RESUMO
Blow flies (Diptera: Calliphoridae) are frequently used in forensic investigations due to their rapid colonization of cadavers. As with other insects, environmental temperature strongly influences their developmental rates. While published research has typically explored not only the impact of the environmental temperature, but also of other factors like tissue type and drug presence on developmental rates, the influence of photoperiod on the developmental rates of forensically relevant blow fly species has remained largely underexplored. Understanding the relationship between photoperiod and developmental times is crucial, as neglecting this aspect could compromise the accuracy of minimum post-mortem interval (minPMI) estimations. The present study investigates the impact of three photoperiod conditions (0:24, 8:16, and 12:12 light:darkness) on the developmental rates of Calliphora vicina, focusing on the duration of the different immature stages and on the total developmental time. Our results revealed significant variation in the intra-puparial stage and total development time across different photoperiods. Notably, a 12:12 photoperiod led to a significantly prolonged intra-puparial stage and total development time compared to the 0:24 photoperiod, suggesting that Calliphora vicina develops faster in total darkness. These findings highlight the importance of considering photoperiod in both laboratory rearing protocols and forensic casework to improve the accuracy and reliability of minPMI estimations. In this regard, preliminary guidelines and recommendations are provided.
Assuntos
Calliphoridae , Entomologia Forense , Larva , Fotoperíodo , Pupa , Animais , Calliphoridae/crescimento & desenvolvimento , Calliphoridae/fisiologia , Pupa/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Comportamento Alimentar , Mudanças Depois da Morte , Dípteros/crescimento & desenvolvimentoRESUMO
Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae) has been collected in human forensic case work. This species is endemic in Malaysia but is not one of the most common species and is often found in outdoor cases. However, it is hypothesized that the presence of L. cuprina larvae may provide useful information in forensic case studies in Malaysia where this species has previously been ignored. This review will discuss the current background knowledge on L. cuprina, particularly when it comes to other forensic cases in Malaysia. General biology as well as key information for forensic work such as geographical distribution and developmental data will be reviewed. Finally, we discuss the potential for L. cuprina to provide beneficial and unique forensic insight into indoor cases with refuse.
Assuntos
Calliphoridae , Entomologia Forense , Larva , Animais , Malásia , Calliphoridae/crescimento & desenvolvimento , Humanos , Larva/crescimento & desenvolvimento , Comportamento Alimentar , Mudanças Depois da Morte , DípterosRESUMO
Recent studies on oestroidean Diptera (Brachycera) are providing a comprehensive and nuanced understanding of the evolutionary history of this remarkably diverse clade of holometabolous insects. The Oestroidea, which includes formidable pests such as various blowflies, botflies, and flesh flies that infest livestock, pets and humans, are mostly composed of beneficial species that act as scavengers or parasitoids on various pest insects. In our research, we used genomic methods to elucidate the phylogenetic position of Nesodexia corsicana Villeneuve, 1911 (Diptera: Calliphoridae), a mysterious oestroid species endemic to Corsica and characterized by distinctive morphological features that have puzzled taxonomists for years. Contrary to initial hypotheses, our results place Nesodexia Villeneuve, 1911 within the Calliphoridae subfamily Rhinophorinae, a small lineage of terrestrial isopod parasitoids. Through detailed morphological analysis of adults of both sexes and eggs, we uncovered significant insights consistent with our phylogenomic reconstruction. The unique morphological features of the species, coupled with its restricted and fragmented habitat, highlight its potential conservation importance. We delineated the area of occupancy for N. corsicana and assessed its "threatened" category using specific IUCN Red List criteria. In addition, we mapped the available habitat within its range and determined potential key biodiversity areas (KBA) triggered by N. corsicana. New potential KBAs are only partially covered by the Corsican Regional Park. Finally, we mapped the distribution of habitats on the island to assess the potential distribution of the species beyond its currently known geographic range.
Assuntos
Calliphoridae , Espécies em Perigo de Extinção , Filogenia , Animais , Calliphoridae/genética , Calliphoridae/crescimento & desenvolvimento , Masculino , Feminino , França , Dípteros/genética , Dípteros/classificação , Dípteros/anatomia & histologiaRESUMO
BACKGROUND: Flystrike, primarily caused by Lucilia cuprina, is a major health and welfare issue for sheep wool industries. Current chemical-based controls can have limited effectiveness due to the emergence of resistance in the parasite. RNA interference (RNAi), which uses double-stranded RNA (dsRNA) as a trigger molecule, has been successfully investigated for the development of innovative pest control strategies. Although RNAi offers great potential, the efficient identification, selection of target genes and delivery of dsRNA represent challenges to be overcome for the successful application of RNAi for control of L. cuprina. RESULTS: A primary L. cuprina (blowfly) embryo cell line (BFEC) was established and confirmed as being derived from L. cuprina eggs by PCR and amplicon sequencing. The BFECs were successfully transfected with plasmids and messenger RNA (mRNA) expressing fluorescent reporter proteins and dsRNA using lipid-based transfection reagents. The transfection of dsRNA into BEFC in this study suggested decreased mRNA levels of target gene expression, which suggested RNAi-mediated knockdown. Three of the dsRNAs identified in this study resulted in reductions of in target gene mRNA levels in BFEC and loss of biological fitness by L. cuprina larvae in a feeding bioassay. CONCLUSION: This study confirms that the novel BFEC cell line can be used to improve the efficacy of dsRNA-mediated screening to accelerate the identification of potential target genes in the development of RNAi mediated control approaches for L. cuprina. The research models established in this study are encouraging with respect to the use of RNAi as a blowfly control method, however further improvement and validation are required for field applicationsnot prefect, and could be ongoing developing. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Assuntos
Larva , Interferência de RNA , Animais , Larva/genética , Larva/crescimento & desenvolvimento , RNA de Cadeia Dupla/genética , Linhagem Celular , Controle de Insetos/métodos , Ovinos , Dípteros/genética , Calliphoridae/genética , Calliphoridae/crescimento & desenvolvimento , Genes de InsetosRESUMO
Ivermectin is one of the most widely used drugs for parasite control. Previous studies have shown a reduction in the abundance and diversity of "non-target" coprophilous organisms due to the presence of ivermectin (IVM) in bovine faecal matter (FM). Due to its breadth of behavioural habits, Calliphora vicina is a suitable dipteran species to evaluate the effects of IVM in FM. The aim of this work was to evaluate the effect of five concentrations of IVM in FM (3000, 300, 100, 30, and 3 ng/g) on the development of C. vicina. The following endpoints were evaluated: survival (between the first larval stage and emergence of new adults), larval development times to pupation and pupation times to adult, and adult emergence (% sex) and LC50. Sampling was performed from larval hatching at 60 and 120 min and at 3, 4, 5, and 12 h, and every 24 h specimens were weighed until pupae were observed. Data were analysed by ANOVA using a non-parametric Kruskal-Wallis test and as a function of elapsed development time and accumulated degree hours (ADH). Mortality at 3000 and 300 ng/g was 100% and 97%, respectively. There were statistically significant delays in adult emergence time (p = 0.0216) and in the ADH (p = 0.0431) between the control group (C) and 100 ng/g. The LC50 was determined at 5.6 ng/g. These results demonstrate the lethal and sub-lethal effects of IVM on C. vicina, while highlighting the usefulness of this species as a bioindicator for ecotoxicological studies.
Assuntos
Calliphoridae , Fezes , Ivermectina , Larva , Animais , Ivermectina/farmacologia , Calliphoridae/efeitos dos fármacos , Calliphoridae/crescimento & desenvolvimento , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Fezes/parasitologia , Bovinos , Análise de Sobrevida , Pupa/efeitos dos fármacos , Pupa/crescimento & desenvolvimento , Feminino , Antiparasitários/farmacologia , Masculino , Dose Letal Mediana , Dípteros/efeitos dos fármacos , Dípteros/crescimento & desenvolvimentoRESUMO
Blow flies (Diptera: Calliphoridae) are generally early colonisers of fresh cadavers, enabling the estimation of a minimum post-mortem interval (minPMI) based on an accurate aging of the oldest immature stages associated with a cadaver. In blow flies, the pupal stage and the subsequent development of the adult take place inside a protective case, the puparium, formed from the hardened and darkened cuticle of the third instar larva. Because the puparium is an opaque structure that shows virtually no external changes, qualitative analyses of the internal tissues can be very informative for determining reliable age-specific morphological markers. Those analyses can be performed using either non-invasive but expensive and not widely accessible techniques, or traditional histological methods, which are invasive as they require the serial sectioning of the sample. Histological methods are often readily available for forensic researchers and practitioners; however, the histological study of blow fly intra-puparial stages has traditionally been hampered by the poor paraffin infiltration of tissues due to the abundance of fat bodies, resulting in usually fragmented sections and the subsequent loss of relevant information. We present here an effective method for the preparation of histological sections of blow fly intra-puparial stages, maximising the paraffin infiltration while enabling the production of clean and entire sections that allow for the use of reliable age-specific morphological markers, thus improving the accuracy of minPMI estimations when access to more costly techniques is not feasible.
Assuntos
Calliphoridae , Entomologia Forense , Mudanças Depois da Morte , Pupa , Animais , Pupa/crescimento & desenvolvimento , Calliphoridae/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Inclusão em Parafina , Humanos , DípterosRESUMO
A carcass is defined as a temporary resource that can support high levels of diversity compared to other resources. The level of diversity often depends on the environmental conditions in which the corpse is found. Calliphoridae (Diptera) are the most important necrophagous insects used in forensic investigations because this family is common, widespread, abundant, and usually the first to colonize a corpse. However, understanding the processes responsible for variation in calliphorid species abundance and richness along gradients in ecology remains a key challenge. In this study, we analyzed the influence of altitude on the abundance and diversity of Calliphoridae species in corpses at three different altitudes (400, 900, and 1500 m a.s.l.) in a mountainous area of southeastern Spain. The results revealed a gradient of decreasing abundance with increasing altitude. An altitudinal substitution of species was observed, with Chrysomya albiceps being found at the lowest altitude and Calliphora vicina at the highest altitude. Seasonal variation was also noted, with Ch. albiceps being the dominant species in the warmer months and C. vicina being the dominant species in winter. Our results confirm the importance of Calliphorids as seasonal, altitudinal, and environmental indicators, given the wide distribution and abundance of this family. This information is of great interest on the interpretation of data in forensic practice.
Assuntos
Altitude , Calliphoridae , Comportamento Alimentar , Entomologia Forense , Estações do Ano , Animais , Espanha , Calliphoridae/crescimento & desenvolvimento , Humanos , Mudanças Depois da Morte , DípterosRESUMO
This study aimed to explore the rate of decomposition of rabbit carcasses and the succession pattern of the associated dipteran flies outdoor, indoor, and on the roof of a 4-story building during the summer and winter. A total of 6,069 flies were recorded, with 30.91% reported as 2 waves outdoor and on the roof in the summer and 69.09% as 4 waves outdoor in the winter. The roof showed the most flies in the summer but the least in the winter, whereas the outdoor showed the most in the winter but the least in the summer. The ground and first floors showed the most indoor flies, while the second and third floors showed the least in both seasons. Indoor carcasses decomposed slower than those outdoor, and those on the second and third floors decomposed slower than those on the ground and first floors. Ten fly species from 8 families were identified in the winter, compared to 6 from 5 families in the summer. The most abundant species was Musca domestica Linnaeus (Muscidae) on the roof in the summer, while it was Chrysomya albiceps (Wiedemannn) (Calliphoridae) outdoor in the winter. The rare species (singletons) were Musca sp. (Muscidae) and Megaselia scalaris (Loew) (Phoridae) on the first floor in both seasons, Scaptomyza pallida (Zetterstedt) (Drosophilidae) on the ground floor in the summer, and Atherigona orientalis Schiner (Muscidae) outdoor in the winter. These data highlight the variance in carcass decomposition and fly composition across outdoor, indoor, and the roof of human dwellings, which could be of forensic importance.
Assuntos
Dípteros , Entomologia Forense , Estações do Ano , Animais , Dípteros/fisiologia , Coelhos , Calliphoridae/crescimento & desenvolvimento , Mudanças Depois da Morte , CadáverRESUMO
This study determined a cost-effective larval diet for rearing Calliphora dubia Macquart for use as a potential managed pollinator in Australia. This fly has potential as a pollination species to support honey bees (Apis mellifera). Larvae of C. dubia were reared mostly in meat meals with varying amounts of either whole egg powder, whole eggs (+ shell), bran flakes, skimmed milk powder, brewer's yeast, or poultry oil. This was done from an economic and production perspective to support commercial rearing. Several laboratory-based studies determined the growth and output from various ingredient combinations. Larvae fed 90% meat meal and 10% whole egg powder developed rapidly through to pupation with a high pupation rate, adult size, and percent adult emergence. Given the high cost and difficulty in sourcing whole egg powder, media comprising mostly meat meals with the addition of bran flakes and whole eggs also supported rapid larval development, pupation rate, and adult emergence. The ideal amount of media/larvae was 0.5 g/larvae to support high pupation rates and adult emergence. Adult eclosion occurred over 4-5 days, even when larvae were laid and fed within 1 h on ample media. Commercial mass rearing would then require daily cohorts of larvae to ensure peak adult fly emergence over 1-2 days for release into a crop. Mass-rearing C. dubia should use meat meal as the base ingredient with bran flakes and whole eggs added and fed at 0.5 g of media/larvae. Based on the current media ingredient costs, rearing 1-m adult C. dubia would cost just over $500 (US$342).
Assuntos
Ração Animal , Calliphoridae , Larva , Animais , Larva/crescimento & desenvolvimento , Calliphoridae/crescimento & desenvolvimento , Ração Animal/análise , Dieta , Pupa/crescimento & desenvolvimento , Feminino , Dípteros/crescimento & desenvolvimento , Dípteros/fisiologiaRESUMO
Determining the minimum postmortem interval (minPMI) from an entomological perspective relies mainly on development data recorded for various species of flies collected from a crime scene or suspicious death. This study focused on the larval and pupal development of Lucilia sericata (Meigen), with an emphasis on the changes of the external morphology of the puparium and its pupal content throughout the duration of metamorphosis. Colonies of L. sericata were reared on 3 types of swine tissue (skeletal muscle, liver tissue, and heart tissue) at 2 different temperature regimes; 24â ±â 1 °C and 30â ±â 1 °C. The overall developmental time, larval width and length, and inner and outer pupal morphology changes were observed and recorded. The results show that: (i) temperature significantly influenced overall development time, as well as changes in larval width and length, but this effect was not dependent on tissue type; (ii) larval development duration was longest on heart tissue, and shortest on skeletal muscle for both temperatures; and (iii) pupation was longest for larvae reared on skeletal muscle at 24â ±â 1 °C, and on liver tissue at 30â ±â 1 °C, while those larvae reared on liver tissue at 24â ±â 1 °C and heart tissue at 30â ±â 1 °C had the shortest pupation period. A seven-character checklist plus 4 landmark stages were developed comprising the external morphology of the puparium and pupal content changes of L. sericata. In conclusion, the study provides larval and pupal development timetables, as well as checklists and photo guides for pupal character development that may be useful for future postmortem determinations.
Assuntos
Calliphoridae , Entomologia Forense , Larva , Pupa , Temperatura , Animais , Pupa/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/anatomia & histologia , Calliphoridae/crescimento & desenvolvimento , Suínos , Metamorfose BiológicaRESUMO
Accurate minimum post-mortem interval (minPMI) estimations often rely on a precise age determination of insect developmental stages, which is significantly influenced by environmental temperature. An optimal preservation of the entomological samples collected at crime scenes is pivotal for a reliable aging of immature insect samples. For blow flies (Diptera: Calliphoridae), the most widely used insect indicators in forensic investigations, an appropriate preservation of tissues is particularly important in the case of puparial samples because aging methods for intra-puparial forms usually depend on morphological analyses; however, although informative soft tissues and structures could be discoloured and/or distorted if they are not properly fixed, there is a lack of studies to assess different methods for the optimal preservation of intra-puparial forms collected in forensic investigations. The present study compares three preservation methods for intra-puparial forms of the blow fly Calliphora vicina Robineau-Desvoidy, 1830: (i) direct immersion into 80% ethanol, (ii) puncturing of the puparium and hot water killing (HWK) prior to preservation in 80% ethanol, and (iii) HWK without puncturing before preservation in 80% ethanol. External and internal morphological analyses of intra-puparial forms of different ages were conducted to assess the quality of preservation. The results indicate that direct immersion in ethanol led to poor preservation, affecting both external and internal tissues. Both methods with HWK resulted in a better preservation, but puncturing resulted, in some cases, in physical damage of the specimens. HWK without puncturing emerged as the optimal preservation method, consistently yielding high preservation scores for both external and internal morphological analyses. These findings have practical implications for forensic practitioners and emphasise the need for updating some published guidelines and protocols in forensic entomology.
Assuntos
Calliphoridae , Etanol , Entomologia Forense , Mudanças Depois da Morte , Pupa , Manejo de Espécimes , Animais , Calliphoridae/crescimento & desenvolvimento , Manejo de Espécimes/métodos , Imersão , Preservação Biológica/métodos , Temperatura AltaRESUMO
Many disciplines are utilized within the field of veterinary forensic sciences, including forensic entomology. Understanding the initial colonization period by flies of forensic importance can contribute to estimating the minimum postmortem interval. There is limited data regarding the time of colonization of animals with fur, and the interpretation of this data is difficult due to the variation in animal models used. The purpose of this study was to examine the initial insect colonization of cats (Felis catus), with light and dark fur. Twelve domestic short-haired cats were placed in cages 15.2 m apart in a grassy field in West Lafayette, IN, United States. Weather data (temperature, precipitation, sun/cloud exposure, humidity), insect activity, time to oviposition, and decomposition changes were documented. Eggs from initial oviposition events were collected and reared to identify the primary colonizing species. Although the time of first oviposition event was not different between the treatments, fur color did affect fly colonization, and cats with dark fur had more oviposition events than cats with light fur (tâ =â 2.639, dfâ =â 4, Pâ =â 0.029). Three species of Lucilia (Diptera: Calliphoridae) colonized the cats on the initial day of placement. Further studies in cats should include the decompositional studies to understand the unique characteristics that occur during each stage of decomposition, which could aid in developing a scoring system for animals with fur. Additional studies could include analyzing how fur length would affect colonization.
Assuntos
Calliphoridae , Entomologia Forense , Oviposição , Animais , Gatos , Calliphoridae/crescimento & desenvolvimento , Calliphoridae/fisiologia , Indiana , Feminino , MasculinoRESUMO
Flies of the family Calliphoridae, commonly called blow flies, are important in the decomposition process. Knowledge on their succession pattern on corpses, species identification and the duration of their life cycle stages can be useful in forensic investigations especially when estimating the post-mortem interval. We performed linear-based morphometrics on the cephalopharyngeal skeleton of four blow fly species found in Jamaica to distinguish species and determine larval development stage. We collected eggs from pigs' heads used as bait in the field and conducted rearing exercises in the laboratory. We used the internal skeletonized structure, the cephalopharyngeal skeleton, to develop a practical and efficient method for species identification. For the first instar, we found species can be differentiated using all the measurements analysed in the study. We found that the mouth hook length may be useful in distinguishing larvae in the second instar. For the larvae in the third instar, the whole length of the skeleton, from mouth hook to length of the dorsal cornue, may be useful for separating species. We provide information on the cephalopharyngeal skeleton of Lucilia lucigerens (James), a blow fly species endemic to Jamaica, for the first time. Our work provides relevant information that could be utilized for species identification and life stage determination if fly evidence is to be incorporated in forensic investigations in Jamaica.
Assuntos
Calliphoridae , Entomologia Forense , Animais , Calliphoridae/anatomia & histologia , Calliphoridae/crescimento & desenvolvimento , Jamaica , Larva , Suínos , Especificidade da EspécieRESUMO
Insect population control through continual releases of large numbers of sterile insects, called sterile insect technique (SIT), is only possible if one can mass-rear large quantities of healthy insects. Adaptation of insect stocks to rearing conditions and artificial feeding systems can have a multitude of negative effects such as inbreeding depression, reduced compatibility with wild strains, unintentional selection for traits that lower fitness after release, and an altered microbiome. Changes to insect microbiomes can have many effects on insects ranging from a reduction in sex pheromones or reduced fitness. Thus understanding these systems is important for mass rearing and the performance of the sterile insect control programs. In this study we explored the microbiome of the New World screwworm, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae) an economically important parasite of warm-blooded animals. Samples from myiases in cows and wild adults were compared to and mass-reared flies used by the SIT program. Significant differences were observed between these treatments, with wild captured flies having a significantly more diverse microbial composition. Bacteria known to stimulate oviposition were found in both wild and mass-reared flies. Two bacteria of veterinary importance were abundant in wild flies, suggesting screwworm is a potential vector of these diseases. Overall, this study provides the screwworm eradication program a platform to continue exploring the effects associated bacteria have on screwworm fitness.
Assuntos
Criação de Animais Domésticos/métodos , Calliphoridae/microbiologia , Microbiota , Animais , Bactérias/classificação , Bactérias/isolamento & purificação , Calliphoridae/crescimento & desenvolvimento , Bovinos , Doenças dos Bovinos/parasitologia , Larva/microbiologia , Panamá , Controle Biológico de Vetores/métodos , Infecção por Mosca da Bicheira/veterináriaRESUMO
Sex is a factor influencing development in many insect species, but is not widely studied in forensically important blow flies. If sex influences blow fly development, knowing the sex of a larva from a corpse can increase precision in estimates of that larva's age. The improved prediction of larval age will make estimates of time since death using entomological evidence better. Larvae lack sexually dimorphic morphological characteristics, so sex is not immediately known visually. To generate sexually dimorphic reference growth curves, a subsample must be large enough to ensure enough males and females are present for comparison. Using two entire age Chrysomya megacephala (Fabricius) cohorts, we evaluated the minimum sample number needed to have enough individuals of both sexes for comparison using 95% prediction intervals. Through a simulation of three trials of 1000 random replicates, we determined that a sample size of 19 would prevent any instance of a comparison not occurring because of insufficient sampling from one sex. As the current method for molecular sex determination can be expensive, we also compared how the results of various subsampling percentages compare those of the entire age cohorts. We found that subsampling at least 50% of an entire cohort leads to almost identical results in comparison to the entire age cohort. Together, these findings will help establish guidelines for generating sex-specific reference growth curves. A uniform approach to generating these sex-specific growth curves will lead to more consistency in age estimates made from them.
Assuntos
Calliphoridae/crescimento & desenvolvimento , Entomologia Forense/métodos , Animais , Larva/crescimento & desenvolvimento , Fatores SexuaisRESUMO
The geographic ranges of forensically informative taxa on decomposing remains vary across regions. To determine which calliphorid flies would be expected to occur in Minnesota and the upper Midwest, individual freshly killed pig carcasses (Sus scrofa L.) were placed in the field in St. Paul, MN, at monthly intervals from May to October 2017 and May to September 2018. Aerial nets, forceps, and pitfall traps were used to collect and preserve associated adult and immature insects. Sixty-four forensically informative insect taxa were recorded, representing three insect orders and 14 families. Ten informative calliphorid species were recorded on carcasses, adding four new Minnesota records. Comparison of species lists from 26 human forensic cases indicated agreement between the two lists, except for Lucilia coeruleiviridis Macquart, Calliphora vomitoria (L.), and Cynomya cadaverina Robineau-Desvoidy, which occurred on pig carcasses but not human remains, and Calliphora livida Hall, which occurred on human remains, but not carcasses. The composite fauna list from cadavers agreed largely with the 2-yr list from pig carcasses.
Assuntos
Biodiversidade , Cadáver , Calliphoridae , Entomologia Forense , Animais , Calliphoridae/crescimento & desenvolvimento , Humanos , Larva/crescimento & desenvolvimento , Minnesota , Sus scrofaRESUMO
Studies under constant temperatures are the most common to estimate the Postmortem Interval (PMI). It is imperative that forensic sciences have data from studies carried out in the field. Therefore, this work aims to: (1) evaluate the parameters (weight, length, development time) associated with the life cycles of Lucilia ochricornis (Wiedemann) (Diptera: Calliphoridae) and Lucilia purpurascens (Walker) under experimental conditions in the field considering fluctuating temperatures, and (2) compare these results with those known and published by the same authors for cultures realized in the laboratory under constant temperatures; which will permit us to contrast the most widely used existing methodologies for forensic application in estimating the minimum postmortem interval (PMImin). For each season of the year, cultures of both species were made in the field, collecting information on temperature, humidity, and photoperiod to perform laboratory cultures, later comparing: development time, length, weight, and Accumulated Degree-Hours (ADH) in both types of cultures. Methods for estimating the PMI were obtained and validated with the information of the cultures grown in the field. The two types of cultures showed differences between each other for both species. The forensic use methods to estimate PMI were enhanced and their precision increased when maximum larval length data were used, and it was also concluded that feeding larval stages are the most accurate to be used in making estimates because the larva is growing. The estimation of the PMI through the use of necrophagous flies development remains reliable for obtaining the PMImin.
Assuntos
Calliphoridae/fisiologia , Características de História de Vida , Animais , Argentina , Calliphoridae/crescimento & desenvolvimento , Temperatura Baixa , Feminino , Entomologia Forense , Temperatura Alta , Larva/crescimento & desenvolvimento , Larva/fisiologia , Masculino , Pupa/crescimento & desenvolvimento , Pupa/fisiologia , Estações do Ano , Especificidade da Espécie , TemperaturaRESUMO
The bioinsecticidal action of Pseudomonas protegens has so far been reported against some target insects, and the mode of action remains unclear. In this study, the pathogenicity potential of a recently isolated strain of this bacterial species against fly larvae of medical and veterinary interest was determined. Preliminary experiments were conducted to determine the biocidal action by ingestion against Musca domestica and Lucilia caesar larvae, which highlighted a concentration-dependent effect, with LC50 values of 3.6 and 2.5 × 108 CFU/mL, respectively. Bacterial septicaemia was observed in the body of insects assuming bacterial cells by ingestion. Such rapid bacterial reproduction in the hemolymph supports a toxin-mediated mechanism of action involving the intestinal barrier overcoming. In order to gain more information on the interaction with the host, the relative time-course expression of selected P. protegens genes associated with virulence and pathogenicity, was determined by qPCR at the gut level during the first infection stage. Among target genes, chitinase D was the most expressed, followed by pesticin and the fluorescent insecticidal toxin fitD. According to our observations and to the diversity of metabolites P. protegens produces, the pathogenic interaction this bacterium can establish with different targets appears to be complex and multifactorial.
Assuntos
Calliphoridae , Moscas Domésticas , Controle de Insetos , Pseudomonas/química , Animais , Calliphoridae/crescimento & desenvolvimento , Moscas Domésticas/crescimento & desenvolvimento , Larva/crescimento & desenvolvimentoRESUMO
Estimating the age of the developmental stages of the blow fly Calliphora vicina (Diptera: Calliphoridae) is of forensic relevance for the determination of the minimum post-mortem interval (PMImin). Fly eggs and larvae can be aged using anatomical and morphological characters and their modification during development. However, such methods can only hardly be applied for aging fly pupae. Previous study described age estimation of C. vicina pupae using gene expression, but just when reared at constant temperatures, but fluctuating temperatures represent a more realistic scenario at a crime scene. Therefore, age-dependent gene expression of C. vicina pupae were compared at 3 fluctuating and 3 constant temperatures, the latter representing the mean values of the fluctuating profiles. The chosen marker genes showed uniform expression patterns during metamorphosis of C. vicina pupae bred at different temperature conditions (constant or fluctuating) but the same mean temperature (e.g. constant 10 °C vs. fluctuating 5-15 °C). We present an R-based statistical tool, which enables estimation of the age of the examined pupa based on the analysed gene expression data.
Assuntos
Calliphoridae/crescimento & desenvolvimento , Calliphoridae/genética , Expressão Gênica , Metamorfose Biológica , Pupa/crescimento & desenvolvimento , Pupa/genética , Temperatura , Animais , Entomologia Forense , Perfilação da Expressão GênicaRESUMO
Myiasis is a parasitosis characterized by an infestation of living vertebrates (humans and other animals) by Diptera larvae, whose occurrence and etiological identification are still neglected by health professionals. Here we analyzed the human myiasis cases registered from 2010 to 2018 in health care units in the municipality of Natal, Northeast region of Brazil. Specifically, we aimed to: I) analyze the medical records of cases documented from 2010 to 2017; II) list the patients predisposing factors; and III) monitor the recent cases diagnosed in health units between August 2017 and March 2018 and report the taxonomic identity of the infesting species. Our data revealed that myiases mainly affect the elderly and individuals with predisposing medical conditions (e.g. senility, filariasis). Regarding the new cases, larvae of Calliphoridae (C. hominivorax (Coquerel, 1858)) and Sarcophagidae [Sarcophaga (Liopygia) ruficornis (Fabricius, 1794), Peckia (Sarcodexia) lambens (Wiedemann, 1830), and Helicobia morionella (Aldrich, 1930)] were identified. Furthermore, this was the first report of a co-infestation with three Sarcophagidae species and also the presence of H. morionella in a human wound. These results reinforce that myiasis is an underreported parasitosis, which may underestimate the ability of previously unreported fly species to feed on living human tissues in the Neotropical Region.