliminary screening of 13 ethanolic plant extracts, belonging to 10 different families, a total of 11 extracts were subjected to detailed toxicity evaluation against the larval stage of the housefly, Musca domestica L. The larvicidal LC50 values were < 100 ppm for Piper nigrum (50.1 ppm), Azadirachta indica (76.9 ppm), Conyza aegyptiaca (77.0 ppm) and Cichorium intybus (96.8 ppm); representing the highest potent extracts among the bioassayed candidates. Punica granatum extract exhibited the lowest toxicity (213.9 ppm). In comparison, commercial insecticides showed supe- rior larvicidal toxicity; accounting to the following LC50 values: 0.029, 0.03, 0.61 and 0.64 ppm for deltamethrin, metho- myl, chlorpyrifos and flufenoxuron, respectively. Combining botanical extracts with insecticides, at equitoxic dosages (e.g., LC25 values), induced potentiating effects for a 44 bioassayed mixtures against the housefly larvae. Moreover, mix- ing the insecticides at LC0 (a concentration level causing no observed mortality) with the LC50 of each of the plant ex- tracts have resulted in 44 paired combinations. Mostly, the factor; S.F. ranged between 1.6 - 1.9; giving rise to high synergistic effects. Specifically, the synergistic effect was much pronounced for mixtures of the insecticide del- tamethrin with different botanical extracts. Most of the tested toxicants induced different forms of developmental effects after exposure of 3 rd larval instars to sublethal concentrations (LC25 ppm). Larvae treated with A. indica, Citrus aurantifo- lia, Eucalyptus globulus (leaves or fruits), P. granatum, Salix safsaf, Sonchus oleraceus, Zea mays, as well as the insecti- cides chlorpyrifos, deltamethrin and methomyl failed to develop into adult stages. Morphologically, there were different forms of pupal and adult abnormalities, where the treatments of P. granatum and S. oleraceus caused abnormal pupal size in addition to pupal-adult intermediate. In the resulted Musca domestica adults, the effects were seen as one-winged in- sects, small size, compressed body and abdomen elongation. Such deformations were attributed to treatments of C. inty- bus, C. aegyptiaca, Piper nigrum and the IGR flufenoxuron. The overall results of the present investigation reveal the broad-spectrum toxic properties of the tested plant extracts against Musca domestica larvae; which may encourage further research on housefly control in tropics using indigenous plants.

Compositional analysis and insecticidal activity of Eucalyptus globulus (family: Myrtaceae) essential oil against housefly (Musca domestica)

The essential oil of Eucalyptus globulus (Myrtales: Myrtaceae) was evaluated for its chemical composition and insecticidal activity against the housefly, Musca domestica L. (Diptera: Muscidae). Chemical composition of E. globulus oil revealed 1,8-cineole (33.6%), α-pinene (14.2%) and d-limonene (10.1%) as major constituents, while vapour profile of E. globulus oil determined through solid phase microextraction (SPME) analysis showed 1,8-cineole (56.5%), α-pinene (16.9%), d-limonene (5.5%) and linalool acetate (3.4%) as principal components. Vapour phase of the oil showed increase in the contents of oxygenated monoterpenes. Insecticidal activity of E. globulus oil was assessed against larvae and pupae of housefly, through two different bioassays: contact toxicity and fumigation. Contact toxicity assay with larva showed lethal concentration, LC50, between 2.73 and 0.60μl/cm2 for different observation days while lethal time, LT50, varied between 6.0 and 1.7 days. In fumigant assay for housefly larvae, LC50 values of 66.1 and 50.1μl/l were obtained in 24h and 48h, respectively. Oil treated larvae showed surface shrinkage, spinous cells proliferation and bleb formation in scanning electron microscopy (SEM) observation. Pupicidal effectivity was measured in terms of percentage inhibition rate (PIR) which was 36.0–93.0% for contact toxicity and 67.9–100% for fumigation toxicity assay. Considerable activity of E. globulus oil against larvae and pupae of housefly demonstrates its potentiality as a viable option for the development of eco-friendly product for housefly control.

A Behavioral Method for Separation of House Fly (Diptera: Muscidae) Larvae From Processed Pig Manure

A behavioral method applicable in biodegradation facilities for separation of house fly (Musca domestica L.) larvae from processed pig manure is presented. The method is based on placing a cover over the larval rearing tray, while escaping larvae are collected in collection trays. Separation units must be placed in a dark room to avoid negative phototactic responses of the larvae. After 24 h of separation, over 70% of the larvae escaped from processed manure and were collected in collection trays. Most of the larvae pupated within 48 h after separation. Mean weight of pupae recovered from manure residue was not significantly different from mean weight of pupae of separated individuals. Eclosion rate of pupae recovered from manure residue was significantly lower than eclosion of separated individuals, and was strongly related to separation success. Factors responsible for escape behavior of larvae are discussed.

The antimicrobial activity of the alcohols fromMusca domestica

Information on the stimulatory and inhibitory effects of cuticular alcohols on growth and virulence of insecticidal fungi is unavailable. Therefore, we set out to describe the content of cuticular and internal alcohols in the body of housefly larvae, pupae, males and females. The total cuticular alcohols in larvae, males and females of Musca domestica were detected in comparable amounts (4.59, 3.95 and 4.03 μg g(-1) insect body, respectively), but occurred in smaller quantities in pupae (2.16 μg g(-1)). The major free alcohol in M. domestica larvae was C(12:0) (70.4%). Internal alcohols of M. domestica larvae were not found. Among cuticular pupae alcohols, C(12:0) (31.0%) was the most abundant. In the internal lipids of pupae, only five alcohols were identified in trace amounts. The most abundant alcohol in males was C(24:0) (57.5%). The percentage content of cuticular C(24:0) in males and females (57.5 and 36.5%, respectively) was significantly higher than that of cuticular lipids in larvae and pupae (0.9 and 5.6%, respectively). Only two alcohols were present in the internal lipids of males in trace amounts (C(18:0) and C(20:0)). The most abundant cuticular alcohols in females were C(24:0) (36.5%) and C(12:0) (26.8%); only two alcohols (C(18:0) and C(20:0)) were detected in comparable amounts in internal lipids (3.61±0.32 and 5.01±0.42 μg g(-1), respectively). For isolated alcohols, antimicrobial activity against 10 reference strains of bacteria and fungi was determined. Individual alcohols showed approximately equal activity against fungal strains. C(14:0) was effective against gram-positive bacteria, whereas gram-negative bacteria were resistant to all tested alcohols. Mixtures of alcohols found in cuticular lipids of larvae, pupae, males and females of M. domestica generally presented higher antimicrobial activity than individual alcohols. In contrast, crude extracts containing both cuticular and internal lipids showed no antifungal activity against the entomopathogenic fungus Conidiobolus coronatus, which efficiently kills adult house flies.

Bactericidal activity of Musca domestica cecropin (Mdc) on multidrug-resistant clinical isolate of Escherichia coli

The housefly (Musca domestica) larvae have been used clinically to cure osteomyelitis, decubital necrosis, lip boil, ecthyma and malnutritional stagnation ever since the Ming/Qing Dynasty (1368 Anno Domini) till now, in China. In prior research, we have cloned and characterized a new gene of antimicrobial peptide cecropin from M. domestica larvae. This peptide was potently active against Gram-positive and Gram-negative bacteria standard strain. In the present study, we evaluated the possibility of Mdc to be a potential bactericidal agent against clinical isolates of multidrug-resistant (MDR) Escherichia coli and to elucidate the related antimicrobial mechanisms. Antimicrobial activity assays indicated a minimal inhibitory concentration (MIC) of 1.56μM. Bactericidal kinetics at MIC showed that Mdc rapid killing of MDR E. coli. Lipopolysaccharide (LPS) dose-dependently suppressed Mdc antibacterial potency indicates that LPS is the initial binding site of Mdc in E. coli. Propidium iodide-based flow cytometry revealed that Mdc causes E. coli membrane permeabilization. Transmission electron micrographs further indicated that a remarkable damage in the bacteria's outer and inner membrane, even the leakage of cytoplasmic contents induced by Mdc. DNA binding experimental result implies that DNA is one of the possible intracellular targets of Mdc. Of note, Mdc did not show a perceptible cytotoxic effect on human red blood cells. Altogether, these results suggest that Mdc could be an excellent candidate for the development of more efficacious bactericidal agents.

Influence of diets on the rearing of predatory flies of housefly larvae

The purpose of this study was to evaluate the survival, development time and morphological measures of immature Ophyra aenescens and Ophyra albuquerquei on different diets. Different proportions of protein and carbohydrates were offered for each species in 10 vials containing 30 eggs each. The vials were placed in a germination chamber at 30°C, relative humidity above 75% and photoperiod of 12 hours. Every day a vial was removed and mortality was evaluated and on the tenth day the length of the cephalic-pharyngeal skeleton (EC) and body size (G) of larvae that survived were evaluated. Survival was higher in diets with more protein (P&lt;0.001). Between the species, mortality was more pronounced in O. albuquerquei in all diets (P&lt;0.001). The EC (P&lt;0.01) and G (P&lt;0.01) showed the same sizes in the diets with higher protein content. For the production of pupae of these species, the diet with more protein and fewer components is more appropriate, and the production is higher in O. aenescens than in O. albuquerquei.

Insecticidal Evaluation of essential oils of Citrus sinensis L. (Myrtales: Myrtaceae) against housefly, Musca domestica L. (Diptera: Muscidae)

The housefly, Musca domestica L., is one of the most common insects, associated with vectoring of various etiological agents. In order to search for effective control agent, the essential oil of sweet orange [Citrus sinensis (L.) Osbeck] was evaluated for its insecticidal activity against the larvae and pupae of housefly using contact toxicity and fumigation bioassays. In the contact toxicity assay, lethal concentration, LC(50) of C. sinensis essential oil against housefly larvae, varied between 3.93 and 0.71 μl/cm(2) for different observation days, while lethal time, LT(50), varied between 5.8 to 2.3 days. Mortality of larvae were significant with different concentrations (F = 2.79, df = 4, P < 0.05) and time (F = 6.69, df = 3, P < 0.01). In fumigant assay for housefly larvae, LC(50) of 71.2 and 52.6 μl/l was obtained in 24 and 48 h, respectively. Scanning electron microscopy of oil treated larvae revealed extreme dehydration and surface distortion while control larvae were free from any of the above symptoms and presented smooth surface, conforming effect of essential oil on housefly larvae. Percentage inhibition rate of oil against housefly pupae was 27.3-72.7% for contact toxicity and 46.4-100% for fumigation assay. Compositional analysis of C. sinensis essential oil using gas chromatography/mass spectrometry (GC-MS) revealed D: -limonene (73.24%), α-pinene (5.86%) and myrcene (4.45%) as major components whereas its vapour profile (solid-phase micro extraction-GC/MS) was dominated by D: -limonene at 92.57%. Significant activity of C. sinensis essential oil against larvae and pupae of housefly, pave the way for its use as eco-friendly housefly control measure.