Ecological and geographical speciation in Lucilia bufonivora: The evolution of amphibian obligate parasitism

Complete Mitochondrial Genome for Lucilia cuprina dorsalis (Diptera: Calliphoridae) from the Northern Territory, Australia

The Australian sheep blowfly, Lucilia cuprina dorsalis, is a major sheep ectoparasite causing subcutaneous myiasis (flystrike), which can lead to reduced livestock productivity and, in severe instances, death of the affected animals. It is also a primary colonizer of carrion, an efficient pollinator, and used in maggot debridement therapy and forensic investigations. In this study, we report the complete mitochondrial (mt) genome of L. c. dorsalis from the Northern Territory (NT), Australia, where sheep are prohibited animals, unlike the rest of Australia. The mt genome is 15,943 bp in length, comprising 13 protein-coding genes (PCGs), two ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs), and a non-coding control region. The gene order of the current mt genome is consistent with the previously published L. cuprina mt genomes. Nucleotide composition revealed an AT bias, accounting for 77.5% of total mt genome nucleotides. Phylogenetic analyses of 56 species/taxa of dipterans indicated that L. c. dorsalis and L. sericata are the closest among all sibling species of the genus Lucilia, which helps to explain species evolution within the family Luciliinae. This study provides the first complete mt genome sequence for L. c. dorsalis derived from the NT, Australia to facilitate species identification and the examination of the evolutionary history of these blowflies.

Lucilia silvarum Meigen (Diptera: Calliphoridae) Is a Primary Colonizer of Domestic Cats (Felis catus)

Lucilia silvarum Meigen (Diptera: Calliphoridae) is widespread throughout North America and Europe. Described in 1826, this blow fly was quickly associated with myiasis in amphibians, and to date has rarely been reported in carrion. There is limited data regarding the time of colonization of animals with fur and the interpretation of this data is difficult due to variation in the animal models used. During an examination of initial insect colonization of cats (Felis catus) with light and dark fur, twelve domestic short-haired cats were placed in cages 15.2 m apart in a grassy field in West Lafayette, Indiana, USA. Eggs from initial oviposition events were collected and reared to identify the colonizing species. Three species of Lucilia (Diptera: Calliphoridae), including L. silvarum, colonized the cats on the initial day of placement. In this study, L. silvarum was the primary colonizer of cats, and this may be the first study where a large number of L. silvarum were collected. Further studies should include development studies on L. silvarum to understand its life history and aid in time of colonization estimations. More work regarding the colonization of furred mammals is needed to further examine L. silvarum as a primary colonizer.

Tracking wildlife diseases using community science: an example through toad myiasis

Parasite and pathogen surveillance is crucial for understanding trends in their distributions and host spectra, as well as to document changes in their population dynamics. Nevertheless, continuous surveillance is time-consuming, underfunded due to the non-charismatic nature of parasites/pathogens, and research infrastructure is usually limited to short-term surveillance efforts. Species observation data provided by the public can contribute to long-term surveillance of parasites using photographic evidence of infections shared on community science platforms. Here, we used public photo repositories to document the occurrence across space and time of Lucilia spp. (Diptera: Calliphoridae), a parasite inducing nasal toad myiasis in the European toad Bufo bufo (Anura: Bufonidae). We found a total of 262 toad myiasis observations on iNaturalist (n = 132), on GBIF (n = 86), on Flickr (n = 41), and on observation.org (n = 3). Our results indicate that the distribution of toad myiasis is regionally limited, despite its host being widely distributed and abundant across a wide region in Europe. Observations were found in 12 countries with relatively low prevalence, including Belgium (3.90%, CI 2.44–6.18), Denmark (1.26%, CI 0.89–1.80), France (0.45%, CI 0.14–1.38), Germany (1.27%, CI 0.92–1.75), Lithuania (0.50%, CI 0.13–1.98), Luxembourg (1.30%, CI 0.42–3.95), the Netherlands (2.71%, CI 1.61–4.52), Poland (0.89%, CI 0.34–2.35), Russia (Kaliningrad Oblast) (4.76%, CI 0.67–27.14), Switzerland (NA), Ukraine (0.87%, CI 0.12–5.91), and in the UK (0.45%, CI 0.28–0.72). Nevertheless, the number of uploaded observations of both parasite infection and host presence indicates a stable increase likely due to the growing popularity of community science websites. Overall, community science is a useful tool to detect and monitor certain wildlife diseases and to recognize potential changes in disease dynamics through time and space.

Evolutionary profile of the family Calliphoridae, with notes on the origin of myiasis

The family Calliphoridae is a group of heterogenous calyptrate flies with a worldwide distribution including species of ecological, veterinary, medical, and forensic importance. Notorious for their parasitic habits, the larvae of many blowflies are characterised - like some other dipteran larvae - by their ability to develop in animal flesh. When parasitism affects a living host, it is termed "myiasis". This has led the Calliphoridae to be considered as a pivotal family in its relationship with a man. Nevertheless, even after more than 50 years of research, the phylogenetic relationships among calliphorid subfamilies together with the evolutionary origin of myiasis remain unclear. In order to elucidate these problems, we constructed three phylogenetic trees by using nucleotide sequence data from cytochrome oxidase subunit one (COI), representing a mitochondrial conservative gene, and nuclear 28S subunit of ribosomal RNA gene (28S rRNA) in order to interpret the evolutionary profile of myiasis in the family Calliphoridae. The sequenced data represented species associated with ectoparasitic life-styles, either saprophagy or facultative and obligate parasitism. A total number of 50 accessions were collected for 28S rRNA, 56 for COI, and 38 for combined sequences phylogeny. Molecular Evolutionary Genetics Analysis (MEGA) software was used to align 2197 nucleotide positions of 28S rRNA and 1500 nucleotide positions of COI with a gap opening penalties and gap extension penalties equalling 20 and 0.1 respectively. The results reveal the non-monophyly of the family Calliphoridae despite the stable monophyletic status of the Chrysomyinae, Luciliinae, and Auchmeromyiinae. Also, our findings recommend ranking the Toxotarsinae as a separate family. Furthermore, comparative analysis of the phylogenetic trees shows that the habit of obligatory myiasis originated independently more than five times. This strengthens our hypothesis that the origin of eating fresh meat is a case of convergent evolution that has taken place after speciation events millions of years ago. Finally, estimating the divergence dates between lineages from molecular sequences provides a better chance of understanding their evolutionary biology.

Lucilia bufonivora, Not Lucilia silvarum (Diptera: Calliphoridae), Causes Myiasis in Anurans in North America With Notes About Lucilia elongata and Lucilia thatuna

In North America, until recently, all cases of anuran myiasis were attributed to Lucilia silvarum (Meigen) or Lucilia elongata Shannon. The latter species is exceedingly rare and its life history is unknown, but L. silvarum is common and was thought to be capable of being either parasitic or saprophytic in North America. Until recently, the anuran parasite Lucilia bufonivora Moniez was thought to be strictly Palearctic, but a study in 2014 has determined this species is established throughout southern Canada. In 2019, a study demonstrated, with molecular and morphological evidence, that two adult flies formerly identified as L. silvarum and reared from amphibian myiasis cases from Canada, are actually L. bufonivora. Although the mentioned study detected relatively high genetic distances with European L. bufonivora, the lack of evident morphological differentiation suggest that they are the same species. The current study examined 12 adult males and eleven adult females morphologically from three additional North American studies. Specimens were examined which had been identified as L. silvarum or L. elongata, and they all proved to be L. bufonivora. We now suspect L. silvarum is strictly saprophagous in North America like they are in the Palearctic Region. We also provide evidence that the pattern of myiasis differs between European and North American specimens.

A field study to evaluate PMI estimation methods for advanced decomposition stages

Estimating the postmortem interval (PMI) is one of the major tasks and a continuous challenge in forensic pathology. It is often an exclusion process of available methods, which ultimately can lead to an unsatisfactory outcome due to poor reliability. This problem is most acute in the late PMI, when decomposition proceeds and some methods (such as rigor, livor, and algor mortis) are no longer applicable. Several methods, such as forensic entomology, skeletal muscle protein degradation, and the study of body decomposition by application of a morphological scoring, are expected to provide further information; however, all have certain limitations and weaknesses. Availability of a tool-box of methods allows a case-specific selection of the most appropriate one(s), or eventually provides improvements in the overall accuracy and precision of the PMI estimation by merging and combining methods. To investigate practical (field) application, eventual interferences, and/or synergetic effects, as well as the robustness of these methods towards specific influencing factors, a field study was conducted, using eight pig cadavers of different body weights and physical coverage, left to decompose under natural conditions for 16 days. Morphological changes during decomposition were assessed using the total body score (TBS), muscle samples were collected to analyze protein degradation, and insect colonization was evaluated. The results reveal strengths and current limitations of all tested methods, as well as promising synergistic effects, and thus, provide a baseline for targeted future research.

How deadly sarcophagid fly larvae are for anurans? New interactions and review to Neotropical region

Myiasis is defined as the infestation of living or necrotic tissues of vertebrates by dipteran larvae. In amphibians, it can be caused by fly larvae belonging to families Calliphoridae, Chloropidae, Muscidae, and Sarcophagidae. In this study, we report new records and infestation intensity of myiasis in anurans from two localities of the Atlantic Forest in southern Brazil, and also present a list with myiasis caused by flesh fly Sarcophagidae species in anurans of the Neotropical region. For this, we surveyed anuran communities during two breeding seasons, examined for myiasis signs, and when positive collected the specimens. We found infested individuals of 13 anurans of seven species. Different Sarcophagidae larva morphotypes were collected, and two of them emerged as adult flies of Lepidodexia (Notochaeta) fumipennis and Peckia (Sarcodexia) lambens, which were both found in the tree frog Bokermannohyla circumdata. We compiled 21 cases of myiasis in anurans in the Neotropical region from the literature reviewed. This data indicated that hosts of different lineages and modes of life can be affected and that death is often fast. The diversity of myiasis-causing flies in anurans in nature is probably a lot greater than expected, especially if we consider that the encounters are occasional, but at relatively high intensities, can cause rapid deaths.