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The Sepsidae (Diptera) of Europe
... According to some authors, the sepsid substance that inhibits predator attacks is produced by an abdominal gland (Dufour gland) present in male and female specimens [31] and has a characteristic and perceptible odor, at least to human beings [30,31]. This odor also possibly acts as a stimulus to the formation of hibernation swarms that can last for many weeks over vegetation, which can comprise of hundreds of individuals, and this has already been observed in a few species of Sepsis, especially S. fulgens, in Europe [30]. ...
... According to some authors, the sepsid substance that inhibits predator attacks is produced by an abdominal gland (Dufour gland) present in male and female specimens [31] and has a characteristic and perceptible odor, at least to human beings [30,31]. This odor also possibly acts as a stimulus to the formation of hibernation swarms that can last for many weeks over vegetation, which can comprise of hundreds of individuals, and this has already been observed in a few species of Sepsis, especially S. fulgens, in Europe [30]. ...
... The Neotropical species of Sepsidae have not been observed forming aggregations as that observed in the Old World, but it is common to encounter temporary aggregation with many individuals close to carcasses and feces of large mammals, which act as a food source to adults, copula location and substrate for breeding immatures [11,12,30,31]. The absence of hibernation swarms in the Neotropical species, coupled with the absence of attack inhibition in A. armata and M. armillata, suggest that the Dufour gland is lacking in these species. ...
Chemical defense consists of the usage of substances that can cause damage to the predator or repel their attacks. A few true fly (Diptera) species use chemical defenses and among the adult ones, these mechanisms have only been formally registered in the family Sepsidae. Some species of this family possess an abdominal gland (Dufour gland) that produces a substance with a characteristic and intense odor. This odor supposedly turns the sepsids unpalatable to their predators. However, there is no study testing this hypothesis with Neotropical species yet. Thus, the aim of this study is to verify if two neotropical species of Sepsidae (Archisepsis armata and Microsepsis armillata) are unpalatable to invertebrate predators (jumping spiders, giant crab spiders, and mantises). The experiment consisted in offering specimens of sepsids (treatment group) and fruit flies (drosophilids; control group) to three species of predators. Furthermore, a study of the internal morphology of the two sepsid species has been performed to verify the presence of the Dufour gland. There has not been any significant predation difference between the sepsids and the control group, and the Dufour gland has not been found in both of them. This data suggests that both neotropical species of sepsids are not unpalatable.
... Sepsid flies (Diptera: Sepsidae) generally depend on decaying organic matter for reproduction and development, and have become a model for the study of sexual selection and ecological adaptation Blanckenhorn, 1999;Blanckenhorn et al., 2000;Eberhard, 1999Eberhard, , 2002Parker, 1972aParker, , 1972bPont & Meier, 2002;Puniamoorthy et al., 2009;Rohner et al., 2015;Rohner et al., 2016;Ward, 1983;Ward et al., 1992). While some species can show marked substrate specialisations, other species may regularly dwell on multiple resources ranging from vertebrate dung to rotting plant matter (Pont & Meier, 2002). ...
... Sepsid flies (Diptera: Sepsidae) generally depend on decaying organic matter for reproduction and development, and have become a model for the study of sexual selection and ecological adaptation Blanckenhorn, 1999;Blanckenhorn et al., 2000;Eberhard, 1999Eberhard, , 2002Parker, 1972aParker, , 1972bPont & Meier, 2002;Puniamoorthy et al., 2009;Rohner et al., 2015;Rohner et al., 2016;Ward, 1983;Ward et al., 1992). While some species can show marked substrate specialisations, other species may regularly dwell on multiple resources ranging from vertebrate dung to rotting plant matter (Pont & Meier, 2002). In Europe several (up to 12) widespread species of the genus Sepsis with very similar ecological niches coexist in and around livestock faeces, often on the same pasture, an ubiquitous resource in many natural and managed agricultural grasslands worldwide (Rohner et al., 2015. ...
... Sepsis neocynipsea is common throughout North America, where it occupies similar niches to those of S. cynipsea in Europe. While overall very rare in numbers but nevertheless widespread in Europe, S. neocynipsea can be locally common at higher altitudes, such as the Alps, where the species typically occurs in sympatry with S. cynipsea (Ozerov, 2005;Pont, 1987;Pont & Meier, 2002;pers. observation). ...
The extent of interspecific gene flow and its consequences for the initiation, maintenance, and breakdown of species barriers in natural systems remain poorly understood. Interspecific gene flow by hybridization may weaken adaptive divergence, but can be overcome by selection against hybrids, which may ultimately promote reinforcement. An informative step towards understanding the role of gene flow during speciation is to describe patterns of past gene flow among extant species. We investigate signals of admixture between allopatric and sympatric populations of the two closely related European dung fly species Sepsis cynipsea and S. neocynipsea (Diptera: Sepsidae). Based on microsatellite genotypes, we first inferred a baseline demographic history using Approximate Bayesian Computation. We then used genomic data from pooled DNA of natural and laboratory populations to test for past interspecific gene flow based on allelic configurations discordant with the inferred population tree (ABBA–BABA test with D-statistic). Comparing the detected signals of gene flow with the contemporary geographic relationship among interspecific pairs of populations (sympatric vs. allopatric), we made two contrasting observations. At one site in the French Cevennes, we detected an excess of past interspecific gene flow, while at two sites in Switzerland we observed lower signals of past microsatellite genotypes gene flow among populations in sympatry compared to allopatric populations. These results suggest that the species boundaries between these two species depend on the past and/or present eco-geographic context in Europe, which indicates that there is no uniform link between contemporary geographic proximity and past interspecific gene flow in natural populations.
Supplementary Information
The online version contains supplementary material available at 10.1007/s11692-023-09612-5.
... Sepsidae is a globally distributed fly family with more than 320 described species (Ozerov 2005), and it is a relatively small, morphologically and ecologically uniform family of the Sciomyzoidea in the acalyptrate series of Diptera (Pont and Meier 2002). Meroplius fukuharai was originally described as the new species of the genus Xenosepsis (Iwasa 1984) and it was later transferred to the genus Meroplius based on morphology and molecular data (Meier 1995a(Meier , 1995b(Meier , 1996Su et al. 2008;Zhao L et al. 2013). ...
... � E, 42.395751 � N) Tieling City, Liaoning Province, China by Dan Yu. Each specimen was identified by Jianfeng Wang according to taxonomic keys (Pont and Meier 2002). The voucher specimens and their DNA were deposited in the Natural History Museum of Shenyang University (Jianfeng Wang, wangjf80@126.com) ...
Meroplius fukuharai is an important sanitary and ecological resource insect. We sequenced and annotated the mitogenome of Meroplius fukuharai which is the first representative of the genus Meroplius with nearly complete mitochondrial data. This mitogenome is 14,803 bp long, which consists of 22 transfer RNA genes, 13 protein-coding genes (PCGs), and two ribosomal RNA genes. All genes have a conservational arrangement with other published species of Sepsidae. Our results also supported the monophyly of Sepsidae, and the genus Meroplius is more closely related to genus Sepsis, Microsepsis, and Archisepsis.
... (iii) Family Sepsidae: Sepsidae is a family of flies commonly known as black scavenger flies or ensign flies. Sepsidae flies are typically dark-colored, often black or dark brown, with a somewhat elongated and slender body (Pont & Meier, 2002). They have distinctive wing markings, with dark spots or bands on their wings. ...
Pollinators are the unsung heroes of our natural world, playing a critical role in maintaining biodiversity and supporting agricultural productivity. From honeybee to the delicate butterfly, these creatures facilitate the reproduction of over 75% of the world’s flowering plants and nearly 35% of global crop production. Humans are deeply dependent on pollinators for their well-being and survival. Pollinators are essential for the production of many of the crops that form the foundation of human diets, including fruits, vegetables, nuts, and seeds. These crops are not only vital sources of nutrition, providing essential vitamins and minerals, but they also contribute to dietary diversity and food security. Beyond direct food sources, pollinators support the cultivation of crops used for livestock feed, which in turn sustains meat and dairy production. The economic value of pollinators is immense, with their pollination services contributing billions of dollars annually to global agriculture. Furthermore, many plants that pollinators help reproduce are crucial for non-food products, such as cotton and medicinal plants. The loss of pollinators would lead to a decline in crop yields and quality, increased food prices, and reduced availability of a variety of nutritious foods. This dependency underscores the importance of conserving pollinator populations to ensure the sustainability and resilience of agricultural systems, ecosystems, and ultimately, human health and livelihoods. Despite their invaluable contributions, pollinators are facing unprecedented threats that jeopardize their survival and the intricate ecological webs they sustain.
... The sole Dipteran OTU was identified as Sepsis flavimana. The distribution of this fly species is, however, restricted to the northern hemisphere [67]. This OTU is probably a member of the Sepsis genus, and closely related to S. flavimana. ...
Background
Over the last decade, increasing attention has been directed to using different substrates as sources of environmental DNA (eDNA) in ecological research. Reports on the use of environmental DNA located on the surface of plant leaves and flowers have highlighted the utility of this DNA source in studies including, but not limited to, biodiversity, invasive species, and pollination ecology. The current study assesses grass inflorescence as a source of eDNA for detecting invertebrate taxa.
Methods and results
Inflorescences from four common grass species in a central South African grassland were collected for high-throughput sequencing analysis. Universal COI primers were utilised to detect Metazoan diversity. The sequencing results allowed for the detection of three Arthropoda orders, with most OTUs assigned to fungal taxa (Ascomycota and Basidiomycota). Some biases were detected while observing the relative read abundance (RRA) results.
Discussion
The observed biases could be explained by the accidental inclusion of invertebrate specimens during sample collection and DNA extraction. Primer biases towards the amplified taxa could be another reason for the observed RRA results. This study provided insight into the invertebrate community associated with the four sampled grass species. It should be noted that with the lack of negative field controls, it is impossible to rule out the influence of airborne eDNA on the observed diversity associated with each grass species. The lack of the inclusion of PCR and extraction blanks in the sequencing step, as well as the inclusion of negative field controls, including other areas for refinement were highlighted, and suggestions were provided to improve the outcomes of future studies.
... (iii) Family Sepsidae: Sepsidae is a family of flies commonly known as black scavenger flies or ensign flies. Sepsidae flies are typically dark-colored, often black or dark brown, with a somewhat elongated and slender body (Pont & Meier, 2002). They have distinctive wing markings, with dark spots or bands on their wings. ...
Global food security and the preservation of ecosystems depend heavily on
pollinators. These varied creatures, which range from birds and bats to bees and
butterflies, aid in reproducing blooming plants, including many crops that support
human populations. Pollinator populations, however, are threatened by several
factors, such as disease, pesticide use, habitat loss, and climate change. The loss
of pollinators presents serious threats to biodiversity and world food production.
This study explores the critical relationship between pollinators, food security,
and the urgent need for global stewardship. It highlights pollinators’ essential
services, emphasizing their role in sustaining agricultural productivity and
supporting natural ecosystems. Additionally, it discusses the multiple challenges
confronting pollinator populations and the far-reaching consequences of their
decline. To address these challenges, a call for global stewardship is imperative.
This entails concerted efforts from governments, conservation organizations,
farmers, scientists, and individuals to protect and restore pollinator habitats,
reduce pesticide usage, promote sustainable agricultural practices, and raise
awareness about the importance of pollinators. Through collaborative action
and effective policies, it is possible to mitigate the threats facing pollinators
and safeguard their crucial role in ensuring food security and biodiversity. The
urgency of prioritizing pollinator conservation as a key component of sustainable
development, advocating for a harmonious relationship between humans and the
natural world for the benefit of present and future generations.
... (iii) Family Sepsidae: Sepsidae is a family of flies commonly known as black scavenger flies or ensign flies. Sepsidae flies are typically dark-colored, often black or dark brown, with a somewhat elongated and slender body (Pont & Meier, 2002). They have distinctive wing markings, with dark spots or bands on their wings. ...
In the intricate web of ecosystems, every species plays a crucial role often
overshadowed by the more charismatic or well-known participants. Wasps are a
group of insects whose ecological significance extends far beyond their reputation
as aggressive predators, and nuisance insects. While commonly associated
with their sting and feared by many, wasps possess a lesser-known but equally
vital role as pollinators in the natural world. At times wasps have displayed a
highly efficient and specialized role as pollinators in figs and orchids. Through a
comprehensive review of scientific literature and empirical evidence, this chapter
explores the species distribution of wasp species across India and the ecological
contributions of wasps as pollinators, shedding light on the threats to wasps and
the conservation strategies.
... In addition to symbiotic gut bacteria and fungi, dung beetles also interact with symbiotic nematodes, as is common in insects in general (e.g., gall-forming flies: Giblin-Davis et al., 2001; black scavenger flies: Pont & Meier, 2002;bark beetles: Susoy & Herrmann, 2014). ...
Many symbionts are sexually transmitted and impact their host's development, ecology, and evolution. While the significance of symbionts that cause sexually transmitted diseases (STDs) is relatively well understood, the prevalence and potential significance of the sexual transmission of mutualists remain elusive. Here, we study the effects of sexually transmitted mutualist nematodes on their dung beetle hosts. Symbiotic Diplogastrellus monhysteroides nematodes are present on the genitalia of male and female Onthophagus beetles and are horizontally transmitted during mating and vertically passed on to offspring during oviposition. A previous study indicates that the presence of nematodes benefits larval development and life history in a single host species, Onthophagus taurus . However, Diplogastrellus nematodes can be found in association with a variety of beetle species. Here, we replicate these previous experiments, assess whether the beneficial effects extend to other host species, and test whether nematode‐mediated effects differ between male and female host beetles. Rearing three relatively distantly related dung beetle species with and without nematodes, we find that the presence of nematodes benefits body size, but not development time or survival across all three species. Likewise, we found no difference in the benefit of nematodes to male compared to female beetles. These findings highlight the role of sexually transmitted mutualists in the evolution and ecology of dung beetles.
... Among the schizophoran families of flies, Sepsidae feature a significant tibial modification known as the osmeterium, which is an exocrine gland on the edge of the hind tibia of males (see e.g., Pont and Meier 2002;Sǔlc 1928). Oxygenated hydrocarbon and putative isoprenoid secretion have been documented (Araujo et al. 2014). ...
The tibial organ of Chloropidae and Milichiidae flies is an obscure feature with taxonomic significance. This study provides the first in-depth investigation into the ultrastructure of the hind leg of 11 genera from all Chloropidae subfamilies using a multimodal microscopy approach. The modified dermal tissue associated with the tibial organ indicates glandular function, as evidenced by the presence of secretory vesicles containing non-proteinaceous elements, potentially indicating lipidic secretion. The overall similarity of the tibial organ between Chloropidae and Milichiidae indicates a shared homology. However, the evolutionary history of this structure is still contentious due to limitations in the phylogenetic relationships of both lineages. Moreover, our findings enable future comparative investigations of other Diptera leg organs that possess secretory ability, which could be homologous across schizophoran families, but not necessarily the organs themselves.
We present a genome assembly from an individual specimen of Nemopoda nitidula (Arthropoda; Insecta; Diptera; Sepsidae). The genome sequence has a total length of 178.40 megabases. Most of the assembly (99.2%) is scaffolded into 6 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 15.98 kilobases in length.
The swarming behaviour of Sepsis fulgens Meigen is discussed, and various aspects of this behavioural phenomenon are analysed.Examples of swarms and observations upon them are given, from published and unpublished sources. The identity of the swarming species is discussed, and then the characteristics of the swarm, the swarming site, size, duration, activity, sex ratio, scent and enemies are summarized. A discussion of some of these aspects follows, and finally a hypothesis is put forward as to the probable function of the swarm: it is suggested that it is a hibernation phenomenon.The infestation of domestic and commercial premises by Sepsis violacea Meigen is briefly reviewed.
Small size may be advantageous to males that mate on the wing. This hypothesis is supported by the results of a comparison of size in males that mate and those that do not. Six species of Diptera (four chironomids, one sepsid and one scatophagid) are examined and in all six, smaller males are more successful at acquiring mates than larger males. Aerobatic ability may be conferred by small size and, if this is so, it could explain why smaller males achieve greater success. The conclusion that small size carries a selective advantage contrasts with the conventional view that large size is a universal determinant of mating success among males.
Males of the dung flySepsis cynipsea(L.) (Diptera: Sepsidae) mate guard before copulation by mounting the female's dorsum upon her arrival at the dung. After completing oviposition, females walk off the dung and vigorously shake to attempt to dislodge the guarding male. Only males that succeed in remaining on the female's dorsum will establish genital contact and copulate. Males are smaller than females, and engage wing clamps (specially modified areas on the femur and tibia of each foreleg) to grip the female's wing bases during guarding. The foretibiae of males and females collected at three phases of pairing (prior to struggling, during struggling and in copula) were measured. No differences in the foretibia size of either males or females across the three phases were found. However, the absolute fluctuating asymmetry of the foretibiae of males differed significantly between phases. On average, males paired in copula were the most symmetrical whilst those paired prior to struggling were the least symmetrical. It was concluded that males with more symmetrical foretibiae are indirectly selected as mates by females because of their better competitive ability to grip the female's wing bases and thereby remain on the dorsum of a struggling female during guarding.
An account is given of seven collections of insects and spiders made in summer 1979 on snowfields above 1100m elevation in the Cairngorm mountains, Scotland. In one comprehensive collection 278 recently deposited animals representing 35 species were obtained in 25 m; the other collections were selective. A high proportion of the roughly 700 specimens obtained have been identified. They represent at least 130 species, including 12 species of Araneae and 34 species each of Coleoptera, Hymenoptera and Diptera. Only 10 species are known to be restricted to ‘montane’ environments and it is concluded that the composition of fallout on mountain snowfields, both in Britain and elsewhere, reflects mainly the nature of the vegetation, and thus of the insect communities, in upwind areas at lower elevations. The discussion concerns the significance of fallout as a resource for high altitude communities and as a manifestation of long-distance migration and potential gene flow among populations of terrestrial arthropods.
SOME species of Diptera utilize freshly dropped cattle dung (cow pats) not only as an oviposition site and larval habitat but also as a male aggregation site where mating occurs1,2. The present investigation shows that the males of some of these species protect their mates, thus preventing the mating activity of the preponderant and aggressive unpaired males from interfering with oviposition. Such co-operative behaviour is most striking in the cosmopolitan yellow dung fly, Scatophaga stercoraria (L.) (Anthomyiidae), but also exists in Saltella sphondylii (Schrank) (Sepsidae) and Copromyza atra (Meigen) (Sphaeroceridae); these three species are closely related only in an ecological sense.
Themira athabasca n. sp. from Circle, Alaska is described, and a revised key to nearctic Themira is given. The sexual morphology and mating behavior of the sympatric arctic and midwestern U. S. species indicate that communities in these habitats demonstrate the parallel evolution of these characteristics. Sexual selection for mating efficiency is proposed as the evolutionary force responsible for the similarity of the communities.
Full-sib heritabilities, phenotypic and genetic correlations of 10 morphological and three life history traits in the European dung fly Sepsis cynipsea are presented. We further supply a within-species test of Cheverud's (1988) conjecture that phenotypic correlations may be good, and much easier to obtain, substitutes for genetic correlations. Males were smaller in all traits except fore femur width. Heritabilities of morphological traits ranged from 0.33 to 0.90 and tended to be higher than the average reported for ectotherms (Mousseau & Roff, 1987). Those for the three female life history traits estimated were lower (0.16–0.32) and about average. Genetic correlations between the sexes ranged from 0.52 to 0.87 and were all less than unity. Differential selection on morphology in males and females can thus be expected to produce fast evolutionary responses in this species. Our analysis revealed also that in S. cynipsea phenotypic correlations are good substitutes for genetic correlations for combinations involving morphological traits, and that genetic correlations derived from the ANCOVA and the family mean methods were very similar. However, the former correspondence may be strongly reduced by the inclusion of particular traits (here male seta length).Keywords: genetic correlation, heritability, life history, morphology, phenotypic correlation, sexual size dimorphism
The sheep headfly, Hydrotaea irritans, and Morellia simplex were the species most frequently associated with cattle at pasture and comprised 69.01 per cent and 13.93 per cent, respectively, of the total fly collection made from grazing cattle. The most prevalent biting fly was Haematobosca stimulans which comprised 4.46 per cent of the total catch. A few clegs, Haematopota pluvialis, and horse flies, Hybomitra distinguenda, were also recorded. A few of the headflies swarming around cattle entered milking parlours and byres and made up, at 38.23 per cent, the highest percentage of the total fly collection from these buildings. Headflies congregated on the windows, particularly those in the roof. Lesser numbers of the flies, Hydrotaea albipuncta, Morellia simplex and Trichopticoides decolor, with similar feeding habits to H irritans were also collected from these windows with a number of those species attracted to excrement. The biting muscids, Stomoxys calcitrans and Haematobosca stimulans, were collected mainly from the outside surfaces at the entrance to milking parlours and byres and comprised 23.53 per cent and 11.18 per cent, respectively, of the total fly collection from these buildings. Stomoxys calcitrans, the stable fly was present on every sample taken from calf houses and comprised 63.79 per cent of the total fly collection from these houses. Two other species, Sepsis violacea and the common housefly Musca domestica, were present on occasions in significant numbers and comprised 20.69 per cent and 9.48 per cent, respectively, of the total fly collection from calf houses.