Flesh fly (Diptera: Sarcophagidae): male terminalia, diversity and expanded geographical distribution from India

Despite its veterinary, medical and forensic importance, the biodiversity of sarcophagid flies (Diptera: Sarcophagidae) has remained poorly investigated in India. We have performed a survey of Sarcophagidae species in connection with a study conducted on Diptera, which exposed the flesh fly diversity in and around the campus of the University of Calicut, Kerala, India. The survey was conducted using traps baited with decomposing fish and chicken liver and by the sweeping method. Eleven species were collected, including four species recorded from this state for the first time, one of which is new to the Indian mainland and the second record after Sundarbans Biosphere Reserve. Male terminalia of Sinonipponia bengalensis, Parasarcophaga choudhuryi, Boettcherisca karnyi, and Boettcherisca nathani are illustrated. This result expands the knowledge on the geographical distribution and habitat occupancy of sarcophagid species as well as their forensic relevance and provides a background for future systematic investigations.

Urban warming and artificial light alter dormancy in the flesh fly

Seasonal changes in temperature and day length are distinct between rural and urban areas due to urban warming and the presence of artificial light at night. Many studies have focused on the impacts of these ubiquitous signatures on daily biological events, but empirical studies on their impacts on insect seasonality are limited. In the present study, we used the flesh fly Sarcophaga similis as a model insect to determine the impacts of urbanization on the incidence and timing of diapause (dormancy), not only in the laboratory but also in rural and urban conditions. In the laboratory, diapause entry was affected by night-time light levels as low as 0.01 lux. We placed fly cages on outdoor shelves in urban and rural areas to determine the timing of diapause entry; it was retarded by approximately four weeks in urban areas relative to that in rural areas. Moreover, almost all flies in the site facing an urban residential area failed to enter diapause, even by late autumn. Although an autumnal low temperature in the urban area would mitigate the negative effect of artificial light at night, strong light pollution seriously disrupts the flesh fly seasonal adaptation.

Museomics and phylogenomics with protein-encoding ultraconserved elements illuminate the evolution of life history and phallic morphology of flesh flies (Diptera: Sarcophagidae)

Background The common name of the Flesh flies (Sarcophagidae) usually relates them with organisms feeding on decomposing organic matter, although the biology of one of the largest radiations among insects also includes predation, coprophagy, and even kleptoparasitism. The question of whether the ancestor of all sarcophagids was a predator or a decomposer, or in association to which host have sarcophagids evolved, has thus always piqued the curiosity of flesh fly specialists. Such curiosity has often been hindered by both the impossibility of having a well-supported phylogeny of Sarcophagidae and its sister group to trace live habits and the scarcity of information on the biology of the group. Using a phylogenomic dataset of protein-encoding ultraconserved elements from representatives of all three subfamilies of Sarcophagidae as ingroup and a large Calyptratae outgroup, a robust phylogenetic framework and timescale are generated to understand flesh fly systematics and the evolution of their life histories. Results The evolutionary history for Sarcophagidae reconstructed here differs considerably from previous hypotheses. Within subfamily Sarcophaginae, a group of predatory flies, including genera Lepidodexia and Boettcheria, emerged as sister-group to the rest of Sarcophaginae. The genera Oxysarcodexia, Ravinia, and Tricharaea, long considered archaic and early-branching coprophagous and sarcosaprophagous lineages, were found nested well within the Sarcophaginae as sister-group to the sarcosaprophagous Microcerella. Predation on invertebrates is suggested as the ancestral and dominant strategy throughout the early evolution of flesh flies. Several transitions from predation to sarcosaprophagy and coprophagy occur across the sarcophagid phylogenetic tree, in contrast with almost no transitions from sarcosaprophagy or coprophagy to predatory habits. Regarding the morphological evolution of flesh flies, there might be a concerted evolution of male genitalia traits, such as the phallotrema position and the juxta, or the vesica and the folding of the phallotrema. One diversification rate shift was inferred in the evolution of sarcophagids, which is related to the origin of genus Sarcophaga. Conclusions This study has a significant impact on understanding sarcophagid evolution and highlights the importance of having a robust phylogenetic framework to reconstruct the ancestral character state of biological and morphological characters. I discuss the evolution of life histories of the family in relation to their hosts or substrates and outline how sarcosaprophagy, coprophagy, and kleptoparasitism behavior on various hosts may have evolved from predation on invertebrates. This study provides a phylogenetic framework for further physiological and comparative genomic work between predatory, sarcosaprophagous, coprophagous, and kleptoparasitic lineages, which could also have significant implications for the evolution of diverse life histories in other Diptera.

Museomics and protein-encoding ultraconserved elements illuminate the evolution of life history and phallic morphology of flesh flies (Diptera: Sarcophagidae)

Background: The common name of the Flesh flies (Sarcophagidae) usually relates them with organisms feeding on decomposing organic matter, although the biology of one of the largest radiations among insects also includes predation, coprophagy, and even kleptoparasitism. The question of whether the ancestor of all sarcophagids was a predator or a decomposer, or in association to which host have sarcophagids evolved, has thus always piqued the curiosity of flesh fly specialists. Such curiosity has often been hindered by both the impossibility of having a well-supported phylogeny of Sarcophagidae and its sister group to trace live habits and the scarcity of information on the biology of the group. Using a phylogenomic dataset of ultraconserved elements from nearly all lineages of Sarcophagidae, a robust phylogenetic framework and timescale are generated to understand flesh fly systematics and the evolution of their life histories. Results: The evolutionary history for Sarcophagidae reconstructed here differs considerably from previous hypotheses. Within subfamily Sarcophaginae, a group of predatory flies, including genera Lepidodexia and Boettcheria, emerged as sister-group to the rest of Sarcophaginae. The genera Oxysarcodexia, Ravinia, and Tricharaea, long considered archaic and early-branching coprophagous and sarcosaprophagous lineages, were found nested well within the Sarcophaginae as sister-group to the sarcosaprophagous Microcerella. Predation on invertebrates is suggested as the ancestral and dominant strategy throughout the early evolution of flesh flies. Several switches from predation to sarcosaprophagy occur across the sarcophagid phylogenetic tree, in contrast with almost no switches from sarcosaprophagy or coprophagy to predatory habits. Regarding the morphological evolution of flesh flies, there might a concerted evolution of male genitalia traits, such as the phallotrema position and the juxta, or the vesica and the folding of the phallotrema. One diversification rate shift was inferred in the evolution of sarcophagids, which is associated with the genus Sarcophaga. Conclusions: This study has a significant impact on understanding sarcophagid evolution and highlights the importance of having a robust phylogenetic framework. I discuss the evolution of life histories of the family in relation to their hosts or substrates and outline how sarcosaprophagy, coprophagy, and kleptoparasitism behavior on various hosts may have evolved from predation on invertebrates. This study has established the framework for further physiological and comparative genomic work between predatory, sarcosaprophagous, coprophagous, and kleptoparasitic lineages, which could also have significant implications for the evolution of diverse life histories in other Diptera.