Control of Muscidae on cattle by flucythrinate ear-tags, the behaviour of these flies on cattle and the effects on fly-dislodging behaviour

In two trials using diary heifers, in the south of England, ear-tags, containing flucythrinate, completely controlled Haematobia irritans (L). Musca autumnalis De Geer on the face were reduced by 41% using one tag and by 76% using two tags per heifer. A single ear-tag reduced numbers of Hydrotaea irritans (Fallén) on the body by 90% and on the teats by more than 55%. Other minor pestering flies were similarly controlled. Control was sustained over the entire 14 weeks duration of the trials which effectively encompassed the fly season of the three main pests.Ear-flicks by the heifers were related to dislodging M. autumnalis from the face, and tail flicks to dislodging Hy. irritans from the belly. These are the two commonest species of nuisance flies and are known to carry pathogenic bacteria.A management plan intended to maximise effective use of insecticidal ear-tags while minimising risks of insecticide resistance is described.

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Résumé Des boucles, contenant du flucythrinate, ont protégé totalement des génisses pour la production de lait contre Haematobia irritans L. lors de deux traitements expérimentaux dans le sud de l'Angleterre.Les effectifs de Musca autumnalis De Geer sur la face des génisses ont été réduits de 41% en utilisant un boucles et de 76% en utilisant deux. Un seul boucles réduit les effectifs d'Hydrotaea irritans Fallén de 90% sur le corps et de plus de 55% sur les pis. Les effectifs d'autres mouches nuisibles de moindre intérêt ont été réduits eux aussi. L'efficacité a été maintenue pendant les 14 semaines du traitement ce qui déborde efficacement le période de vol des 3 principales espèces de mouches nuisibles. Les battements d'oreille des génisses sont destinés à chasser M. autumnalis du visage, et les coups de queue à chasser H. irritans du ventre.Ce sont les deux principales espèces de mouches nuisibles connues comme vecteurs de bactéries pathogènes.Un programme est proposé pour optimaliser l'efficacité des boucles, tout en limitant les risques de résistance aux insecticides.

     

Mites of the familyMacrochelidae as predators of two species of dung-breeding pest flies

Nine species of macrochelid mites [Macrocheles “glaber” (Müller),M. aestivus Halliday,M. mammifer Berlese,M. peniculatus Berlese,M. robustulus (Berlese),M. merdarius (Berlese),M. peregrinus Krantz,M. eurygaster Krantz,Glyptholaspis confusa (Foà) were tested in the laboratory as predators of 2 species of dung-breeding pest flies (Musca vetustissima Walker,Haematobia irritans exigua de Meijere). The mites varied in their ability to attack the 2 fly species at both egg and larval stages. larger mites were generally more effective predators than the smaller species. The level of predation imposed byM. “glaber” onMusca vetustissima also varied with the developmental stage of both predator and prey.      

实验感染卵圆鲳鲹的刺激隐核虫DG1虫株胞口的超微结构研究

作者从卵圆鲳鲹Trachinotus blochii分离了一株刺激隐核虫Cryptocaryon irritans,再经人工感染的方法收集各期虫体,制成电镜样品,对虫体的胞口超微结构进行了观察.同时,用银染和免疫荧光染色以及共聚焦显微镜对虫体的胞口周围及内部的纤维和微管进行了观察.结果表明刺激隐核虫的胞口结构与前口类纤毛虫(Prostome)的胞口结构有诸多相似之处,而与归属于膜口类Ophryoglenina小瓜虫差异较大,因此,作者认为刺激隐核虫的分类更适合归属于前口类Prostome,而不是膜口类Ophryoglenina.     

Estimation of the effects of buffalo fly (Haematobia irritans exigua) on the milk production of dairy cattle based on a meta-analysis of literature data

Published reports on the effect of buffalo fly Haematobia irritans exigua De Meijere (Diptera: Muscidae) and the closely related horn fly (H. irritans) were examined and analysed using non-linear weighted regression techniques in an attempt to establish the relationship between daily production loss (D), average number of parasites (n) and the average damage per parasite per day (d), and to provide estimates of expected losses in milk yield (MYD) and live-weight gain (LWG) in dairy cattle. A Mitscherlich three-parameter model was used to explain the relationship between the total loss of production attributable to buffalo flies and the average number of flies associated with cattle. This model was significant (P<0.01), with R2 = 20.2% and predicted a threshold number of flies (n = 30) below which no adverse effects would be noted. At a moderate level of infestation (n = 200) dMYD was 2.6 ml/fly/day and dLWG was 0.14 g/fly/day, resulting in estimated daily losses in milk yield (D(MYD)) and live-weight gain (D(LWG)) of 520 ml and 28 g, respectively.     

The prevalence of Stephanofilaria sp. in buffalo fly, Haematobia irritans exigua, in Central Queensland

Abstract  Buffalo fly ( Haematobia irritans exigua ) infestations of cattle are associated with characteristic lesions, the initial cause of which has been attributed to a filarial nematode of the genus Stephanofilaria , for which the fly acts as a vector. Survey work in the 1980s estimated the prevalence of microfilaria in female buffalo fly in Queensland at 2.91%. Since then no information has been published and the current prevalence of microfilarial infection in buffalo fly is not known. Buffalo fly were collected from four geographically distinct sites in Central Queensland in mid-summer 2004 and were dissected to estimate Stephanofilaria sp. infection rates . Larval stages of the nematodes were recovered from female flies from all four sites and the percentage of female flies from which nematodes were recovered ranged from 29% to 57%. The average number of larvae recovered from infected female flies ranged from 1.25 to 1.75. Whereas no infected male flies were found from Sites 2–4, larvae were recovered from 43% of male flies collected at Site 1. This high prevalence of filarial infection in buffalo flies implies a correspondingly high level of transmission to cattle in Central Queensland.     

齿股蝇属一新种和一新亚种记述：（双翅目：蝇科）

作者在整理我国内蒙古和东北地区采集的蝇科标本,发现齿股蝇属Ｈｙｄｒｏｔａｅａ Ｒ．－Ｄ．,１９３０中一新种和一新亚种。昭盟齿股蝇Ｈｙｄｒｏｔａｅａ ｚｈａｏｍｅｎｇａ Ｘｕｅ,ｓｐ．ｎｏｖ．和长白齿股蝇Ｈｙｄｒｏｔａｅａ ｓｃａｍｂｕｓ ｃｈａｎｇｂａｉｅｎｓｉｓ ｓｓｐ．ｎｏｖ．模式标本存于沈阳师范学院昆虫研究所。     

Abundance of stable flies on heifers treated for control of horn flies with organophosphate impregnated ear tags

Ear tags containing 40% organophosphate insecticides (diazinon or diazinon plus chlorpyrifos-ethyl) were applied to control Haematobia irritans (L.) (Diptera: Muscidae) in treated (TG01 and TG02) and untreated (UG01 and UG02) groups of Holstein heifers born in 2001 and 2002, respectively. Control and treated groups were assessed for the abundance of Stomoxys calcitrans (L.) (Diptera: Muscidae) from August 2001 to April 2002 and again from August 2002 to April 2003. The treatment had a high efficacy for control of horn flies (maximum median number per heifer of TG01 and TG02 = 5) but a low effect on the abundance of stable flies. The total numbers of S. calcitrans were 1251 (42.9% of the total) and 1668 (57.1%) for TG01 and UG01, and 1423 (48.8%) and 1494 (51.2%) in TG02 and UG02, respectively. No significant difference in stable fly burden was found in 55 of the 76 weeks evaluated. A unimodal peak of abundance in the spring was found during the first fly season, and a bimodal abundance, with peaks in the spring and autumn, during the second season. No strong associations between horn fly and stable fly burdens was found in individuals of the CG01 (correlation coefficient = 0.13, P > 0.05) or CG02 (correlation coefficient = 0.538, P < 0.05, determination coefficient = 0.289).     

Cattle breed-variation in infestation by the horn fly Haematobia irritans

A study was carried out to assess the resistance of pure and cross-bred groups of cattle to the horn fly Haematobia irritans (Linnaeus) (Diptera: Muscidae) in northern Argentina. Pure-bred cattle were Criolla, Iberian Bos taurus Linnaeus (Artiodactyla: Bovidae) and Nellore, Bos indicus Linnaeus (Artiodactyla: Bovidae). Cross-bred cattle were Hereford, British B. taurus (34%) X Nellore (66%) and Hereford (66%) X Nellore (34%). All were heifers and animals were maintained in two groups, each containing a mixture of pure and cross-breeds. The lowest fly numbers were found on Criolla heifers and the highest on Hereford X Nellore cross-breeds. However, it could not be determined from this study whether this was a consequence of breed and/or size, as Criolla heifers were lighter than the corresponding Hereford X Nellore heifers. Fly numbers on the heifers followed an approximately negative binomial distribution. However, the ranking of individual animals in their level of infestation within subgroups was not consistent. Hence, culling the most infested heifers on any given date would at best give only a small improvement in H. irritans control.     

Purification and characterization of a trypsin-like enzyme with fibrinolytic activity present in the abdomen of horn fly, Haematobia irritans irritans (Diptera: Muscidae)

This work describes the purification and characterization of a trypsin-like enzyme with fibrinolytic activity present in the abdomen of Haematobia irritans irritans (Diptera: Muscidae). The enzyme was purified using a one-step process, consisting of affinity chromatography on SBTI-Sepharose. The purified protease showed one major active proteinase band on reverse zymography with 0.15% gelatin, corresponding to a molecular mass of 25.5 kDa, with maximum activity at pH 9.0. The purified trypsin-like enzyme preferentially hydrolyzed synthetic substrates with arginine residue at the P1 position. The K _m values determined for three different substrates were 1.88 × 10^–4, 1.28 × 10^–4, and 1.40 × 10^–4 M for H--benzoyl-Ile-Glu-Gly-Arg-p-nitroanilide (S2222), dl-Ile-Pro-Arg-p-nitroanilide (S2288), and DL-Phe-Pip-Arg-p-nitroanilide (S2238), respectively. The enzyme was strongly inhibited by typical serine proteinase inhibitors such as SBTI (soybean trypsin inhibitor, K _i = 0.19 nM) and BuXI (Bauhinia ungulata factor Xa inhibitor, K _i = 0.48 nM), and less inhibited by LDTI (leech-derived tryptase inhibitor, K _i = 1.5 nM) and its variants LDTI 2T and 5T (0.8 and 1.5 nM, respectively). The most effective inhibitor for this protease was r-aprotinin (r-BPTI) with a K _i value of 39 pM. Synthetic serine protease inhibitors presented only weak inhibition, e.g., benzamidine with K _i = 3.0 × 10^–4 M and phenylmethylsulfonyl fluoride (PMSF) showed traces of inhibition. The purified trypsin-like enzyme also digested natural substrates such as fibrinogen and fibrin net. The protease showed higher activity against fibrinogen and fibrin than did bovine trypsin. These data suggest that the proteolytic enzyme of H. irritans irritans is more specific to proteins from blood than are the vertebrate digestive enzymes. This enzyme's characteristics may be an adaptation resulting from the feeding behavior of this hematophagous insect.     

Origin,evolution, phylogeny and taxonomy of Pulex irritans

The human flea Pulex irritans Linnaeus, 1758 (Siphonaptera: Pulicidae) is one of the most studied species together with the cat flea Ctenocephalides felis Bouché, 1835, because they have a cosmopolitan distribution and are closely related to humans. The present study aimed to carry out a comparative morphometric and molecular study of two different populations of P. irritans (Spain and Argentina). Accordingly, internal transcribed spacer (ITS)1 and ITS2 of rDNA and the partial cytochrome c oxidase subunit 1 (cox1) and cytochrome b (cytb) mtDNA genes of these taxa were sequenced. Furthermore, the taxonomy, origin, evolution and phylogeny of P. irritans was assessed. The morphometric data obtained did not show significant differences between P. irritans specimens from Spain and Argentina, even when these two populations were collected from different hosts; however, there was a considerable degree of molecular divergence between both populations based on nuclear and mitochondrial markers. Thus, it is proposed that P. irritans, in contrast with other generalist fleas, maintains a certain degree of morphological similarity, at least between Western Palearctic and Neotropical areas. Furthermore, two well defined geographical genetic lineages within the P. irritans species are indicated, suggesting the existence of two cryptic species that could be discriminated by a polymerase chain reaction‐linked restriction fragment length polymorphism.