Diversity response of necrophagous dipteran communities and their functional groups to an anthropization gradient

The anthropization process exerts a profound effect on ecosystems, causing alterations in biodiversity, habitat structure, and species composition, ultimately disrupting the delicate balance of natural environments. The aim of the present study was to explore the ecological dynamics of necrophagous Sarcophagidae and Calliphoridae flies along an anthropization gradient. This research investigated alpha and beta diversity patterns to unravel the impact of human-induced environmental changes on these insect communities and also assesses the dynamics of functional groups in relation to their impact on medical and forensic fields. Five distinct habitats, ranging from urban to forested areas, were surveyed in two Departments in the Province of Chaco, Argentina. Necrophagous flies were collected using van Someren-Rydon canopy traps across three seasons. Two main functional groups were analyzed: oviparous flies (Calliphoridae) and larviparous flies (Sarcophagidae). Results indicated a significant negative correlation between Sarcophagidae species richness and anthropization, whereas Calliphoridae showed increased abundance in highly anthropized sites. The combined assemblage of Calliphoridae+Sarcophagidae exhibited significant relationships across all community parameters evaluated. Beta diversity analysis revealed turnover as the main process shaping dipteran communities along the anthropization gradient, with spatial species replacement dominating. This underscores the importance of interspecific spatial segregation in dipteran community composition. In conclusion, this study enhances our understanding of the ecological adaptations of necrophagous dipterans to anthropogenic disturbances. The observed shifts in diversity and abundance have implications for forensic investigations and public health, emphasizing the need for nuanced monitoring and conservation strategies. This research contributes valuable insights into the intricate ecological interactions of these insect communities within changing ecosystems.

Evaluation of environmental and local factors on urban sarcosaprophagous Diptera: a case study with Sarcophagidae

The urbanization process affects the structure of insect communities, favouring biotic homogenization processes by promoting adequate conditions for the establishment of synanthropic species. Considering the scarce knowledge about the ecology of Neotropical sarcophagids, we compared the flesh fly community from two different urban zones in two contrasting seasons and examined the response of the Sarcophagidae assemblage to landscape and microhabitat variables. Adult flies were collected in 13 sites with two traps (total number of traps 26) baited with 200 g of hydrated bone meal. A total of 2312 adult sarcophagids were collected belonging to 27 species; Oxysarcodexia paulistanensis (Mattos, 1919) represented >48% of the total sample. The local factor of insolation explained both the abundance and species richness of sarcophagids, collections being higher and richer in traps exposed to sunlight compared with traps placed in the shade regardless of the season. Richness was also affected by the environment, being higher in traps exposed in suburban rather than urban sites. The combination of these factors (sub-urban environment and availability of open areas) could explain the Sarcophagidae assemblage. The average number of sarcophagid species collected was related to the season, providing a good opportunity to assess the temporal variability of this family in the region.

Synanthropy of Sarcophaginae (Diptera: Sarcophagidae) From Southern Brazil and Its Sanitary Implications

Although different feeding habits have been reported for Sarcophaginae (Diptera, Sarcophagidae), most species are associated with decomposing organic matter such as feces and decaying corpses. This study provides the synanthropy index for males of species of Sarcophaginae collected during a 12-mo period in three different environments (urban, rural, and wild) of the state of Rio Grande do Sul, in Southern Brazil, linking this parameter with the sanitary issue. This article also investigated the presence of pathogenic bacteria on the external surface of Oxysarcodexia paulistanensis (Mattos), the most abundant species collected using a sanitized entomological net. Almost all the species collected most abundantly, including O. paulistanensis (n = 241), Ravinia advena (Walker) (n = 87), and O. thornax (Walker) (n = 58), were classified as synanthropic; O. thornax was the species with the highest synanthropy index (+80.3). Escherichia coli (Escherich), Shigella spp. (Enterobacteriaceae), and Staphylococcus aureus (Rosenbach) (Staphylococcaceae) were isolated and identified from the external surface of O. paulistanensis. The isolation and identification of pathogenic bacteria, and their synanthropic behavior, adds weight to potential role of some flesh flies, as O. paulistanensis, in a sanitary context.

Seasonal Fluctuations in Sarcophagidae (Diptera: Calyptratae) Assemblages in the Humid Chaco Ecoregion, Argentina

The seasonal fluctuations of flesh fly (Diptera: Sarcophagidae) assemblages were investigated from March 2015 to February 2016 in five habitat types in the Humid Chaco ecoregion, Chaco Province, Argentina. Three of the habitats were anthropized: an urban area, a cattle farm, and an alfalfa crop; and two were natural: a savanna and a forest. Flesh flies were collected monthly at 25 sampling points, five per habitat. In total, 5,790 male specimens comprising 55 species distributed in 15 genera were collected. The assemblage composition of flesh flies in each habitat and season was analyzed in terms of abundance, species richness, and diversity. In addition, the correlation between these community parameters and climatic factors (precipitation 7 and 14 d before samplings, temperature, and relative humidity) were evaluated in each habitat. The highest abundance and species richness of Sarcophagidae were registered in May (autumn) and June (winter), respectively. The lowest diversity values were observed between August and September (end of winter and early spring) in all habitats. However, flesh flies were present and well represented (in terms of species richness) throughout the year in all habitat types. Fluctuations in the abundance of the most abundant species collected were analyzed. The climatic factors were correlated with diversity and species richness in the urban, cattle farm, and savanna habitats. This study revealed that flesh fly assemblages differed temporally between different types of habitats in accordance with climatic factors and microclimate conditions.

Flesh Flies (Diptera: Sarcophagidae) Attracted to a Snake Carcass (Boa constrictor) in Yucatan Peninsula, Mexico

A study was carried out to determine Sarcophagidae diversity attracted to the different stages of decomposition of a Boa constrictor cadaver during late winter in the Yucatan Peninsula. As a result of this study, seven species of Sarcophagidae were documented, Oxysarcodexia conclausa (Walker, 1861) (Diptera: Sarcophagidae), Peckia (Euboettcheria) volucris (Wulp, 1895) (Diptera: Sarcophagidae), Blaesoxipha (Gigantotheca) plinthopyga (Wiedemann, 1830) (Diptera: Sarcophagidae), Oxysarcodexia amorosa (Schiner, 1868) (Diptera: Sarcophagidae), Ravinia derelicta (Walker, 1853) (Diptera: Sarcophagidae), Ravinia effrenata (Walker, 1861) (Diptera: Sarcophagidae), and Titanogrypa (Cucullomyia) placida (Aldrich, 1925) (Diptera: Sarcophagidae), The last five species listed are the first documentation of their presence in the Yucatan Peninsula in Mexico. Sarcophagids were present throughout the decomposition process; however, the greatest abundance and diversity of this family were present during the advanced decay stage. This is the first work on flesh flies in the region and the first in the country that has focused on wildlife.

The Effect of Anthropization on Sarcophagidae (Diptera: Calyptratae) Community Structure: An Assessment on Different Types of Habitats in the Humid Chaco Ecoregion of Argentina

Sarcophagidae (Diptera) are of great interest from a veterinary, medical, and forensic viewpoint, and are potential bioindicators for environmental impact assessments. In this study, we evaluated changes in abundance, species richness, and diversity of flesh flies in different habitat types in the Humid Chaco ecoregion of South America: 1) anthropized habitats: urban, cattle farm, and alfalfa crop, and 2) natural habitats: savanna and forest. We hypothesized that sarcophagid fly community parameters are affected by the anthropization and that spatial turnover will contribute more to the overall beta diversity than nestedness between habitats. In each habitat, samplings were conducted monthly from March 2015 to February 2016 in 25 sites, 5 per habitat, totaling 300 independent samples at the end of the study. We collected 5,790 Sarcophagidae (55 species). Community parameters of Sarcophagidae were evaluated and compared. The ecological effects of anthropization and habitat type were observed in the present study. As expected, our results showed the highest abundance, species richness, and diversity in the savanna and forest habitats (natural), whereas the lowest values were registered in the urban and alfalfa crop habitats, supporting the hypotheses of anthropization as the main driver of diversity loss. In addition, sarcophagid assemblages differed between all habitats and the overall dissimilarity was structured by spatial turnover. The main conclusion of this research is that flesh fly community structure is greatly affected by anthropization and habitat type, and this would be related to canopy cover and microclimate conditions of each environment.

Facultative Viviparity in a Flesh Fly (Diptera: Sarcophagidae): Forensic Implications of High Variability in Rates of Oviparity in Blaesoxipha plinthopyga (Diptera: Sarcophagidae)

Flesh flies are major primary consumers of carrion and are commonly found on human remains. Due to this latter feeding habit, their development rates can be used to provide temporal information in forensic investigations. This is usually done by referencing published flesh fly development datasets. Flesh flies are typically assumed to be strictly viviparous and datasets reporting their development rates therefore start at the first larval instar. However, an increasing number of studies has identified oviposition by flesh flies, including the forensically relevant species Blaesoxipha plinthopyga Wiedemann. To assess the impact of egg-laying behavior on casework, oviparity rates and time before larval hatching were assessed under controlled laboratory conditions that reflect common casework conditions in Harris County, Texas. We demonstrated systematic deposition of viable eggs but at a very variable rate between samples. Similarly, the duration between oviposition and larval hatching was highly variable, with some eggs taking more than a day to hatch after deposition. These results highlight the need to account for embryonic development in forensic investigations including B. plinthopyga and advocates for the re-evaluation of the assumed strict viviparity of the Sarcophagidae.

Necrophagous Fly Assembly: Evaluation of Species Bait Preference in Field Experiments

The assembly of species that colonize animal organic matter, their relative abundance, and dynamics are affected by the environmental and biogeographical conditions to which these resources are exposed. Baited trap studies are essential for research on the diversity, seasonality, distribution and population dynamics of necrophagous flies. Decomposing baits provide the necessary stimulus for flies to aggregate on them. In this study, three types of bait of animal origin with different organic chemical composition were compared in terms of the diversity, richness, abundance, and species composition of saprophagous flies species that were attracted to them. Bone-meal (BM), cow liver (CL), and rotten chicken viscera (CV) were used as bait to collect flies. In total, 3,387 Calliphoridae, Sarcophagidae, and Muscidae adult flies were collected. The most abundant species were Lucilia ochricornis (Wiedemann 1830), Chrysomya albiceps (Wiedemann 1819) (Diptera: Calliphoridae), Peckia (Sarcodexia) lambens (Wiedemann 1830) (Diptera: Sarcophagidae), and Ophyra capensis (Wiedemann 1818) (Diptera: Muscidae). The type of bait had significant effects on both the total richness (F2,18 = 57.08; P < 0.0001) and the effective number of species (F2,18 = 12.81; P = 0.0003) per trap. The average richness was higher in traps baited with chicken viscera, followed by cow liver and finally by bone-meal. The composition of cow liver and bone meal species constitute subsets of the species collected with chicken viscera, thus using the three baits would not increase the number of species detected. These results indicate that chicken viscera is the most efficient bait for testing or assessing necrophagous fly diversity.

Geographical Distribution, Biodiversity, and Species Richness of Medically Important Necrophagous Flies in Central Iran

There have been some investigations carried out about necrophagous flies and their biodiversity indices in Iran. In the present study, the species composition of flies, their richness, and biodiversity were investigated in central Iran. In a cross-sectional study, specimens were collected monthly in three different climate areas of Qom Province. Species diversity, species richness, and species evenness were calculated to estimate the species biodiversity of flies. In total, 7,291 flies were collected and identified using valid identification keys that classified flies into four families and 15 different species. The largest collection of flies was obtained in the mountainous areas comprising 36.2% of specimens. Moreover, five forensically important species of fly were collected in this region with the potential to cause human and animal myiasis: Calliphora vicina, Lucilia sericata, Musca domestica, Wohlfahrtia nuba, and Chrysomya albiceps. There were slight differences in species richness and diversity indices in the areas. In mountainous areas, the Shannon-Wiener index and richness were maximum (H' = 1.87, S = 13). The evenness based on the Shannon evenness index in the mountainous areas was 0.728 and 0.719 in desert areas, whereas it was the highest (0.764) in the semidesert areas. Moreover, high values of the Jaccard similarity index were observed in captured necrophagous fly species in all the areas. The necrophagous fly fauna and species diversity indices were high because of an increase in the evenness. In general, some well-known forensically important species of flies were collected that proved the potential of myiasis occurrence in this area.

Is rapid cold-hardening an aerobic process? Characterization of changes in metabolic activity during its induction and effects of anoxia in flesh fly

Rapid cold-hardening (RCH) is a type of phenotypic plasticity that promotes a swift improvement of cold tolerance in insects. A brief exposure to mild cold dramatically increases insect survival to a subsequent cold exposure that would be lethal otherwise. In adult male flesh fly, Sarcophaga bullata, as little as 15 min at 5 °C significantly improved organismal survival at -7°C from 0 to 66.7 ± 11.1%. In this study, we investigated whether this RCH response is an aerobic process in S. bullata by characterizing changes in metabolic activity during its induction. At the level of whole organism, CO₂ production continued at a level above our detection limit, and a relatively greater rate was observed during the early phase before it stabilized after ~1 h of the RCH induction. Similarly, in isolated flight muscle tissues, those maintained at 5 °C for 10 min exhibited significantly greater rates of oxygen consumption, compared to those maintained at 5 °C for 1 h (2.82 ± 0.29 vs. 1.36 ± 0.22 μl O₂ mg^-1 DM h^-1). When these tissues were exposed to LaCl₃, a treatment that should inhibit RCH ex vivo, oxygen consumption rates of the muscles were reduced significantly to a level similar to those that had been maintained at 5 °C for 1 h. Interestingly, however, the RCH response was still evident among individuals exposed to chilling under anoxia. Compared to those exposed to anoxia for 30 min only at 25 °C, flies exposed to 5 °C for 2 h under anoxia following the initial exposure exhibited a significantly greater level of cold tolerance at -7.5 °C (41.7 ± 7.1 vs. 91.8 ± 3.9%). Our results suggest that while relatively greater rates of metabolic activity are associated with the early phase of the RCH induction, it can proceed under the anoxic condition, thereby suggesting its independence to aerobic respiration.

Dipteran Attraction to a Variety of Baits: Implications for Trapping Studies as a Tool for Establishing Seasonal Presence of Significant Species

Monitoring and collection of fly taxa (Diptera: Calliphoridae; Muscidae; Sarcophagidae) of medical, veterinary, and agricultural importance is often routine practice, providing data on target species presence, distribution and abundance. Collection practices currently involve baited trapping and while an inherent bias accompanying the choice of bait is acknowledged, there is little consistency in bait choice between studies and insufficient assessment of trapping success rates for bait types in current use. This study aimed to examine the effect of bait choice on trapping results for six commonly used bait types; a commercial bait (Envirosafe Fly Attractant, Envirosafe Products) and a combination of mixtures of liver, horse manure and 5% sodium sulfide (Na2S). Trapping success was compared under different seasonal conditions (Summer, Autumn, and Spring) to determine the most attractive bait for calliphorid species, with a secondary comparison of kangaroo versus ox liver occurring under summer conditions. Baits containing Na2S were the most successful in captures of all target taxa, with the addition of manure desirable, yielding increased diversity of taxa. Kangaroo liver baits attracted high numbers of Chrysomya spp. (Robineau-Desvoidy, Diptera: Calliphoridae), while Lucilia spp. (Robineau-Desvoidy, Diptera: Calliphoridae) were comparatively underrepresented in traps using liver alone. The use of a combined ox liver/manure/Na2S bait is recommended as the gold standard for generic screening of necrophagous flies. Where more specific target fly taxa are desired, such as Chrysomya spp. or Lucilia spp. only, alternate baits such as kangaroo or lamb may prove more attractive/successful.

Immunosuppressive effects of the limonoid azadirachtin, insights on a nongenotoxic stress botanical, in flesh flies

The tetranortriterpenoid azadirachtin (Aza) is a well-known insect growth disruptor of plant origin. Although its actions on insects have been extensively studied; fragmentary reports are available from the immunological point of view. Therefore, in the present study, total (THC) and differential hemocyte counts (DHC), nodulation, phenoloxidase (PO) activity, immune-reactive lysozymes and inducible nitric oxide (NO) were assessed, as measures of immune responses, in Sarcophaga argyrostoma 3^rd instars challenged individually with M. luteus or Aza, or in combination with both compared to the control larvae. THC was significantly declined after 12 h and 24 h of treatment with Aza. DHC varied considerably; in particular, plasmatocytes were significantly decreased after 36 h and 48 h of treatment with Aza; whereas granulocytes were significantly increased. Nodulation was significantly increased with the increase of time after all treatments. Challenging with M. luteus significantly increased the activity of PO in hemocytes and plasma; whereas such activity was significantly decreased after treatment with Aza or combined Aza and M. luteus. Treatment with Aza or M. luteus alone or in couple significantly increased lysozyme activity of fat body, hemocytes and plasma. However, challenging with M. luteus significantly increased NO concentration in the same tissues. A hypothetical model of Aza as a potential mutagen is presented. However, no genotoxic effect was observed through tracking apoptosis-associated changes in Aza-treated hemocytes via flow cytometry-based apoptosis detection. Our study suggests that the integration of Aza, as an eco-friendly pesticide, with bacterial biopesticides may be a successful approach for controlling insect pests.

Diversity, Daily Flight Activity and Temporal Occurrence of Necrophagous Diptera Associated with Decomposing Carcasses in a Semi-Arid Environment

The harsh conditions of the Brazilian seasonally dry tropical forest known as Caatinga pose challenges to the insects specialized in the exploitation of ephemeral resources. We investigated the diversity and daily flight activity of dipterans associated with decomposing rat carcasses in a field experiment performed in the semi-arid region of Pernambuco State, Brazil. We also analyzed the temporal arrival of adult insects on the carcasses at three stages of decomposition: early, intermediate, and advanced. We collected 1173 individuals, of which Muscidae had the highest abundance (36.5%), followed by Sarcophagidae (28.1%), Calliphoridae (25.2%), and Fanniidae (10.2%). Chrysomya albiceps (Wiedemann, 1819) (Calliphoridae), Fannia pusio (Wiedemann, 1830) (Fanniidae), Atherigona orientalis (Schiner, 1868), and Musca domestica (Linnaeus, 1758) (Muscidae) were the most abundant species. The richness reached its maximum value on the second day of decomposition, with 18 species, decreasing to 8 species on the last day of decomposition (7 days). The ecological indices of diversity, dominance, and evenness varied little among the stages. There was an overlap of most species throughout the decomposition, although the overall abundance was higher at the intermediate stage for Calliphoridae, Muscidae, and Sarcophagidae. In accordance to previous studies, nocturnal flight was rare, as approximately 8% of insects were captured at night. Our results expand the knowledge on ecological and behavioral aspects of necrophagous flies under inhospitable environments, such as the dry season in the Caatinga. The dominance of the invasive species C. albiceps reinforced here illustrates its geographical expansion towards the countryside of Northeastern Brazil.

Effects of gender, age, and nutrition on circadian locomotor activity rhythms in the flesh fly Sarcophaga crassipalpis

In many animal species, circadian rhythms of behavior are not constant throughout the lifetime of the individual but rather exhibit at least some degree of plasticity. In the present study, we have examined the potential influences of gender, age, and nutrition (presence or absence of liver) on the expression of circadian locomotor activity rhythms in the flesh fly Sarcophaga crassipalpis. We found no significant differences in endogenous circadian period under constant dark conditions with respect to gender, nutrition, or age for the duration of our experiments. On the other hand, both male and female flesh flies, as expected, were predominantly diurnal under light-dark cycles, but the pattern of entrainment differed between the sexes. Females also displayed higher activity levels than males. Also, in contrast with males, female activity levels increased with age. Moreover, females exhibited an extraordinary, but transient (one to three days), departure from diurnality which we characterize as "extended dark activity" (EDA). This phenomenon appeared as a continuous bout of locomotor activity that extended at least three hours into the early half of the dark phase at levels at least twice the median of the overall locomotor activity for the individual fly. EDA occurred as an age-dependent response to liver consumption, never appearing prior to day 4 post-eclosion but, thereafter, transpiring within one or two days after a 48-h exposure to liver. These results suggest a linkage between physiological events associated with egg provisioning and locomotor activity in the anautogenous flesh fly. Furthermore, our findings identify the existence of multiple influences on the expression of circadian clock-regulated behavior.

Insects Associated with Pig Carrion in Two Environments of the Brazilian Savanna

Studies of carrion fauna have increased in Brazil and have contributed to the knowledge of this fauna in the national territory. Brazil has continental dimensions and presents various biomes in its territorial area. Most of the carrion fauna have seldom been studied, and this is especially true for the Savanna or "Cerrado." The present research examined the fauna visiting carrion in two environments and two seasons in a rural area situated in a region of Cerrado in southeastern Brazil. The two environments studied were a pasture and a fragment of semi-deciduous forest. Samples were collected during the dry and humid seasons of the year. The study identified the diversity and relative abundance of species attracted to pig carcasses (Sus scrofa L.) exposed in each environment and season. Eight pig carcasses (10 ± 1 kg) were placed in traps, and adult insects attracted to the traps were collected during the decay of the carcasses. A total of 92,489 insects were collected during the experiments. The Diptera was the most frequent order (92.2%) represented by 27 families and at least 124 species. This was followed by Coleoptera (4.4%) represented by 14 families and at least 65 species. Sarcophagidae had the greatest diversity of species, followed by Muscidae and Calliphoridae. Several species were collected only during a specific period of the year or in a single environment. The results are important from an ecological point of view and for Medico-Legal Forensic Entomology.

Upregulation of heat-shock proteins in larvae, but not adults, of the flesh fly during hot summer days

Heat-shock proteins (HSPs) are highly expressed when organisms are exposed to thermal stresses. The HSPs are considered to play significant roles in thermal adaptation because they function as molecular chaperones facilitating proper protein synthesis. The expression of HSPs under field conditions, however, has not been evaluated much, and their importance, based on the ecological contexts in nature, is still unclear. We investigated this aspect in the larvae and adults of the flesh fly, Sarcophaga similis. These larvae spend their larval life in the carrion or faeces of vertebrates; therefore, they are less mobile and are occasionally exposed to high temperature. In contrast, the adults of this species can fly and, therefore, they are highly mobile. Massive transcription of Hsps was detected both in the larvae and adults in a laboratory heat-shock experiment. The larvae in the field showed no or less Hsp production on thermally mild days, whereas considerable upregulation of Hsp expression was detected on days with high temperature. The adults can also be exposed to thermal stress as high as 40 °C or higher in the field. However, most of the flies showed no or less Hsp expression. The observations in the experimental cage under field conditions revealed behavioural thermoregulation of adults through microhabitat selection. The present study demonstrates ontogenetic alteration of the strategy to overcome thermal stress in an insect; in the field, less mobile larvae use physiological protection against heat (HSP production), whereas highly mobile adults avoid the stress behaviourally (through microhabitat selection).

Filth Fly Activity Associated With Composted and Noncomposted Beef Cadavers and Laboratory Studies on Volatile Organic Compounds

Commercial livestock facilities are faced with the challenge of managing large amounts of waste including manure and animal mortalities. One method of disposing of dead animals is composting. The cadavers are enveloped in carbon material that creates a barrier between the dead tissue and the surrounding environment. Dead tissue can release materials that not only contaminate the soil but also the groundwater and nearby surface water. Animal cadaver composting is designed to facilitate decomposition without the aid of carrion-feeding insects and reduce the presence of common pathogens associated with animal waste and dead tissue. The aim of this study was to evaluate insect activity associated with composted and exposed beef cadavers, specifically filth flies that can serve as mechanical vectors of important human pathogens such as E. coli 0157:H7. Greater numbers of all types of arthropods were trapped overall at the exposed animal site than the composted animal site. Most importantly, the number of filth flies was significantly lower at the composted site (P = 0.0009). Laboratory analysis of volatile organic compounds from composted and noncomposted rats indicated that known fly attractants such as dimethyl disulfide may be inhibited by the composting process. Implementing composting programs at livestock facilities could reduce the risk of flies spreading harmful pathogens to surrounding areas, including farms that grow fresh produce.

Fly rounds: Validation and pilot of a novel epidemiologic tool to guide infection control response to an infestation of Sarcophagidae flies in a community hospital's perioperative department

During an outbreak of Sarcophagidae, or flesh flies, in a community hospital's perioperative department, the infection prevention and control (IPC) department developed, validated, and piloted a novel epidemiologic tool to track hourly fly prevalence by room. Interrater reliability of the tool was measured as 0.88 and hourly point prevalence counts were superimposed on floor plans to create heat maps. Such surveillance tools allowed more timely decision making in conjunction with the operations of the hospital incident command system.

Two New Species of Oxysarcodexia Townsend (Diptera: Sarcophagidae) From the Chaco Forest Ecoregion of South America

Two new Neotropical species of the genus Oxysarcodexia Townsend (Diptera: Sarcophagidae) from Chaco ecoregion of Argentina are described, O. berthet, sp. nov. and O. ibera, sp. nov. Both species were recovered from localities in the eastern part of the Chaco forest (Humid Chaco). The descriptions are based on the male external morphology and terminalia. Photographs and SEM images are provided to aid in the identification of the species.

Diversity of Sarcosaprophagous Calyptratae (Diptera) on Sandy Beaches Exposed to Increasing Levels of Urbanization in Brazil

Sandy beaches are among the most impacted ecosystems worldwide, and the effects of urbanization on the biodiversity of these habitats are largely unknown, particularly in Brazil. We investigated the composition and structure of assemblages of sarcosaprophagous insects (Diptera: Calliphoridae, Sarcophagidae, and Muscidae) on six sandy beaches exposed to differential levels of human impact in Pernambuco State, Brazil. In total, 20,672 adults of 40 species were collected, of which 70% were Calliphoridae. Sarcophagidae had the highest diversity with 26 species of nine genera. A strong overlap in the composition of the assemblages across the six beaches was observed, with only a few species being restricted to one type of beach. The flesh flies Dexosarcophaga carvalhoi (Lopes), Peckia intermutans (Walker), and Titanogrypa larvicida (Lopes) occurred exclusively in beaches under low anthropogenic impact. Species with strong medical and veterinary importance such as Synthesiomyia nudiseta (Wulp) occurred even in beaches under low human presence. The invasive species Chrysomya albiceps (Wiedemann) and Chrysomya megacephala (F.) (Calliphoridae) were dominant in all beaches, which exposes the vulnerability of sandy beaches to exotic species. Our data imply that sarcosaprophagous flies can be used as early biological indicators to suggest urbanization in coastal environments.

Changes in microRNA abundance may regulate diapause in the flesh fly, Sarcophaga bullata

Diapause, an alternative developmental pathway characterized by changes in developmental timing and metabolism, is coordinated by molecular mechanisms that are not completely understood. MicroRNA (miRNA) mediated gene silencing is emerging as a key component of animal development and may have a significant role in initiating, maintaining, and terminating insect diapause. In the present study, we test this possibility by using high-throughput sequencing and qRT-PCR to discover diapause-related shifts in miRNA abundance in the flesh fly, Sarcophaga bullata. We identified ten evolutionarily conserved miRNAs that were differentially expressed in diapausing pupae compared to their nondiapausing counterparts. miR-289-5p and miR-1-3p were overexpressed in diapausing pupae and may be responsible for silencing expression of candidate genes during diapause. miR-9c-5p, miR-13b-3p, miR-31a-5p, miR-92b-3p, miR-275-3p, miR-276a-3p, miR-277-3p, and miR-305-5p were underexpressed in diapausing pupae and may contribute to increased expression of heat shock proteins and other factors necessary for the enhanced environmental stress-response that is a feature of diapause. In S. bullata, a maternal effect blocks the programming of diapause in progeny of females that have experienced pupal diapause, and in this study we report that several miRNAs, including miR-263a-5p, miR-100-5p, miR-125-5p, and let-7-5p were significantly overexpressed in such nondiapausing flies and may prevent entry into diapause. Together these miRNAs appear to be integral to the molecular processes that mediate entry into diapause.

Taxonomic Revision of Lipoptilocnema (Diptera: Sarcophagidae), With Notes on Natural History and Forensic Importance of Its Species

Lipoptilocnema Townsend is a small genus of Neotropical Sarcophaginae with a distinctive genitalic morphology. This genus is revised based on the examination of the type series and large numbers of specimens of the seven previously known species, plus three new ones herein described, one from Argentina (L. delfinado Mulieri and Mello-Patiu, sp. nov.), and two from Brazil (L. savana Mulieri and Mello-Patiu, sp. nov. and L. tibanae Mulieri and Mello-Patiu, sp. nov.). All species are described or redescribed and illustrated. Distribution maps and a key for male identification are provided. The taxonomic position of this genus is reviewed and the interpretation of phallic structures is discussed. Notes on the natural history of Lipoptilocnema species are provided, and their potential importance as PMI indicators is highlighted, including the first record of Lipoptilocnema reared from a dead human body.

The Auditory System of the Dipteran Parasitoid Emblemasoma auditrix (Sarcophagidae)

Several taxa of insects evolved a tympanate ear at different body positions, whereby the ear is composed of common parts: a scolopidial sense organ, a tracheal air space, and a tympanal membrane. Here, we analyzed the anatomy and physiology of the ear at the ventral prothorax of the sarcophagid fly, Emblemasoma auditrix (Soper). We used micro-computed tomography to analyze the ear and its tracheal air space in relation to the body morphology. Both tympana are separated by a small cuticular bridge, face in the same frontal direction, and are backed by a single tracheal enlargement. This enlargement is connected to the anterior spiracles at the dorsofrontal thorax and is continuous with the tracheal network in the thorax and in the abdomen. Analyses of responses of auditory afferents and interneurons show that the ear is broadly tuned, with a sensitivity peak at 5 kHz. Single-cell recordings of auditory interneurons indicate a frequency- and intensity-dependent tuning, whereby some neurons react best to 9 kHz, the peak frequency of the host's calling song. The results are compared to the convergently evolved ear in Tachinidae (Diptera).

Eavesdropping to Find Mates: The Function of Male Hearing for a Cicada-Hunting Parasitoid Fly, Emblemasoma erro (Diptera: Sarcophagidae)

Females of several species of dipteran parasitoids use long-range hearing to locate hosts for their offspring by eavesdropping on the acoustic mating calls of other insects. Males of these acoustic eavesdropping parasitoids also have physiologically functional ears, but so far, no adaptive function for male hearing has been discovered. I investigated the function of male hearing for the sarcophagid fly Emblemasoma erro Aldrich, an acoustic parasitoid of cicadas, by testing the hypothesis that both male and female E. erro use hearing to locate potential mates. I found that both male and nongravid female E. erro perform phonotaxis to the sounds of calling cicadas, that male flies engage in short-range, mate-finding behavior once they arrive at a sound source, and that encounters between females and males at a sound source can lead to copulation. Thus, cicada calling songs appear to serve as a mate-finding cue for both sexes of E. erro Emblemasoma erro's mate-finding behavior is compared to that of other sarcophagid flies, other acoustic parasitoids, and nonacoustic eavesdropping parasitoids.

Assessment of the Abundance and Diversity of Calliphoridae and Sarcophagidae (Diptera) in Sites With Different Degrees of Human Impact in the Iberá Wetlands (Argentina)

The aim of the present study was to explore the diversity and describe the spatial distribution of Calliphoridae and Sarcophagidae along an urbanization gradient in the Iberá Wetlands. The flies were collected at 18 sampling points, three per site. In total, 3,318 flies were collected (3,077 blow flies and 241 flesh flies), distributed in 13 genera and 33 species. Calliphoridae was the most abundant, comprised 92.74% of all adult flies. Chrysomya albiceps (Wiedemann), Cochliomyia macellaria (F.), Chrysomya megacephala (F.), and Chrysomya putoria (Wiedemann) were the most abundant species, representing 82.21% of the total sample. The genus Oxysarcodexia Townsend was the most diverse with 10 species represented. The abundance of exotic species represents 62.85% of the total sample, showing a reduction toward less disturbed sites. The results of this study indicated that sites with intermediate impact had higher diversity than those where the disturbances are high or absent. Our findings provide the first assessment of Calliphoridae and Sarcophagidae diversity in the area of the Iberá Wetlands.

Postmortem Attraction of Sarcosaprophagous Diptera to Tramadol-Treated Rats and Morphometric Aspects of the Developed Larvae

The presence of some specific drugs in animal tissues may affect the time of minimal postmortem intervals estimated during forensic entomological investigations. To test the effects of a specific drug on decomposition, a field study was conducted at Fayoum University campus, Egypt, from March to May 2013, using tramadol, a synthetic analgesic opioid used to treat moderate to severe pain in humans. Albino rats were used as the animal model during this study. The duration of the fresh stage of tramadol treated rat (Ttr) carcasses was significantly shorter (2.4 ± 0.27 days) compared to tramadol free rat (Tfr) carcasses (6.4 ± 0.49 days). The dry carcass stage of Ttr lasted longer (10.3 ± 0.99 days) as compared to (7.4 ± 0.18 days) the Tfr carcass. The decomposition process of the (Ttr) carcass was not significantly faster (24.9 ± 1.58 days) as compared to (Tfr) carcasses (29.5 ± 1.69). Lucilia cuprina (Wiedemann), Chrysomya albiceps (Wiedemann), and Musca domestica L. were less attracted to Ttr carcass-baited traps than traps with Tfr carcasses. However, females of Sarcophaga spp. showed a greater attraction to Ttr carcasses. Females of another sarcophagid fly, Wohlfahrtia spp. exhibited similar attraction tendencies to both types of trap baits. Larvae of S. argyrostoma (Robineau-Desvoidy) collected from Ttr carcasses developed to a significantly longer total body length (10.4 ± 0.04 mm) as compared to the average length of the larvae collected from Tfr carcasses (8.9 ± 0.34 mm). During days 9-13 after rat death, the relative lengths of larvae from Ttr carcasses were not significantly different from Tfr carcasses. Larvae fed on Ttr carcasses pupated 2 days later than the control larvae.

PHARMACOLOGICAL REGULATION OF DIGESTION IN THE ANAUTOGENOUS FLESH FLY, Sarcophaga crassipalpis, BY SIMPLE INJECTION OF 6-HYDROXYDOPAMINE

Female anautogenous Sarcophaga flesh flies need a protein meal to start large-scale yolk polypeptides (YPs) production and oocyte maturation. Protein meal rapidly elicits a brain-dependent increase in midgut proteolytic activity. Trypsin and chymotrypsin together represent over 80% of protease activity in liver-fed flies. Abdominal injection of 6-hydroxydopamine (6-OHDA) dose-dependently prohibits this increase in proteolytic activity at translational level in a similar way as post liver feeding decapitation. Delayed injection of 6-OHDA later than 6 h post liver meal has no effect. In flesh flies, chemical decapitation by 6-OHDA, by interrupting the brain-gut dopaminergic signaling, can be used as tool for the controlled inhibition of midgut proteolytic activity and subsequent ovarial development. Inhibition of ovarial development is probably indirect due to a deficit in circulating amino acids needed for YPs synthesis.

Sex-biased Patterns of Saprophagous Calyptratae (Diptera) Collected With Different Baits of Animal Origin

The aim of the present study was to explore the response behavior of males and females of different families of Calyptratae (Diptera) to two different baits (rotten liver and feces) as separate attractants. We describe the sex bias toward these baits for species of Calliphoridae, Muscidae, and Sarcophagidae and compare the general patterns of this sex bias according to the family or trophic guild. In total, 15 species of Sarcophagidae, 10 species of Muscidae, and 9 species of Calliphoridae were analyzed. A female-biased pattern was observed for most calliphorids and for all muscids, whereas a male-biased pattern was more frequent among sarcophagids. The female captures on each kind of bait were assessed as a potential indicator of potential breeding substrates of the species. Three different trophic guilds and their pattern of sex bias were compared. The results obtained allow hypothesizing on the biological traits of saprophagous species, especially on their potential breeding substrates, and assessing proper sampling methods.

Differential peptidomics highlights adipokinetic hormone as key player in regulating digestion in anautogenous flesh fly, Sarcophaga crassipalpis

Females of anautogenous flesh flies, Sarcophaga crassipalpis, need a protein meal in order to produce their first batch of eggs. This protein meal elicits an increase in midgut proteolytic activity that is under neuropeptidergic regulation. Time series of decapitation and rescue experiments of liver fed flies evidenced the need of a peptide factor released by corpora cardiaca (CC) within 4h post protein feeding in order to assure complete protein digestion. Q-Exactive quantitative differential peptidomics analysis on CC of sugar fed flies and flies 5h post protein feeding respectively, showed a unique consistent decrease in the stored amount of adipokinetic hormone (AKH) ranging between 16% up to 63%. Injection of AKH into liver fed decapitated flies as well as sugar fed intact flies resulted in dose dependent enhanced midgut proteolytic activity up to the level of intact protein fed flies. This suggests a key role of AKH in food depended reproduction.

Evaluation of the infestation rate of Blaesoxipha alcedo in the carrion roller scarab Canthon cyanellus cyanellus and its effect on reproductive behavior

This study documents Blaesoxipha alcedo (Aldrich; Diptera: Sarcophagidae) parasitizing the necrophagous ball roller beetle Canthon cyanellus cyanellus LeConte collected over 2 yr, and evaluates the reproductive behavior of parasitized beetles. Up to 52% of the beetles collected in the field had been parasitized and exhibited modified sexual behavior. In general, 21% of the males and 24% of the females had been parasitized. The number of parasitized males peaked in August 2000 (52%), but that of females peaked in May 2001 (52%). The lowest percentage of parasitized males (7%) was recorded in September 2000, June 2001, and July 2001; for females, parasitism was lowest in June 2000 (10%). The larva of this sarcophagid fly penetrates the host through the tegumentary membrane, leaving a scar. The larvae feed on the gonads of male and female C. c. cyanellus, castrating them, causing the loss of their ability to recognize individuals of the opposite sex, preventing reproduction, and lowering overall reproductive success.

[A case of gingival myiasis caused by Wohlfahrtia magnifica]

Myiasis is an infestation of living or dead tissue of humans and animals by diptera larvae. Gingival myiasis is a rare pathology and is mainly associated with poor oral hygiene, alcoholism, senility, suppurative lesions, mouth breathing, mental retardation and hemiplegia. Myiasis is most common during summer since the fly population increases during this season. Mostly it occurs in farmers and people who live in tropical climates. Gingival myiasis in humans in Turkey is limited to only a few cases. According to our literature research, this is the first case of gingival myiasis produced by larvae of Wohlfahrtia magnifica in a Turkish adult. According to our best knowledge, it is also the first gingival myiasis case that one of the causative larva had grown to the adult stage in Turkey. A 43 years old male patient who perceived the presence of live maggots in his mouth was referred to our clinic. Clinical findings of gingival myiasis were observed. The patient had no history of systemic disease but oral hygiene was poor. Clinical and radiographic examination indicated that he had chronic periodontitis. Before the dental treatment seven larvae and during the scalling five larvae were elevated from the gingival sulcus. The body of the larvae composed of 12 segments and they were 8-10 mm in length. One of the larvae which was sent to the microbiology laboratory were placed into sheep liver to resume life and the other larvae were placed into 70% alcohol solution. After 9-10 days, the larva which was placed in the liver became pupa. Approximately 15 days later, the pupa became an adult fly. The larvae were identified as the second stage larvae of Wohlfahrtia magnifica. Treatment consisted of removal of the maggots from the gingival sulcus, followed by scaling and oral hygiene instruction. Non-surgical periodontal treatment was applied and the patient was followed-up for 3 months. After non-surgical periodontal treatment, patient didn't accept the flap operation. The most important point for the prevention of gingival myiasis is to establish a good oral hygiene, together with the elimination of environmental factors which support the proliferation of the flies.

Extensive reorganization of behavior accompanies ontogeny of aggression in male flesh flies

Aggression, costly in both time and energy, is often expressed by male animals in defense of valuable resources such as food or potential mates. Here we present a new insect model system for the study of aggression, the male flesh fly Sarcophaga crassipalpis, and ask whether there is an ontogeny of aggression that coincides with reproductive maturity. After establishing that reproductive maturity occurs by day 3 of age (post-eclosion), we examined the behavior of socially isolated males from different age cohorts (days 1, 2, 3, 4, and 6) upon introduction, in a test arena, with another male of the same age. The results show a pronounced development of aggression with age. The change from relative indifference to heightened aggression involves a profound increase in the frequency of high-intensity aggressive behaviors between days 1 and 3. Also noteworthy is an abrupt increase in the number of statistically significant transitions involving these full-contact agonistic behaviors on day 2. This elevated activity is trimmed back somewhat by day 3 and appears to maintain a stable plateau thereafter. No convincing evidence was found for escalation of aggression nor the establishment of a dominance relationship over the duration of the encounters. Despite the fact that aggressive interactions are brief, lasting only a few seconds, a major reorganization in the relative proportions of four major non-aggressive behaviors (accounting for at least 96% of the total observation time for each age cohort) accompanies the switch from low to high aggression. A series of control experiments, with single flies in the test arenas, indicates that these changes occur in the absence of the performance of aggressive behaviors. This parallel ontogeny of aggressive and non-aggressive behaviors has implications for understanding how the entire behavioral repertoire may be organized and reorganized to accommodate the needs of the organism.

Useless hearing in male Emblemasoma auditrix (Diptera, Sarcophagidae)--a case of intralocus sexual conflict during evolution of a complex sense organ?

Sensory modalities typically are important for both sexes, although sex-specific functional adaptations may occur frequently. This is true for hearing as well. Consequently, distinct behavioural functions were identified for the different insect hearing systems. Here we describe a first case, where a trait of an evolutionary novelty and a highly specialized hearing organ is adaptive in only one sex. The main function of hearing of the parasitoid fly Emblemasoma auditrix is to locate the host, males of the cicada species Okanagana rimosa, by their calling song. This task is performed by female flies, which deposit larvae into the host. We show that male E. auditrix possess a hearing sense as well. The morphology of the tympanal organ of male E. auditrix is rather similar to the female ear, which is 8% broader than the male ear. In both sexes the physiological hearing threshold is tuned to 5 kHz. Behavioural tests show that males are able to orient towards the host calling song, although phonotaxis often is incomplete. However, despite extensive observations in the field and substantial knowledge of the biology of E. auditrix, no potentially adaptive function of the male auditory sense has been identified. This unique hearing system might represent an intralocus sexual conflict, as the complex sense organ and the behavioural relevant neuronal network is adaptive for only one sex. The correlated evolution of the sense organ in both sexes might impose substantial constraints on the sensory properties of the ear. Similar constraints, although hidden, might also apply to other sensory systems in which behavioural functions differ between sexes.

Synanthropy of sarcophagidae (Diptera) in La Pintada, Antioquia-Colombia

Recently, populations of flies have increased in numbers given the elevated levels of organic matter waste produced by anthropic activities and domestication of animals. Such increase represents a worldwide health concern, since flies can be vectors of human diseases. The great variety of feeding and developmental habits of flies of the family Sarcophagidae taking place on animal corpses, feces and decomposed organic matter make them potential vectors of pathogens. Herein, we evaluated the synanthropic index (SI), as well as other ecological aspects of this family, through simultaneous monthly samplings in three areas with different degrees of human disturbance (urban, rural and forest). Each area had four van Someren Rydon traps, each one with a different bait (i.e., human feces, chicken viscera, fish and decomposing onion). Traps were active during 48 hours each month, and specimen collection was made every 12 hours. A total of 7 446 Sarcophagidae individuals were collected (1275 males and 6171 females), belonging to 27 species and nine genera. Tricharaea (Sarcophagula) canuta (Sl = +96.67), Oxysarcodexia taitensis (SI = +93.85), Peckia (Peckia) chrysostoma (SI = +90.00) and Tricharaea (Sarcophagula) occidua (SI = +88.76) exhibited the highest values of synanthropy index, revealing a strong preference for human settlements. The most abundant species were Oxysarcodexia conclausa (21.80%), Ravinia effrenata (18.67%), Oxysarcodexia bakeri (11.45%) and Oxysarcodexia taitensis (10.20%), all of which exhibited preference for urban environments. Additionally, we are reporting seven new records of Sarcophagid flies for Colombia: Oxysarcodexia angrensis, Oxysarcodexia bakeri, Oxysarcodexia diana, Oxysarcodexia similata, Oxysarcodexia timida, Peckia (Peckia) pexata and Titanogrypa (Cucullomyia) placida.

Calcium signaling mediates cold sensing in insect tissues

The ability to rapidly respond to changes in temperature is a critical adaptation for insects and other ectotherms living in thermally variable environments. In a process called rapid cold hardening (RCH), insects significantly enhance cold tolerance following brief (i.e., minutes to hours) exposure to nonlethal chilling. Although the ecological relevance of RCH is well-established, the underlying physiological mechanisms that trigger RCH are poorly understood. RCH can be elicited in isolated tissues ex vivo, suggesting cold-sensing and downstream hardening pathways are governed by brain-independent signaling mechanisms. We previously provided preliminary evidence that calcium is involved in RCH, and here we firmly establish that calcium signaling mediates cold sensing in insect tissues. In tracheal cells of the freeze-tolerant goldenrod gall fly, Eurosta solidaginis, chilling to 0 °C evoked a 40% increase in intracellular calcium concentration as determined by live-cell confocal imaging. Downstream of calcium entry, RCH conditions significantly increased the activity of calcium/calmodulin-dependent protein kinase II (CaMKII) while reducing phosphorylation of the inhibitory Thr306 residue. Pharmacological inhibitors of calcium entry, calmodulin activation, and CaMKII activity all prevented ex vivo RCH in midgut and salivary gland tissues, indicating that calcium signaling is required for RCH to occur. Similar results were obtained for a freeze-intolerant species, adults of the flesh fly, Sarcophaga bullata, suggesting that calcium-mediated cold sensing is a general feature of insects. Our results imply that insect tissues use calcium signaling to instantly detect decreases in temperature and trigger downstream cold-hardening mechanisms.

Determining the age of adult flesh flies, Boettcherisca peregrina, using pteridine fluorescence

To assess the potential application of pteridine fluorescence in determining the age of adult Boettcherisca peregrina (Diptera: Sarcophagidae) Robineau-Desvoidy and further for the postmortem interval, the age-dependent changes of pteridine fluorescence were investigated for the adults maintained at five constant temperatures. From the results, significant linear relationships were found between pteridine fluorescence and the age of the adults maintained at 16, 20, 24, 28 or 32 °C (P < 0.001, r(2) > 0.85). In addition, the relationships between the rate of pteridine accumulation and temperature were well described using linear equations for adult females and males. Then for each cohort of the flies at the ambient temperature, a calendar was constructed and used to determine the ages of females and males, respectively, in which was recorded in reverse time order the amount of pteridine accumulated per hour by the flies and their expected pteridine level when they emerged at the specified time. A significant linear relationship between estimated ages and chronological ages was observed for female or male adults, with the mean errors of the estimated ages of ±1.82 days for females and ±1.58 days for males. It is suggested that pteridine fluorescence analysis has a potential value in determining the age of adult B. peregrina.

Representation of the brain's superior protocerebrum of the flesh fly, Neobellieria bullata, in the central body

The central complex of the insect brain is a system of midline neuropils involved in transforming sensory information into behavioral outputs. Genetic studies focusing on nerve cells supplying the central complex from the protocerebrum propose that such neurons play key roles in circuits involved in learning the distinction of visual cues during operant conditioning. To better identify the possible sites of such circuits we used Bodian and anti-synapsin staining to resolve divisions of the superior protocerebrum into discrete neuropils. Here we show that in the fly Neobellieria bullata, the superior protocerebrum is composed of at least five clearly defined regions that correspond to those identified in Drosophila melanogaster. Intracellular dye fills and Golgi impregnations resolve "tangential neurons" that have intricate systems of branches in two of these regions. The branches are elaborate, decorated with specializations indicative of pre- and postsynaptic sites. The tangentially arranged terminals of these neurons extend across characteristic levels of the central complex's fan-shaped body. In this and another blowfly species, we identify an asymmetric pair of neuropils situated deep in the fan-shaped body, called the asymmetric bodies because of their likely homology with similar elements in Drosophila. One of the pair of bodies receives collaterals from symmetric arrangements of tangential neuron terminals. Cobalt injections reveal that the superior protocerebrum is richly supplied with local interneurons that are likely participants in microcircuitry associated with the distal processes of tangential neurons. Understanding the morphologies and arrangements of these and other neurons is essential for correctly interpreting functional attributes of the central complex.

The central complex of the flesh fly, Neobellieria bullata: recordings and morphologies of protocerebral inputs and small-field neurons

The central complex in the brains of insects is a series of midline neuropils involved in motor control, sensory integration, and associative learning. To understand better the role of this center and its supply of sensory information, intracellular recordings and dye fills were made of central complex neurons in the fly, Neobellieria bullata. Recordings were obtained from 24 neurons associated with the ellipsoid body, fan-shaped body, and protocerebral bridge, all of which receive both visual and mechanosensory information from protocerebral centers. One neuron with dendrites in an area of the lateral protocerebrum associated with motion-sensitive outputs from the optic lobes invades the entire protocerebral bridge and was driven by visual motion. Inputs to the fan-shaped body and ellipsoid body responded both to visual stimuli and to air puffs directed at the head and abdomen. Intrinsic neurons in both of these structures respond to changes in illumination. A putative output neuron connecting the protocerebral bridge, the fan-shaped body, and one of the lateral accessory lobes showed opponent responses to moving visual stimuli. These recordings identify neurons with response properties previously known only from extracellular recordings in other species. Dye injections into neurons connecting the central complex with areas of the protocerebrum suggest that some classes of inputs into the central complex are electrically coupled.

Effects of bait age, larval chemical cues and nutrient depletion on colonization by forensically important Calliphorid and Sarcophagid flies

Species colonization patterns on corpses and the frequency of carrion fly oviposition and larviposition are affected by decomposition stage and previous maggot colonization. This study investigated these effects on meat bait colonization by Victorian Diptera of forensic importance. Bait treatments were: 'aged' (aged for 4 days at 22 °C, allowing some decomposition); 'nutrient-depleted' [aged for 4 days at 22 °C with feeding Calliphora vicina (Robineau-Desvoidy) (Diptera: Calliphoridae) larvae]; 'extract' (fresh bait mixed with liquid formed by feeding C. vicina larvae), and 'fresh' (untreated control bait). Statistical analysis (α = 0.05) revealed that colonization frequency differed significantly among treatments (Welch's F(3,18.83) = 4.66, P < 0.05). Post hoc tests showed that fresh and extract baits were colonized extensively throughout the experiment with no significant difference, whereas the colonization of nutrient-depleted baits was significantly lower. This suggests that larval digestive enzymes, larval excreta and cuticular hydrocarbons have less effect on colonizing Diptera than the nutritional content of meat. The colonization of aged baits did not differ significantly from that of fresh, extract or nutrient-depleted baits. A further experiment testing 'very aged' (aged for 8 days at 28 °C), 'larvae-added' (fresh bait with C. vicina larvae added before placement) and 'fresh' (untreated control) baits revealed that very aged baits were colonized significantly less frequently than either fresh or larvae-added baits (Welch's F(2, 6.17) = 17.40, P < 0.05).

Physiological trade-offs of forming maggot masses by necrophagous flies on vertebrate carrion

Necrophagous flies that colonize human and animal corpses are extremely efficient at locating and utilizing carrion. Adult flies deposit eggs or larvae on the ephemeral food resource, which signals the beginning of intense inter- and intra-species competition. Within a short period of time after egg hatch, large larval aggregations or maggot masses form. A period of intense larval feeding ensues that will culminate with consumption/decomposition of all soft tissues associated with the corpse. Perhaps the most distinctive feature of these feeding aggregations is heat production; that is, the capacity to generate internal heat that can exceed ambient temperatures by 30°C or more. While observations of maggot mass formation and heat generation have been described in the research literature for more than 50 years, our understanding of maggot masses, particularly the physiological ecology of the aggregations as a whole, is rudimentary. In this review, an examination of what is known about the formation of maggot masses is presented, as well as arguments for the physiological benefits and limitations of developing in feeding aggregations that, at times, can represent regions of intense competition, overcrowded conditions, or a microclimate with elevated temperatures approaching or exceeding proteotoxic stress levels.

Thermoperiodic regulation of the circadian eclosion rhythm in the flesh fly, Sarcophaga crassipalpis

We recorded the eclosion time of the flesh fly, Sarcophaga crassipalpis, at different depths in the outdoor soil and under temperature cycles with various amplitudes in the laboratory, to examine the timing adjustment of eclosion in response to temperature cycles and their amplitudes in the pupal stage. In the soil, most eclosions occurred in the late morning, which was consistent with the eclosion time under pseudo-sinusoidal temperature cycles in the laboratory. The circadian clock controlling eclosion was reset by temperature cycles and free-ran with a period close to 24h. This clock likely helps pupae eclose at an optimal time even when the soil temperature does not show clear daily fluctuations. The eclosion phase of the circadian clock progressively advanced as the amplitude of the pseudo-sinusoidal temperature cycle decreased. This response allows pupae located at any depth in the soil to eclose at the appropriate time despite the depth-dependent phase delay of the temperature change. In contrast, the abrupt temperature increase in square-wave temperature cycles reset the phase of the circadian clock to the increasing time, regardless of the temperature amplitude. The rapid temperature increase may act as the late-morning signal for the eclosion clock.

Carrion mimicry in a South African orchid: flowers attract a narrow subset of the fly assemblage on animal carcasses

BACKGROUND AND AIMS

Although pollination of plants that attract flies by resembling their carrion brood and food sites has been reported in several angiosperm families, there has been very little work done on the level of specificity in carrion mimicry systems and the importance of plant cues in mediating such specialization. Specificity may be expected, as carrion-frequenting flies often exploit different niches, which has been interpreted as avoidance of interspecific competition. Interactions between the orchid Satyrium pumilum and a local assemblage of carrion flies were investigated, and the functional significance of floral traits, especially scent, tested. Pollination success and the incidence of pollinator-mediated self-pollination were measured and these were compared with values for orchids with sexual- and food-deceptive pollination systems.

METHODS AND KEY RESULTS

Observations of insect visitation to animal carcasses and to flowers showed that the local assemblage of carrion flies was dominated by blow flies (Calliphoridae), house flies (Muscidae) and flesh flies (Sarcophagidae), but flowers of the orchid were pollinated exclusively by flesh flies, with a strong bias towards females that sometimes deposited live larvae on flowers. A trend towards similar partitioning of fly taxa was found in an experiment that tested the effect of large versus small carrion quantities on fly attraction. GC-MS analysis showed that floral scent is dominated by oligosulfides, 2-heptanone, p-cresol and indole, compounds that also dominate carrion scent. Flesh flies did not distinguish between floral and carrion scent in a choice experiment using olfactory cues only, which also showed that scent alone is responsible for fly attraction. Pollination success was relatively high (31·5 % of flowers), but tracking of stained pollinia also revealed that a relatively high percentage (46 %) of pollen deposited on stigmas originates from the same plant.

CONCLUSIONS

Satyrium pumilum selectively attracts flesh flies, probably because its relatively weak scent resembles that of the small carrion on which these flies predominate. In this way, the plants exploit a specific subset of the insect assemblage associated with carrion. Pollination rates and levels of self-pollination were high compared with those in other deceptive orchids and it is therefore unlikely that this mimicry system evolved to promote outcrossing.

Heat shock response to hypoxia and its attenuation during recovery in the flesh fly, Sarcophaga crassipalpis

In this study, pharate adults of the flesh fly Sarcophaga crassipalpis were exposed to two, four, seven, or ten days of severe hypoxia (3% oxygen) to evaluate its impact on emergence and the expression of genes encoding heat shock proteins (Hsps) and heat shock regulatory elements. A four-day exposure to hypoxia significantly reduced survival, but more than seven days was required to reach the LD(50). Eight genes encoding Hsps, at least one from each major family of Hsps (Hsp90, Hsp70, Hsp60, Hsp40, and sHsps) and two genes encoding proteins involved in Hsp regulation (heat shock factor, hsf, and sirtuin) were cloned, and expression levels were assessed during and after hypoxia using qRT-PCR. Most, but not all hsps studied, were significantly up-regulated during hypoxia, and expression levels for most of the hsps reverted to control levels a few hours after return to normoxia. Hsp70 was the most responsive to hypoxia, increasing expression several hundred fold. By contrast, hsp90 and hsp27 showed little response to hypoxia but did respond to recovery. Neither hsf nor sirtuin were elevated by hypoxia, an observation consistent with their assumed post-transcriptional regulatory roles. These data demonstrate a strong Hsp response to hypoxia, suggesting an important role for Hsps in responding to low oxygen environments.