Hydrocarbon and Fatty Acid Composition from Blowfly Eggs Represents a Potential Complementary Taxonomic Tool of Forensic Importance.

One of the most important contributions of forensic entomology is to assist criminal expertise to determine the postmortem interval, which depends on the duration of the immature stages of insects of forensic interest. On the other hand, the time of development of the different stages varies according to the species; therefore, its identification is essential. Currently, few studies have investigated the use of cuticular hydrocarbons, and none regarding fatty acids, as complementary taxonomic tools to expedite species identification. Therefore, we evaluated whether cuticular hydrocarbons together with fatty acids of eggs of flies of the family Calliphoridae, main group of forensic interest, can be used to distinguish species. The analyses were performed by chromatographic techniques. The results show that there are significant differences between the composition of cuticular hydrocarbons and fatty acids between species and, therefore, they can be used to provide a complementary taxonomic tool to expedite the forensic expertise.

Pollen metabarcoding as a tool for tracking long-distance insect migrations.

Insects account for a large portion of Earth's biodiversity and are key players for ecosystems, notably as pollinators. While insect migration is suspected to represent a natural phenomenon of major importance, remarkably little is known about it, except for a few flagship species. The reason for this situation is mainly due to technical limitations in the study of insect movement. Here, we propose using metabarcoding of pollen carried by insects as a method for tracking their migrations. We developed a flexible and simple protocol allowing efficient multiplexing and not requiring DNA extraction, one of the most time-consuming part of metabarcoding protocols, and apply this method to the study of the long-distance migration of the butterfly Vanessa cardui, an emerging model for insect migration. We collected 47 butterfly samples along the Mediterranean coast of Spain in spring and performed metabarcoding of pollen collected from their bodies to test for potential arrivals from the African continent. In total, we detected 157 plant species from 23 orders, most of which (82.8%) were insect-pollinated. Taxa present in Africa-Arabia represented 73.2% of our data set, and 19.1% were endemic to this region, strongly supporting the hypothesis that migratory butterflies colonize southern Europe from Africa in spring. Moreover, our data suggest that a northwards trans-Saharan migration in spring is plausible for early arrivals (February) into Europe, as shown by the presence of Saharan floristic elements. Our results demonstrate the possibility of regular insect-mediated transcontinental pollination, with potential implications for ecosystem functioning, agriculture and plant phylogeography.

Is there anybody in there? Entomological evidence from a boat burial at Øksnes in Vesterålen, northern Norway.

Although there are several well preserved Viking boat burials from Norway, until recently palaeoecological research on their context has often been limited. Research on fossil insect remains in particular can provide valuable forensic information even in the absence of an actual body. Here we present archaeoentomological information from a boat burial at Øksnes in Vesterålen, northeast Norway, an area where Norse and Sami traditions overlap. Excavated in 1934, organic preservation from the burial was limited to parts of the boat and a clump of bird feathers which were preserved in the Tromsø University Museum, and from which fossil insects were recovered. The insect assemblage from Øksnes includes the blowfly, Protophormia terraenovae (Rob.-Des.), which indicates exposure of the body and the probable timing of the burial. The high numbers of the human flea, Pulex irritans L. from among the feathers, suggests that these, probably from a pillow under the corpse, originated from within a domestic context. Deposition of flowers as part of the burial is discussed on the basis of the insect fauna. The absence of a body and any associated post burial decay fauna implies its exhumation and disposal elsewhere and this is discussed in the context of other exhumed medieval burials and Saga and other sources.

Optimization of an artificial tick feeding assay for Dermacentor reticulatus.

BACKGROUND: The development of standardized in vitro feeding methods for ixodid ticks has been hampered by their complex feeding behaviour and the long duration of their blood meal. In this study, we aimed to optimize several parameters for the in vitro feeding of adult Dermacentor reticulatus. METHODS: Ticks were fed on heparinized bovine blood collected at a slaughterhouse, using a modified silicone membrane feeding assay. Effects on tick feeding and fecundity of different blood meal treatments (freezing, irradiation, addition of antibiotics), ambient conditions (increased CO2 concentration) and phagostimulant use (addition of 2 g/l and 4 g/l glucose to the blood meal) were systematically evaluated. RESULTS: Although fungal growth occurred more frequent in feeding units of ticks fed on defrosted blood, the attachment rate, engorgement mass and fecundity of females fed on defrosted blood did not significantly differ from that of ticks fed on fresh blood. A reduction in the fecundity of female D. reticulatus ticks was observed when ticks were fed with gamma-irradiated blood or untreated blood compared to blood treated with gentamycin. Both the engorgement mass and fecundity increased when ticks were fed at a 5% CO2 level. A non-significant increase in the engorgement mass and engorgement rate of D. reticulatus was observed when blood was supplemented with 4 g glucose per litre compared to 2 g/l. CONCLUSION: An artificial feeding method was adapted for the feeding of adult D. reticulatus ticks. Of all parameters tested, only the artificial feeding at 5% CO2 levels resulted in a significant increase (P < 0.05) in the engorgement mass and fecundity of female D. reticulatus ticks. The supplementation of blood with antibiotics resulted in a significantly higher tick fecundity in comparison to ticks fed with untreated or irradiated blood.

Quantifying and predicting Drosophila larvae crawling phenotypes.

The fruit fly Drosophila melanogaster is a widely used model for cell biology, development, disease, and neuroscience. The fly's power as a genetic model for disease and neuroscience can be augmented by a quantitative description of its behavior. Here we show that we can accurately account for the complex and unique crawling patterns exhibited by individual Drosophila larvae using a small set of four parameters obtained from the trajectories of a few crawling larvae. The values of these parameters change for larvae from different genetic mutants, as we demonstrate for fly models of Alzheimer's disease and the Fragile X syndrome, allowing applications such as genetic or drug screens. Using the quantitative model of larval crawling developed here we use the mutant-specific parameters to robustly simulate larval crawling, which allows estimating the feasibility of laborious experimental assays and aids in their design.

Generalist Behavior Describes Pollen Foraging for Perceived Oligolectic and Polylectic Bees.

Native bees provide essential pollination services to cultivated and wild plants worldwide. Despite the need to conserve pollinators, the foraging patterns of native bees are poorly understood. Classic concepts of resource use have typically categorized bee species as specialists or generalists based on floral visitation patterns. While intraspecific variation in bee foraging likely depends on local land use, sex, and phenological period, among other factors, these potential drivers of floral visitation are rarely explicitly investigated. In this study, we explore the potential for inter- and intra-specific variation in floral visitation by investigating the pollen loads of two solitary, similarly sized, ground-nesting native bee species within the Apinae, Melissodes tepaneca (Cresson) and Diadasia rinconis (Cockerell), categorized as generalist and specialist based on past floral visitation studies, respectively. Our analyses reveal generalist foraging and indicate that natural habitat availability significantly drives pollen load composition for both species. The putative specialist, D. rinconis, exhibited significant differences in pollen load composition between males and females, between pan and net collection methods, and between the different phenological periods. The putative generalist, M. tepaneca, exhibited significant differences in pollen load composition between the sexes, but only in the late season. Both species exhibited significant preference levels for multiple native plant species across the study region. Given that pollen collection is essential for native bee population persistence across natural and human-dominated habitats, our findings suggest consideration of both pollen collection and floral visitation patterns to holistically describe floral usage and develop pollinator conservation strategies.

Laboratory rearing of solitary bees and wasps.

Ecological experiments often require standardized methods that exclude natural variation and allow manipulation of a single parameter. It has been shown that domesticated honey bee larvae are raisable in a controlled environment. Here we demonstrate that this approach is also transferable to wild solitary bees and wasps without inducing negative effects on their development. Wells may also be supplemented with the antibiotic substance oxytetracycline to control the presence of bacteria. The method thus provides a useful tool to investigate offspring recruitment and larval development in solitary bees and wasps, plus their responses to manipulation of factors as for example diets, toxins and microbiota.

In-vitro antimicrobial, antibiofilm, cytotoxic, antifeedant and larvicidal properties of novel quinone isolated from Aegle marmelos (Linn.) Correa.

BACKGROUND: Plant metabolites have wide applications and have the potential to cure different diseases caused by microorganisms. The aim of the study was to evaluate the antimicrobial, antibiofilm, cytotoxic, antifeedant and larvicidal properties of novel quinine isolated from Aegle marmelos (Linn.) Correa. METHODS: A compound was obtained by eluting the crude extract, using varying concentrations of the solvents by the chromatographic purification. Broth micro dilution method was used to assess the antimicrobial activity and anticancer study was evaluated using MTT assay. Larvicidal activity was studied using leaf disc no-choice method. RESULTS: Based on the IR, 13C NMR and 1H NMR spectral data, the compounds were identified as quinone related antibiotic. It exhibited significant activity against Gram positive and Gram negative bacteria. The lowest Minimum Inhibitory Concentration (MIC) of the compound against Bacillus subtilis and Staphylococcus aureus was 100 and 75 µg mL(-1) respectively. Against Escherichia coli and Pseudomonas aeruginosa it exhibited MIC value of 25 µg mL(-1). The MIC of the compound against Aspergillus niger, A. clavatus, Penicillium roqueforti was 20 µg mL(-1) and that against Fusarium oxysporum (20 µg mL(-1)), A. oryzae (40 µg mL(-1)), and Candida albicans (60 µg mL(-1)), respectively. It showed effective antibiofilm activity against E. coli, S. typhii and P. aeroginosa at 8 µg mL(-1) and did not exhibit considerable cytotoxic activity against Vero and HEP2 cell lines. Additionally, the compound documented significant antifeedant and larvicidal activities against Helicoverpa armigera and Spodoptera litura at 125, 250, 500 and 1000 ppm concentrations. CONCLUSION: The results concluded that the compound can be evaluated further in industrial applications and also an agent to prepare botanical new pesticide formulations.

Taxis assays measure directional movement of mosquitoes to olfactory cues.

BACKGROUND: Malaria control methods targeting indoor-biting mosquitoes have limited impact on vectors that feed and rest outdoors. Exploiting mosquito olfactory behaviour to reduce blood-feeding outdoors might be a sustainable approach to complement existing control strategies. Methodologies that can objectively quantify responses to odour under realistic field conditions and allow high-throughput screening of many compounds are required for development of effective odour-based control strategies. METHODS: The olfactory responses of laboratory-reared Anopheles gambiae in a semi-field tunnel and A. arabiensis females in an outdoor field setting to three stimuli, namely whole human odour, a synthetic blend of carboxylic acids plus carbon dioxide and CO(2) alone at four distances up to 100 metres were measured in two experiments using three-chambered taxis boxes that allow mosquito responses to natural or experimentally-introduced odour cues to be quantified. RESULTS: Taxis box assays could detect both activation of flight and directional mosquito movement. Significantly more (6-18%) A. arabiensis mosquitoes were attracted to natural human odour in the field up to 30 metres compared to controls, and blended synthetic human odours attracted 20% more A. gambiae in the semi-field tunnel up to 70 metres. Whereas CO(2) elicited no response in A. arabiensis in the open field, it was attractive to A. gambiae up to 50 metres (65% attraction compared to 36% in controls). CONCLUSIONS: We have developed a simple reproducible system to allow for the comparison of compounds that are active over medium- to long-ranges in semi-field or full-field environments. Knowing the natural range of attraction of anopheline mosquitoes to potential blood sources has substantial implications for the design of malaria control strategies, and adds to the understanding of olfactory behaviour in mosquitoes. This experimental strategy could also be extended from malaria vectors to other motile arthropods of medical, veterinary and agricultural significance.

Studies on the ovitraps baited with hay and leaf infusions for the surveillance of dengue vector, Aedes albopictus in northeastern India.

Ovitraps baited with hay and leaf infusions were evaluated for enhancing the oviposition response of gravid females of the dengue vector Aedes albopictus. The egg density per trap (mean ± SEmean) was the highest with 30% infusions of Pennisetum grass hay (623.6 ± 41) and rice straw (580 ± 51.3), which corresponded to oviposition activity index (OAI) of 0.62. Infusions (5-50%) of mango and banana leaves with OAI ranging from -0.36 to 0.39 were not observed to enhance the oviposition response significantly over control. Rice straw and Pennisetum grass hay are available round the year in northeastern India and the use of these infusions can be a cost effective way to augment the ovitrap surveillance of dengue vectors.

Laboratory colonization of Lucilia sericata Meigen (Diptera: Caliphoridae) strain from Hashtgerd, Iran.

BACKGROUND & OBJECTIVES: The treatment of wounds with live green bottle fly larvae is receiving considerable attention in many countries. Laboratory rearing of Lucilia sericata is crucially important for the treatment of wounds. STUDY DESIGN: The study was carried out for mass rearing of green bottle flies from April to November 2010. Hand catch and net trap baited with beef and cattle liver were used to collect adult flies from the field. The collected samples were placed in appropriately labeled tubes and sent to the laboratory. Adult stage flies reared in the insectary were used for species identification using specific keys. RESULTS: A total of 89 flies (55 females and 34 males) were collected from Hashtgerd area. In the first generation, 299 flies were produced in the laboratory including 105 (35.12%) males, and 194 (64.88%) females. The female/male sex ratio was 1.61 for parents, whereas it was 1.84, 1.30 for F1 and F2 generations respectively. In total, 432 flies were reared in F3 generation including 173 (40.04%) males, and 259 (59.96%) females, and the sex ratio was 1.49. CONCLUSION: Setting up the mass rearing of sheep blowfly at the School of Public Health, Tehran University of Medical Sciences is an important step in producing candidate flies for the treatment of myiasis by maggot therapy in future.

Harmonic radar: efficacy at detecting and recovering insects on agricultural host plants.

BACKGROUND: In pest management research, harmonic radar systems have been largely used to study insect movement across open or vegetation-poor areas because the microwave signal is attenuated by the high water content of vegetation. This study evaluated whether the efficacy of this technology is sufficient to track insects in vegetative landscapes. RESULTS: Field efficacy data were collected using portable harmonic microwave radar and electronic dipole tags mounted on adults of three economically important pests: Leptinotarsa decemlineata (Say), Diabrotica virgifera virgifera (LeConte) [corrected] and Conotrachelus nenuphar Herbst. Detection and recovery of tagged Colorado potato beetles, plum curculios and western corn rootworms was high within and among potato plants, moderate within apple trees and high within, but not between, corn plants respectively. The efficacy of the radar depends on the ability of the operator to move around the host, scanning for a signal 'sightline' with the tagged insect among plant structures. CONCLUSION: The detection rate of tagged insects by harmonic radar systems is high enough to track the walking path of pests through low row crops such as potato, tall row crops such as corn or tall but well-separated trees of orchard-type crops by adapting the scanning procedure to the vegetative architecture.

The role of research in molecular entomology in the fight against malaria vectors.

The text summarizes the principal current fields of investigation and the recent achievements of the research groups presently contributing to the Molecular Entomology Cluster of the Italian Malaria Network. Particular emphasis is given to the researches with a more direct impact on the fight against malaria vectors.

Insect succession on a decomposing piglet carcass placed in a man-made freshwater pond in Malaysia.

This entomological study was conducted in a man-made freshwater pond in a palm oil plantation in Tanjung Sepat, Selangor from 23 July 2007 by using pig (Sus scrofa) as a carcass model. A 1.5 month old piglet (5 kg), which died of asphyxia after being accidentally crushed by its mother, was thrown into a pond. Observation was made for ten days; one visit per day and climatological data were recorded. On the first two days, the piglet carcass sunk to the bottom of the pond. The carcass floated to the surface on the third day but no fly activities were seen. The blow fly, Chrysomya megacephala and Chrysomya rufifacies started to oviposit on the fourth day. Other than adult flies, a spider (Arachnida) was also observed on the carcass. Bubbles accumulated at the mouthpart, and the abdomen was greenish black. A lot of blow fly eggs were seen on the body surface on the fifth day (floating decay), along with first and second instars C. megacephala crawling under the piglet's skin. On the sixth day, adult blow fly, C. megacephala,and C. rufifacies,and muscid flies, Ophyra spinigera and Musca domestica were observed on to the carcass. High numbers of first and second instars of flies were observed wandering around the body surface with C. megacephala larvae being the predominant species. Two prominent maggot masses occurred on seventh and eighth days. Bloated deterioration stage began on day eighth exposing rib bones, humerus bones and intestines. Carcass was partially sinking and the maggot masses were at the water level. On day ninth, the carcass was partially sinking and three maggot masses were observed on the exposed surface. There were very few adult flies, including a scarab beetle was sighted on the carcass at this stage. The carcass along with the maggots sunk on day tenth, leaving an oily layer on the water surface.

Identification of forensically important fly eggs using a potassium permanganate staining technique.

Fly eggs found in corpses can be utilized as entomological evidence in forensic investigations of deaths if the species of fly and the developmental rate at a temperature similar to the death scene are known. The species identification of fly eggs is particularly important, and previously, scanning electron microscope has been used for this purpose. Herein, we report a simple technique, using light microscopy, to identify forensically important eggs of Chrysomya rufifacies (Macquart), Chrysomya megacephala (Fabricius), Chrysomya pacifica Kurahashi, Chrysomya nigripes Aubertin, Aldrichina grahami (Aldrich), Lucilia cuprina (Wiedemann), Musca domestica L. and Megaselia scalaris (Loew). A 1% potassium permanganate solution was used to stain egg surfaces for 1 min, followed by dehydration in 15, 70, and 95%, absolute alcohol (each solution for 1 min) and the eggs were permanently mounted. The characteristics are based on the width of plastron, morphology of plastron area surrounding the micropyle and chorionic sculpturing, with the length of egg being used as supplemental feature.

Individual number change of Empoasca spp. cicadas species in potato.

We investigated the individual number change of Empoasca spp. cicadas species that are living in potatoes for 3 years. We applied the "100 plants" method for the determination for the individual number once per week. Based on the data determined that the settling of adult begins on the last days of May, and valid presence will be followed till the end of the breeding-season. The individual number was gradually increased during the settling, and reached the peak in 1990 on 23 July, in 2000 on 6 August and in 2001 on 22 July. We determined the individuals gathered during the collection. In the population of Empoasca spp. The E. solani Curtis and the E. decipiens Paoli played the dominant role. The E. vitis Göthe was also present with insignificant individual number. Beside the adults many larvae and nymphs were living on the potato which means that the Empoasca spp. Can reproduce also on the potato. At the time of peak individual number in 1999 1876 larvae, 344 nymphs and 400 adults were present on 100 plants, in 2000 (according to the previous order) 3340, 580, 1280, and in 2001 there were 954, 786 and 285. The rainfall in Hungary was disadvantageous in the investigated period, especially the year 2000. During the rain-free period the temperature was high and the relative humidity of the air was low. However, we could state that the increase of the cicada individual number was not restrained by the heat (30-35 degrees C) days. The decrease was in connection with the ageing of the plant stock.