Carina Mara de Souza

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.

Effect of Nandrolone Decanoate on the Development of Three Species of Chrysomya (Diptera: Calliphoridae), Flies of Forensic Importance in Brazil

ABSTRACT Necrophagous insects are valuable tools for postmortem interval (PMI) estimation or for determining the cause of death. Due to the increase in deaths related to drug abuse, it is crucial to know how these substances affect the development of flies that feed on corpses, to avoid errors in the PMI estimates. This study evaluated the effect of nandrolone decanoate, an anabolic androgenic steroid, on the development of immatures of Chrysomya megacephala (F.), Chrysomya putoria (Wiedemann), and Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae) when added to an artificial rearing diet. Four experimental groups were delineated: three of them were given diets containing 4.5, 22.5, or 45 mg/kg nandrolone decanoate; and a drug-free control group. Weights were recorded at 12-h intervals from larval eclosion to pupation. No statistically significant differences were observed in mean larval weights, emergence interval, or emergence rates for all groups. However, differences in the three species were observed during the larval development. Initially, C. putoria reared in the highest concentration of decanoate showed greater weight gain. However, at older ages, immatures reached lower mean weights than the control group. For C. albiceps, the highest concentration of decanoate contributed to an effective lack of weight gain during almost the entire course of larval development. Therefore, the influence of any drug on development should always be considered.

Molecular Characterization of Peckia (Pattonella) intermutans (Walker,1861) (Diptera: Sarcophagidae) based on the Partial Sequences of theMitochondrial Cytochrome Oxidase I Gene

We analyzed nucleotide sequences that constitute a part of the mitochondrial cytochrome oxidase subunit I (COI) gene from individuals of Peckia (Pattonella) intermutans (Walker, 1861) (Diptera: Sarcophagidae) of different populations from the States of Sao Paulo and Bahia, Brazil. Indices of genetic variability were calculated and phylogenetic tests (Maximum Parsimony) were applied. The presence of at least five haplotypes among sampled individuals was observed. Pairwise sequence differences within P. (P.) intermutans haplotypes were lower than the pairwise sequence differences between the haplotypes and outgroup species. This finding, in addition to the phylogenetic analyzis performed in this study, validates the use of molecular tools for distinguishing species of P. (P.) intermutans from other sarcophagids already molecularly characterized in Brazil so far. The greatest number of haplotypes (n = 3), genetic diversity (π = 0.01), and nucleotidic differences (k = 2.38) were found from specimens in Ubatuba, reflecting the low rate of genetic flow in this population compared to those from other locations; this was probably influenced by the local ecotope, i.e., the tropical rainforest called “Mata Atlântica”. At collection areas within the rainforest, the vegetal cover is well preserved and this could significantly influence evolutive factors such as population size and selection towards genetic drift, supporting variability maintenance. Further investigations should be conducted for a better understanding of this finding and for expanding knowledge about the close relationships among P. (P.) intermutans and other sarcophagids of forensic importance.

Egg Developmental Time and Survival of Chrysomya megacephala and Chrysomya putoria (Diptera: Calliphoridae) Under Different Temperatures.

ABSTRACT Chrysomya megacephala (F.) and Chrysomya putoria (Wiedemann) (Diptera: Calliphoridae) are considered of forensic, medical, and veterinary importance in Brazil because of their necrophagous and synanthropic behaviour. The development of flies can be influenced by temperature, and species from the same genus usually have different responses to external variables. The egg development of blow fly can be a useful complementary technique to estimate the minimum postmortem interval. Thus, this study aimed to compare the egg developmental time and survival of C. megacephala and C. putoria at different temperatures to determine the optimal temperature for egg development and the linear regression for developmental time and temperature, thereby determining the minimum threshold (t) and thermal summation constant (K) for each species. Adults of both species were collected in the region of Campinas city, São Paulo state, Brazil. Eggs were incubated at eight constant temperatures between 05 ± 1°C and 35 ± 1°C and the egg developmental time and survival were evaluated. There was no egg survival at 5 and 10°C. The K for C. megacephala and C. putoria were 179.41 HD and 189.94 HD, respectively. The regression slopes and t (10°C) were similar for both species. The optimal temperature for egg survival was between 25 and 35°C, for C. megacephala and 20 and 30°C, for C. putoria. The present data were similar to most data available in the literature, but differences in the same species are a possibility.