Effects of ivermectin on development of Calliphora vicina, Robineau-Desvoidy 1830 (Diptera, Calliphoridae).

Ivermectin is one of the most widely used drugs for parasite control. Previous studies have shown a reduction in the abundance and diversity of "non-target" coprophilous organisms due to the presence of ivermectin (IVM) in bovine faecal matter (FM). Due to its breadth of behavioural habits, Calliphora vicina is a suitable dipteran species to evaluate the effects of IVM in FM. The aim of this work was to evaluate the effect of five concentrations of IVM in FM (3000, 300, 100, 30, and 3 ng/g) on the development of C. vicina. The following endpoints were evaluated: survival (between the first larval stage and emergence of new adults), larval development times to pupation and pupation times to adult, and adult emergence (% sex) and LC50. Sampling was performed from larval hatching at 60 and 120 min and at 3, 4, 5, and 12 h, and every 24 h specimens were weighed until pupae were observed. Data were analysed by ANOVA using a non-parametric Kruskal-Wallis test and as a function of elapsed development time and accumulated degree hours (ADH). Mortality at 3000 and 300 ng/g was 100% and 97%, respectively. There were statistically significant delays in adult emergence time (p = 0.0216) and in the ADH (p = 0.0431) between the control group (C) and 100 ng/g. The LC50 was determined at 5.6 ng/g. These results demonstrate the lethal and sub-lethal effects of IVM on C. vicina, while highlighting the usefulness of this species as a bioindicator for ecotoxicological studies.

The Effects of Gunshot Residue Components (Pb, Ba, and Sb) on the Life History Traits of Lucilia sericata (Diptera: Calliphoridae).

The present study aimed to investigate the impact of gunshot residue (GSR) components (Pb, Sb, and Ba) on the life history parameters of Lucilia sericata (Meigen, 1826) (Diptera: Calliphoridae). This experiment was carried out at the Zoology Department, the Ondokuz Mayis University in 2020. About 50 larvae, respectively were exposed to the chicken liver with four different concentrations of GSR particles and life history parameters recorded. A two-way analysis of variance (Two way ANOVA) was used on the larval weight, and length, development time, percentage of pupal and larval survival. Pearson's correlation coefficient was used to assess the association between life-history parameters and the concentration of GSR. The total development times decreased with increasing Sb, Ba, and Pb concentrations in the diets 1-3 d when compared to the control The results showed that Ba and Sb significantly decreased larval and pupal survival and GSR decreased the pupa and adult weight as compared to the control. We concluded that life-history parameters of L. sericata are sensitive to GSR residue and heavy metal changes in the environment. The presence of gunshot residue in the corpse should be kept in mind in a criminal investigation.

Effect of a novel juvenoid fenoxycarb on the pupal-adult transformation in the blowfly, Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae).

Chrysomya megacephala (Fabricius, 1794) (Diptera, Calliphoridae) acts as a vector of many disease-causing pathogens. It causes myiasis in human beings and other living vertebrates. In the present study, the effect of a juvenile hormone analog (JHA), fenoxycarb, was evaluated on pupal-adult transformation by exposing pupae (0 and 1-day-old) of blowfly. Pupae were topically treated with different concentrations of the compound, viz., 20, 40, and 80 µg/µl applied on the posterior dorsum with the help of a micropipette. The effects comprised various developmental aberrations, such as delayed pupal-adult ecdysis duration, pupal mortality, formation of pupal-adult intermediates, eclosion failure, reduced adult emergence, and formation of abnormal adults. The freshly molted pupae (0 day) were more susceptible as compared to 1-day-old pupae. Pupal mortality was highest at 80 µg. Normal adult emergence was completely inhibited at day 0 pupae treated with 80 µg of the fenoxycarb. These results demonstrate that fenoxycarb was capable of successfully inhibiting the pupal-adult transformation, and thus, it can be used to control this myiasis-causing agent.

Effect of Zolpidem Tartrate on the Developmental Rate of Forensically Important Flies Chrysomya megacephala (Diptera: Calliphoridae) and Chrysomya saffranea.

Entomotoxicology is an emerging science in the forensic investigation of death; it now influences judicial activities. Briefly, carrion flies ingest various chemicals as they feed on a cadaver. In entomotoxicology, such toxicological compounds are qualitatively and quantitatively analyzed in insects recovered from carrion. Some of these chemicals can disrupt flies' cellular physiology, leading to acceleration or delay in their developmental rate. In this study, the effect of zolpidem-contaminated tissue on the dipteran flies Chrysomya megacephala (Fabricius 1794) and Chrysomya saffranea (Bigot 1877) was assessed. Zolpidem tartrate is a sedative-hypnotic compound commonly used to treat anxiety and sleeping disorders, but it is associated with death from suicide. The effects were tested by providing the flies with liver tissue treated with various concentrations of zolpidem tartrate. The morphological parameters and development rate for all life cycle stages of treated insects were determined and used to estimate postmortem intervals. Results showed that the morphological parameters, i.e., weight, width, and length and rate of development of C. megacephala and C. saffranea was negatively associated with zolpidem tartrate concentration of C. saffranea, were negatively associated with the concentration of zolpidem tartrate, indicating that arthropod evidence evaluation can help establish the cause and time of death.

Lead toxicity in Lucilia cuprina and electrochemical analysis: a simple and low-cost alternative for forensic investigation.

Entomotoxicology allows the detection and analysis of substances such as poisons, drugs, and metals in necrophagous insects using analytical protocols. In a forensic situation related to death by gunshot, the gunshot residue (GSR) is dispersed at the crime scene and may be consumed by necrophagous insects. Lead (Pb) is the most abundant metal in GSR samples and it can be determined using non-portable methods. However, the toxicity effects of GSR samples on Lucilia cuprina (Diptera: Calliphoridae) and the detection of Pb via portable electrochemical methods have not been investigated. This study describes for the first time the toxicity analysis of Pb on immature L. cuprina through their survival rate and influence of Pb on immature development. In addition, the bioaccumulation of Pb in the larvae samples was determined based on square wave anodic stripping voltammetry (SWASV) measurements. The results revealed a low limit of detection to Pb (6.5 µg L-1) and the analytical performance was satisfactory because it measures Pb levels in larvae exposed to a diet containing 50 µg Pb g-1. Furthermore, the levels of Pb influenced the survival rate and development time of the immature L. cuprina. Larvae exposed to a high concentration of the metal (50 µg Pb g -1) showed statistically significant changes (p < 0.05). The presence of Pb in immature L. cuprina can be used to estimate the post-mortem interval; thus, the present study provides important information in forensic entomology.

Effect of Terbufos (Organophosphate) on the Cadaveric Colonization Process: Implications for Postmortem Interval Calculation.

The determination of necrophagous fly specie's development time is considered an accurate method for estimating postmortem interval (PMI). However, pesticides and other chemicals can alter the flies' life cycle, inducing errors in PMI estimation. Thus, this work aimed to evaluate the effect of different doses of Terbufos (Organophosphates) on the temporal dispersion pattern and development of immature dipterans associated with decaying rat carcasses. For this, 150 g female Wistar rats received, via gavage, 200 µl of Terbufos (5 or 10 mg/kg) or distilled water (control) and, after 30 min of administration, the animals were euthanized and distributed in suspended traps to decompose under environmental conditions. The dispersing immatures were collected daily, and their development time was monitored until the emergence of adult flies. After data analysis, it was observed that Terbufos altered 1) the temporal pattern of larval dispersion; 2) the composition and structure of the colonizing assemblage (emerged adults); 3) species' development time, accelerating or delaying their cycle, depending on the dose used; and 4) the califorids and sarcophagids emergence rate, increasing the mortality of pupae from intoxicated carcasses. Thus, this work demonstrates experimentally that Terbufos directly influences the development of flies with forensic potential and discusses the implications for PMI estimation, which can assist in future investigative processes with suspected poisoning by this organophosphate.

Developmental changes in larvae of the oriental latrine fly, Chrysomya megacephala, exposed to deltamethrin.

The Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae) has a worldwide distribution and is considered of medical and veterinary importance. Its synanthropic behavior combined with the visitation of decaying organic matter allows it to mechanically transmit pathogens to human and animals. Pyrethroids are widely used pesticides, effective in low doses against a broad spectrum of insects. Our objective was to evaluate the action of K-Othrine® on the post-embryonic development of C. megacephala. First instar larvae were exposed to different concentrations of K-Othrine® (3.75 × 10-5 g a.i/mL (low), 7.5 × 10-5 g a.i/mL (intermediate low), 1.125 × 10-4 g a.i/mL (intermediate), 1.5 × 10-4 g a.i/mL (intermediate high), and 2.5 × 10-4 g a.i/mL (high)) mixed into artificial diets and a control with no pesticide. We measured weight, time of development, sex ratio, larval and pupal mortality, and esterase patterns. The mean weight values at intermediate low and intermediate concentrations were significantly lower compared with the control; additionally, the development time was delayed compared with the control. The larval and pupal mortality differed among the treatments. The larvae had six esterase regions, which altered its relative activity at 48 h and 72 h after insecticide ingestion. Further studies must investigate the effects of different insecticides on the post-embryonic development of C. megacephala.

Optimizing a Dual-Choice Cube Olfactometer Design for Measuring Adult Secondary Screwworm (Diptera: Calliphoridae) Attraction to a Resource.

Detecting and locating a carrion resource is critical for the reproduction of necrophagous insects and initiating forensically important timelines. Blow flies (Diptera: Calliphoridae) primarily use olfactory cues in the form of volatile organic compounds to locate a suitable resource. Factors governing detecting and locating a resource have been studied using various behavior assays with modifications to suit the experiment design, such as the dual-choice cube olfactometer, which was examined in the current study. Systems optimization ensures biologically relevant and consistent results across replicates. In this study, two responses were measured: 1) leaving cube for either control or treatment and 2) choice between control and treatment. Phenotype (e.g., male, non-gravid, gravid) and total blow fly, Cochliomyia macellaria (Fabricius) (Diptera: Calliphoridae), number to respond were measured. Four parameters were assessed for their impact on response: 1) adjustment time in cube before trial, 2) trial length, 3) sugar/water presence, and 4) screening type in arms. Approximately, 70% of all phenotypes responded to liver with the 30-min adjustment period where only 50% responded with other adjustment periods. Trial length had a significant impact on response (35% increase in the 8 h trial compared to shorter durations); however, significant response to treatment was lost by increasing trial length. The presence of sugar/water decreased gravid and non-gravid response by 35% but did not impact males. Screening had no influence on overall or treatment response. Data indicate experiment design impacts fly response. Future studies should optimize parameters for their given fly population prior to initiating experiments.

Chrysomya bezziana (Diptera: Calliphoridae) infestation in two Malaysian cats treated with oral lotilaner.

The most common fly species associated with screwworm myiasis in Southeast Asia is Chrysomya bezziana (Ch. bezziana), the Old-World screwworm. Treatment of screwworm myiasis in cats traditionally has comprised subcutaneous injection of ivermectin or oral administration of nitenpyram, combined with aggressive tissue debridement and larval removal under general anaesthesia. Two cats diagnosed with cutaneous myiasis caused by the larvae of Ch. bezziana were treated with lotilaner. In both cats, a single dose of lotilaner at 6-26 mg/kg, killed all larvae within 24 h, negating the need for general anaesthesia. Both cats were simultaneously infested with Lynxacarus radovskyi (L. radovskyi) which also was eradicated with lotilaner. No adverse reactions were observed and both cats recovered without complications.

L'espèce de mouche la plus fréquemment associée à la lucile bouchère en Asie du sud-est est Chrysomya bezziana (Ch. bezziana), espèce du vieux continent. Le traitement chez le chat consiste en une injection sous-cutanée d'ivermectine ou une administration orale de nitenpyram, associé à un débridement tissulaire agressif et retrait des larves sous anesthésie générale. Deux chats avec myase cutanée causée par les larves de Ch. Bezziana ont été traités avec lotilaner. Pour les deux chats, une dose unique de lotilaner à 6-26 mg/kg, a tué toutes les larves en 24h, sans besoin d'anesthésie générale. Les deux chats ont été infestés simultanément par Lynxacarus radovskyi (L. radovskyi) qui a également été éradiqué par le lotilaner. Aucune réaction indésirable n'a été observée chez les deux chats guéris sans complication.

La especie de mosca más común asociada con la miasis de larvas barrenadoras en el sudeste asiático es Chrysomya bezziana (Ch. Bezziana), la larva barrenadora del Viejo Mundo. El tratamiento de la miasis de larva barrenadora en los gatos ha consistido tradicionalmente en inyección subcutánea de ivermectina o administración oral de nitenpiram, combinado con debridamiento agresivo de tejido y eliminación de larvas bajo anestesia general. Dos gatos diagnosticados con miasis cutánea causada por las larvas de Ch. bezziana fueron tratados con lotilaner. En ambos gatos, una dosis única de lotilaner a 6-26 mg/kg, eliminó a todas las larvas en 24 h, evitando la necesidad de anestesia general. Ambos gatos estaban infestados simultáneamente con Lynxacarus radovskyi (L. radovskyi), que también fue erradicada con lotilaner. No se observaron reacciones adversas y ambos gatos se recuperaron sin complicaciones.

A espécie de mosca mais comumente associada à miíase no sudeste da Ásia é a Chrysomya bezziana (Ch. bezziana), a larva de rosca do Velho Mundo. O tratamento da miíase por larva de rosca em gatos tradicionalmente inclui injeção subcutânea de ivermectina ou administração oral de nitempiram, associado com debridamento agressivo do tecido e remoção larval sob anestesia geral. Dois gatos diagnosticados com miíase cutânea causada pelas larvas de Ch. bezziana foram tratados com lotilaner. Nos dois gatos, uma dose única de lotilaner de 6 a 26 mg / kg matou todas as larvas em 24 horas, negando a necessidade de anestesia geral. Ambos os gatos foram infestados simultaneamente com Lynxacarus radovskyi (L. radovskyi), que também foi erradicada com lotilaner. Nenhuma reação adversa foi observada e os dois gatos se recuperaram sem complicações.

Effects of Methamphetamine on the Development and Its Determination in Aldrichina grahami (Diptera: Calliphoridae).

Age determination of necrophagous flies serves as an important tool for postmortem interval (PMI) estimation in forensic investigations. Drugs or toxins in cadavers may alter the developmental time of larvae, and lead to deviation in PMI estimation. Methamphetamine (MA), as one of the most abused psychostimulant drugs in Asia and North America, is often involved in forensic entomotoxicological cases. This study investigated the effects of MA (0, 45, 90, and 180 ng/mg) on the developmental rate, morphology, and survival of Aldrichina grahami (Aldrich, 1930). The results showed that 1) the developmental time to reach the pupal instar was statistically slower for the larvae reared on rabbit mince containing MA than for the control; 2) the mean length of the larvae exposed to MA concentrations was longer than those of the control; 3) the mean weight of the pupae exposed to the highest concentration of MA was significantly lighter than those of the control; 4) the GC-MS method can detect the content of MA in A. grahami immatures and empty puparia (EP).