Identification of Escherichia coli isolated from flies (Insecta: Diptera) that inhabit the environment of dairy farms harboring extraintestinal virulence markers.

AIMS: We investigate extraintestinal pathogenic genes (ExPEC) related to virulence of Escherichia coli in flies from the dairy environment. METHODS AND RESULTS: We collected 217 flies from nine dairy farms, which were submitted to microbiological culture. Fifty-one E. coli were identified using mass spectrometry. Eleven dipteran families were identified, with a predominance of Muscidae, and a minor frequency of Tachinidae, Drosophilidae, Sphaeroceridae, Ulidiidae, Syrphidae, Chloropidae, Calliphoridae, Sarcophagidae, and Piophilidae. A panel of 16 virulence-encoding genes related to ExPEC infections were investigated, which revealed predominance of serum resistance (traT, 31/51 = 60.8%; ompT, 29/51 = 56.9%), iron uptake (irp2, 17/51 = 33.3%, iucD 11/51 = 21.6%), and adhesins (papC, 6/51 = 11.8%; papA, 5/51 = 9.8%). CONCLUSIONS: Our findings reveal Dipterans from milking environment carrying ExPEC virulence-encoding genes also identified in clinical bovine E. coli-induced infections.

Forensically Relevant Flesh Flies (Diptera, Sarcophagidae, Sarcophaginae) of Southern Brazil.

Flesh flies comprise a large fly family distributed worldwide that has great importance for forensic entomology. A robust and updated checklist of Sarcophaginae flies recorded in Southern Brazil is presented, based on material collected in the Rio Grande do Sul state and on a literature review. The forensic importance (high, moderate, or none) of the recorded flesh flies for estimating the postmortem interval (PMI) or inferring cases of neglect was determined based on their ecological habits. A total of 2,831 specimens representing 38 taxa were collected from three studies. Oxysarcodexia was the most abundant and species-rich genus in all three studies. Dexosarcophaga carvalhoi (Lopes) was registered for the first time in Southern Brazil. The checklist for Southern Brazil comprises 91 species distributed in 19 genera, with Oxysarcodexia, Peckia, and Lepidodexia representing the richest genera. Considering the importance of species for PMI estimation, 10, 42, and 39 species were classified as having high, moderate, or no forensic relevance, respectively. Moreover, five myiasis-causing sarcophagine flies recorded in Southern Brazil were considered to have the potential to reveal cases of neglect or mistreatment. This study revealed that Microcerella halli (Engel) and Peckia (Euboettcheria) australis (Townsend) are the most important species for PMI estimation in Southern Brazil, as they are often found breeding in corpses in this region.

Factors Affecting the Composition and Succession of Beetles in Exposed Pig Carcasses in Southern Brazil.

Coleoptera is one of the largest taxon among animals and exhibits diverse eating habits. When associated with decaying corpses, beetles can be of great value in estimating the postmortem interval. In order to consolidate a useful database for the forensic field, it is necessary to study the entomological fauna associated with the carcasses in different geographical regions since the diversity of insects varies according to the biogeoclimate zone. Thus, this study aimed to assess the influence of environmental and ecological factors on the composition and succession of beetles associated with pig carcasses exposed in southern Brazil. Collections were carried out during the hot/dry and cold/wet seasons. A total of 415 specimens belonging to 18 Coleoptera families were sampled. The highest total abundance (n = 329) and diversity (n = 44 taxa) were recorded in the cold/wet season, corresponding to approximately 80% of the total sampled from the two seasons. Dermestidae (26.7%) was the family most abundantly sampled. Regarding eating habits, in an increasing order of importance were necrophagous (43.3%), predator (31.6%), and omnivorous (0.05%). In the hot/dry season, there was no faunal succession. In the cold/wet season, the succession was more associated with differences in abundance than to the presence or absence of a specific taxon by decomposition stage. Considering all the factors analyzed in the current study, three species of beetles, Dermestes maculatus DeGeer (Dermestidae), Euspilotus azureus (Sahlberg, 1823) (Histeridae), and Oxelytrum discicolle Brullé, 1840 (Silphidae), could be identified as being of the greatest forensic relevance in this biogeoclimatic zone.

Synanthropy of Sarcophaginae (Diptera: Sarcophagidae) From Southern Brazil and Its Sanitary Implications.

Although different feeding habits have been reported for Sarcophaginae (Diptera, Sarcophagidae), most species are associated with decomposing organic matter such as feces and decaying corpses. This study provides the synanthropy index for males of species of Sarcophaginae collected during a 12-mo period in three different environments (urban, rural, and wild) of the state of Rio Grande do Sul, in Southern Brazil, linking this parameter with the sanitary issue. This article also investigated the presence of pathogenic bacteria on the external surface of Oxysarcodexia paulistanensis (Mattos), the most abundant species collected using a sanitized entomological net. Almost all the species collected most abundantly, including O. paulistanensis (n = 241), Ravinia advena (Walker) (n = 87), and O. thornax (Walker) (n = 58), were classified as synanthropic; O. thornax was the species with the highest synanthropy index (+80.3). Escherichia coli (Escherich), Shigella spp. (Enterobacteriaceae), and Staphylococcus aureus (Rosenbach) (Staphylococcaceae) were isolated and identified from the external surface of O. paulistanensis. The isolation and identification of pathogenic bacteria, and their synanthropic behavior, adds weight to potential role of some flesh flies, as O. paulistanensis, in a sanitary context.

The risk of oral transmission in an area of a Chagas disease outbreak in the Brazilian northeast evaluated through entomological, socioeconomic and schooling indicators.

Chagas disease is a neglected tropical disease strongly associated with low socioeconomic status, affecting nearly 8 million people - mainly Latin Americans. The current infection risk is based on acute case reports, most of which are typically associated with oral transmissions. In the semi-arid region of Northeastern Brazil, serious outbreaks of this transmission type have surged in the last years. One of those occurred in 2016 in the state of Rio Grande do Norte. Rural residents of four municipalities surrounding Marcelino Vieira ingested sugar cane juice - which was probably ground with Trypanosoma cruzi-infected insects. Eighteen cases of Chagas disease were confirmed serologically, with two deaths reported. Socioeconomic information, schooling of residents and the structure of peridomestic and domestic environments in the rural area of Marcelino Vieira, along with entomological indicators, were investigated to understand better the factors related to the outbreaks in this region. We found triatomines (mainly Triatoma brasiliensis) in 35% (24/67) of domiciliary units and all rocky outcrops inspected (n = 7). Overall, 25% (91/357) of examined T. brasiliensis were infected by T. cruzi in artificial ecotopes, with almost the same prevalence in the sylvatic environment (22%; 35/154). Among all ecotopes investigated, wood/tile/brick piles were the ones linked to high insect infestations and triatomine T. cruzi infection prevalence. Ninety-five percent of people interviewed recognized the triatomines and knew the classic route of transmission of disease - triatomine bite-dependent. However, only 7.5% admitted knowledge that Chagas disease can also be acquired orally - which poses a risk this transmission route currently recognized. Here, we highlight the physical proximity between humans and triatomine populations with high T. cruzi infection prevalence as an additional risk factor to oral/vector contaminations. In sum, residents have low income, low level of education, and/or a willful disregard for the routes of Chagas disease transmission (specifically oral transmission), a combination of factors that may have favored the Chagas disease outbreak. We here provide recommendations to avoid further outbreaks.

First description of the immature stages of Fannia sabroskyi Seago, 1954 (Insecta, Diptera, Fanniidae).

Egg, larvae and the puparium of Fannia sabroskyi Seago, 1954 (Diptera, Fanniidae) are described and illustrated for the first time. The following structures have been documented: pseudocephalon, antennal complex, maxillary palpus, facial mask, anterior spiracle, cephaloskeleton structures, thoracic and abdominal processes, anal division, and posterior spiracle. Due to its necrophagous habit, this species may be of potential forensic importance for estimating the postmortem interval in criminal investigations. The information presented herein may be useful to distinguish the immature forms of Fannia species and to supplement the database for identification of Neotropical species of Fanniidae. In addition, it is also important for evolutionary and phylogenetic studies.

Drivers of molecular and morphometric variation in Triatoma brasiliensis (Hemiptera: Triatominae): the resolution of geometric morphometrics for populational structuring on a microgeographical scale.

BACKGROUND: The protozoan Trypanosoma cruzi circulates in semiarid areas of northeastern Brazil in distinct ecotopes (sylvatic, peridomestic and domestic) where Triatoma brasiliensis Neiva, 1911 is the most important Chagas disease vector. In this study, we analyzed microevolutionary and demographic aspects of T. brasiliensis populations at the ecotypic, micro and macro-geographic scales by combining morphometrics and molecular results. Additionally, we aimed to address the resolution of both markers for delimiting populations in distinct scales. METHODS: We sampled populations of T. brasiliensis from distinct ecotypic and geographic sites in the states Rio Grande do Norte (RN) and Paraíba (PB). The geometric morphometry was carried out with 13 landmarks on the right wings (n = 698) and the genetic structure was assessed by sequencing a region of cytochrome b mitochondrial gene (n = 221). Mahalanobis distance (MD) and coefficient of molecular differentiation (ΦST) were calculated among all pairs of populations. The results of comparisons generated MD and ΦST dendrograms, and graphics of canonical variate analysis (CVA). RESULTS: Little structure was observed for both markers for macro-geographic scales. Mantel tests comparing geographic, morphometric and genetic matrices showed low correlation (all R2 < 0.35). The factorial graphics built with the CVA evidenced population delimitation for the morphometric data at micro-geographic scales. CONCLUSIONS: We believe that T. brasiliensis carries in its genotype a source of information to allow the phenotypical plasticity across its whole distribution for shaping populations, which may have caused a lack of population delimitation for CVAs in morphometric analysis for macro-geographic scale analysis. On the other hand, the pattern of morphometric results in micro-geographic scales showed well-defined groups, highlighting the potential of this tool to inferences on the source for infestation.

Clinical study of Maggot therapy for Fournier's gangrene.

Fournier's Gangrene is a fulminating necrotizing fasciitis of the perineum and genitalia. Standard treatment involves immediate excision of all necrotic tissue, aggressive antibiotic coverage, and supportive medical care. Still, the infection is commonly fatal or disfiguring. Wound treatment with disinfected blowfly larvae (maggot debridement therapy or MDT) has been shown to be highly effective, with multiple studies demonstrating effective debridement, disinfection, and promotion of granulation tissue. MDT also has been associated with preservation of viable tissue and minimised blood loss. This report describes a prospective clinical study of MDT for Fournier's gangrene aimed to test the hypothesis that early use of maggots could decrease the number of surgical treatments required to treat Fournier's gangrene. Subjects were provided with one initial surgical excision, followed by debridement using only medical grade Lucilia sericata larvae. Only two subjects were enrolled, both diabetic men. Intensive care and culture-directed antimicrobial coverage were administered as usual. Maggot debridement was associated with the disappearance of necrotic tissue, control of infection and granulation tissue growth. In both subjects, wounds healed without requiring further surgical resection or anatomical reconstruction. Maggot therapy decreased the number of surgical procedures that otherwise would have been necessary, and led to favourable outcomes.

First molecular phylogeny of Paralucilia Brauer & Bergenstamm, 1891 (Insecta, Diptera, Calliphoridae): A preliminary approach.

Paralucilia Brauer & Bergenstamm, 1891 (Diptera, Oestroidea, Calliphoridae) is a small genus of blowflies restricted to the Neotropical region, which is commonly reported on decaying corpses and vertebrate carcasses. The number of species currently assigned to this genus and their denominations are contentious, with either three or five species recognized by different authors. This taxonomic instability results in a lack of consensus in species determination, making it impossible to compare results from different studies as well as to elaborate confident taxonomic keys. In order to solve some of the most commonly reported taxonomic conflicts within this genus, to the best of our knowledge, this study presents the first phylogenetic hypothesis for the relationships among Paralucilia species, based on molecular analysis of the COI, ITS2, 28S, and 16S genes. Maximum parsimony, maximum likelihood, and Bayesian inference analyses were used for phylogenetic reconstruction and divergence time estimation analyses. Intra- and interspecific genetic distances were calculated among species using the COI dataset. The results showed that at least three of the five currently accepted species are well defined: P. fulvinota, P. pseudolyrcea, and P. paraensis, however, a significant level of intraspecific variation was observed in P. fulvinota. These findings will assist future revisions of the description, classification, and distribution of species of Paralucilia, as well as in the elaboration of taxonomic keys. Additionally, we show that it is possible to clarify the evolutionary history of this Neotropical genus using supplementary evidence such as morphology and molecular data.

In vitro evaluation of the association of medicinal larvae (Insecta, Diptera, Calliphoridae) and topical agents conventionally used for the treatment of wounds.

Wound healing is a complex process involving multiple biochemical and cellular events and represents a neglected public health issue. As a consequence, millions of people worldwide suffer from chronic wounds. The search for new treatment alternatives is therefore an important issue. In the context of wound healing, Maggot Debridement Therapy (MDT) is an inexpensive treatment with few contraindications and very promising results. This study aimed to evaluate the in vitro feasibility and implications of larvae (= MDT) use when combined with topical agents as a strategy to identify additive or synergistic combinations. The weight and survival rate of Cochliomyia macellaria (Fabricius) (Insecta, Diptera, Calliphoridae) larvae reared in an in vitro wound with either honey, hydrogel, 10% papain gel, essential fatty acids (EFA), collagenase, or silver sulfadiazine were evaluated after 24, 48 and 72 h. Hydrogel (for weight: 24 and 72 h; for survival: 24 h) and 10% papain gel (for weight: 48 h; for survival: 48 and 72 h) demonstrated the least interference in larval weight gain and survival rate, when compared to the control group. The results obtained in this study showed that the combined use of larvae and hydrogel or 10% papain gel may be promising to maximize the tissue repair. Honey, EFA and collagenase could be used to prepare the bed of the dry wounds to receive the MDT.

Redescription and new records of Ontholestes brasilianus Bernhauer, 1906 (Coleoptera: Staphylinidae: Staphylininae).

The genus Ontholestes Ganglbauer includes 35 species distributed mainly in Eurasia, with a few additional species in Africa and North and South America (Herman, 2001; Yang Zhou, 2012; Smetana Shavrin, 2013; Rougemont, 2016). According to Asenjo et al. (2013), the South American record of the Palearctic species Ontholestes murinus (Linnaeus, 1758) for Brazil made by J. Guérin (1953) seems doubtful. Ontholestes murinus was recorded for the first time outside the Palaearctic region by Smetana (1981), from Newfoundland, in Canada, as an adventive species (e.g., Downie and Arnett, 1996; Brunke et al., 2011), but its occurrence in Brazil remains to be confirmed; if the Guérin (1953) record was based on a mistaken identification or mislabeled specimen, this would reduce the number of species distributed in this region from two to one. With respect to O. brasilianus Bernhauer, although it has been confirmed for Peru, Brazil and Argentina (Herman, 2001; Asenjo et al., 2013; Newton, 2015; Newton Caron, 2015), no specific localities of occurrence have been reported since its description in 1906. Thus, to solve problems of misidentification with Neotropical species of this genus, in this study we redescribe Ontholestes brasilianus and provide the first illustrations of the beetle including its aedeagus and a short key for South American species. Additionally, new records from South America are listed here.

Attraction and Oviposition of Lucilia eximia (Diptera: Calliphoridae) to Resources Colonized by the Invasive Competitor Chrysomya albiceps (Diptera: Calliphoridae).

The present study aimed to determine if the presence of immatures of the invasive blow fly species Chrysomya albiceps (Wiedemann) influences the adult behavior of the native species Lucilia eximia (Wiedemann) in Brazil. The level of attraction and oviposition by the native species was assessed in a dual-choice assay. The evaluation was based on sex and stage of ovarian development of L. eximia adults to a resource not colonized (NCR) or colonized (RPC) with eggs, different instars, or densities of C. albiceps. A significant difference in attraction was observed based on sex and stages of ovarian development. Males and nongravid females were more attracted to RPC, whereas gravid females preferred NCR. Moreover, males exhibited the lowest response in all assays among the three sex categories examined. In general, adults preferably oviposited on NCR rather than RPC. Also, between the eggs and second instar treatments, L. eximia laid more eggs on RPC with eggs than second instars (predatory stage). Lucilia eximia attraction to second-instar C. albiceps at different densities was marginally significant. Overall, results indicate the invasive species, C. albiceps, is impacting the behavior of the native blow fly, L. eximia, with regards to its attraction and colonization of vertebrate carrion, which could explain why native blow fly populations have significantly decreased since the introduction of C. albiceps.

The use of DNA barcode for identifying species of Oxysarcodexia Townsend (Diptera: Sarcophagidae): A preliminary survey.

Oxysarcodexia is one of the Neotropical richest genera within the Sarcophagidae family. Medical, veterinary and forensic importance of these flies are due to their association with corpses, cases of myiasis in humans and domestic animals, and being pathogen carriers. Regarding morphological identification, molecular techniques, especially the DNA-based ones, arise as useful alternatives or complementary methodologies for species identification. Thus, in this study we aimed to investigate the potential of the COI marker (barcode region) to delimit Oxysarcodexia species in comparison with the morphological identification criteria. A COI fragment was amplified and the length of the sequences after alignment were of 648bp (149 parsimoniously informative variable sites). According to the Neighbor-Joining phylogenetic tree, specimens of the same morphological species were clustered in monophyletic clades (82-100% bootstrap branch support). Species-level resolution thus achieved was successful, despite low interspecific divergence (1.8-2.3%) and since interspecific variation was higher than intraspecific divergence (0.1-1.2%). Therefore, the use of COI barcode sequences supports differentiation and identification of the Oxysarcodexia species studied.

Phenotypic polymorphism of Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae) may lead to species misidentification.

Species identification is an essential step in the progress and completion of work in several areas of biological knowledge, but it is not a simple process. Due to the close phylogenetic relationship of certain species, morphological characters are not always sufficiently distinguishable. As a result, it is necessary to combine several methods of analysis that contribute to a distinct categorization of taxa. This study aimed to raise diagnostic characters, both morphological and molecular, for the correct identification of species of the genus Chrysomya (Diptera: Calliphoridae) recorded in the New World, which has continuously generated discussion about its taxonomic position over the last century. A clear example of this situation was the first record of Chrysomya rufifacies in Brazilian territory in 2012. However, the morphological polymorphism and genetic variability of Chrysomya albiceps studied here show that both species (C. rufifacies and C. albiceps) share very similar character states, leading to misidentification and subsequent registration error of species present in our territory. This conclusion is demonstrated by the authors, based on a review of the material deposited in major scientific collections in Brazil and subsequent molecular and phylogenetic analysis of these samples. Additionally, we have proposed a new taxonomic key to separate the species of Chrysomya found on the American continent, taking into account a larger number of characters beyond those available in current literature.

Developmental rates of immatures of three Chrysomya species (Diptera: Calliphoridae) under the effect of methylphenidate hydrochloride, phenobarbital, and methylphenidate hydrochloride associated with phenobarbital.

Entomotoxicology is focused on obtaining data on necrophagous entomofauna, for criminal investigations purposes. This study aimed to evaluate the effect of different concentrations of methylphenidate hydrochloride, phenobarbital, and their association on the developmental rate, larval and pupal survivorship, and the interval of emergence of adults of Chrysomya albiceps (Wiedemann), Chrysomya megacephala (Fabricius), and Chrysomya putoria (Wiedemann) (Diptera: Calliphoridae). Considering the therapeutic dose (TD) of methylphenidate hydrochloride (0.29 mg/Kg), the concentrations tested were 10× TD, 50× TD, and 100× TD. For phenobarbital, the concentrations used were 1× TD (=150 mg/Kg), 3.3× TD, and 6.7× TD. For the association of the drugs, the combinations used were 10× TD-methylphenidate hydrochloride plus 1× TD-phenobarbital, 50× TD-methylphenidate hydrochloride plus 3.3× TD-phenobarbital, and 100× TD-methylphenidate hydrochloride plus 6.7× TD-phenobarbital. The control group, without addition of drug, was maintained under the same conditions of temperature (25 ± 1 °C), humidity (70 ± 10%), and photoperiod (12 h). Specimens of each group were weighed every 12 h until pupariation. The developmental rate of the three Chrysomya species immatures was monitored. For C. albiceps the developmental time was delayed in 24 h for methylphenidate hydrochloride group and in 12 h for the phenobarbital and the drugs association groups. The effect was observed only at specific ages for C. megacephala, without altering the developmental time. For C. putoria, the developmental time was delayed in 12 h for methylphenidate hydrochloride group and in 24 h for the phenobarbital and the drugs association groups. The emergence interval was similar among all experimental groups, but larval and pupal viabilities were affected in different ways.

Standardization of histological procedures for the detection of toxic substances by immunohistochemistry in Dipteran larvae of forensic importance.

Immunohistochemistry (IHC) technique is an alternative toxicological analysis to detect drugs in insects of forensic importance, but it requires thorough histological procedures. In this study, we tested different fixatives--phosphate-buffered paraformaldehyde 4% (PP), Carnoy's fluid (CF), Kahle's solution (KS), ethanol in different concentrations, and ethanol associated to PP and CF, time of fixation and histological processes for dipteran larvae's tissue, aiming to develop a sample preparation protocol for IHC application. A suitable fixation was achieved using PP for 12 and 24 h, CF for 3 h, 70% ethanol for 19 days, and 70% ethanol/CF for 2 h/3 h. Postfixation using negative pressure, two immersions in xylene for 30 min each, and one in xylene plus paraffin for 45 min increased tissue preservation. An immunohistochemical test for cocaine detection was performed using monoclonal benzoylecgonine antibody from mouse, peroxidase-conjugated anti-mouse IgG and visualized by 3,3'-diaminobenzidine method showed these histological procedures didn't compromise antigenicity.

Dipterans associated with a decomposing animal carcass in a rainforest fragment in Brazil: notes on the early arrival and colonization by necrophagous species.

This study aimed to provide the first checklist of forensically-important dipteran species in a rainforest environment in Northeastern Brazil, a region exposed to high rates of homicides. Using a decomposing pig, Sus scrofa L. (Artiodactyla: Suidae), carcass as a model, adult flies were collected immediately after death and in the early stages of carcass decomposition. To confirm actual colonization of the carcass, insects that completed their larval development on the resource were also collected and reared until adult stage. A diverse assemblage of dipterans composed of at least 28 species from seven families with necrophagous habits was observed within minutes after death. Besides Calliphoridae and Sarcophagidae, species from forensically-important families such as Phoridae, Anthomyiidae, and Fanniidae were also registered. Eleven species were shown to complete their development on the carcass. The majority of individuals emerged from larvae collected at the dry stage of decomposition. Hemilucilia segmentaria Fabricius (Diptera: Calliphoridae), H. semidiaphana (Rondani), and Ophyra chalcogaster (Wiedemann) (Muscidae) were the dominant species among the colonizers, which supports their importance as forensic evidence in Brazil.

Bionomics of two forensically important blowfly species Chrysomya megacephala and Chrysomya putoria (Diptera: Calliphoridae) reared on four types of diet.

The use of heterogeneous animal tissues for the rearing of necrophagous insect species can produce uneven biological data, which can compromise the determination of larval age and, consequently, estimates for post-mortem intervals. We investigated the development of two species, Chrysomya megacephala and Chrysomya putoria (Diptera: Calliphoridae), reared on four substrates: minced beef (control) and semi-synthetic diets with the addition of sardine, rumen or chicken eggs. No differences in total developmental times were detected among larvae reared on different diets. Length and width of larvae were partially affected by the type of food. Third instar larvae and pupae of both species were heavier on beef treatment when compared with other substrates. Overall mortality was lower when beef was used as food. Longevity of adults and sex ratio were not negatively affected by the use of diets. Egg-based diet was the least effective for both species. Given the fact that several bionomical parameters of larvae reared on diets were close to those obtained when minced beef was offered, and considering the putrid odour, frequency of contamination and lack of homogeneity of animal tissue, semi-synthetic diets can be used for rearing C. megacephala and C. putoria.

Comparação dos padrões de atratividade de Hermetia illucens (Diptera, Stratiomyidae) associada a carcaças de Rattus norvergicus enterradas e tratadas com hormônios esteróides / Comparison of attraction patterns of Hermetia illucens (Diptera, Stratiomyidae) associated to buried Rattus norvergicus carcasses with steroid hormones treatment

Hermetia illucens (L.) (Diptera, Stratiomyidae) é uma espécie abundante em todo o continente americano. No entanto, ainda há poucos estudos no Brasil abordando aspectos em relação a sua biologia e ecologia, em particular associados a estudos forenses. Neste trabalho, nós observamos os efeitos de hormônios esteróides na decomposição corporal de Rattus norvergicus, variedade Wistar enterrados na atração de H. illucens. Além da presença de diversas espécies de larvas e adultos de insetos freqüentemente encontrados em carcaças nessas condições, observou-se uma grande quantidade de imaturos de H. illucens. Essa espécie representou aproximadamente 22 por cento de todos os espécimes coletados, tendo aparecido somente nos animais que receberam tratamento com esteróides sexuais dos tipos testosterona, progesterona e estradiol. Dentre esses, a maior abundância foi verificada nos que haviam recebido testosterona (68 por cento). A presença de imaturos de H. illucens, apenas nos animais que receberam o tratamento com esteróides, em experimentos realizados em dois anos consecutivos revela uma possível atração/seleção dessa espécie por corpos com quantidades aumentadas de hormônios sexuais. Esse comportamento pode ser particularmente útil para a entomologia forense no que diz respeito à estimativa do intervalo pós-morte (IPM), particularmente quando tem como base informações sobre o ciclo de vida e ecologia de insetos necrófagos.

Hermetia illucens (L.) (Diptera, Stratiomyidae) is an abundant species in the entire American continent. Nevertheless, there are few studies in Brazil dealing with aspects of its biology and ecology, particularly associated with forensic studies. In this study we intended to observe the effects of steroids hormones in the corporal decomposition of buried Rattus norvergicus from the Wistar variety in the attraction of H. illucens. Besides the presence of several insect species commonly found in carcasses, a great amount of immature H. illucens was observed. This species represented approximately 22 percent of all collected specimens and it was only found in the animals that have received treatment with sexual steroids, such as testosterone, progesterone and estradiol. Among the animals under treatment, the greater abundance was verified in those who had received testosterone (68 percent). The presence of immatures of H. illucens only in the animals that received hormone treatments in experiments accomplished in two consecutive years strongly suggests a possible attraction of this species for bodies with different amounts of sexual hormones. This behavior can also be relevant for the forensic entomology in regard to the post-mortem interval (PMI) estimation, particularly when the PMI is based on information about the necrophagous insect's life cycle and ecology.

[Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae) developmental rate on artificial diet with animal tissues for forensic purpose]. / Taxa de desenvolvimento de Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae) em dieta artificial acrescida de tecido animal para uso forense.

Forensic entomology uses biological and ecological aspects of necrophagous insects to help in criminal investigations to estimate the post-mortem interval (PMI) or to determine the cause of death. Recent papers demonstrated that the presence of toxins in decomposing tissues may alter the insect developmental rate of insects exploiting such tissues as food. Thus, preliminary tests with artificial diets in laboratory are necessary to create a database to investigate and quantify the modifications that can occur with the collected insects from a criminal scene, avoiding any errors on the PMI estimates. The present study aimed to evaluate the developmental rate of Chrysomya albiceps (Wiedemann) reared on: a) artificial diets containing animal tissues: bovine liver (D1), raw muscle (D2), stomach (D3), and chicken heart (D4); b) artificial diet without animal tissue (D5); and c) a control group (C), which had only meat. The efficiency of each substrate was assessed by immature weight gain (mg), larval developmental time, larval and pupal survival, emergence interval and adult size. D1 to D4 diets did not restrict C. albiceps development; however, larvae reared on D1 and D2 diets presented a lower adult emergence rate. D3 and control group showed similarities regarding the efficiency parameters (rate and emergence interval). Thus, the use of diet D3, artificial diet with stomach, is the most recommended.