RESUMO

The most widely used herbicides in the world are glyphosate formulations. These have been used in self-poisoning and accidental poisoning. Dermestes maculatus (Coleoptera: Dermestidae) and Lucilia sericata (Diptera: Calliphoridae) are associated with decomposing human and animal remains. The aim of the study was to evaluate Roundup Full® II effects on saprophagous insects´ development. For this, green bottle flies and hide beetles were exposed to different doses of the herbicide. The duration of life cycles was recorded by observations made every 8 and 24 h. To register possible variations in size, external morphology, and female proportion, specimens of all developmental stages were collected. The duration of developmental stages in L. sericata did not change due to the herbicide, but this reduced all size parameters of puparium with pupae inside, the weight of L1, and of adults. The larval stage and total duration in D. maculatus were decreased by the highest dose, while size parameters of hide beetles remained unchanged at all development stages. In both flies and beetles, there was no evidence of abnormal external morphology and the female proportion did not change in response to the herbicide. Finally, this study exhibited an impact on L. sericata and D. maculatus, so the possibility that the herbicide may affect other forensically important species should be considered, but more work is needed. Taxonomic determination could be done as usual; however, caution should be exercised when estimating the postmortem interval. This study represents the first to analyze a glyphosate-based herbicide associated with Forensic Entomology.

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Studies under constant temperatures are the most common to estimate the Postmortem Interval (PMI). It is imperative that forensic sciences have data from studies carried out in the field. Therefore, this work aims to: (1) evaluate the parameters (weight, length, development time) associated with the life cycles of Lucilia ochricornis (Wiedemann) (Diptera: Calliphoridae) and Lucilia purpurascens (Walker) under experimental conditions in the field considering fluctuating temperatures, and (2) compare these results with those known and published by the same authors for cultures realized in the laboratory under constant temperatures; which will permit us to contrast the most widely used existing methodologies for forensic application in estimating the minimum postmortem interval (PMImin). For each season of the year, cultures of both species were made in the field, collecting information on temperature, humidity, and photoperiod to perform laboratory cultures, later comparing: development time, length, weight, and Accumulated Degree-Hours (ADH) in both types of cultures. Methods for estimating the PMI were obtained and validated with the information of the cultures grown in the field. The two types of cultures showed differences between each other for both species. The forensic use methods to estimate PMI were enhanced and their precision increased when maximum larval length data were used, and it was also concluded that feeding larval stages are the most accurate to be used in making estimates because the larva is growing. The estimation of the PMI through the use of necrophagous flies development remains reliable for obtaining the PMImin.

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RESUMO

Obtaining the specific development time of each species of forensic interest is crucial for the estimation of an accurate and reliable Minimum Postmortem Interval (PMImin). In Argentina, Lucilia ochricornis (Wiedemann) and Lucilia purpurascens (Walker) (Diptera: Calliphoridae) were masked under the name Lucilia cluvia (Walker) for a long time still in forensic expertise. For this reason, the objective of this work is to deepen the study of the development time of these species and utilize this relevant information in the generation of different associated methods that can be used in forensics to estimate the PMI. Immature stages of L. ochricornis and L. purpurascens were reared in a brood chamber according to the following temperature treatments: 13.4, 15.1, 22.3, and 23.6°C. The development time of each stage/state of these flies was recorded as well as the resulting accumulated degree-hours (ADH), to build isomorphen diagrams and thermal summation models for each species. The development time and ADH were different between both species and their development stages. On the other hand, the methods provided for estimating PMImin provide the forensic entomologist more tools to reach accurate and reliable estimates.

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RESUMO

The early arrival and colonization of species belonging to the family Calliphoridae (Insecta: Diptera) on a corpse represent one of the most reliable means of estimating minimum postmortem interval (PMImin). However, information on the development and life cycles of some Argentine species in this family is not complete. The objective of this work was to contribute new information regarding the larval body size of neotropical species that allow, through the construction of forensic methods, the estimation of a more precise and specific PMImin. This work was conducted on laboratory cultures of larvae of Lucilia ochricornis (Wiedemann) and Lucilia purpurascens (Walker) using as average temperatures: 13.4, 15.1, 22.6, and 23.3°C, which represent the four seasons of the year for the province of Salta. With this information, we constructed isomegalen diagrams and growth models for the obtained variables of larval length and body weight. The mean values of length and body weight differ between both species, indicating that L. purpurascens exceeded L. ochricornis in both variables. In contrast, within each species the mean length and weight remained unchanged between culture temperatures for the three larval instars. Isomegalen diagrams can be used for the entire range of temperatures worked in the laboratory, but the body size entered is approximate. The growth models allow the use of point data but are specific for each culture temperature used.

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Fluoxetine is a selective serotonin reuptake inhibitor, commonly used for the treatment of a variety of psychopathological conditions. As such, fluoxetine may be expected to appear in clinical and forensic cases. Dermestes maculatus De Geer (Coleoptera: Dermestidae) has been recognized as a relevant component of the insect fauna associated with decomposing human and animal remains. Experiments were conducted to study the effect of fluoxetine on developing D. maculatus using two-drug administration models: a non-living animal model (pork muscle) and a living one (Sus scrofa L. pigs). We assessed the duration of immature stages and total life cycle, as well as morphological parameters (body length, cephalic width, and weight). The effect of fluoxetine was studied at an overdose concentration: In the non-living animal model the drug was mixed with macerated pork muscle (2000 mg/kg) and in the living animal model, pigs were given the drug orally (833 mg/kg). A control was used for each model. Daily observations were performed from the beginning to the end of the experiments. GC-MS was used for drug detection and quantification. There were no statistically significant differences in the duration of immature stages, life cycle, larval mortality, morphological parameters, or sex ratio, between treatment and control, regardless of the drug administration model. Given that fluoxetine had no detectable effect on the development of D. maculatus, detection of this drug in forensic situations would not compromise the accuracy of PMI estimations.

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The morphologic features of Talaromyces udagawae Stolk and Samson are here described and illustrated. This teleomorphic Ascomycota fungus was isolated from soil obtained in Buenos Aires province (Argentina) from beneath a human cadaver in an advanced state of decomposition. After washing and serial dilution of the soil along with moist-chamber techniques for fungal cultivation, T. udagawae formed very restricted colonies of bright yellow color on different growth media with 8-ascospored asci. The ascospores were ellipsoidal and ornamented. The anamorphic state was not observed. Molecular-genetic techniques identified the species. The present record is the first of the species in Argentina, pointing it as a tool to identify soils where cadaver decomposition occurs.

Se describen e ilustran las características morfológicas de Talaromyces udagawae Stolk y Samson. Se aisló el estado teleomórfico de este hongo Ascomycota de suelo obtenido en la provincia de Buenos Aires (Argentina), por debajo de un cadáver humano en avanzado estado de descomposición. Las muestras de suelo fueron analizadas mediante lavado, dilución seriada y cámaras húmedas, técnicas ampliamente usadas para el estudio de hongos de suelo. T. udagawae formó colonias muy restringidas de color amarillo brillante en diferentes medios de cultivo, con ascos con 8 ascosporas. Las ascosporas eran elipsoidales y ornamentadas. No fue hallado el estado anamórfico. La especie también fue identificada mediante técnicas moleculares. El presente registro es el primero de la especie en la Argentina y el único que la postula como herramienta para identificar suelos donde ocurre una descomposición cadavérica.

Assuntos

RESUMO

The morphologic features of Talaromyces udagawae Stolk and Samson are here described and illustrated. This teleomorphic Ascomycota fungus was isolated from soil obtained in Buenos Aires province (Argentina) from beneath a human cadaver in an advanced state of decomposition. After washing and serial dilution of the soil along with moist-chamber techniques for fungal cultivation, T. udagawae formed very restricted colonies of bright yellow color on different growth media with 8-ascospored asci. The ascospores were ellipsoidal and ornamented. The anamorphic state was not observed. Molecular-genetic techniques identified the species. The present record is the first of the species in Argentina, pointing it as a tool to identify soils where cadaver decomposition occurs.

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Experiments were conducted to study the life cycle of Dermestes maculatus and to establish the total developmental time and the developmental time of immature stages, in relation with six different temperatures. We also analyzed the variations in size, morphology, and other indicators of temporal variation during life cycle of D. maculatus, in relation with temperature. One hundred larvae were selected per experiment, reared individually. The remaining larvae were reared to evaluate and establish temporal variations among the instars (length, cephalic width, and dry weight). In all trials, survivorship was greater than 50% and seven larval instars were found. Data of the average developmental time of immature stages and of the total cycle, at different temperatures, are provided. This is of relevance when estimating particularly, a minimum PMI. No relation between morphometric parameters and temperature was found, suggesting that other random factors may have been involved. Thus, this indicates that the method of isomegalen diagrams could not be used for calculating PMI.

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Beetles associated with carrion play an important role in recycling organic matter in an ecosystem. Four experiments on decomposition, one per season, were conducted in a semirural area in Bahía Blanca, Argentina. Melyridae are reported for the first time of forensic interest. Apart from adults and larvae of Scarabaeidae, thirteen species and two genera of other coleopteran families are new forensic records in Argentina. Diversity, abundance, and species composition of beetles showed differences between stages and seasons. Our results differed from other studies conducted in temperate regions. Four guilds and succession patterns were established in relation to decomposition stages and seasons. Dermestidae (necrophages) predominated in winter during the decomposition process; Staphylinidae (necrophiles) in Fresh and Bloat stages during spring, summer, and autumn; and Histeridae (necrophiles) and Cleridae (omnivores) in the following stages during those seasons. Finally, coleopteran activity, diversity and abundance, and decomposition rate change with biogeoclimatic characteristics, which is of significance in forensics.

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RESUMO

Carcasses represent a trophic and reproductive resource or shelter for arthropods, which are a representative component of the decomposition process. Four experiments, one per season, were conducted in a semi-rural area of Bahía Blanca, Argentina, to study the trophic roles of cadaveric beetles, evaluating the abundance, composition and dominance during all decomposition stages and seasons. Species of necrophagous, necrophilous and omnivorous habits were found. Abundance, composition and dominance of beetles in relation to their trophic roles changed according to seasons and decomposition stages. Guilds and patterns of succession were established in relation to those periods. Trophic roles could be an indicator of beetle associations with decomposition stages and seasons.