Insect faunal succession on buried goat carcass in Aligarh Region of Uttar Pradesh, India, with implications in forensic entomology

Background Studies on the insect fauna of animal corpses, used as a vertebrate model, may help forensic investigation cases to estimate the post-mortem-interval (PMI), cause of death, and crime-scene location. Likewise, entomofauna of buried corpses can assist in determining the post-burial-interval (PBI), movement of the body or hiding of the crime. The bodies buried under the soil decompose at a slower rate than the body exposed. Also, there are fewer insects that can go underground to locate the corpse. Such types of studies on the insect fauna of buried carrion can help in forensic investigation cases. The current study aims to determine the succession of a goat carcass buried shallowly in an outdoor habitat of the Aligarh Region, North India. Results In the present study, we examined a goat carcass buried at a depth of nine inches to determine the type of insects capable of colonizing buried animal carcass in the study area of Aligarh, Uttar Pradesh, India. We have found five species of Diptera, three species of Coleoptera, one Hemipteran species, and one Hymenopteran species. Adult Dipterans found during different samplings were Megaselia scalaris (Loew 1866), Chrysomya megacephala (Fabricius 1794), and Calliphora vicina (Robineau-Desvoidy, 1830). Dipterans’ immature stages were found to be of Synthesiomyia nudiseta (van der Wulp, 1883) and Hydrotaea capensis (Wiedemann, 1830) Megaselia scalaris. Adults of Saprinus quadriguttatus (Fabricius, 1798), Saprinus splendens (Paykull, 1811), and Onthophagous quadridentatus (Fabricius, 1798) of order Coleoptera. Adult Cydnus species (Fabricius, 1803) of Hemiptera and Dorylus species (Fabricius, 1793) of Hymenoptera have also been recorded. During the sampling, the authors reported the stages of carcass disintegration and the insects associated with it. Conclusions Flies, beetles, and ants have been recorded in association with the buried goat carcass, which may add to the knowledge of colonization of buried bodies in India and around the globe. S. nudiseta, H. capensis, and M. scalaris, which are found on the goat carrion in the current study, have also been reported on human corpses in the past. Furthermore, M. scalaris found consistently on two sampling dates beneath the ground on the goat carcass and was also seen running on the grave’s surface. In addition, authors have reported several species belonging to different order and families, corresponding to various stages of decomposition of corpse which were earlier not known from buried corpses from India. So, it is crucial and may have implications in medicolegal cases.

Unwelcome guests at farms breeding the black soldier fly, Hermetia illucens (L.) (Diptera Stratiomyidae)

Livestock farms represent a source of attraction for other species, which find food resources on the animals themselves, in the food supplied to them, in their manure, etc. Insect farms too can suffer infestation by different organisms living on substrates or behaving as parasites and/or predators. Breeding of the black soldier fly (BSF), Hermetia illucens (L.) requires organic materials which are attractive for other arthropods (commensals, mycetophages, scavengers, etc.). During recent years, the breeding system adopted at the Di.Pro.Ve.S. of the Università Cattolica del Sacro Cuore, Piacenza (Italy), has suffered the presence of the following ‘pests’: Megaselia scalaris (Loew) (Diptera Phoridae), Muscina stabulans (Fallén) (Diptera Muscidae), Monomorium pharaonis (L.) (Hymenoptera Formicidae) and Caloglyphus berlesei (Michael) (Astigmata Acaridae). The use of fermented fruit, vegetables or of an artificial diet to induce egg laying proved to be attractive for small flies such as M. scalaris. This species also takes advantage of the aqueous sugar solution used to feed BSF adults. Infestations by M. scalaris are worrying because its larvae can compete efficiently with those of the BSF in substrate colonisation. Likewise, M. stabulans can be attracted by the substrates, even though this species has not shown the same levels of high competitiveness as the previously mentioned species. M. pharaonis was observed to prey on eggs and newborn BSF larvae. Lastly, infestations by the mite C. berlesei were detected when conditions for the larval development of the BSF were not optimal. This species could also be harmful for the workers involved in the breeding. The establishment of insect and mite populations inside BSF rearing boxes suggests that a careful analysis should be made based on the location of the breeding facility and a series of measures should of course be adopted when this kind of structure and activities are designed and realised.

First record of a parasitoid, Megaselia (M) scalaris (Diptera: Phoridae) of fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) from India

The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), has become a major threat in maize cultivation since its invasion to India in 2018. The humpbacked fly, Megaselia scalaris (Loew) (Diptera: Phoridae), was recorded as a laboratory parasitoid of FAW, for the first time in India. Initially, 30–40 maggots of M. (M) scalaris emerged out from the dead pre-pupa and pupa of laboratory-reared FAW. The fly laid up to 15 eggs on the outer surface of 6th instar larva or pre-pupa of the FAW. The incubation period was 1–2 days. The fly had 3 larval instars which lasted 3–4 days and a pupal period of 10–11 days. The adults survived for 6–7 days.

A Study of the Pupal Development of Five Forensically Important Flies (Diptera: Brachycera)

Holometabolous insects undergo complete metamorphosis, and hence, they have different phases of development (egg, larva, pupa, and adult), which occupy distinct ecological niches. The pupae of several fly species are surrounded by the puparium, which is a rigid structure, usually formed by the integument of the last larval instar. The puparium presents unique characteristics distinct from those of the larval and adult phases. During intrapuparial development, it is possible to distinguish at least four fundamental and continuous steps, namely: 1) larval–pupal apolysis, 2) cryptocephalic pupa, 3) phanerocephalic pupa, and 4) pharate adult. The objective of this work was to describe the external morphology of the distinct phase of development for five species that were collected, identified, and raised in the laboratory; intrapuparial development was studied by fixing immature specimens at regular intervals; the morphological analyses were performed with the aid of both light and scanning electron microscopy. Under the conditions established (27 ± 1.0 or 23 ± 1.0°C, 60 ± 10% relative humidity, 12 h of photoperiod), the minimum time for intrapuparial development was: 252 h for Megaselia scalaris (Loew 1966) (Phoridae), 192 h for Piophila casei (Linnaeus 1758) (Piophilidae), Fannia pusio (Wiedemann 1830) (Fanniidae), and Musca domestica (Linnaeus 1758) (Muscidae), and 96 h for Chrysomya megacephala (Fabricius 1794) (Calliphoridae). Intrapuparial development has defined steps, and distinct species responded differently to the same environmental conditions. In addition, it is possible to establish a sequential rule without ignoring the specific characteristics of each taxon.

First detection of Megaselia scalaris (Loew) (Diptera: Phoridae) as a facultative endoparasitoid of Nezara viridula (L.) (Hemiptera: Pentatomidae)

Background The phorid fly Megaselia scalaris (Loew) (Diptera: Phoridae) is an omnivorous species, capable of exploring a large variety of environments and ecological niches. It is known as an important detritivore species with maggots feeding on a variety of food of both animal and plant origin. Results The present study reports M. scalaris as an endoparasitoid attacking colonies of the southern green stink bug Nezara viridula (L.) for the first time. This case of parasitism was observed inside rearing cages of N. viridula at the Plant Protection Research Institute, Dokki, Egypt in August 2020. We firstly identified adult individuals of M. scalaris which were found moving erratically within the cages using relevant identification keys. To verify that N. viridula individuals are parasitized by the same parasitoid and they are not infected with other parasitoids, some of the parasitized bugs were transferred to a separate cage at the same laboratory conditions and the developmental stages of the dipteran parasitoid were observed until the adult emergence. Conclusion The present investigation revealed that M. scalaris could be included to the recorded parasitoid species of N. viridula, and further studies should be carried out to assess the efficacy of this fly as a biocontrol agent.

First Report on Megaselia scalaris Loew (Diptera: Phoridae) Infestation of the Invasive Pest Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) in China

The invasive pest Spodoptera frugiperda first emerged in China in January 2019 and has, to date, migrated to 29 provinces and municipalities in China, causing heavy crop damage in large areas. As a response to this invasive species from the environment, some indigenous natural enemies have been discovered and reported after S. frugiperda invasion. In this paper, parasitic flies were collected and identified from S. frugiperda collected in the Yunnan, Guangxi, and Henan provinces and the Chongqing municipality in China. By using both conventional and molecular approaches, we were able to show that all the parasitic flies of S. frugiperda identified in the four regions were Megaselia. scalaris, and that they attacked the pest larvae and pupae. This is the first report on an indigenous Chinese Megaselia species that has parasitic ability against the invasive pest S. frugiperda, potentially providing new ideas for pest control in China.