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Fly Larvae (fly + larva)
Selected AbstractsDevelopment of the Insect Pathogenic Alga HelicosporidiumTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 3 2006VERENA-ULRIKE BLÄSKE-LIETZE ABSTRACT. This study examined the morphogenesis and replication dynamics of the different life stages (cysts, filamentous cells, vegetative cells) of Helicosporidium sp., a non-photosynthetic, entomopathogenic alga. The isolate (SjHe) used originated from an infected black fly larva. Filamentous cell transformation into vegetative cells and autosporulation during vegetative cell replication were observed under controlled in vitro conditions. The transformation process was initiated by a partial swelling of the filamentous cell along with the reorganization of the nuclear material. Two subsequent nuclear and cell divisions resulted in the release of 4 rod-shaped daughter cells, which divided into oval to spherical vegetative cells. These underwent several cycles of autosporogenic cell division. Multiple-passaged vegetative cell cultures formed non-motile, adherent cell clusters (palmelloid colonies). Vegetative replication dynamics were also observed in 2 experimental noctuid hosts, Spodoptera exigua and Helicoverpa zea. The average density of helicosporidial cells produced per microliter hemolymph exceeded cell concentrations obtained in vitro by 15- and 46-fold in S. exigua and H. zea, respectively. Cyst morphogenesis was only observed in the hemolymph, whereas no cysts differentiated at various in vitro conditions. [source] Feeding by Hessian fly [Mayetiola destructor (Say)] larvae does not induce plant indirect defencesECOLOGICAL ENTOMOLOGY, Issue 2 2007JOHN F. TOOKER Abstract 1.,Recent research has addressed the function of herbivore-induced plant volatiles in attracting natural enemies of feeding herbivores. While many types of insect herbivory appear to elicit volatile responses, those triggered by gall insects have received little attention. Previous work indicates that at least one gall insect species induces changes in host-plant volatiles, but no other studies appear to have addressed whether gall insects trigger plant indirect defences. 2.,The volatile responses of wheat to feeding by larvae of the Hessian fly Mayetiola destructor (Say) (Diptera: Cecidomyiidae) were studied to further explore indirect responses of plants to feeding by gall insects. This specialist gall midge species did not elicit a detectable volatile response from wheat plants, whereas a generalist caterpillar triggered volatile release. Moreover, Hessian fly feeding altered volatile responses to subsequent caterpillar herbivory. 3.,These results suggest that Hessian fly larvae exert a degree of control over the defensive responses of their host plants and offer insight into plant-gall insect interactions. Also, the failure of Hessian fly larvae to elicit an indirect defensive response from their host plants may help explain why natural enemies, which often rely on induced volatile cues, fail to inflict significant mortality on M. destructor populations in the field. [source] Susceptibility of black fly larvae (Diptera: Simuliidae) to lawn-care insecticides individually and as mixturesENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2003Jay P. Overmyer Abstract Urban and suburban watersheds have the potential to be highly impacted by chemicals, especially insecticides to control insect pests on lawns, ornamental plants, and home gardens. Three of the most common lawn-care insecticides detected in urban watersheds, carbaryl, chlorpyrifos, and malathion, have been evaluated using an acute orbital shaker toxicity test to determine their respective concentrations that produce 50% mortality (LC50) in Simulium vittatum Zetterstedt cytospecies IS-7 larvae. Results of the 48-h LC50 tests show chlorpyrifos to be the most toxic to black fly larvae (LC50 = 0.28 ,g/L) followed by carbaryl (LC50 = 23.72 ,g/L) and malathion (LC50 = 54.20 ,g/L). These insecticides were also tested as binary and ternary mixtures using the toxic unit (TU) approach. Toxicity was shown to be greater than additive for the ternary mixture of chlorpyrifos,carbaryl,malathion (LC50 = 0.56 TU) and the binary mixtures of chlorpyrifos,malathion (LC50 = 0.72 TU) and carbaryl-malathion (LC50 = 0.78 TU). The binary combination of chlorpyrifos and carbaryl was shown to be additive (LC50 = 0.98 TU). These results indicate that aquatic invertebrate populations in urban and suburban streams may experience a higher-than-expected increase in toxicity-related effects when all three chemicals are present in the waterway. [source] Genes encoding a group of related small secreted proteins from the gut of Hessian fly larvae [Mayetiola destructor (Say)]INSECT SCIENCE, Issue 5 2006MING-SHUN CHEN Abstract A group of related genes has been isolated and characterized from the gut of Hessian fly larvae [Mayetiola destructor (Say)]. Members in this group appear to encode proteins with secretary signal pep tides at the N-terminals. The mature putative proteins are small, acidic proteins with calculated molecular masses of 14.5 to 15.3 kDa, and isoelectric points from 4.56 to 4.88. Northern blot analysis revealed that these genes are expressed predominantly in the gut of Hessian fly larvae and pupae. Two related genes, G10K1 and G10K2, were isolated as tandem repeats. Both genes contain three exons and two introns. The intron/exon boundaries were conserved in terms of amino acid encoding, suggesting that they arose by gene duplication. The fact that the frequency of this group of clones in a gut cDNA library higher than that of total cDNA clones encoding digestive enzymes suggested that this group of proteins may perform an important function in the gut physiology of this insect. However, the exact functions of these proteins are as yet known since no sequence similarity could be identified between these proteins and any known sequences in public databases using standard methods. [source] Cuterebra cutaneous myiasis: case report and world literature reviewINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 4 2008Elizabeth Delshad MD Background, Most cases of myiasis in North America are caused by fly larvae from South America or Africa, as these cases represent travelers returning from endemic regions. The etiology of creeping eruptions and furuncular lesions in North American patients who have no history of recent travel can therefore be a diagnostic problem. Among cases acquired in North America, Cuterebra species are the usual cause. Dermatologists and dermatopathologists should be aware that this unusual infestation may occur without a travel history. Method, Here we report a case of Cuterebra cutaneous myiasis acquired in New Jersey. A world literature review of articles on Cuterebra myiasis in humans, without age or year restriction, was performed. The pertinent references of those articles were also searched. Results, Most cases occur in the skin, as a furuncle. Sometimes a cutaneous creeping eruption is present. Children account for at least half of the reported cases. The infestations tend to occur in the late summer, and most frequently in the north-eastern and southern states of the United States. An overview of the clinical and histopathologic diagnostic features are presented. Conclusions, Though rare, myiasis can occur in North America without a travel history. Awareness of this entity, its epidemiologic patterns and diagnostic characteristics, can prevent lengthy delays in diagnosis and unnecessary treatments. [source] Food Habits of Four Bottom-Dwelling Gobiid Species at the Confluence of the Danube and Hron Rivers (South Slovakia)INTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 4-5 2007k Adámek Abstract Since 1997, three new Neogobius species (Neogobius kessleri, N. fluviatilis and N. melanostomus) have been regularly recorded in the Slovak part of the Danube River, formerly inhabited only by one native gobiid species (Proterorhinus marmoratus). The study of their food habits proved that the amphipod Corophium curvispinum, chironomid larvae and pupae, caddis fly larvae (Hydropsyche sp.) and mayfly nymphs (Ephoron virgo, Potamanthus luteus) were the most important food items contributing to the similarity of the diets of the gobiid species. Fish (0+ Zingel zingel and Sander lucioperca) appeared in the diet of N. kessleri only. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Aromatic plants in blue tit Cyanistes caeruleus nests: no negative effect on blood-sucking Protocalliphora blow fly larvaeJOURNAL OF AVIAN BIOLOGY, Issue 2 2008Adčle Mennerat Nesting birds use several behavioural or physiological defence mechanisms against parasites. On Corsica, female blue tits Cyanistes caeruleus incorporate fresh fragments of a limited number of aromatic plants in the nest cup, from the end of nest construction until fledging. Some of these plants negatively affect bacterial growth and host location by blood-sucking mosquitoes in laboratory conditions. In natural populations, Corsican blue tit chicks are exposed to the highest levels of blood-sucking ectoparasitic blow flies Protocalliphora spp. reported in Europe. These ectoparasites can have severe negative effects on chick development and survival probabilities, especially when food constraints are elevated. Here we investigated in several natural Corsican blue tit populations the hypothesis that aromatic plants brought to the nest have anti-blow fly effects during the chick-rearing stage. We predicted that: 1) the amount of aromatic plants should be negatively related to blow fly infestation intensity across nests, 2) experimental addition of aromatic plants in nests should reduce blow fly infestation intensity, and 3) nestlings should be in better physical condition in nests where aromatic plants were experimentally added. No significant relation was found between amount of aromatic plants in nests and blow fly infestation intensity. Experimental addition of aromatic plants did not reduce blow fly infestation intensity and did not affect the chick phenotypic parameters we measured. We conclude that aromatic plants in blue tit nests are not used as a defence against ectoparasitic Protocalliphora blow flies in our study population. [source] Myiasis as a risk factor for prion diseases in humansJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 9 2006O Lupi Abstract Prion diseases are transmissible spongiform encephalopathies of humans and animals. The oral route is clearly associated with some prion diseases, according to the dissemination of bovine spongiform encephalopathy (BSE or mad cow disease) in cattle and kuru in humans. However, other prion diseases such as scrapie (in sheep) and chronic wasting disease (CWD) (in cervids) cannot be explained in this way and are probably more associated with a pattern of horizontal transmission in both domestic and wild animals. The skin and mucous membranes are a potential target for prion infections because keratinocytes and lymphocytes are susceptible to the abnormal infective isoform of the prion protein. Iatrogenic transmission of Creutzfeldt,Jakob disease (CJD) was also recognized after corneal transplants in humans and scrapie was successfully transmitted to mice after ocular instillation of infected brain tissue, confirming that these new routes could also be important in prion infections. Some ectoparasites have been proven to harbour prion rods in laboratory experiments. Prion rods were identified in both fly larvae and pupae; adult flies are also able to express prion proteins. The most common causes of myiasis in cattle and sheep, closely related animals with previous prion infections, are Hypoderma bovis and Oestrus ovis, respectively. Both species of flies present a life cycle very different from human myiasis, as they have a long contact with neurological structures, such as spinal canal and epidural fat, which are potentially rich in prion rods. Ophthalmomyiases in humans is commonly caused by both species of fly larvae worldwide, providing almost direct contact with the central nervous system (CNS). The high expression of the prion protein on the skin and mucosa and the severity of the inflammatory response to the larvae could readily increase the efficiency of transmission of prions in both animals and humans. [source] Role of bacteria in the oviposition behaviour and larval development of stable fliesMEDICAL AND VETERINARY ENTOMOLOGY, Issue 1 2006A. Romero Abstract., Stable flies, Stomoxys calcitrans (L.), are the most important pests of cattle in the United States. However, adequate management strategies for stable flies, especially for pastured cattle, are lacking. Microbial/symbiont-based approaches offer novel venues for management of insect pests and/or vector-borne human and animal pathogens. Unfortunately, the fundamental knowledge of stable fly,microbial associations and their effect on stable fly biology is lacking. In this study, stable flies laid greater numbers of eggs on a substrate with an active microbial community (> 95% of total eggs oviposited) than on a sterilized substrate. In addition, stable fly larvae could not develop in a sterilized natural or artificial substrate/medium. Bacteria were isolated and identified from a natural stable fly oviposition/developmental habitat and their individual effect on stable fly oviposition response and larval development was evaluated in laboratory bioassays. Of nine bacterial strains evaluated in the oviposition bioassays, Citrobacter freundii stimulated oviposition to the greatest extent. C. freundii also sustained stable fly development, but to a lesser degree than Serratia fanticola. Serratia marcescens and Aeromonas spp. neither stimulated oviposition nor supported stable fly development. These results demonstrate a stable fly bacterial symbiosis; stable fly larval development depends on a live microbial community in the natural habitat, and stable fly females are capable of selecting an oviposition site based on the microbially derived stimuli that indicate the suitability of the substrate for larval development. This study shows a promising starting point for exploiting stable fly,bacterial associations for development of novel approaches for stable fly management. [source] Seasonal changes in prevalence and intensity of Hypoderma actaeon in Cervus elaphus from central SpainMEDICAL AND VETERINARY ENTOMOLOGY, Issue 2 2001C. De La Fuente-López Summary Hypodermosis in red deer, Cervus elaphus Linnaeus (Artilodactyla: Cervidae), caused by the warble fly, Hypoderma actaeon Latreille (Diptera: Oestridae), was studied at Quintos de Mora (Toledo, Spain) over a one-year period between October 1994 and September 1995. One hundred and twenty-five red deer were examined for the presence of warble fly larvae. The prevalence of warbles was 44.8% and the intensity of infection was 38.29 (SD ± 61.32) warbles/deer infected. Clear seasonal variations were observed in prevalence and intensity, with the highest values in the autumn and winter. Statistically significant differences were observed in prevalence and intensity among age groups. In contrast, no differences were found in prevalence and intensity between males and females. [source] Escaping parasitism in the selfish herd: age, size and density-dependent warble fly infestation in reindeerOIKOS, Issue 3 2007Per Fauchald It has been suggested that animals may escape attack from mobile parasites by aggregating in selfish herds. A selfish herd disperses the risk of being attacked among its members and the per individual risk of parasite infection should therefore decrease with increasing animal density through the encounter,dilution effect. Moreover, in a selfish herd, dominant and agile animals should occupy the best positions and thereby receive fewer attacks compared to lower ranked animals at the periphery. We tested these predictions on reindeer (Rangifer tarandus tarandus) parasitized by warble flies (Hypoderma tarandi). Warble flies oviposit their eggs on reindeer during summer and induce strong anti-parasitic behavioural responses in the herds. In this period, reindeer are sexually segregated; females and calves form large and dense herds while males are more solitary. After hatching, the warble fly larvae migrate under the skin of their host where they encyst. In the present study encysted larvae were counted on newly slaughtered hides of male calves and 1.5 year old males from 18 different reindeer herds in Finnmark, northern Norway with large contrasts in reindeer density. In reindeer, body mass is correlated with fitness and social status and we hypothesized that individual carcass mass reflected the animal's ability to occupy the best positions within the herd. Larval abundance was higher among the 1.5 year old males than among the calves. For calves we found in accordance with the selfish herd hypothesis a negative relationship between larval abundance and animal density and between larval abundance and body mass. These relationships were absent for the 1.5 year old males. We suggest that these differences were due to different grouping behaviour where calves and females, but not males, aggregated in selfish herds where they escaped parasitism. [source] Establishment of an in vitro sciarid fly larvae assay to study plant resistanceANNALS OF APPLIED BIOLOGY, Issue 2 2009M. Chabannes Abstract Mechanisms underlying natural plant resistance to herbivorous invertebrates are still poorly understood in comparison with bacterial or fungal interactions. One reason is the difficulty in reliably and reproducibly assessing the effects under controlled conditions. This article describes a newly developed in vitro biological assay system that enables the interactions between sciarid larvae and plants, whose roots they feed on, to be studied under highly controlled conditions. The bioassay eliminates the problems created by the often variable environmental factors by providing an aseptic arena where experimental plants can be germinated and grown on agar within a Petri dish. Sciarid fly eggs are then collected, sterilised and added to the Petri dish. The system allows the eggs to hatch and the larvae to feed on the plant roots. A range of developmental parameters can then be recorded over time which can then be correlated with the experimental plant type. This assay system also allows a simultaneous comparison or ,choice chamber' between two (or more) different genotypes. The assay should greatly help to facilitate the identification of new components involved in insect resistance mediated pathway via the characterisation of mutant plants. [source] The Preservation of Invertebrates in 16th-Century Cesspits at St Saviourgate, York,ARCHAEOMETRY, Issue 1 2004L. M. E. McCobb The taphonomy of invertebrates from 16th-century cesspits at St Saviourgate, York, was investigated. Earthworms, fly larvae and puparia are preserved through replication in calcium phosphate, a process facilitated by acidic cesspit pore water and by the presence of abundant organic matter, bones and shells. Features preserved by mineralization include muscles, blood vessels and setae. Non-mineralized invertebrate remains include puparia and beetles. Py,GC/MS (flash pyrolysis,gas chromatography/mass spectrometry) revealed a very high level of preservation of structural biomolecules, with all the protein and chitin markers that are evident in the living forms still being detectable in the divalent remains. [source] | |||||||||||||