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81.
The mite Ornithonyssus bursa (Berlese) (Mesostigmata: Macronyssidae) is considered a poultry pest causing important infestations in chickens and it is considered a potential vector of arbovirus. Despite being considered a common parasite in wild birds, there is scarce published information about its potential hosts and effects on them. Here we present new bird hosts for O. bursa, assess the presence of Alphavirus, Flavivirus and Bunyavirus in mites from three host species, and discuss its potential impact on wild bird populations. We found O. bursa infecting five raptor and six passerine wild bird species. For nine of these species, this is the first record of infection by O. bursa. Although all analysed mites were negative for the examined arboviruses, the small sample size of mites does not allow further conclusions at the present moment. Because of the general nature of this ectoparasite, its presence in migratory long dispersal and endangered bird species, and the seropositivity for arboviruses in some of the species studied here, we consider it critical to assess the role of O. bursa and other ectoparasites as vectors and reservoirs of pathogens and as potential deleterious agents in wild bird populations.  相似文献   
82.
This entomological survey examines the spatial and seasonal distribution patterns of flea species infesting dogs in Spain. Bioclimatic zones covering broad climate and vegetation ranges were surveyed according to size. In a cross‐sectional spatial survey carried out from late May 2013 to mid‐July 2015, 1084 dogs from 42 different locations were examined. A total of 3032 fleas were collected and identified as belonging to the following species: Ctenocephalides felis (Siphonaptera: Pulicidae) (81.7%, 2476 fleas); Ctenocephalides canis (11.4%, 347 fleas); Pulex irritans (Siphonaptera: Pulicidae) (6.9%, 208 fleas), and Echidnophaga gallinacea (Siphonaptera: Pulicidae) (0.03%, one flea). Variables observed to have effects on flea abundance were animal weight, sex, length of hair and habitat. In the seasonal survey conducted from June 2014 to June 2015, 1014 fleas were collected from 239 dogs at 30 veterinary practices across Spain. Peaks in C. felis abundance were observed in early summer and late autumn, whereas high numbers of P. irritans and C. canis were recorded in autumn. Numbers of fleas detected in winter were low overall. Based on these findings, the present study updates the spatial and seasonal distributions of flea species in Spain and assesses the impacts of host and habitat variables on flea infestation.  相似文献   
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84.
Current developments in biomedicine are presenting us with difficult ethical decisions and raising complex policy questions about how to regulate these new developments. Particularly vexing for governments have been issues related to human embryo experimentation. Because some of the most promising biomedical developments, such as stem cell research and nuclear somatic transfer, involve such experimentation, several international bodies have drafted documents aimed to provide guidance to governments when developing biomedical science policy. Here I focus on two such documents: the Council of Europe's Convention for the Protection of Human Rights and Dignity of the Human Being and the Additional Protocol to the Convention for the Protection of Human Rights and Dignity of the Human Being. I argue that by using human dignity as a criterion to determine the permissibility of particular human embryo research practices, these documents cannot aid in identifying research that would be contrary to human dignity. Thus, they fail to guide public policy on embryo experimentation. Their use of human dignity as a criterion makes their task of offering guidance unfeasible because the concept as used in these documents is too vague and is applied in contradictory ways. I discuss the main goals of these documents and their claims in relation to human embryo research. I then discuss how they have influenced public policy in several countries. Finally, I show that although these Council of Europe treaties attempt to serve as public policy guides in the area of embryo research, they fail to do so.  相似文献   
85.
Gall formation is a specialised form of phytophagy that consists of abnormal growth of host plant tissue induced by other organisms, principally insects and mites. In the mainly parasitoid wasp subfamily Doryctinae, gall association, represented by gall inducers, inquilines and their parasitoids, is known for species of seven genera. Previous molecular studies recovered few species of six of these genera as monophyletic despite their disparate morphologies. Here, we reconstructed the evolutionary relationships among 47 species belonging to six gall‐associated doryctine genera based on two mitochondrial and two nuclear gene markers. Most of the Bayesian analyses, performed with different levels of incomplete taxa and characters, supported the monophyly of gall‐associated doryctines, with Heterospilus (Heterospilini) as sister group. Percnobracon Kieffer and Jörgensen and Monitoriella Hedqvist were consistently recovered as monophyletic, and the validity of the monotypic Mononeuron was confirmed with respect to Allorhogas Gahan. A nonmonophyletic Allorhogas was recovered, although without significant support. The relationships obtained and the gathered morphological and biological information led us to erect three new genera originally assigned to Psenobolus: Ficobolus gen.n. (F. paniaguai sp.n. and F. jaliscoi sp.n. ), Plesiopsenobolus gen.n. (Pl. mesoamericanus sp.n. , Pl. plesiomorphus van Achterberg and Marsh comb.n. , and Pl. tico sp.n. ), and Sabinita gen.n. (S. mexicana sp.n. ). The origin of the gall‐associated doryctine clade was estimated to have occurred during the middle Miocene to early Oligocene, 16.33–30.55 Ma. Our results support the origin of true gall induction in the Doryctinae from parasitoidism of other gall‐forming insects. Moreover, adaptations to attack different gall‐forming taxa on various unrelated plant families probably triggered species diversification in the main Allorhogas clade and may also have promoted the independent origin of gall formation on at least three plant groups. Species diversification in the remaining doryctine taxa was probably a result of host shifts within a particular plant taxon and shifts to different plant organs. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:0021F253‐4ABA‐4EAA‐A7A9‐FC0AD1932EA3  相似文献   
86.
Abstract. The abdominal colour pattern of Eristalis arbustorum (L.) shows seasonal variation, with animals emerging in spring being darker than those emerging during summer. One of the most important environmental cues influencing the abdominal colour pattern is developmental temperature. An experiment was carried out to establish which period during the immature stages was important in determining final adult colour pattern. The results indicate a good relationship between the length of the pupal period and both the extent of the paler markings on the abdomen and the grey score of these markings. The length of the larval period did not have any effect on adult colour pattern.  相似文献   
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88.
1. Body postures adopted by an animal can serve behavioural functions, homeostasis, or energy balance. 2. We investigated the function of holding the gaster curled forward under the thorax in acacia ants, Pseudomyrmex spinicola Emery, by testing whether ants adopted this posture for defence, thermoregulation, or for efficient locomotion. 3. For the defence hypothesis, we expected an increase in the proportion of ants with curled gasters after a visual threat, a vibrational disturbance of a branch, or the release of nestmate's alarm pheromones. Our data did not support these predictions. 4. For the thermoregulation hypothesis, we found a positive correlation between temperature and proportion of curled‐gaster ants. However, we did not find a reduction in the proportion of curled‐gaster ants after shading them, as predicted by this hypothesis. 5. Our data supported the locomotion hypothesis: curled‐gaster ants walked 1 cm s?1 faster than ants with the gaster held straight. Straight‐gaster ants walked with the thorax closer to the surface, a posture that likely shifts the centre of gravity closer to the surface in a manner similar to gaster curling. 6. Studying the role of the body posture in acacia ants and other insects will provide a better understanding of the kinematics of walking in challenging angles with respect to gravity.  相似文献   
89.
Little is known about how the virulence of a human pathogen varies in the environment it shares with its vector. This study focused on whether the virulence of Trypanosoma cruzi (Trypanosomatida: Trypanosomatidae), the causal agent of Chagas' disease, is related to altitude. Accordingly, Triatoma dimidiata (Hemiptera: Reduviidae) specimens were collected at three different altitudes (300, 700 and 1400 m a.s.l.) in Chiapas, Mexico. The parasite was then isolated to infect uninfected T. dimidiata from the same altitudes, as well as female CD‐1 mice. The response variables were phenoloxidase (PO) activity, a key insect immune response, parasitaemia in mice, and amastigote numbers in the heart, oesophagus, gastrocnemius and brain of the rodents. The highest levels of PO activity, parasitaemia and amastigotes were found for Tryp. cruzi isolates sourced from 700 m a.s.l., particularly in the mouse brain. A polymerase chain reaction‐based analysis indicated that all Tryp. cruzi isolates belonged to a Tryp. cruzi I lineage. Thus, Tryp. cruzi from 700 m a.s.l. may be more dangerous than sources at other altitudes. At this altitude, T. dimidiata is more common, apparently because the conditions are more beneficial to its development. Control strategies should focus activity at altitudes around 700 m a.s.l., at least in relation to the region of the present study sites.  相似文献   
90.
Culicoides (Diptera: Ceratopogonidae) are vectors of pathogens that affect wildlife, livestock and, occasionally, humans. Culicoides imicola (Kieffer, 1913) is considered to be the main vector of the pathogens that cause bluetongue disease (BT) and African horse sickness (AHS) in southern Europe. The study of blood‐feeding patterns in Culicoides is an essential step towards understanding the epidemiology of these pathogens. Molecular tools that increase the accuracy and sensitivity of traditional methods have been developed to identify the hosts of potential insect vectors. However, to the present group's knowledge, molecular studies that identify the hosts of C. imicola in Europe are lacking. The present study genetically characterizes the barcoding region of C. imicola trapped on farms in southern Spain and identifies its vertebrate hosts in the area. The report also reviews available information on the blood‐feeding patterns of C. imicola worldwide. Culicoides imicola from Spain feed on blood of six mammals that include species known to be hosts of the BT and AHS viruses. This study provides evidence of the importance of livestock as sources of bloodmeals for C. imicola and the relevance of this species in the transmission of BT and AHS viruses in Europe.  相似文献   
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