Resumen La entomotoxicología forense, que analiza insectos necrófagos para detectar sustancias tóxicas, es crucial en la determinación de causas de muerte y la estimación del intervalo post-mortem. Este estudio se centró en Peckia intermutans (Walker) (Diptera: Sarcophagidae) como marcador para la detección de metanol, un alcohol potencialmente letal presente como adulterante en bebidas alcohólicas debido a su bajo costo y parecido con el etanol. Se desarrolló un método de cromatografía de gases-espectrometría de masas (HS-GC-MS) para detectar metanol y se estudió su efecto sobre el tiempo de desarrollo, supervivencia y morfología de las moscas de la carne. Las larvas se criaron en sustratos de hígado enriquecidos con metanol (300, 500 y 1000 mg/kg). Los resultados mostraron: el método desarrollado detectó metanol en todos los estadios; el metanol afectó el tiempo de desarrollo de las moscas; la supervivencia aumentó con una mayor concentración de metanol; y los cambios morfológicos fueron evidentes en el peso. Este estudio ofrece valiosa información sobre la investigación entomotoxicológica del Ecuador, por lo que se debe considerar los cambios morfológicos de P. intermutans para evitar estimaciones inexactas de los intervalos post-mortem.

Abstract Forensic entomotoxicology, which analyzes necrophagous insects to detect toxic substances, is crucial in determining causes of death and estimating the post-mortem interval. This study focused on Peckia intermutans (Walker) (Diptera: Sarcophagidae) as a marker for detecting methanol, a potentially lethal alcohol often added as an adulterant in alcoholic beverages due to its low cost and similarity to ethanol. A gas chromatography-mass spectrometry (HS-GC-MS) method was developed to detect methanol, and its effects on the development time, survival, and morphology of flesh flies were investigated. Larvae were reared on liver substrates enriched with methanol (300, 500, and 1000 mg/kg). Results showed: the developed method detected methanol in all instars; methanol affected the developmental time of the flies; survival increased with higher methanol concentration; and morphological changes were evident in weight. This study provides valuable information on entomotoxicological research in Ecuador, emphasizing the need to consider morphological changes in P. intermutans to avoid inaccurate estimations of post-mortem intervals.

ABSTRACT Entomofauna associated with decaying cadavers may be useful in criminal investigation, either through the development of immature insects of interest or through entomological succession in corpses. These factors may vary if the insects are exposed to toxic substances that can modify the insect's developmental cycle, as well as its own occurrence, which would imply significant changes in the results of any investigation. However, there are few studies on how contamination by toxic compounds can affect the action of insects on carcasses and their consequence for forensic expertise. Therefore, this study aimed to test the hypothesis that the normal visitation of flies and beetles is altered in insecticide-contaminated carcasses. The experiment was carried out in a sugarcane plantation, using pig carcasses contaminated with insecticide and the same number of carcasses without any type of contamination as a control. In all experiments, the contaminated carcasses reached the final phase of decomposition in a longer time than the uncontaminated carcasses of the control group. A total of 2.767 specimens were collected and identified, 2.103 individuals from the order Diptera and 664 from the order Coleoptera. There was a significant geometric regression adjustment during the decomposition phases only for the control group, different from the contaminated carcasses in which this pattern did not occur. Results show that contamination by insecticide alters decomposition time and phase, altering the action of flies and beetles, affecting the abundance, composition of species as well as their activities, which can alter the data used by experts in criminal experts. investigation corpses insect s cycle occurrence However expertise Therefore insecticidecontaminated plantation experiments group 2767 2 767 2.76 identified 2103 103 2.10 66 Coleoptera occur abundance activities 276 76 2.7 210 10 2.1 6 27 7 2. 21 1

ABSTRACT Corpses in Brazil are commonly hidden in sugarcane plantations in the attempt to delay their finding and hinder the solution of the crime. On the other hand, these plantations are regularly sprayed with insecticides for pest control. Until now no study has reported the effects of insecticides on ant fauna. This study aimed to test the hypothesis that if a body hidden in a monoculture is accidentally contaminated by an insecticide, both the carcass decomposition pattern and the Formicidae fauna will be affected. To accomplish this, pig carcasses contaminated and non-contaminated were placed in a sugarcane monoculture environment and subsequently examined for data collection every 24 hours. The concentration used to contaminate the carcasses was 20 grams per liter of thiamethoxam. The decomposition patterns of contaminated carcasses were changed, in turn affecting the behavior of Formicidae fauna. A total of 5318 ants were collected, 3397 in contaminated carcasses and 1919 in non-contaminated carcasses, and 30 species of 11 genera were identified. According to the analysis, there are no differences between the composition of species between contaminated and non-contaminated carcasses, however, a significant difference was observed in the composition of species along the stages of decomposition between the two types of carcasses. Therefore, our hypothesis has been confirmed, contaminated carcasses undergo changes in their normal pattern of decomposition and the fauna of ants that act on them. As this group of insects has great importance for forensic sciences, the analysis of the experts should take these results into account.

Resumen La intoxicación aguda con plaguicidas es un problema de salud pública mundial. En los países en desarrollo los plaguicidas causan hasta un millón de casos de intoxicación y hasta 20.000 muertes anuales. En México, se ha reportado que debido a las intoxicaciones por xenobióticos, entre ellos los plaguicidas, fallecen 1.400 personas anualmente. En el presente trabajo se optimizó un método para detectar y cuantificar malatión en larvas de mosca (Diptera) de tercer estadio, que eclosionaron sobre carne de cerdo Sus scrofa domesticus tratada con la dosis letal de malatión para humanos (60 g/60 kg). Se trabajó con una biomasa de 1,5 g a la cual se le agregó 1,2 mL de fase, se agitó por espacio de 5 min y se centrifugó por 10 min a 10.000 rpm. El sobrenadante se analizó por HPLC, usando una fase de metanol-agua (70/30). El tiempo de retención del malatión fue de 4,1 min. Se encontró que el límite de detección fue de 0,301 ppm de malatión; la técnica y el procedimiento utilizados servirán como herramienta indirecta para identificar la presencia de este tóxico de una manera relativamente sencilla y su uso en casos judiciales.

Abstract Acute pesticide poisoning is a global public health problem. In developing countries pesticides cause up to one million cases of poisoning and up to 20,000 deaths annually. In Mexico, it has been reported that due to intoxications by xenobiotics, among them pesticides, 1,400 people die annually. In the present work a method was optimized to detect and quantify malathion in third instar fly larvae (Diptera) that hatched in pork meat, Sus scrofa domesticus, treated with the lethal dose in humans of malathion (60 g/60 kg). A biomass of 1.5 g which was added 1.2 mL of phase, stirred by space 5 min and centrifuged for 10 min at 10.000 rpm. The supernatant was analyzed by HPLC, using a methanol-water phase (70/30). The retention time of malathion was 4.1 min. The detection limit was calculated at 0.301 ppm. The technique and procedure used will serve as an indirect tool to identify the presence of the toxin in a relatively simple way in court cases.

The use of insects to identify drugs in a cadaver has often been explored in the field of entomotoxicology. There are accurate methods; however, they require a high cost and are very time-consuming. The objective of this study was to develop two methods based on differential pulse voltammetry (DPV) and fluorescence excitation-emission matrix (EEM) spectroscopy to classify necrophagous larvae (Chrysomya megacephala, C. albiceps, Lucilia sp. and Cochliomyia macellaria) containing flunitrazepam. The voltammograms of larval extract samples were analyzed by principal component analysis (PCA), successive projection algorithm (SPA) and genetic algorithm (GA): linear and quadratic discriminant analysis (LDA and QDA). The EEM fluorescence data from larval extract samples were analyzed by 2D and parallel factor analysis (PARAFAC) with LDA. These results suggest that DPV and EEM combined with chemometrics can be used as tools for the classification of flunitrazepam in fly larvae presenting innovative applications.