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81.
E.L. Sproston I.D. Ogden M. MacRae K.J. Forbes J.F. Dallas S.K. Sheppard A. Cody F. Colles M.J. Wilson N.J.C. Strachan 《Journal of applied microbiology》2010,109(3):829-838
Aims: To assess whether flies and slugs acquire strains of Campylobacter jejuni and Campylobacter coli present in local ruminant faeces. Methods and Results: Campylobacter was cultured from flies, slugs and ruminant faeces that were collected from a single farm in Scotland over a 19‐week period. The isolates were typed using multi‐locus sequence typing (MLST) and compared with isolates from cattle and sheep faeces. Campylobacter jejuni and Camp. coli were isolated from 5·8% (n = 155, average of 75 flies per pool) and 13·3% (n = 15, average of 8·5 slugs per pool) of pooled fly and slug samples, respectively. The most common sequence type (ST) in flies was Camp. coli ST‐962 (approx. 40%) regardless of the prevalence in local cattle (2·3%) or sheep (25·0%) faeces. Two positive slug pools generated the same ST that has not been reported elsewhere. Conclusions: Despite their low carriage rate, flies are able to acquire Campylobacter STs that are locally present, although the subset carried may be biased when compared to local source. Slugs were shown to carry a previously unreported Campylobacter ST. Significance and Impact of the Study: This study has demonstrated that flies carry viable Campylobacter and may contribute to the transfer of STs within and between groups of animals on farms. Further, they may therefore present a risk to human health via their contact with ready‐to‐eat foods or surfaces. 相似文献
82.
There is a growing body of evidence indicating the potential value of essential oils as control agents against a range of arthropod ectoparasites, particularly lice, mites and ticks. Toxicity has been demonstrated following immersion and physical contact with treated surfaces, as well as after exposure to the vapour of these oils; the last of these factors implies that there is a neurotoxic, rather than simply a mechanical, pathway in their mode of action. However, the volatile nature of essential oils suggests that their residual activity is likely to be short‐lived. A possible advantage of essential oils over conventional ectoparasite treatments may refer to their reported ovicidal efficacy, although it is unclear whether this results from neurotoxicity or mechanical suffocation. There are many difficulties in comparing the findings of existing studies of essential oil toxicity. One major issue is the wide variation among batches in the relative concentrations of oil constituents. A second issue concerns the fact that many experimental designs make it difficult to confirm that the effect seen is attributable to the oil; in many cases inappropriate controls mean that the effects of the excipient on mortality cannot be distinguished. Hence, it is important that an excipient‐only control is always included in these bioassays. Furthermore, in direct contact assays, when attempting to identify the toxicity pathway of the essential oil tested, it is important to include a hydrophobic control. Without this, it is impossible to distinguish simple mechanical effects from neurological or other cellular toxicity. The use of essential oils in the control of veterinary ectoparasites is an area which holds considerable potential for the future and research into their use is still at an early stage. More extensive field trials, the standardization of components, the standardization of extraction, the standardization of good experimental design, mammalian toxicology profiling and excipient development, as well as further investigation into the residual activities and shelf‐lives of these oils are all required to allow the full realization of their potential. 相似文献
83.
84.
Chromosomal analysis of more than 500 larval black flies from 19 sites in Armenia and Turkey revealed five taxa in the Prosimulium hirtipes group: Prosimulium frontatum Terteryan, Prosimulium rachiliense Djafarov cytoform ‘A,’ P. rachiliense Djafarov cytoform ‘B,’ Prosimulium tomosvaryi (Enderlein), and a new species of Prosimulium. To associate the names rufipes (Meigen) and tomosvaryi with cytological entities, larvae from the respective type localities in Germany were characterized chromosomally. Prosimulium frontatum is restricted to the Caucasus Mountains where studied populations have five unique inversions. It is most closely related to cytoforms ‘A’ and ‘B’ of P. rachiliense, the three taxa sharing one unique inversion. The two cytoforms of P. rachiliense are separated by about 1200 km, obscuring decisions about their reproductive isolation. The names rachiliense and possibly pronevitschae Rubtsov apply to cytoform ‘A’ in Armenia, whereas the name fulvipes (Edwards) might apply to cytoform ‘B’ in Turkey and to material formerly identified in Turkey as P. rufipes. Populations of P. tomosvaryi in Armenia are chromosomally distinct from previously studied populations in Europe and Morocco, although tied to European and Turkish populations by a shared X‐linked inversion. We conservatively view Armenian, European, and Turkish populations of P. tomosvaryi as a single, polymorphic species. A new species, chromosomally related to P. hirtipes (Fries) and P. tomosvaryi by two uniquely shared inversions, was discovered in Turkey. © 2014 The Linnean Society of London 相似文献
85.
86.
Pablo Montoya Pablo Liedo Betty Benrey Jorge Cancino Juan F. Barrera John Sivinski Martin Aluja 《Biological Control》2000,18(3):216
Diachasmimorpha longicaudata (Ashmead) parasitoids were released by air on a weekly basis over 1600 ha of commercial mango orchards, backyard orchards, and patches of native vegetation, at a density of ca. 940 parasitoids/ha. Releases were made during 2 consecutive years, beginning at flower onset and lasting until the end of the production cycle. Two areas, 7 km apart, were compared. In one area parasitoids were released, whereas the other area was used as a control. During the 2nd year treatments were reversed. Fruit was sampled in commercial mango orchards and in backyard orchards to assess levels of parasitism in fruit fly larvae. Highly significant differences in percentage parasitism were found in release and control zones in backyard orchards. Furthermore, trapping results indicated that D. longicaudata releases were associated with ca. 2.7-fold suppression of Anastrepha spp. populations in backyard orchards. Results suggest that suppression might be affected by environmental conditions and by the parasitoid:fly ratio achieved. Anastrepha obliqua McQuart populations were suppressed more effectively by use of parasitoids than those of Anastrepha ludens Loew, perhaps due to the type of host fruits used by each species. Augmentative parasitoid releases in marginal areas surrounding commercial orchards (backyard orchards, wild vegetation) can substantially suppress fly populations. Through this approach, the number of flies that later move into commercial orchards can be significantly reduced. Such a strategy, when combined with sound orchard management schemes, can allow growers to produce clean fruit without the need to resort to the widespread use of insecticides. 相似文献
87.
Otranto D Brianti E Cantacessi C Lia RP Máca J 《Medical and veterinary entomology》2006,20(4):358-364
Abstract. Flies belonging to the subfamily Steganinae (Drosophilidae) display unusual zoophilic feeding habits at the adult and/or larval stage. Phortica variegata (Fallén) feeds on tears or eye liquid around the eyes of humans and carnivores. When feeding it is a potential vector of Thelazia callipaeda (Railliet and Henry) eyeworms. Adult and larval stages of this fly may be easily confused with other species belonging to the same genus, and little is known on the biology and ecology of P. variegata . In April–November 2005, a total of 969 P. variegata were collected in an area with a high prevalence of canine thelaziosis. The number of flies collected weekly was then related to climatic and environmental parameters (e.g. temperature, relative humidity and total rainfall) recorded daily at the collection site. The highest number of Phortica were collected during July–August. The sex ratio (number of males : females) rose from ∼ 0.5 during May–July, to ∼ 3.0 in August and 181 during September–October. Distributional data, representing 242 sites at which P. variegata has been collected in Europe, were analysed using a desktop implementation of the genetic algorithm for rule-set prediction (GARP) to model ecological requirements across Europe, as well as in Italy. P. variegata is shown to be mainly active at 20–25 °C and 50–75% RH. The ecological niche model suggests with a high degree of confidence that large areas of Europe are likely to represent suitable habitat for this species, mostly concentrated in central Europe. The results reported here contribute basic knowledge on the ecology and geographical distribution of P. variegata flies, which will be fundamental to gaining a better understanding of their role as vectors of human and animal pathogens. 相似文献
88.
89.
Field studies in South Africa showed that floral spur length in the Disa draconis complex (Orchidaceae) varies enormously between populations in the southern mountains (means = 32–38 mm), lowland sandplain (mean = 48 mm), and northern mountains (means = 57–72 mm). We tested the hypothesis that divergence in spur length has resulted from selection exerted through pollinator proboscis length. Short-spurred plants in several southern mountain populations, as well as long-spurred plants in one northern mountain population, were pollinated by a horsefly, Philoliche rostrata (Tabanidae), with a proboscis length that varied from 22 to 35 mm among sites. Long-spurred plants on the sandplain were pollinated by the tanglewing fly, Moegistorynchus longirostris (Nemestrinidae), which has a very long proboscis (mean = 57 mm). Selection apparently favors long spurs in sandplain plants, as artificial shortening of spurs resulted in a significant decline in pollen receipt and fruit set, although pollinaria removal was not significantly affected. Fruit set in the study populations was limited by pollen availability, which further suggests that selection on spur length occurs mainly through the female component of reproductive success. 相似文献
90.
Abstract Water balance characteristics of temperate zone fly pupae are compared with the characteristics of flies inhabiting the tropics. The flies, all of which were reared without diapause, had very similar equilibrium weights that were quite high (av 0.90-0.92), thus implying a limited capacity to absorb water from a subsaturated atmosphere. Likewise, the critical transition temperatures (CTT) were nearly the same for all the flies. Net transpiration rates at 20o C are a function of size, but the rate is less size dependent as temperature increases. When water loss is examined across a broad temperature range, as described by activation energies, it is apparent that the tropical flies lose water at a greater rate than their temperate zone counterparts. Activation energy may be a good parameter to use in evaluating habitat preference and suitability for a species because it describes water loss as a function of temperature, and thus is likely to be a good indicator of the insect's response to the fluctuating temperatures that occur naturally. 相似文献