Vertical location of ephemeral resources by adult Diptera: Implications for the colonization of cadavers in high-rise buildings

Sarcosaprophagous flies (Diptera) rank among the most common insects associated with human-transformed environments all over the world. Synanthropic species of the families Calliphoridae, Muscidae, Sarcophagidae and Phoridae, in particular, have tremendous forensic importance due to their ability to colonize human cadavers and thus provide information on minimum post-mortem interval. Recently, cases of flies colonizing cadavers inside buildings of different heights drew attention to the vertical dispersal abilities of these flies, a subject that has received little attention. We investigated the vertical distribution of sarcosaprophagous flies in an urban environment, using uninhabited buildings as experimental models in Northeastern Brazil. To assess the vertical stratification of flies, one in every three floors of nine buildings was sampled using traps baited with bovine spleen, from the ground to the 27th floor. Calliphoridae was the most abundant family (52.9%), followed by Muscidae (41.2%), Sarcophagidae (3.2%) and Phoridae (2.7%). Most of the insects were collected at ground level (78.8%), with a decreasing abundance registered on the higher floors. Nevertheless, adults of the four families tested here were able to reach substrates as high as the 15th floor, which corresponds to approximately 48 m in height. Regarding calliphorids, seven species were identified, of which Chrysomya albiceps (30.4%) and C. megacephala (68.3%) were the most abundant. This is, to our knowledge, the first detailed, replicated study on vertical resource localization of sarcosaprophagous flies.

Diversity, Daily Flight Activity and Temporal Occurrence of Necrophagous Diptera Associated with Decomposing Carcasses in a Semi-Arid Environment

The harsh conditions of the Brazilian seasonally dry tropical forest known as Caatinga pose challenges to the insects specialized in the exploitation of ephemeral resources. We investigated the diversity and daily flight activity of dipterans associated with decomposing rat carcasses in a field experiment performed in the semi-arid region of Pernambuco State, Brazil. We also analyzed the temporal arrival of adult insects on the carcasses at three stages of decomposition: early, intermediate, and advanced. We collected 1173 individuals, of which Muscidae had the highest abundance (36.5%), followed by Sarcophagidae (28.1%), Calliphoridae (25.2%), and Fanniidae (10.2%). Chrysomya albiceps (Wiedemann, 1819) (Calliphoridae), Fannia pusio (Wiedemann, 1830) (Fanniidae), Atherigona orientalis (Schiner, 1868), and Musca domestica (Linnaeus, 1758) (Muscidae) were the most abundant species. The richness reached its maximum value on the second day of decomposition, with 18 species, decreasing to 8 species on the last day of decomposition (7 days). The ecological indices of diversity, dominance, and evenness varied little among the stages. There was an overlap of most species throughout the decomposition, although the overall abundance was higher at the intermediate stage for Calliphoridae, Muscidae, and Sarcophagidae. In accordance to previous studies, nocturnal flight was rare, as approximately 8% of insects were captured at night. Our results expand the knowledge on ecological and behavioral aspects of necrophagous flies under inhospitable environments, such as the dry season in the Caatinga. The dominance of the invasive species C. albiceps reinforced here illustrates its geographical expansion towards the countryside of Northeastern Brazil.

Assemblage of Necrophagous Diptera in Atlantic Insular Environments and Response to Different Levels of Human Presence

Islands act as natural laboratories for ecological studies to explain bioinvasion processes and, in this scenario, necrophagous Diptera have never been used as model organisms. This study aimed to (i) describe assemblages of necrophagous Diptera (Calliphoridae and Sarcophagidae) in two insular environments of different origins and distances from mainland, (ii) investigate the effect of anthropogenic impact on the assemblage of carrion flies, (iii) to quantify the establishment of invasive species in the two islands, and (iv) to infer about the conservation status of the islands based on the ecological parameters. Sampling was performed in 2011-2012, in the dry and rainy season. Insects were collected by using traps with chicken liver or sardine baits. In each island, environments exposed to different degrees of human impact were sampled. Ecological analyses were carried out to characterize the assemblages of Calliphoridae and Sarcophagidae, with emphasis on the relation between native and invasive species. In total, 99,862 adults of 21 species of blow flies and flesh flies were collected. Overall abundance in the oceanic island was higher than in the continental island, although the richness of species was higher in the latter. The type of bait did not influence diversity of species sampled in either island. No difference was observed in total richness of both families according to the gradient of anthropogenic impact, in both islands. The invasive species Chrysomya megacephala (Fabricius) was classified as dominant in all environments, irrespective of the anthropogenic impact, which raises concern about the conservation status of each island.

Diptera of Medico-Legal Importance Associated With Pig Carrion in a Tropical Dry Forest

The diversity of necrophagous Diptera is largely unknown in seasonally dry tropical forests, despite their medical, veterinary, and forensic relevance. We performed a study in the dry Caatinga forest exclusive to Brazil in order to assess the diversity and temporal pattern of Diptera species using pig carcasses as substrates. Adults were collected daily until complete skeletonization. We collected 17,142 adults from 18 families, 10 of which comprise species with known necrophagous habits. The most abundant families were Calliphoridae (47.3% of specimens), Sarcophagidae (20.8%), and Muscidae (15.5%), whereas Sarcophagidae stood out in terms of richness with 21 species. The native Cochliomyia macellaria (F.) (Diptera: Calliphoridae) and the invasive Chrysomya albiceps (Wiedmann) (Calliphoridae) were the dominant species. A total of 18 species reached the carcass during the first 48 h postdeath. The bloated and active decay stages had the highest richness and abundance of dipterans. From a forensic standpoint, C. macellaria and C. albiceps are likely to aid in establishing postmortem interval due to their early arrival and high abundance on the carcass. Despite harsh environmental conditions, the Caatinga harbors a rich assemblage of dipterans that play a key role in carrion decomposition. Their medico-veterinary importance is strengthened by the poor local sanitary conditions.

Uma lista atualizada das espécies de diptera causadoras de miíases na pecuária no Nordeste do Brasil

Apresentamos aqui uma lista atualizada, baseada em dados da literatura e em estudos de campo realizados de 2009 a 2013, relacionada à ocorrência de espécies de Diptera causadoras miíases na região Nordeste do Brasil, de acordo com o ambiente e o hospedeiro no qual a espécie foi observada. A maioria dos casos de miíases envolveu ovelhas e não teve seu agente causal identificado. Dezenove espécies previamente conhecidas como agentes obrigatórios ou facultativos foram registrados em vários ambientes, incluindo a região semi-árida, onde caprinos são frequentemente criados. Somente duas espécies foram identificadas como agentes causadores de miíases em animais domésticos, Cochliomyia hominivorax e Dermatobia hominis. A presença de espécies invasoras pode estar associada com a expansão local de miíases secundárias em animais domésticos.

Trace element concentrations in blood and hair of young apprentices of a technical-professional school

The concentrations of total Fe, Cu, Mn, Zn, Pb, Cr, Ni and Ca in the whole blood of young male apprentices of a technical-professional school, who are exposed to low doses of fumes from manual metal arc welding of mild steel, were monitored over their 2 years of apprenticeship in order to evaluate the influence of occupational exposure on biological metal levels. The results were compared with those from a control group of the same sex and age and living in the same geographic area. For comparison, monitoring of the same metal levels in the hair of both groups of individuals were also carried out. In the apprentices, the mean metal concentrations in blood at the end of the study were statistically significantly higher for Cu, lower for Fe and Mn and similar for the remaining metals. The levels of Fe significantly decreased whereas the levels of Cu were significantly increased during the study. A systematic influence of the exposure period on the levels of Mn was not observed. All the metal concentrations measured in the blood and hair of both apprentices and controls fell in the very large range of published reference levels. Seasonal variation (higher levels in the summer) of the hair metal concentrations were observed for Mn, Cu, Pb, Ni, Zn and Ca.

Alternative Routes for the Horizontal Transmission of a Nucleopolyhedrovirus

Two alternative routes for nucleopolyhedrovirus transmission were investigated using Mamestra brassicae larvae: cannibalism of infected larvae and the release of virus prior to the death of the diseased host. The low frequency of cannibalism observed suggests that this is not a relevant transmission route in this species. However, larvae were shown to transfer viable virus to the environment before death through either defecation or regurgitation. Over 40% mortality was observed in larvae reared in diet containers where infected hosts had previously fed. Virus transfer to cabbages also occurred before death of the infected host, as revealed by plant bioassay. Virus was not detected in the feces or regurgitate of diseased larvae until the late stages of infection.