Morphology and identification of first instars of the European and Mediterranean blowflies of forensic importance. Part II. Luciliinae

An illustrated identification key to early instar larvae of forensically important Muscidae (Diptera) of the western Palaearctic region

There is a significant gap in the availability of comprehensive identification keys for the early larval stages of forensically important fly species. While well-documented identification keys exist for the third instar larvae, particularly for the Calliphoridae, Muscidae and Sarcophagidae families, there is a notable scarcity of keys for the first, except Calliphoridae, and the second instar larvae, with no such resources available for muscid species. The second instar larvae suffer the most from the lack of morphological descriptions and available identification keys. The Muscidae is one of the most frequently reported dipteran families of forensic importance colonising animal cadavers and human corpses. Nevertheless, descriptions of the morphology of their early instars remain scarce and limited to only a few species, thus their larval identification is challenging or impossible. Considering the numerous challenges associated with studying small-sized entomological material, we tested whether it is feasible to identify muscid flies to the species or at least genus level based predominantly on the details of the cephaloskeleton. To overcome the obstacle of observing details of small sclerites, especially their shapes and interconnections, we effectively employed confocal laser scanning microscopy (CLSM) as a supplementary method for light microscopy (LM). This study provides an identification key for first and second instar larvae of forensically important muscid species from the western Palaearctic (Europe, North Africa, Middle East). The proposed key primarily utilises details of the cephaloskeleton with only addition of external morphology.

Pedicle myiasis by Lucilia caesar (Diptera, Calliphoridae): An emerging disease in roe deer from north-western Spain

A total of 35 male roe deer (Capreolus capreolus) from Lugo province (north-western Spain) were examined for pedicle myiasis between 2020 and 2022. All these animals had died by different causes and were examined or preserved just after their death to avoid post-mortem infestations. After external and internal head inspection, five animals were diagnosed with severe myiasis at the basis of the antlers (14.29%; 95% confidence interval = 5.38-31.04). All the affected bucks presented a cutaneous wound (1.5-15 cm in diameter) around the pedicles with extensive tissue destruction, exposition of frontal and parietal bones, and massive infestation by dipteran larvae (2-12 mm long). Four of five roe deer showed whitish egg clusters adhered to the basis of the antlers. Moreover, in one animal, six larvae had penetrated the cranial cavity, and in two of them larvae were also found in the nasopharyngeal cavity. All the cases were recorded in summer (May-August). Morphological identification and subsequent molecular confirmation revealed that all animals were infested by different larval stages of Lucilia caesar (Diptera: Calliphoridae). This study represents the first report of pedicle myiasis in Spain. Since this disease is reported sporadically, the detection of five cases in a short period of time suggests an increase in the incidence of this myiasis.

Interactive Key for Third Instar Larvae of Neotropical Blow Flies (Insecta, Diptera, Calliphoridae): the Contribution of Computational Tools to Assist in Species Identification

Calliphoridae (Insecta, Diptera), popularly known as blow flies or carrion flies, as most are necrophagous comprises one of the most relevant families of insects on forensics. Currently, more than 1500 blow fly species are known, the majority of which can be found in the Old World. In the Neotropics, it is estimated that there are approximately 20 species of forensic importance. In view of the taxonomic impediment associated with the identification of immatures, in this study, we present an interactive identification key for third instar larvae of necrophagous Calliphoridae species. This key includes 12 Neotropical blow fly species of forensic importance, more than 70 pictures, schemes, and definitions glossary and is free to access.

A preliminary study on the distribution of necrophagous flies on Hainan Island, China

To date, there have been no studies on necrophagous fly populations on Hainan Island in China. Thus, we investigated the species composition of necrophagous flies as well as their geographic distribution on Hainan Island for the first time. Ten sites in different climatic regions across the island were sampled for 7 days per location from November 1, 2018 to February 28, 2019 and from July 1, 2019 to October 31, 2019. Bottle traps made of 1.5 L soft plastic bottles were used to trap necrophagous flies. The collected individuals were identified to species. The specimens represented 5 families and 28 species. Chrysomya megacephala (Fabricius, 1794) was the most dominant species, followed by Chrysomya rufifacies (Macquart, 1843), Hemipyrellia ligurriens (Wiedemann, 1830), Boettcherisca peregrine (Robineau-Desvoidy, 1830), Parasarcophaga dux (Thomson, 1868), Parasarcophaga misera (Walker, 1849), Synthesiomyia nudiseta (Wulp, 1883), and Ophyra chalcogaster (Wiedemann, 1924). The largest collection of flies was obtained in the semiarid region. Species richness was highest in the subhumid region and was higher in summer than in winter, but there were exceptions, such as L. hainanensis (Fan,1965), Boettcherisca formosensis (Lopes, 1961), and Muscina stabulans (Fallen, 1817). Fannia pusio (Wiedemann, 1830), and Boettcherisca formosensis (Lopes, 1961) were newly recorded species on Hainan Island. Of the necrophagous flies collected during the study, we propose several predominant species based on the criteria of distribution, occurrence frequency, and resource preference. Our results not only investigate necrophagous flies on Hainan Island but also accumulate data for criminal investigations in the region.

Wound myiasis in a wild boar by Lucilia caesar (Diptera: Calliphoridae): First case and current status of animal myiasis by this species

The first case of myiasis caused by Lucilia caesar (L.) (Diptera: Calliphoridae) in a wild boar, Sus scrofa L. (Artiodactyla: Suidae) is described. The myiasis occurred in October 2019 in Southern Italy and the identification of the agent was based on adult male morphology. The wild boar had a wound on its right side, near the neck, which was largely infested by larvae. The ecology, distribution and current literature status about cases of animal myiasis by this species is also included.

Ultrastructure of the Immature Stages of Musca domestica (Diptera: Muscidae: Muscinae)

Musca domestica (Linnaeus, 1758) is a muscoid species that is widespread throughout the world and acts as a mechanical vector of different enteropathogens primarily in underdeveloped countries. The adult and its immature forms are associated with decaying organic matter and can be seen visiting human corpses and animal carcass, and the larvae can also cause an infestation on human and animal wounds, feeding on the tissues. These characteristics make them have a forensic significance and, mainly, a great sanitary importance. This study aimed to analyze and describe morphological aspects of their immature stages of M. domestica, including the eggs, the first-, second-, and third-instar larvae, and the puparium using scanning electron microscopy (SEM). The eggs have standard format that all muscoid flies shared. The exochorion has some modified cells that were used for embryonic respiration. The first-instar larvae present two openings on the posterior spiracle as in the second-instar larvae, but with the last one, we can observe the anterior spiracle structure. The third-instar larvae, as in some other Muscidae species, have a posterior spiracular opening with a sinuous form that is located near the edge of the spiracular plate. The puparium morphology is equal to the third instar with a respiratory structure that helps the breathing during the metamorphosis process. This article supports the need for knowledge over the morphological characteristics of the immature forms of the muscoid Diptera (Linnaeus, 1758) at the same time helping with the correct identification of this insect phase.

Detection of benzodiazepines in decomposing rabbit tissues and certain necrophagic dipteran species of forensic importance

The determination of benzodiazepines (carbamazepine and clobazam) in rabbit carcass tissues and larvae of three Calliphorid flies is described. After feeding the rabbits with lethal and toxic doses, samples of larvae and carcass tissues were studied. Residual drugs were determined using Ultra-high-performance liquid chromatography – quadrupole time-of-flight mass spectrometry (UHPLC/QTOF-MS). Benzodiazepines and its main active metabolites have been detected in the rabbit tissues at different retention times depending on the dosage used (lethal or toxic). A total of 1150 insects were collected and 800 larvae of the flies Chrysomya albiceps, Lucilia sericata and L. silvarum were used in the analysis. The presence of benzodiazepines in the rabbit tissues has been shown to typically affect the larval development cycle of the three necrophagous flies. Chrysomya albiceps larvae feed on drugs developed faster, while the development of L. sericata and L. silvarum larvae slowed. These results indicate that drugs have an impact on the life cycles of insects, which suggests that the presence of these substances is a factor that needs to be taken into account when estimating the post-mortem interval (PMI).

Nosocomial Myiasis Caused by Lucilia sericata (Diptera: Calliphoridae) in a Pediatric Patient in Mexico

Prevention of nosocomial myiasis, or hospital-acquired larvae infestation, should be an essential part of all hospital infection control programs. However, little is known about nosocomial myiasis, despite the extensive medical and psychological effects it has on patients and their families and the negative effects it has on hospitals' reputation and finances. This report describes a case of nosocomial myiasis of a 13-year-old boy who was admitted to a pediatric intensive care unit for congestive heart failure, anemia, uremic encephalopathy, hypertension, and severe respiratory distress. Ten days after admission, the pediatrician and the nurse perceived an increase in the volume of the gingival mucosa of the upper buccal vestibule and the presence of fly larvae. The maggots were sent to the Instituto de Diagnostico y Referencia Epidemiologicos for identification and were found to be Lucilia sericata larvae. This report highlights the need to educate medical and paramedical personnel, as well as creation and implement protocols in hospitals to avoid nosocomial myiasis and improvement of general sanitation.

Forensically Relevant Blow Flies in Lebanon Survey and Identification Using Molecular Markers (Diptera: Calliphoridae)

Calliphoridae are among the first insects associated to decomposing animal remains. We have collected 1,841 specimens of three calliphorid genera: Calliphora, Lucilia, and Chrysomya, from different Lebanese localities as a first step in implementing a database of insects of forensic relevance for the country. Blow-flies are crucial for the estimation of the postmortem interval. DNA-based identification is a rapid and accurate method, often used for morphologically similar species, especially for immatures or incomplete specimens. In this study, we test the suitability of three genetic markers to identify adults and immature stages of calliphorids, viz., mitochondrial cytochrome c oxidase subunit I (COI) barcode, a region including partial sequences of mitochondrial Cyt-b-tRNAser-ND1, and second internal transcribed spacer (ITS2) region of nuclear ribosomal DNA. Forty Lebanese specimens of various developmental stages (egg, larva, wandering third instar, pupa, newly emerged adult, and mature adult) were identified among the three calliphorid genera: Calliphora, Lucilia, and Chrysomya, and compared with published sequences to confirm their specific assignation. Phylogenetic analyses showed the robustness of ITS2 and COI to identify calliphorids at species level. Nevertheless, ITS2 failed to discriminate Lucilia caesar (Linnaeus) (Diptera, Calliphoridae) from Lucilia illustris (Meigen) (Diptera, Calliphoridae), and COI had a similar issue with Lucilia sericata (Meigen) (Diptera, Calliphoridae) and Lucilia cuprina (Wiedemann) (Diptera, Calliphoridae). Thus, these two markers are complementary. This work contributes new nucleotide sequences for Lebanon. It is a first step in implementing a molecular database of forensic relevant insects for the country.

DNA Barcoding in Forensic Entomology - Establishing a DNA Reference Library of Potentially Forensic Relevant Arthropod Species

Throughout the years, DNA barcoding has gained in importance in forensic entomology as it leads to fast and reliable species determination. High-quality results, however, can only be achieved with a comprehensive DNA barcode reference database at hand. In collaboration with the Bavarian State Criminal Police Office, we have initiated at the Bavarian State Collection of Zoology the establishment of a reference library containing arthropods of potential forensic relevance to be used for DNA barcoding applications. CO1-5P' DNA barcode sequences of hundreds of arthropods were obtained via DNA extraction, PCR and Sanger Sequencing, leading to the establishment of a database containing 502 high-quality sequences which provide coverage for 88 arthropod species. Furthermore, we demonstrate an application example of this library using it as a backbone to a high throughput sequencing analysis of arthropod bulk samples collected from human corpses, which enabled the identification of 31 different arthropod Barcode Index Numbers.

Description of Larval Instars To Fill a Gap in Forensic Entomology: The Larvae of Paralucilia pseudolyrcea (Diptera: Calliphoridae)

A fundamental assumption of forensic entomology for estimating the postmortem interval is that insect species are accurately identified, which depends on diagnostic morphological characters. Larvae of the blow fly Paralucilia pseudolyrcea (Mello, 1969) (Diptera: Calliphoridae) were sampled from four corpses in the state of Paraná, Brazil, but despite the forensic importance of this species, morphological data for the identification of its larval instars are lacking, limiting its usefulness in such cases. Thus, the main goal of this study was to describe the larval instars of P. pseudolyrcea. The material was obtained from a colony established by larvae collected from a corpse of a murder case. Overall, the distribution of spines is a key character for identifying this species in the first, second and third instars. Other characteristics, such as the presence of an accessory oral sclerite, the small cirri, the number of lobes of the anterior spiracle and the morphology of posterior spiracles, separates P. pseudolyrcea from other necrophagous blow flies. The detailed morphological description provided here facilitates the identification of larval instars of P. pseudolyrcea and their differentiation from those of other calliphorid species.

Morphology of immature stages of blow fly, Lucilia sinensis Aubertin (Diptera: Calliphoridae), a potential species of forensic importance

Lucilia sinensis Aubertin (Diptera: Calliphoridae) is a blow fly species of potential forensic importance since adults are attracted to, and colonize, decomposing vertebrate remains. Blow fly larvae associated with human corpses can be useful evidence in forensic investigations; however, their use is dependent in most cases on proper species identification and availability of developmental data. For identification, morphological information on each life stage is traditionally used. We used scanning electron microscopy (SEM) to examine the ultrastructure of eggs, all instars, and puparia, of L. sinensis. The important characteristics used to differentiate L. sinensis from other species are provided. Distinctive features of the eggs are the slight widening median area extending almost the entire length. The last abdominal segment of the first instar bears elongated outer ventral tubercles along the rim of the last abdominal segment. These tubercles, as well as the well developed median and outer dorsal tubercles, are more prominent in the second and third instars. The surface integument of the tubercles is equipped with circular rows of microtrichia. Pairs of inner dorsal tubercle are absent. Each anterior spiracle is comprised of 9-12 papillae arrange in a single row in the second and third instars. As for the third instar, the dorsal spines between the first and second thoracic segments are delicate, narrow, small, and close together (as row or set). The peristigmatic tufts adjacent to the posterior spiracle of the third instar are moderately branches of short, fine hairs, but minute in puparia. In conclusion, the prominent outer ventral tubercle in all instars and puparia is a new diagnostic feature of L. sinensis and helpful in differentiating it from other Lucilia species that are forensically important. The description of immature L. sinensis in this study will be useful for forensic entomologists in countries where this species exists.

DNA-barcoding of forensically important blow flies (Diptera: Calliphoridae) in the Caribbean Region

Correct identification of forensically important insects, such as flies in the family Calliphoridae, is a crucial step for them to be used as evidence in legal investigations. Traditional identification based on morphology has been effective, but has some limitations when it comes to identifying immature stages of certain species. DNA-barcoding, using COI, has demonstrated potential for rapid and accurate identification of Calliphoridae, however, this gene does not reliably distinguish among some recently diverged species, raising questions about its use for delimitation of species of forensic importance. To facilitate DNA based identification of Calliphoridae in the Caribbean we developed a vouchered reference collection from across the region, and a DNA sequence database, and further added the nuclear ITS2 as a second marker to increase accuracy of identification through barcoding. We morphologically identified freshly collected specimens, did phylogenetic analyses and employed several species delimitation methods for a total of 468 individuals representing 19 described species. Our results show that combination of COI + ITS2 genes yields more accurate identification and diagnoses, and better agreement with morphological data, than the mitochondrial barcodes alone. All of our results from independent and concatenated trees and most of the species delimitation methods yield considerably higher diversity estimates than the distance based approach and morphology. Molecular data support at least 24 distinct clades within Calliphoridae in this study, recovering substantial geographic variation for Lucilia eximia, Lucilia retroversa, Lucilia rica and Chloroprocta idioidea, probably indicating several cryptic species. In sum, our study demonstrates the importance of employing a second nuclear marker for barcoding analyses and species delimitation of calliphorids, and the power of molecular data in combination with a complete reference database to enable identification of taxonomically and geographically diverse insects of forensic importance.

Connecting the Dots: From an Easy Method to Computerized Species Determination

Differences in growth rate of forensically important dipteran larvae make species determination an essential requisite for an accurate estimation of time since colonization of the body. Interspecific morphological similarities, however, complicate species determination. Muscle attachment site (MAS) patterns on the inside of the cuticula of fly larvae are species specific and grow proportionally with the animal. The patterns can therefore be used for species identification, as well as age estimation in forensically important dipteran larvae. Additionally, in species where determination has proven to be difficult—even when employing genetic methods—this easy and cheap method can be successfully applied. The method was validated for a number of Calliphoridae, as well as Sarcophagidae; for Piophilidae species, however, the method proved to be inapt. The aim of this article is to assess the utility of the MAS method for applications in forensic entomology. Furthermore, the authors are currently engineering automation for pattern acquisition in order to expand the scope of the method. Automation is also required for the fast and reasonable application of MAS for species determination. Using filters on digital microscope pictures and cross-correlating them within their frequency range allows for a calculation of the correlation coefficients. Such pattern recognition permits an automatic comparison of one larva with a database of MAS reference patterns in order to find the correct, or at least the most likely, species. This facilitates species determination in immature stages of forensically important flies and economizes time investment, as rearing to adult flies will no longer be required.

Wound Myiasis Caused by Sarcophaga (Liopygia) Argyrostoma (Robineau-Desvoidy) (Diptera: Sarcophagidae): Additional Evidences of the Morphological Identification Dilemma and Molecular Investigation

In Mediterranean countries, Sarcophaga (Liopygia) crassipalpis, Sarcophaga (L.) argyrostoma, and Sarcophaga (L.) cultellata share the same ecological niche and can be responsible of myiasis. In this study, the main morphological characters of a larva found in a hospitalized woman were described and illustrated by light and SEM microscopy and the features discussed. Then, a fragment within the mitochondrial encoded cytochrome c oxidase subunit I (coxI) gene of ~735 bp was amplified and sequenced. The molecular investigation was necessary to confirm the species Sarcophaga (Liopygia) argyrostoma (99% of identity). Our findings showed that morphological descriptions of larvae of three Mediterranean species of Liopygia available in several papers might not be clear enough to allow for comparison and correct identification. Until results of reliable comparative studies of larvae of all three species will be available, the use of molecular tools is crucial, to avoid misleading or incomplete identification, and in particular when a myiasis becomes a legal issue.

The blowflies of the Madeira Archipelago: species diversity, distribution and identification (Diptera, Calliphoridaes. l.)

Knowledge on the taxonomic diversity and distribution of blowflies from the Madeira Archipelago is updated. New and interesting findings are reported for poorly studied islands and islets of this archipelago, together with a brief analysis of the diversity of Macaronesian Calliphoridae s. l. Seven blowfly species were collected during this study, including the first records of Calliphora vicina Robineau-Desvoidy, 1830, Chrysomya albiceps (Wiedemann, 1819), Lucilia sericata (Meigen, 1826), Pollenia rudis (Fabricius, 1794) and Stomorhina lunata (Fabricius, 1805) from Porto Santo, and of Calliphora vicina, Lucilia sericata and Stomorhina lunata from Desertas Islands. The presence of Calliphora loewi Enderlein, 1903 in Madeira Laurisilva forest is discussed and its first instar larva is redescribed, revealing important differences in relation to its original description. An identification key to the adult Madeiran blowflies is provided for the first time.

Morphology and identification of first instar larvae of Australian blowflies of the genus Chrysomya of forensic importance

Light microscopy photographs, line illustrations and scanning electron microscopy micrographs are provided for first instar larvae of six Australian species of Chrysomya. All species have confirmed or potential in forensic investigations given their carrion-breeding habits. Morphology of the first instar larvae of Ch. nigripes, Ch. rufifacies, Ch. saffranea and Ch. varipes is revised, while larvae of Ch. incisularis and Ch. latifrons are described for the first time. The following morphological structures are documented: pseudocephalon, antennal complex, maxillary palpus, facial mask, thoracic and abdominal spinulation, spiracular field, posterior spiracles and cephaloskeleton. New diagnostic features of the cephaloskeleton and the spinulation of the abdominal segments are described. Verification of earlier descriptions revealed major discrepancies between published data, especially in the case of Ch. nigripes. The present results allow clarification, correction and, especially, complementation of the existing information provided by numerous authors. Finally, an identification key for first instar larvae of Australian necrophagous Chrysomya is presented.

Application of DNA barcoding for identifying forensically relevant Diptera from northern Thailand

In recent decades, forensic entomology has become a useful tool in criminal investigations all over the world. Species-specific identification of flies plays an important role in this field and is obligatory for accurate calculation of the post-mortem interval. However, not all important colonizers of a corpse can be identified by common morphological keys. Due to similar morphology and the lack of keys for some taxa, especially for immature stages, DNA barcoding has become more popular during the last recent years. This development is particularly important for countries like Thailand, in which forensic entomology is a newly developing research area and which faces several challenges such as a high biodiversity of fly species. The most commonly used barcoding region in forensic entomology, the mitochondrial cytochrome oxidase subunit 1 (coI) gene, as well as a 1000-bp-long region of the 28S nuclear rRNA gene, was used to analyze and establish the molecular barcodes of 13 different species of flies of forensic relevance in northern Thailand.

Muscle attachment site (MAS) patterns for species determination in European species of Lucilia (Diptera: Calliphoridae)

Species identification is generally assessed to be more difficult in larval stages than in adult forms. Especially closely related species such as Lucilia caesar and Lucilia illustris are difficult to identify. The aim of this study was to simplify species determination in Lucilia larvae for entomological and forensic purposes. Muscle attachment site (MAS) patterns were previously found to be a good tool for species determination in blowfly larvae. Here, distinctive MAS patterns are presented for European Lucilia ampullacea, L. caesar, L. illustris, L. richardsi, L. sericata, and L. silvarum. A joint pattern for the genus Lucilia is provided for a quick classification of a larva to the genus.

Confocal laser scanning microscopy as a valuable tool in Diptera larval morphology studies

Larval morphology of flies is traditionally studied using light microscopy, yet in the case of fine structures compound light microscopy is limited due to problems of resolution, illumination and depth of field, not allowing for precise recognition of sclerites' edges and interactions. Using larval instars of cyclorrhaphan Diptera, we show the usefulness of confocal laser scanning microscopy (CLSM) for studying the morphological characters of immature stages by taking advantage of the autofluorescent properties of cephaloskeleton structures. We compare data obtained from killed but unprepared larvae with those from larvae prepared by clearing according to two commonly used methods, either with potassium hydroxide or with Hoyer's medium. We also evaluated the CLSM application for examining already slide-mounted larvae stored in museum collections and those freshly prepared. Our results indicate that CLSM and 3D reconstruction are excellent for visualizing small, compound structures of cylrorrhaphan larvae cephaloskeleton, if appropriate clearing techniques, i.e. the application of KOH, are used. Maximum intensity projection of confocal data sets obtained from material freshly prepared and that stored in museum collection does not differ. Because of this and the fact that KOH is commonly used as a clearing method to examine the cephaloskeleton of Diptera larvae, it is possible, and highly recommended, to use slides already prepared with this method for re-examination by CLSM. We conclude that CLSM application can be an invaluable source of data for studies of larval morphology of Cyclorrhapha by way of taxonomic diagnoses, character identification and improvement in characters homologization.

Larval morphology of Atherigona orientalis (Schiner) (Diptera: Muscidae) -a species of sanitary and forensic importance

Larval morphology is documented using both light and scanning electron microscopy for all three instars of the muscid fly Atherigona orientalis (Schiner), which is a species of known sanitary and forensic importance found in tropical and subtropical areas of all biogeographic regions. The unpaired sclerite in a form of a spicule is reported herein in the second and the third instar larvae. Occurrence of this sclerite was hitherto unknown in the second instar larvae of Muscidae and was only known from the third instar of several species, however not in a form of a spicule. Our study is the first report of the occurrence of the "sensory organ X" in all three larval instars of a species representing the family Muscidae. The bubble membrane, previously known only from third instar cyclorrhaphan larvae, is reported herein for the first time in the second instar. Characters allowing for discrimination of A. orientalis larvae from other forensically important Muscidae are summarised.

Ultrastructure of immature stages of Lucilia cuprina (Diptera: Calliphoridae) using scanning electron microscopy

The blowfly Lucilia cuprina is distributed worldwide and is a mechanical vector of pathogens. It can cause myiasis in humans and is strongly related to forensic entomology, as it is frequently found on human and animal corpses. However, most of the L. cuprina found on corpses are the immature stages of this fly. Correct identification is very important for forensic entomology but at present only the identification keys of adult L. cuprina are available. Thus, the aim of this paper was to describe and analyze the morphological characteristics of all larval instars and the puparia of L. cuprina using scanning electron microscopy (SEM).

Identifying 1st instar larvae for three forensically important blowfly species using "fingerprint" cuticular hydrocarbon analysis

Calliphoridae are known to be the most forensically important insects when it comes to establishing the minimum post mortem interval (PMImin) in criminal investigations. The first step in calculating the PMImin is to identify the larvae present to species level. Accurate identification which is conventionally carried out by morphological analysis is crucial because different insects have different life stage timings. Rapid identification in the immature larvae stages would drastically cut time in criminal investigations as it would eliminate the need to rear larvae to adult flies to determine the species. Cuticular hydrocarbon analysis on 1st instar larvae has been applied to three forensically important blowflies; Lucilia sericata, Calliphora vicina and Calliphora vomitoria, using gas chromatography-mass spectrometry (GC-MS) and principal component analysis (PCA). The results show that each species holds a distinct "fingerprint" hydrocarbon profile, allowing for accurate identification to be established in 1-day old larvae, when it can be challenging to apply morphological criteria. Consequently, this GC-MS based technique could accelerate and strengthen the identification process, not only for forensically important species, but also for other entomological samples which are hard to identify using morphological features.