Ultrastructure of immature stages of the black dump fly: Ophyra aenescens (Wiedemann, 1830) (Diptera: Muscidae: Azeliinae).

Ophyra aenescens (black dump fly) originally belonged to the New World, however, now it is spread worldwide. This fly is a mechanical vector of some pathogenic microorganisms and eggs of the human botfly (Dermatobia hominis). The adults are associated with decaying matter and the immature stages colonize animal and human corpses. It is considered an important muscid species for forensic entomology. The aim of this study was to describe the morphology of the eggs, the three larval instars and the puparia of O. aenescens using scanning electron microscopy (SEM). The spiracular opening of the first instar has an interruption in the middle of its length. Comparing to the other instar, the ventral tubercles are only developed in the first instar. The anterior spiracles have a variation in the numbers of spiracular ramification. The puparia morphology is similar to the third instar larvae, however the cephalic region is retracted and on the third thoracic segment, a respiratory structure is present. In conclusion, the SEM technique used and the results obtained are helpful to describe and differentiate the immature stages of O. aenescens and consequently support forensic and medical entomology.

Detection and preliminary physico-chemical properties of antimicrobial components in the native excretions/secretions of three species of Chrysomya (Diptera, Calliphoridae) in Brazil.

Antibiotic-resistant bacteria in hospitals and communities increasingly threaten public health in Brazil and the rest of the World. There is an urgent need for additional antimicrobial drugs. Calliphorid blowfly larvae are a rich source of antimicrobial factors but the potential of Neotropical species has been neglected. This preliminary study evaluates the antimicrobial activity of the native excretions/secretions of larvae of three species of Brazilian calliphorids, Chrysomya megacephala, Chrysomya albiceps and Chrysomya putoria. Native excretions/secretions were collected from third instar larvae, sterile filtered and tested for antibacterial activity against Staphylococcus aureus 9518, Escherichia coli K12 4401 and Serratia marcescens 365. Turbidometric assays were made in micro-plates, using an ELISA reader, with readings taken up to 22 h. Bacterial suspensions at the start and end of each experiment were also serially diluted, spread on nutrient agar plates and then colony forming units counted. The physico-chemical characteristics of the native excretions/secretions were also tested by freezing/thawing, boiling, and protease digestion. The native excretions/secretions of larvae from these three Chrysomya species significantly inhibited bacterial growth. Therefore, Brazilian calliphorid flies could potentially provide new classes of antibiotics.

Ultrastructural studies of some character of Diptera (Muscidae) of forensically importance.

Insects are important in the decomposition of cadavers. In the field of forensic entomology, the taxonomic identification is essential to proceed to any procedure. The use of these insects in medico criminal investigation is the object of forensic entomological studies; the flies are generally attracted to cadavers and one of the most important contributions is to estimate the postmortem interval. The scanning electron microscopy, which allows rapid and accurate identification of character could be used to help identify different species of forensics flies, has been highlighted as it allows better visualization of the external morphology of immature and some adults. The aim of this study was to describe the katepisternals in females of Morellia humeralis and Biopyrellia bipuncta; the ommatidia of the compounds eyes of the male of B. bipuncta; the antennae of females of Ophyra aenescens and Ophyra albuquerquei and the ocellar triangle of the last two species and O. chalcogaster examined by scanning electron microscopy to help increase the anatomical database on flies for forensic importance. The katepisternals of M. humeralis and B. bipuncta were densely covered by different groups of sensilla. The surface of the ocellar region of O. aenescens was not covered by sensilla, but in O. albuquerquei and O. chalcogaster were densely covered by different types of sensilla. The coeloconic sensilla were only found in the flagellum of O. albuquerquei.

Ultrastructure of immature stages of Cochliomyia macellaria (Diptera: Calliphoridae), a fly of medical and veterinary importance.

Cochliomyia macellaria (Diptera: Calliphoridae) is known as the secondary screwworm because it causes secondary or facultative myiasis when the larvae feed on necrotic tissues. This fly has a significant medical and veterinary importance since it has been reported to transport eggs of Dermatobia hominis (human botfly), which can cause significant economic losses to livestock. Since this screwworm has been collected colonizing both pig carcasses and human cadavers, it is considered one of the most important species for forensic entomology studies. Scanning electron microscopy (SEM) gives detailed information on the morphological characteristics which can help identify the immature forms of the flies. The aim of this study was to describe and analyze the morphological characteristics of the eggs, all the larval instars, and the puparia of Cochliomyia macellaria using SEM. The egg is ellipsoid and the dorsal surface is concave. The islands inside the median area had no anastomosis, but some perforations could be observed. From the second larval instar onwards, besides the intersegmental spines, other bands of spines were observed at the abdominal segments. Two spiracular openings were visible on the first and second larval instars, which were not expected. These characteristics are specific to Cochliomyia genus. The number and the general aspect of the spine tips in the cephalic region, the intersegmental bands on the abdomen, and the number of the spiracular openings could together help identify C. macellaria.

Ultrastructure of immature stages of Lucilia cuprina (Diptera: Calliphoridae) using scanning electron microscopy.

The blowfly Lucilia cuprina is distributed worldwide and is a mechanical vector of pathogens. It can cause myiasis in humans and is strongly related to forensic entomology, as it is frequently found on human and animal corpses. However, most of the L. cuprina found on corpses are the immature stages of this fly. Correct identification is very important for forensic entomology but at present only the identification keys of adult L. cuprina are available. Thus, the aim of this paper was to describe and analyze the morphological characteristics of all larval instars and the puparia of L. cuprina using scanning electron microscopy (SEM).

First record of acari Arrenurus Dugès, 1834 as a parasite of Odonata species in Brazil

Water mites are common and widespread parasites of some aquatic insects in freshwater habitats. This is the first record of acari Arrenurus Dugès, 1834, as a parasite of Odonata in Brazil. Water mites were sampled from Miathyria marcella (Selys, 1857) and Ischnura fluviatilis (Selys, 1876).

Ácaros aquáticos são parasitas comuns de alguns insetos aquáticos em habitats de água doce. Este é o primeiro registro do ácaro Arrenurus Dugès, 1834, como parasita de Odonata no Brasil. Ácaros aquáticos foram coletados em Miathyria marcella (Selys, 1857) e Ischnura fluviatilis (Selys, 1876).

Ultrastructure of immature stages of Peckia (Euboetcheria) collusor (Diptera: Sarcophagidae).

Peckia (Euboettcheria) collusor (Diptera: Sarcophagidae) is a necrophagous insect and represents an important role in forensic entomology, as it is always collected at animal/human corpses. Immature sarcophagids are extremely similar in morphological aspects and can be found colonizing both fresh and mummified bodies. Flesh fly larvae are reported to cause accidental myiasis. In the Neotropical regions little is known about the ultrastructure of immature stages of Sarcophagidae. Scanning electron microscopy gives detailed information on the morphological characters, which can help identify the immature forms of the flies. The aim of this study is to identify larvae and puparia of P. (E.) collusor using this methodology. The integument with net-like patches and the shape and disposition of intersegmental spines of the larval instars can be used to distinguish this flesh fly larva. The number of spiracular ramifications is variable at larval instars. The puparia are very similar to third instar larvae, except for the cephalic structures that are retracted. In conclusion, scanning electron microscopy could help entomologists to identify the immature forms of P. (E.) collusor in forensic investigations and consequently serves as a tool in crime scene investigations.

Ultrastructure of larvae and puparia of the blowfly Chrysomya megacephala (Diptera: Calliphoridae).

Chrysomya megacephala is a forensic important fly, and its immature forms also cause myiasis. The adults are the first insects to reach a carcass and can oviposit just a few hours after arrival. Therefore, the knowledge of immature stages of flies is essential for correct identification of the species found on corpses. Scanning electron microscopy (SEM) gives detailed information on the morphological characters that can help identify the immature forms of flies. The aim of this study is to identify larvae and puparia of C. megacephala using SEM. The larval instar body of C. megacephala is similar at all instars. The integument is smooth with small spines located at the limit of all segments. The cephalic region has a group of robust spines with one or two tips. The puparia are very similar to third instar larvae, except for the cephalic structures that are retracted. The integument shows the wrinkles from the third instar larvae and posterior spiracle disc with three spiracular openings localized on the top of an elevation. In conclusion, SEM provides some characteristics to distinguish among Chrysomya species that could help entomologists to identify immature found on corpses.

Ultrastructure of immature stages of the blowfly Chrysomya putoria (Wiedemann, 1818) (Diptera: Calliphoridae).

Forensic entomology is an area of science that serves as a tool in crime scene investigations. Usually, flies are the first insects to reach a carcass and can oviposit just a few hours after arrival. Therefore, the knowledge of immature stages is essential for correct identification of the species found on corpses. Scanning electron microscopy (SEM) gives detailed information about morphological characters helping to identify the immature forms of flies. Chrysomya putoria (Wiedemann) is a very important fly for forensic entomology, because it has high population densities and is easily found in colonizing carcasses, moreover, it is also a possible causative agent for secondary myiasis. The aim of this study is to identify larvae and puparia of C. putoria using SEM. The first instar larvae were composed of 12 smooth segments separated by spines. Antennae and maxillary palps were visible. Anterior spiracle was absent and only one spiracular opening could be seen at the posterior spiracle. Second and third larval instars were similar to first instar, except for the presence of anterior spiracle that is composed by 11-12 spiracular ramifications. At the anal segment, two spiracular openings were found in second instars and three openings in third instar larvae. Puparia showed a retracted cephalic region and none of the head structures were visible.

Ultramorphological characteristics of immature stages of Chrysomya albiceps (Wiedemann 1819) (Diptera: Calliphoridae), a fly specie of forensic importance.

Forensic entomology is an area of science that serves as a tool in crime scene investigations. Usually, flies are the first insects to reach a dead body and can oviposit just a few hours after arrival. Therefore the knowledge of immature stages is essential for correct identification of the species found on corpses. Scanning electron microscopy gives detailed information about morphological characters helping to identify the immature forms and consequently serves as a tool in crime scene investigations. C. albiceps is a very important fly for forensic entomologists because its larvae are almost always present on a dead body and it is facultative predators and therefore can alter the composition of species present at the carcass. The aim of this study is to identify eggs, larvae, and puparia of C. albiceps using SEM. Eggs were elongated with the anterior region ending in a "Y" shape and the posterior end was tapered. The micropyle was a well-adorned orifice with some projections around it. The first instar larva was composed of 12 segments separated by spines. Only one spiracular opening could be seen at the posterior spiracle. Body tegument was smooth and tubercles were not seen. Antennae and maxillary palps were visible. Second and third larval instars were very similar to first instar, except for the presence of anterior spiracle. However, body tegument was composed of net-like patches and tubercles were visible. Tubercles present at the third instar larvae were robust and erect. Puparia showed a retracted cephalic region and curved tubercles.

Rearing Chrysomya megacephala on artificial diets composed of varying concentrations of albumin

Larvae of the blowfly Chrysomya megacephala were reared on an artificial diet composed of five different concentrations of albumin (2, 4, 6, 8 and 10 percent) and the control group was fed on putrid bovine meat. No larvae developed in the 2 and 10 percent albumin concentrations. The period from newly hatched larvae to adults reared on 4, 6 and 8 percent albumin was 13.1, 13.1 and 13.6 days, respectively, whereas for the control group, it was 11.2 days. Concentrations of 4, 6 and 8 percent albumin proved viabile for larval periods of 29.3, 44.0 and 57.3 percent, respectively, whereas for the control group, it was 77.3 percent. Pupal viability was 77.3, 36.4 and 83.7 percent, while for the control group, it was 84.5 percent; the newly hatched larvae to adult viability was 21.3, 16.0 and 48.0 percent, respectively, and for the control group, it was 65.3 percent.

O presente trabalho teve como objetivo avaliar o desenvolvimento pós-embrionário de Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae) em dietas artificiais à base de albumina nas concentrações de 2 por cento, 4 por cento, 6 por cento, 8 por cento e 10 por cento de albumina e como controle foi utilizada a carne bovina moída putrefata. Não houve desenvolvimento nas dietas de concentração 2 por cento e 10 por cento de albumina. A duração do período de larva a adulto foi 13,1; 13,1 e 13,6 dias, respectivamente, e a do controle foi de 11,2 dias. As dietas artificiais nas concentrações 4, 6 e 8 por cento de albumina apresentaram viabilidades larvais de 29,3; 44,0 e 57,3 por cento, respectivamente e o controle 77,3 por cento; as viabilidades de pupa foram 77,3; 36,4 e 83,7 por cento e o controle 84,5 por cento, respectivamente; as viabilidades de larva a adulto foram 21,3; 16,0 e 48,0 por cento e o controle foi de 65,3 por cento, respectivamente.

Identification of fly eggs using scanning electron microscopy for forensic investigations.

Forensic entomology is the science that studies the role of insects in decomposing corpses and one of the most common uses is to estimate the post-mortem interval (PMI) based on insect activity on a decomposing body. Usually, flies are the first insects to reach a carcass and are able to oviposit on carrion within a few hours after death. Scanning electron microscopy (SEM) gives detailed information about morphological characters helping to identify the immature forms of flies and consequently serves as a tool in crime scene investigations. Sometimes, only eggs and larvae are found in corpses. Some dipteral species are important because their larvae develop in organic matter. The aim of this study is to identify eggs of species of forensic importance, such as Chrysomya megacephala, Chrysomya putoria, Lucilia cuprina, Lucilia eximia and Ophyra aenescens, using scanning electron microscopy (SEM). C. megacephala had no anastomosis or holes at the top of the islands and C. putoria had few anastomoses and no holes, whereas L. eximia and O. aenescens were found to have anastomoses and holes and L. cuprina had only anastomoses. The median area was bifurcated anteriorly in C. megacephala, L. eximia and O. aenescens and rounded in C. putoria and L. cuprina. Also the sculptures observed in the chorionic cells, the length and the way that median area ends up posteriorly are characteristics of great diagnostic value to identify muscoids of forensic importance.

Biological activity of yangambin on the postembryonic development of Chrysomya megacephala (Diptera: Calliphoridae).

Phytochemicals endowed with hormonal, antihormonal, or toxic activity are potential agents for insect control. Thus, we became interested in testing Brazilian plant metabolites on Chrysomya megacephala (F.) (Diptera: Calliphoridae), a public health menace that is one of the most prevalent flies in Brazilian urban areas. We tested the lignan yangambin, from the leaves of Ocotea duckei Vattimo (Lauraceae). Topical treatment of eggs and first instars with yangambin as well as feeding larvae a yangambin-treated diet resulted in inhibition of postembryonic development, morphological alteration, and oviposition reduction.