Alternative diets for Chrysomya putoria, an Old World screwworm fly

Biological behavior of Chrysomya putoria (Wiedemann, 1819) (Diptera: Calliphoridae) after refrigeration: Logistics for use in Biotherapy

The influence of refrigeration on the post-embryonic development of Chrysomya putoria larvae was evaluated, regarding its resistance in the logistics of storage and distribution in biotherapy. Previously sterilized larvae were submitted to four periods of storage under refrigeration (T1=12 h, T2=24 h, T3=48 h and T4=72 h) and control (without sterilization and refrigeration). Newly hatched larvae (0.200 g) were stored between 3 and 9ºC. After refrigeration, 40 neo-larvae (in triplicate) were transferred to 50 g of protein diet and incubated in an acclimatized chamber. There was a significant difference in the larval body mass (T1 and T2) and in the duration of larval, pupal and total development (T3 and T4). The sex ratios found in the four treatments did not differ from what was expected. Normality rates were 100% for all treatments. There was no significant difference between the Control, T1 and T2 treatments for larval, pupal and total viability. There was a significant difference between control (C) and T4 (larval viability), between C, T3 and T4 (pupa) and between C and T4 (total). C. putoria has resistance under refrigeration and storage of up to 56 h, presenting viability above 70% for use in biotherapy.

Biological Response of Chrysomya putoria (Wiedemann, 1818) (Diptera: Calliphoridae) Pupae After Submersion in Freshwater

Forensic Entomology uses arthropods to aid in legal investigations. This study checked the biological response of Chrysomya putoria pupae to submersion in fresh water for up to 6 d, evaluating the critical submersion time, survival rate, and development time of the flies. Adults were collected using fish baits in two typical traps. Seven hundred and twenty fourth-generation pupae with 2 d of development were used and separated into submergence intervals: 24, 48, 72, 96, 120, and 144 h. An additional 120 pupae were used as a control. Each treatment was done in triplicate, consisting of 40 pupae distributed in four tulle-sealed test tubes containing 10 pupae each. All tubes of each treatment were co-adhered in test tube racks and were submerged in mineral water in a container with constant oxygenation, except those of the control group, which were not submerged. The tubes were removed from the water according to their respective submersion interval, until 144 h was completed. The control group had a survival rate of 90%, while the 24-h treatment had 85% and the 48-h treatment had 35.8%. The critical submersion time for pupae was 72 h, with 100% mortality by 144 h. The average development time for the control group was 3.2 d, while the 24- and 48-h treatments developed in 4.3 and 6.3 d, respectively. The longer the individuals were submerged, the lower the survival rate was, while the development time increased. The data obtained in this study have potential in applications to estimate the interval of submersion of a cadaver.

Evaluation of Chilean Boldo Essential Oil as a Natural Insecticide Against Chrysomya megacephala (Diptera: Calliphoridae)

Chrysomya megacephala (Fabricius, 1794) is a vector of enteric bacteria, protozoa, helminths, and viruses. These Diptera can also be responsible for secondary myiasis in several animal species. Therefore, it is easy to understand the relevance of studies focusing on C. megacephala dissemination control. The employment of essential oils as natural insecticides must be considered as a promising alternative for the replacement of synthetic insecticides. In this context, the essential oil obtained from Chilean boldo leaves should be highlighted. The aim of the present work was to assess the insecticidal activity of Chilean boldo essential oil against C. megacephala blowflies in different life stages (larva, pupa, and adult). The essential oils were extracted from commercial samples of Chilean boldo leaves by hydrodistillation and were mixed to produce a pool that was employed in the study. Gas chromatographic techniques were used to enable the identification and quantification of the pool's components. Larvae, pupae, and adult insects of C. megacephala were exposed (topical application) to different concentrations of this essential oil pool. After that, the larvicidal, pupicidal, and insecticidal actions of the oil were tested. Its toxicity might be associated with compounds such as eucalyptol, linalool, α-pinene, limonene, and ascaridole, either acting alone or by synergic effects. Interestingly, the pupae appeared to be stronger than the larvae and adult insects, needing higher doses of essential oil to be killed. The oil's toxic effects could be useful to control C. megacephala dissemination in all of its development phases.

Desenvolvimento pós-embrionário de Chrysomya putoria (Calliphoridae) em carne equina e sua importância para a entomologia e veterinária forenses

RESUMO Devido à importância médica, veterinária, ambiental e forense do califorídeo Chrysomya putoria (Diptera), foi avaliado o desempenho apresentado por estágios imaturos criados em carne de cavalo. Os espécimes foram colocados em câmaras aclimatizadas reguladas a 30 ºC, 60 ± 10% UR e 14 horas de fotofase. Os estágios larval e pupal concluíram seu desenvolvimento em 4,16 e 4,12 dias, respectivamente. As larvas pós-alimentação e pupas com 24h de idade pesaram, em média, 58,06 e 40,10mg, respectivamente. As taxas de emergência registradas foram de 65% nas condições experimentais propostas. Como os compostos orgânicos voláteis são diferentes na decomposição de um animal para outro, este trabalho e outros realizados com a mesma dieta são os mais apropriados para estimativa de intervalo post mortem envolvendo cavalos.

Evaluation of the influence of the antibiotic ciprofloxacin in the development of an Old World screwworm fly, Chrysomya putoria

Chrysomya putoria (Wiedemann) (Diptera: Calliphoridae), an Old World screwworm fly, is a species with potential for maggot therapy practice and has been described in myiasis and forensic entomology studies. The objective of the present study was to assess the action of different ciprofloxacin concentrations on the growth and development of C. putoria. First instar maggots of the third generation were raised on 60 g of chicken gizzard homogenate in 65% agar diet and received ciprofloxacin chloridrate. Each concentration of the antibiotic tested (3.33 µg/mL, 6.66 µg/mL, and 13.33 µg/mL) and the control (no antibiotic) were replicated four times (40 maggots/replication). The control received distilled water instead of the antibiotic. Maggots were kept in an acclimatized chamber at 30° C during the day and 28° C at night, with 70 + 10% RH and a 14:10 L:D photoperiod. They were weighed in batches of five and stored in test tubes sealed with nylon fabric and elastic. Microsoft Excel and STAT were used for the analysis. The variation among the maggot weight means and the duration of the maggot stage, pupal stage, and time to total development (neolarvae to adult) were analyzed by Student's t-test (α= 5%). The viabilities and the normality rates were compared using ANOVA, and the expected sex ratio frequency was tested by the chisquared test (χ(2)). There was no significant difference among the four treatments regarding mean individual maggot weight, mean duration of the maggot inoculation until abandonment, the duration of the maggot and pupal stages, and the total duration of all stages. The sex ratios found in the four treatments did not differ from the expected. Only treatment 2 (6.66 µg/mL concentration of ciprofloxacin) differed significantly from the control in maggot and total viability. The antibiotic did not seem to alter C. putoria development in the postembryonic period.

Effects of the antibiotics Gentamicin on the postembryonic development of Chrysomya putoria (Diptera: Calliphoridae)

We evaluate the effects the antibiotic Gentamicin on the development of Chrysomya putoria (Wiedemann, 1818). Third-generation, first-instar larvae were reared in a climatic chamber on 60 g of homogenate + agar 65% and were treated with three concentrations of Gentamicin: 4.44 mg/ml, 13.33 mg/ml, and 66.66 mg/ml. The control consisted of distilled water. The relationships between mean body mass of mature larvae (measured after diet abandonment, in batches of five individuals), duration of larval and pupal stages, and overall duration of development were analyzed. The actual sex ratio was compared against the expected using the chi square. None of the parameters measured differed significantly among the four treatments, with one exception: when Gentamicin concentration was 13.33 mg/ml, larval viability differed significantly from the control. All larvae from all treatments were considered normal. We conclude that the antibiotic did not significantly alter the development of C. putoria (Wiedemann) (Diptera: Calliphoridae).

Sterilization of Chrysomya putoria (Insecta: Diptera: Calliphoridae) eggs for use in biotherapy

Large-scale, quality-controlled laboratory production of fly larvae is needed for biotherapy. The objective of this study was to assess the action of glutaraldehyde on the sterilization of Chrysomya putoria eggs by applying pharmaceutical sterility tests. Egg masses with 0.600 g were divided into three parts of 0.200 g, the eggs were separated using sterile distilled water, and the suspensions obtained were mixed with activated 2% glutaraldehyde solution. After 15-min contact, the suspensions were filtered through Whatman filter paper, and the glutaraldehyde residue obtained in the filtrate was neutralized by rinsing with Tryptone Soy Broth. The treated eggs were placed aseptically on Petri dishes containing gauze moistened with sterile saline solution. About 10% of the sterilized mass was transferred to test tubes containing Tryptone Soy Broth and Fluid Thioglycollate Broth. The tubes were incubated, respectively, at 22.5 and 35.0°C for 14 d to verify egg mass sterility. The plates containing the rest of the eggs (90%) were sealed with plastic film and kept in a climatized chamber at 30°C/d, 28°C per night, 60 ± 10% relative humidity, and under a 12-h light period to assess insect viability and survival. Each experiment was carried out in triplicate using a biological class II safety cabinet. No change in color or turgidity was observed with the agent tested, proving the sterility of the product and that there was no trace of contamination. Forty larvae (in three replications) in the periods of 12, 24, and 48 h after sterilization, when transferred to diet, produced larvae, pupae, and total viability similar to the control (larvae without sterilization). However, for the 72-h treatment, larvae and total viability were significantly lower than for the other treatments. There was no significant difference for the pupal stage. The product tested was shown to be efficacious for use as a sterilizer of C. putoria eggs for all the parameters assessed.