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

Flesh Flies (Diptera: Sarcophagidae) of Forensic Importance Collected From Pig Carcasses in the Cerrado of Northeastern Brazil

Sarcophagidae is a family of true flies frequently found colonizing carcasses and corpses as adults and/or larvae, therefore, they are of great forensic value in the medico-legal field. Thus, this study aims to inventory the sarcophagids species and describe their succession process in the decomposition of swine carcasses in the Cerrado (savanna-like vegetation), Brazilian Northeastern region. A total of 10,819 specimens were collected, belonging to 45 sarcophagid species. Of this total, one species was recently described (Helicobia neuzalmeidae Silva, Brasil, De-Souza & Carvalho-Filho), two [Blaesoxipha (Acanthodotheca) denieri (Blanchard) and Dexosarcophaga pusilla Lopes] are new records for the Cerrado biome, five [Argoravinia (Argoravinia) catiae Carvalho Filho & Esposito, B. (A.) denieri, Nephochaetopteryx orbitalis (Curran & Walley), Peckia (Sarcodexia) tridentata (Hall) and Tricharaea (Sarcophagula) ramirezi (Lopes)] are new records for the Northeast region and eight are new records for the state of Maranhão. The species A. (A.) catiae, Blaesoxipha (Gigantotheca) stallengi (Lahille), D. pusilla, H. neuzalmeidae, Lipoptilocnema misella Lopes, Oxysarcodexia bakeri (Aldrich) and Retrocitomyia retrocita (Hall) were collected for the first time in pig carcasses. Peckia (Sarcodexia) lambens (Wiedemann) and Oxysarcodexia thornax (Walker) were the most abundant species. In both collection seasons, five species were carcasses pioneers at an early stage. The majority of species (42 spp.) were collected during the dry season, primarily during the black putrefaction (39 spp.) and butyric fermentation (30 spp.) stages. The greatest number specimens (n = 6,484) were recorded during the rainy season, at the butyric fermentation (n = 2,517) and black putrefaction (n = 2,080).

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.

The Impact of the Entomopathogenic Fungus Conidiobolus coronatus on the Free Fatty Acid Profile of the Flesh Fly Sarcophaga argyrostoma

Simple Summary

The interaction between insect and fungus is characterised on the one hand by the parasite developing more effective strategies of host exploitation, and on the other, by the host mounting increasingly robust defences though Red Queen dynamics or coevolutionary arms races. Furthermore, depending on gene flow and differences in selection pressure between sites, both host and parasite may demonstrate local adaptation to their counterpart or develop more general resistance or offensive traits. As the cuticle is considered the first line of defence of the insect, changes in the FFA profile may well influence susceptibility or resistance to fungal invasion. Our findings indicate that Sarcophaga argyrostoma demonstrates stage-specific resistance to Conidiobolus coronatus infection and suggests that FFAs play a role in resistance to fungal infection in flesh flies. These findings not only increase our knowledge of the entomopatogenic potential of fungi, but also of the growing level of infection by C. coronatus in humans and other mammals. Also, the presented research suggests that FFAs demonstrate antifungal activity which may be helpful in designing new antifungal treatments.

Abstract

The chemical composition of the insect cuticle varies remarkably between species and their life stages. It can affect host resistance and substrate utilization by invading entomopathogen fungi, such as the soil fungus Conidiobolus coronatus. In this study, Sarcophaga argyrostoma flies were exposed to sporulating C. coronatus colonies for 24 h; the pupae were resistant, but the adults demonstrated 60% mortality. Although the pupae demonstrated no sign of infection nor any abnormal development, our findings indicate that after 24 h of contact with the fungus, the pupae demonstrated a 25.2-fold increase in total cuticular free fatty acids (FFAs) and a 1.9-fold decrease in total internal FFAs. Also, the cuticular FFA increased from 26 to 30, while the internal FFA class increased from 13 to 23. In exposed adults, the total mass of cuticular FFAs increased 1.7-fold, while the number of FFAs stayed the same (32 FFAs). Also, the internal FFA class increased from 26 to 35 and the total FFA mass increased 1.1-fold. These considerable differences between adults and pupae associated with C. coronatus exposure indicate developmental changes in the mechanisms governing lipid metabolism and spatial distribution in the organism, and suggest that cuticular lipids play a vital role in the defence against pathogenic fungi.