Muscid Species Research Articles

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.

The Muscidae (Diptera) from the Atlantic Forest of Serra de Paranapiacaba, southestern Brazil

A first survey of Muscidae in the State of São Paulo (Southeastern Brazil) is presented here with a one-year of Malaise trap collecting from August 2010 to July 2011 at the Biological Reserve Alto da Serra de Paranapiacaba (23°46′00″-23°47′10″S, 46°18′20″-46°20′40″W, 750-891 m of altitude). A total of 1,284 individuals of muscids were collected, and 15 genera and 39 species of Muscidae were identified. So far, only one muscid species had been recorded to the Reserve, which now has its Muscidae diversity increased to 40 species. Thirteen species are new records for the State of São Paulo. With this, the number of species of Muscidae species known to occur in the State of São Paulo is increased to 169. The interval between November and February was higher in number of individuals and number of species. Muscidae presented a seasonal pattern, with more abundance and diversity in that interval. The study area is covered by secondary forest and very close to São Paulo metropolitan area, and the composition of the fauna of Muscidae signalizes this environment changing and anthropic stress with nine species with synanthropic habits, two of them are typically synanthropic species.

Wing morphometrics of medically and forensically important muscid flies (Diptera: Muscidae)

Many muscid flies (Diptera: Muscidae) are well-known as medical, veterinary, and forensically significant insects, thus correct species identification is critically important before applying for fly control and determining a minimal postmortem interval (PMImin) in forensic investigations. Limited in taxonomic keys and taxonomists, as well as scanty in advanced molecular laboratories lead to difficulty in identification of muscids. To date, a landmark-based geometric morphometric analysis of wings has proven to be a promising alternative technique for identifying many insect species. Herein, we assessed wing morphometric analysis for identification of six medically and forensically important muscids, namely Musca domestica Linnaeus, Musca pattoni Austen, Musca ventrosa Wiedemann, Hydrotaea chalcogaster (Wiedemann), Hydrotaea spinigera Stein, and Dichaetomyia quadrata (Wiedemann).A total of 302 right wing images were digitized based on 15 homologous landmarks and wing shape variation among genera and species was analyzed using canonical variate analysis, whereas sexual shape dimorphism of M. domestica, M. ventrosa, and D. quadrata was analyzed using discriminant function analysis. The cross-validation revealed a relatively high percentage of correct classification in most species, ranging from 86.4% to 100%, except for M. pattoni, being 67.5%. Misidentifications were mainly due to cross-pairings of the genus Musca; M. domestica VS M. pattoni VS M. ventrosa. The accuracy of classification using cross-validation test demonstrated that wing shape can be used to evaluate muscid flies at the genus- and species-level, and separate sexes of the three species analyzed, with a high reliability. This study sheds light on genus, species, and sex discrimination of six muscid species that have been approached using wing morphometric analysis.

Sex Chromosome Evolution in Muscid Flies.

Sex chromosomes and sex determining genes can evolve fast, with the sex-linked chromosomes often differing between closely related species. Population genetics theory has been developed and tested to explain the rapid evolution of sex chromosomes and sex determination. However, we do not know why the sex chromosomes are divergent in some taxa and conserved in others. Addressing this question requires comparing closely related taxa with conserved and divergent sex chromosomes to identify biological features that could explain these differences. Cytological karyotypes suggest that muscid flies (e.g., house fly) and blow flies are such a taxonomic pair. The sex chromosomes appear to differ across muscid species, whereas they are conserved across blow flies. Despite the cytological evidence, we do not know the extent to which muscid sex chromosomes are independently derived along different evolutionary lineages. To address that question, we used genomic and transcriptomic sequence data to identify young sex chromosomes in two closely related muscid species, horn fly (Haematobia irritans) and stable fly (Stomoxys calcitrans). We provide evidence that the nascent sex chromosomes of horn fly and stable fly were derived independently from each other and from the young sex chromosomes of the closely related house fly (Musca domestica). We present three different scenarios that could have given rise to the sex chromosomes of horn fly and stable fly, and we describe how the scenarios could be distinguished. Distinguishing between these scenarios in future work could identify features of muscid genomes that promote sex chromosome divergence.

The identification of the species of the ‘Spilogona contractifrons species-group’ and the ‘Spilogona nitidicauda species-group’ (Diptera, Muscidae) based on morphological and molecular analysis

Muscid species of the ‘Spilogona contractifrons species-group’ (Spilogona alticola (Malloch, 1920), S. arctica (Zetterstedt, 1838), S. contractifrons (Zetterstedt, 1838), S. orthosurstyla Xue & Tian, 1988) and of the ‘Spilogona nitidicauda species-group’ (S. nitidicauda (Schnabl, 1911), S. hissarensis Hennig, 1959, S. imitatrix (Malloch, 1921), S. platyfrons Sorokina, 2018) are notoriously difficult to distinguish. In this paper, their morphological features are analysed, images of the male head, frons and abdomen of all the species are given, and the male terminalia are figured. The study of extensive material has shown that all the morphologically recognised species in each of these groups are valid species. An identification key is provided for both groups of species. To confirm the morphological differences, genetic differences in the cytochrome oxidase I gene of flies of the ‘Spilogona contractifrons species-group’ and of the ‘Spilogona nitidicauda species-group’ were analysed. It is shown that members of both groups of species have not only distinguishing morphological characters but also fixed substitutions in the DNA sequences. Since a low interspecific polymorphism is known in the Muscidae Latreille, 1802, the revealed genetic distances confirm the existence of separate species or subspecies in each of the groups studied.

Characterization of the complete mitochondrial genome of Hydrotaea spinigera (Diptera: Muscidae) with phylogenetic implications

Abstract Hydrotaea spinigera Stein is a muscid species with high forensic importance. To further supplement the genome-level features of related species, the complete mitochondrial genome of H. spinigera is amplified, sequenced, annotated, analyzed, and compared with 13 other species of the family Muscidae. This mitogenome is 15,517 bp in length, with a standard set of 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and a typical non-coding control region. The gene organization, base composition, and secondary structures of tRNA genes of this mitogenome are similar to other dipteran species. Phylogenetic analyses based on all the mitochondrial PCGs and rRNA genes for 14 muscid and one outgroup taxa are performed using Bayesian inference (BI) and maximum likelihood (ML) analysis. The inferred trees indicate that the Muscidae, the subfamily Muscinae, and the tribes Azeliini and Reinwardtiini are monophyletic, whereas the monophyly of the subfamily Azeliinae and the tribe Muscini is not supported.

Houseflies speaking for the conservation of natural areas: a broad sampling of Muscidae (Diptera) on coastal plains of the Pampa biome, Southern Brazil

The Brazilian Coastal Plain of the Pampa Biome (CPPB), has suffered fragmentation caused by resource extraction and cattle raising. In turn, conservation proposals are needed to prevent the anthropisation of Pampa natural areas. The first step towards conservation proposals by using insects is fauna inventories, providing data support for legislators. Thus, we undertook a regional and broad-scale sampling survey to investigate the diversity of Muscidae flies in protected and non-protected areas of CPPB. In addition, we carried out an ecological guild diversity analysis as a metric approach of bioindication. The Muscidae sampling resulted in 6314 specimens, 98 species taxa in 31 genera. Based on diversity estimators, our sampling represents 70–86% of all muscids of CPPB. The highest diversity occurs in Pelotas streams (non-protected) and Taim Ecological Station (a huge protected area). Despite the fact these areas are more diversified and present more predatory muscid species than others, invasive species associated with livestock were observed at a higher level, providing evidence of the impact of livestock proximity to protected areas. Based on biological characters of Muscidae species and ecological guild analysis, we were able to identify: (i) high diversity of carnivorous species associated with forested and more preserved areas and (ii) a high level of a few saprophagous species as indicator of anthropisation process. In general, our results represent a significant step towards understanding Muscidae in Southern Brazil, and we demonstrate how the population ecology of muscid flies supports data to conservation proposals.

Complete mitochondrial genome of a forensically important muscid, Hydrotaea chalcogaster (Diptera: Muscidae), with notes on its phylogenetic position

Abstract Muscidae are a dipteran family which is important for forensic investigations. However, it has received limited attention in forensic entomological experiments as a reason of identification issues. It is hard to identify specimens by morphological methods, especially in developmental stages. Therefore, complete mitochondrial genome sequences can be important tool in forensic entomology for identifying species. In this study we sequenced and analyzed the first complete mitochondrial genome from a forensically important Muscidae species Hydrotaea (=Ophyra) chalcogaster by next-generation sequencing. The mitochondrial genome of the sequenced species is circular molecules of 17,076 bp which have the typical mitochondrial genome complement of 13 protein-coding genes, 22 tRNAs, two ribosomal RNA genes and a control region. Rearrangements of gene positions are identical with the ancestral insect genome. Furthermore, phylogenetic relationships of the family Muscidae were evaluated in regard to mitochondrial protein coding genes. The inferred trees indicate that the Muscidae is a paraphyletic family. These data provide additional information for molecular identification of muscid species.

Lethal Effects of the Insect Growth Regulator Cyromazine Against Three Species of Filth Flies, Musca domestica, Stomoxys calcitrans, and Fannia canicularis (Diptera: Muscidae) in Cattle, Swine, and Chicken Manure.

The presence of various species of filth flies is a widespread problem where livestock, including poultry, are maintained and where manure accumulates. The house fly, Musca domestica L.; the stable fly, Stomoxys calcitrans (L.); and the little house fly, Fannia canicularis (L.) (each Diptera: Muscidae), the target pests in our study, can mechanically spread diseases, and S. calcitrans can bite cattle, causing losses in meat and milk production. Chemical control is widely used to suppress filth flies, but resistance to conventional insecticides has become problematic. Hence, an alternative approach, insect growth regulators (IGRs), has been adopted by many livestock producers. We assessed the ability of the IGR cyromazine in granular and granular-based aqueous formulations to suppress the three muscid species from developing in poultry, cattle, and swine manure collected from commercial livestock production facilities. Each of the two formulations provided either strong or complete control of the pests for the 4-wk duration of the study, excluding the granular formulation that provides control of only F. canicularis developing in poultry manure for 2 wk. The two cyromazine-based IGR formulations appear to be effective tools that, if rotated appropriately with other insecticides, can be incorporated into integrated pest management strategies for filth fly suppression.

Ultrastructure of immature stages of the black dump fly: Ophyra aenescens (Wiedemann, 1830) (Diptera: Muscidae: Azeliinae)

Ophyra aenescens (black dump fly) originally belonged to the New World, however, now it is spread worldwide. This fly is a mechanical vector of some pathogenic microorganisms and eggs of the human botfly (Dermatobia hominis). The adults are associated with decaying matter and the immature stages colonize animal and human corpses. It is considered an important muscid species for forensic entomology. The aim of this study was to describe the morphology of the eggs, the three larval instars and the puparia of O. aenescens using scanning electron microscopy (SEM). The spiracular opening of the first instar has an interruption in the middle of its length. Comparing to the other instar, the ventral tubercles are only developed in the first instar. The anterior spiracles have a variation in the numbers of spiracular ramification. The puparia morphology is similar to the third instar larvae, however the cephalic region is retracted and on the third thoracic segment, a respiratory structure is present. In conclusion, the SEM technique used and the results obtained are helpful to describe and differentiate the immature stages of O. aenescens and consequently support forensic and medical entomology.

Use of DNA sequences to identify forensically important fly species and their distribution in the coastal region of Central California

Forensic entomology has gained prominence in recent years, as improvements in DNA technology and molecular methods have allowed insect and other arthropod evidence to become increasingly useful in criminal and civil investigations. However, comprehensive faunal inventories are still needed, including cataloging local DNA sequences for forensically significant Diptera. This multi-year fly-trapping study was built upon and expanded a previous survey of these flies in Santa Clara County, including the addition of genetic barcoding data from collected species of flies.Flies from the families Calliphoridae, Sarcophagidae, and Muscidae were trapped in meat-baited traps set in a variety of locations throughout the county. Flies were identified using morphological features and confirmed by molecular analysis. A total of 16 calliphorid species, 11 sarcophagid species, and four muscid species were collected and differentiated. This study found more species of flies than previous area surveys and established new county records for two calliphorid species: Cynomya cadaverina and Chrysomya rufifacies. Differences were found in fly fauna in different areas of the county, indicating the importance of microclimates in the distribution of these flies. Molecular analysis supported the use of DNA barcoding as an effective method of identifying cryptic fly species.

A xenodiagnostic method using Musca domestica for the diagnosis of gastric habronemosis and examining the anthelmintic efficacy of moxidectin

Equine habronematidosis has a global distribution and is caused by three spirurid species, Habronema muscae, Habronema microstoma and Draschia megastoma. A case of cutaneous habronematidosis in a stallion in a stable in Dubai, UAE gave occasion to investigate the parasite situation on the farm.Patent H. muscae infections were diagnosed in 18 out of 49 horses in a stable in Dubai, UAE with a xenodiagnostic test using houseflies as indicator host. All horses in the stable were treated with a single dose of moxidectin administered orally as 2% gel in a dosage of 0.4mg/kg body weight and the efficacy of this targeted treatment was studied. Habronema infection was terminated in all horses. A fly survey conducted at the farm prior and after treatment revealed two muscid species: Musca domestica and Stomoxys calcitrans. Only M. domestica caught at the farm showed a natural infection with Habronema larvae prior and shortly after anthelmintic treatment. Later, examination of flies caught at the farm in monthly intervals up to the end of observation (8 months after treatment) gave negative results. The absence of infection in the intermediate host was an indication of the eradication of stomach worms. The described xenodiagnostic test is a useful tool to diagnose H. muscae infections and can be used to evaluate the efficacy of nematocides in equines.

The ability of the blowflies Calliphora vomitoria (Linnaeus), Calliphora vicina (Rob-Desvoidy) and Lucilia sericata (Meigen) (Diptera: Calliphoridae) and the muscid flies Muscina stabulans (Fallén) and Muscina prolapsa (Harris) (Diptera: Muscidae) to colonise buried remains

The blowflies Calliphora vomitoria (Linnaeus), Calliphora vicina (Rob-Desvoidy) and Lucilia sericata (Meigen) exhibited a limited ability to colonise pig liver baits buried in loose soil. Calliphora vomitoria colonised baits buried at 5 cm but no deeper whilst C. vicina and L. sericata colonised remains at 10 cm but not at 20 cm. The baits were colonised by larvae hatching from eggs laid on the surface of the soil. Both C. vomitoria and L. sericata were able to develop from eggs through to adulthood on baits that were infested before being buried and the larvae developed at similar rates and pupariated at similar depths to larvae developing on baits on the soil surface. The muscid flies Muscina stabulans (Fallén) and Muscina prolapsa (Harris) colonised remains buried in loose soil at a depth of 40 cm and even when presented with baits on the soil surface their larvae tended to remain in the soil beneath the baits. In compacted soil, M. stabulans colonised baits buried at 10 cm but M. prolapsa only colonised those buried at 5 cm. In both muscid species, the adult flies were instantly attracted to feed on fresh blood and laid eggs in the soil above buried baits within 30min of them being introduced into the cages. The adult muscid flies did not attempt to burrow into the soil and their larvae colonised the baits from eggs laid on the soil surface. This information could be useful in determining whether a body was stored above ground before being buried and/or the time since burial occurred.

The population ecology of Muscina stabulans (Fallén) (Diptera: Muscidae), along an Urban-Rural Gradient of Buenos Aires, Argentina

The false stable fly, Muscina stabulans (Fallén), was surveyed along an urban-rural gradient at Almirante Brown, Buenos Aires province, Argentina. Samples were taken at monthly intervals from May 2005 to April 2007. Hourly captures of adult flies (10:00 am-04:00 pm) were taken at each sampling date with a hand net. The baits used were 250 g of rotten cow liver and 250 g of fresh dog faeces exposed in shaded and sunny areas. The entire sample accumulated 358 specimens. The number of specimens captured during the second year was higher than in the fi rst year. Muscina stabulans was more abundant at urban-suburban sites. Females showed significant preferences for cow liver. We caught more specimens in shaded areas. The hourly activity increased toward the afternoon at the three sites. The present work was the first ecological study related to a muscid species in Argentina.

Assembly rules in Muscid Fly assemblages in the grasslands Biome of Southern Brazil

The distribution of muscid species (Diptera) in grasslands fragments of southern Brazil was assessed using null models according to three assembly rules: (a) negatively-associated distributions; (b) guild proportionality; and (c) constant body-size ratios. We built presence/absence matrices and calculated the C-score index to test negatively-associated distributions and guild proportionality based on the following algorithms: total number of fixed lines (F L), total number of fi xed columns (F C), and the effect of the average size of the populations along lines (W) for 5000 randomizations. We used null models to generate random communities that were not structured by competition and evaluated the patterns generated using three models: general, trophic guilds, and taxonomic guilds. All three assembly rules were tested in each model. The null hypothesis was corroborated in all F L X F C co-occurrence analyses. In addition, 11 analyses of the models using the W algorithm showed the same pattern observed previously. Three analyses using the W algorithm indicated that species co-occurred more frequently than expected by chance. According to analyses of co-occurrence and guild proportionality, the coexistence of muscid species is not regulated by constant body size ratios. In fl ies of the grasslands, no rule was identified. Yet, a consensus did emerge from our analyses: species co-occur more frequently than expected by chance, indicating that aggregation is a recurring phenomenon among flies with saprophagous adults and predatory larvae. Therefore, competition does not seem to play an important role in the determination of muscid assemblages in the grasslands in Southern Brazil.

Dolichophaonia gallicola (Albuq.) (Diptera: Muscidae): espécie cecidógena ou inquilina?

Zalepidota piperis Rubs. (Diptera Cecidomyiidae) is a stem-gall former on Piper arboreum Aub. (Piperaceae) which occurs during spring in Rio de Janeiro Atlantic Forest. Eight inquilin species and four parasitoid species were also obtained from this gall. Dolichophaonia gallicola (Albuq.) (Diptera: Muscidae) larvae were frequently found inside the gall as inquilin species. The uncommon cecidogenous habit of this muscid species on Pteridium aquilinum Kunth (Pteridophyta), as recorded in the literature, is discussed.

Arthropod Faunal Composition on Kentucky Equine Premises

Thirty-nine arthropod species representing the families Muscidae, Chloropidae, Tabanidae, Simuliidae, Culicidae, and Ixodidae were collected from Kentucky equine premises using dry ice-baited canopy traps, light traps, water samples, tick drags, and animal inspections during late April to mid-October 1987 and 1988. Thirty-three species were collected from canopy traps, consisting of 74.3% muscid, 16.7% chloropid, 5.0% simuliid, 3.8% tabanid, and 0.2% culicid species. Light traps attracted eight culicid and water samples yielded three culicid species. One ixodid species was collected with drags, and animal inspections yielded two muscid and two ixodid species. Comparison of species assemblages among farms and across years using multivariate principal component analysis (PCA) yielded three distinct principal components, and PCA scores for each farm per year were correlated with biotic and abiotic environmental factors and management practices. The proximity to cattle herds was the best predictor of similarity in species assemblages among farms, reflecting the high percentage of muscid species collected. Poor management practices were partially responsible for proportionally larger populations of culicids, ixodids, and muscids on some farms.

Differential Susceptibility of Maggots of Several Species to Droppings from Chickens Fed Insecticide-Treated Rations1

The susceptibility of larvae of Musca domestica L., Fannia pusio (Wiedemann), Chrysomya megacephala (F.), and Parasarcophaga argyrostoma (Robineau-Desvoidy) to droppings from poultry given feed containing the following 22 insecticides was determined: American Cyanamid 12008 (O,O-diethyl S-(isopropylthio) methyl phosphorodithioate), American Cyanamid 18706 (O,O-dimethyl S-(N-ethylcarbamoylmethyl) phosphorodithioate), Bayer 22408 (O,O-diethyl O-naphthalimido phosphorothioate), Bayer 25141 (O,O-diethyl O-p-methylsulfinylphenyl phosphorothioate), Bayer 29493 (O,O-dimethyl O-[4-methylthio)-m-tolyl] phosphorothioate), butonate (95%) and related compounds (5%), DDVP, Delnav® (a mixture of 2,3-p-dioxanedithiol S,S-bis (O,O-diethyl phosphorodithioate) (70%) and related compounds), Dibrom® (1,2-dibromo-2,2-dichloroethyl dimethyl phosphate), dicapthon, dimethoate, Dowco 105 (O-4-tert-butyl-2-chlorophenyl O-methyl ethylphosphoramidothioate), Dowco 109 (O-4-tert-butyl-2-chlorophenyl O-methyl methylphosphoramidothioate), Isolan® (l-isopropyl-3-methyl-5-pyrazolyl dimethylcarbamate), Kepone® (decachlorooctahydro-l ,3,4-metheno-2H-cyclobuta[cd]pentalen-2-one), Perthane® (a mixture of diethyl diphenyl dichloroethane (95%) and related reaction products (5%)), phosphamidon, Pyrolan® (3-methyl-l-phenyl-5-pyrazolyl dimethylcarbamate), ronnel, Ruelene® (O-4-tert-butyl-2-chlorophenyl O-methyl methylphosphoramidate), Sevin® (l-naphthyl N-methylcarbamate), and Bacillus thuringiensis var. thuringiensis Berliner. The two muscid species were in most instances more tolerant of the insecticide-containing manure than either the sarcophagid or calliphorid. Several organic phosphate insecticides (American Cyanamid 12008, Bayer 22408, and dimethoate) were highly toxic to the larvae of all four species at levels in the feed ranging between 40 and 80 p.p.m. The carbamate insecticides included in the feed had no apparent effect on larval mortality while the two chlorinated hydrocarbon insecticides, Kepone and Perthane, exhibited but slight toxicity. The bacillus appeared to have limited usefulness for general fly control when administered in the feed to chickens.

Haematophagy by Two Non-biting Muscid Flies and its Relationship to Tabanid Feeding

Feeding by a number of non-biting muscid species on blood made available by biting flies is known to occur in the Old World (Hammer, 1941; West, 1951). Species in several genera are involved, but particularly Musca. In North America, Hydrotaea tuberculata Rondani has been observed feeding in association with horse flies and stable flies (Tashiro and Schwardt, 1953). Often in these feeding associations, flies of the non-biting species not only visit abandoned wounds, but also wait near a feeding fly or attempt to feed simultaneously with it.