果树介壳虫寄生蜂资源的研究

介壳虫是果树的重要害虫,研究利用寄生蜂的自然控制作用是果树介壳虫生物防治和综合治理的重要途径。本论述了果树介壳虫寄生蜂资源的研究,报道了小蜂总科寄生蜂5科25属63种。     

Insights on the taxonomy of Haemoproteus parasites infecting cracid birds

The Haemosporida order is a well-supported clade of heteroxenous parasites transmitted by dipteran insects and frequently found parasitizing wild birds. These parasites have already been reported in all zoogeographic regions of the world, except for Antarctica. One of the potential hosts of haemosporidians is the Cracidae family, which includes approximately 50 species, 22 of which are present in Brazil, classified within nine genera. Data on haemosporidian infecting individuals of the Cracidae family is scarce, with only three Haemoproteus species being recorded in this group of birds. We found Haemoproteus spp. infection in all Penelope obscura bronzina analyzed. Among the parasites found, we observed two lineages of Haemoproteus (PENOBS02 and PENOBS03), which were characterized by morphological, molecular and phylogenetic approaches. The morphological data on cracid haemosporidian parasites, together with our phylogenetic results, allows discussions on the taxonomy of the Haemoproteus parasites that infect birds of the Cracidae family.     

基于部分18S rDNA, 28S rDNA和COI基因序列的索科线虫亲缘关系

通过PCR扩增获得我国常见昆虫病原索科线虫6属10种18S rDNA、28S rDNA(D3区)和COI基因序列,结合来自GenBank中6属10种索科线虫的18S rDNA同源序列,用邻接法和最大简约法构建系统进化树。结果显示:12属索科线虫分为三大类群,第一大类群是三种罗索属线虫(Romanomermis)先聚在一起,再与两索属(Amphimermis)和蛛索属(Aranimermis)线虫聚为一支;在第二大类群中,六索属(Hexamermis)、卵索属线虫(Ovomermis)和多索属(Agamermis)亲缘关系最近,先聚在一起,再与八腱索属(Octomyomermis)和Thaumamermis线虫聚为一支。第三大类群由索属(Mermis)和异索属(Allomermis)线虫以显著水平的置信度先聚在一起,再与蠓索属(Heleidomermis)和施特克尔霍夫索属(Strelkovimermis)线虫聚为一支。从遗传距离看,基于3个基因的数据集均显示索科线虫属内种间差异明显小于属间差异,武昌罗索线虫(R.wuchangensis)和食蚊罗索线虫(R.culicivorax)同属蚊幼寄生罗索属线虫,其种间的遗传距离最小。     

The more insect trypanosomatids under study-the more diverse Trypanosomatidae appears

From 10 trypanosomatids genera six comprise monogenetic parasites of insects and for the rest of four genera insects may serve as vectors. The invertebrate host is an essential element of trypanosomatids life cycle, but from more than 900 recognised vertebrate hosts only about 500 species of insects have been discovered to be the hosts of homoxenous trypanosomatids. Nothing or very little is known about insect trypanosomatids in many extensive areas such as South East Asia, Australia, Japan and some others. Each new region explored brings many new findings. Recently flagellates were found in new insect species and families. The border of parasites distribution was expanded till Central Asia, Far East and North over the Polar Circle. As paleogeographical events are now under contemplating in trypanosomatids phylogeny researches so northern insect trypanosomatids may attract some attention as the elements of postglacial fauna which is definitely young. Very broad host specificity of insect trypanosomatids and high probability to isolate non-specific parasite show causes that only the investigation of a culture may solve the question 'what parasite was really isolated?'. Examination of cell morphotypes in the host has clearly demonstrated that they are not sufficient for classification and may lead us to be mistaken. The number of insect trypanosomatid cultures is inadequate for characterisation of the diversity of insects trypanosomatids. Trypanosoma is actually the only trypanosomatid genus which is out of questions. Insect trypanosomatids comprise the most diversified part of trypanosomatids evolutionary tree. Recent ssrRNA phylogenetic analysis and morphological data show that three insect isolates represent new lineages on trypanosomatid evolutionary tree, as well as dendrograms derived from PCR data demonstrated some new groups of isolates. Therefore, the more insect trypanosomatids are involved in laboratory investigations--the more new clusters or/and new lineages are appearing on the tree.     

Regiocrella, a new entomopathogenic genus with a pycnidial anamorph and its phylogenetic placement in the Clavicipitaceae

A new genus, Regiocrella, is described with two species, R. camerunensis and R. sinensis, based on specimens collected in Cameroon and China. Both species are parasitic on scale insects (Coccidae, Homoptera). Morphological and molecular evidence place the new genus in the Clavicipitaceae (Hypocreales), despite its combination of characters that are atypical of that family; Regiocrella is characterized by having perithecia partly immersed in a subiculum, noncapitate asci, unicellular fusiform ascospores and pycnidial-acervular conidiomata. The two new species, R. camerunensis and R. sinensis, are distinguished based on ascospore and perithecium size. Morphological characters were evaluated and compared to other genera in the Clavicipitaceae, especially those parasitic on scale insects or with pycnidial-acervular anamorphs or synanamorphs (i.e. Aschersonia, Ephelis or Sphacelia): Atkinsonella, Balansia, Claviceps, Epichl?e, Hypocrella, Myriogenospora and Neoclaviceps. The phylogenetic relationships of Regiocrella were examined with three gene loci: large subunit nuclear ribosomal DNA (LSU), translation elongation factor 1-alpha (TEF), and RNA polymerase II subunit 1 (RPB1). The results of this study confirm that Regiocrella is distinct from other genera in the Clavicipitaceae and that its two species form a monophyletic group. Regiocrella is shown to be closely related to the scale insect pathogen Hypocrella and the plant-associated genera Balansia, Claviceps, Epichl?e, Myriogenospora and Neoclaviceps. This study also provides insights into the evolution of pycnidial-acervular conidiomata and scale insect parasitism within the Clavicipitaceae. Plant-associated genera form a monophyletic group correlated with Clavicipitaceae subfamily Clavicipitoideae sensu Diehl. We also demonstrate that scale insect parasites have multiple evolutionary origins within the family and genera with pycnidial-acervular anamorphs or synanamorphs have a single origin.     

Sociality in a Malagasy allodapine bee, Macrogalea antanosy, and the impacts of the facultative social parasite, Macrogalea maizina

Social parasitism has been researched extensively in many taxa of social insects, including ants, wasps and bees. However, little research has been done on allodapine bees, a taxon that has numerous independent origins of social parasitism. This study looks at two species of Macrogalea from Madagascar, one of which was previously believed to be a social parasite. Macrogalea is an important genus to study as it is the sister clade to all other allodapine genera, and the species of Macrogalea in Madagascar diverged recently, meaning that the study of a social parasite in this genera would provide insights into the very early stages of social parasite evolution. Macrogalea maizina was determined to be facultatively parasitic based on the presence of many traits that are common to other allodapine social parasites. The host, Macrogalea antanosy, was found to be quasisocial, with most females within a colony being able to reproduce. This has unique consequences for a parasitic strategy, as any invading parasite has no need to remove a queen or suppress the reproduction of the other colony members, a strategy that has been commonly observed for facultative parasites in other taxa. Received 10 May 2005; revised 22 July 2005; accepted 24 August 2005.     

Protozoan parasites of British small rodents

Thirty-five species of protozoan parasites belonging to thirteen genera have now been recorded for British small rodents. These include species of Entamoeba, Giardia, Spironucleus, Trichomonas, Chilomastix, Eimeria and Cryptosporidium in the gut; Trypanosoma, Hepatozoon and Babesia in the blood; and Toxoplasma, Frenkelia and Sarcocystis in the tissues. Recent advances have progressed along two lines, the elucidation of the life-cycles of the species of Frenkelia and Sarcocystis , which are now known to involve a carnivore as the final host, and laboratory studies on those parasites that can be maintained in laboratory animals. It is now possible to draw up a definitive list of hosts and parasites and this should serve as a basis for studies on the epidemiology of these parasites and their possible effects on their hosts.     

Weaving resistance: silk and disease resistance in the weaver ant <Emphasis Type="Italic">Polyrhachis dives</Emphasis>

Social insects are at risk from a diverse range of parasites. The antibiotic-producing metapleural gland is an ancestral trait in ants which is thought to be one of their primary mechanisms of resistance. However, the metapleural gland has been lost secondarily in three ant genera, which include weaver ants that are characterised by the remarkable construction of their nests using larval silk. Silken nests may have allowed reduced investment in costly disease resistance mechanisms like the metapleural gland if the silk has antimicrobial properties, as in other insects, or is a hygienic substrate. Here we examine this hypothesis in the weaver ant Polyrhachis dives. We found no evidence of a beneficial effect of silk. The presence of silk did not improve the already high resistance of ants to the entomopathogenic fungus Metarhizium, the ants only rarely interacted with the silk regardless of whether they were exposed to Metarhizium or not, and silk also did not inhibit the in vitro germination or growth of Metarhizium. Furthermore, silk was found in vitro to be heavily contaminated with the facultative entomopathogenic fungus Aspergillus flavus, and many more ants sporulated with this fungus when kept with silk in vivo than when they were kept without silk. Further work is needed to examine the effects of silk on other parasites and of silk from other weaver ants. However, the results in combination suggest that silk in P. dives is unlikely to provide protection against parasites and that it is also not a hygienic substrate. Alternative explanations may therefore be needed for the loss of the metapleural gland in weaver ants.     

Revision of the Genera Thyca, Stilifer, Scalenostoma, Mucronalia and Echineulima (Mollusca, Prosobranchia, Eulimidae)

All species that have been described of the genera mentioned in the title are listed and their systematic position given. The species of Stilifer (with 11 species, including S. inflatus sp.n. and 5. concavus sp.n.) are parasites of starfishes. Scalenostoma (3 species) are parasites of stone corals. Thyca (with 8 species) is removed from Capulidae, and included in Eulimidae. T. hawaiiensis sp.n. is described. The species of Thyca are parasites of starfishes. The species of Mucronalia (including M. trilineata sp.n.) are probably parasites of ophiuroids and Echineulima (with 4–6 species, including E. ponderi sp.n.) are parasites of echinoids. All species are figured, their characteristics are given and their host species and distributions are listed. Keys are given to the species of each genus, except Mucronalia. The genera Stilimella Laseron and Hyperlia Pilsbry are synonymized with Scalenostoma and the genera Kiramodulus Kuroda, Granulithyca Habe and Bessomia Berry are considered subgenera of Thyca.     

Phylogenetic evidence for an animal pathogen origin of ergot and the grass endophytes

Grass-associated fungi (grass symbionts) in the family Clavicipitaceae (Ascomycota, Hypocreales) are species whose host range is restricted to the plant family Poaceae and rarely Cyperaceae. The best-characterized species include Claviceps purpurea (ergot of rye) and Neotyphodium coenophialum (endophyte of tall fescue). They have been the focus of considerable research due to their importance in agricultural and grassland ecosystems and the diversity of their bioactive secondary metabolites. Here we show through multigene phylogenetic analyses and ancestral character state reconstruction that the grass symbionts in Clavicipitaceae are a derived group that originated from an animal pathogen through a dynamic process of interkingdom host jumping. The closest relatives of the grass symbionts include the genera Hypocrella, a pathogen of scale insects and white flies, and Metarhizium, a generalist arthropod pathogen. These data do not support the monophyly of Clavicipitaceae, but place it as part of a larger clade that includes Hypocreaceae, a family that contains mainly parasites of other fungi. A minimum of 5-8 independent and unidirectional interkingdom host jumps has occurred among clavicipitaceous fungi, including 3-5 to fungi, 1-2 to animals, and 1 to plants. These findings provide a new evolutionary context for studying the biology of the grass symbionts, their role in plant ecology, and the evolution of host affiliation in fungal symbioses.     

The physiology of itch

The perception of itch is associated with many parasites and their vectors, especially following penetration of the skin by the parasites themselves, as in cercarial dermatitis of schistosome infections, or penetration of arthropod mouthparts during blood feeding. Many ectoparasites such as scabies, lice and fleas, provoke sensations of itch - even when the insects are no longer (or have never been) present, giving rise to the phenomenon of delusory parasitosis. Itch, and the host 'grooming' responses with which it is associated, is increasingly recognized as an important factor in modulating vector feeding behaviour, which can have profound effects on the transmission dynamics of vector borne parasites. As a background to future reviews of this developing subject, we asked John Alexander, author of the classic Arthropods and Human Skin (Springer-Verlag, 1984), to explain what is itch, and to discuss what is known about its underlying Physiology.     

Oceanic barriers as indicated by scombrid fishes and their parasites

Four genera of scombrid fishes (26 species) and their copepod (32 species) and monogenean ectoparasites (25 species) were used to test the hypothesis that the East Pacific Barrier is responsible for the most pronounced break in the circum-tropical warm water fauna of the continental shelves, and not the New World Barrier. Analysis at the species level showed that there is a primary centre of diversity in the West Pacific, and a secondary centre in the West Atlantic. The former, almost entirely, shares its species of the largely coastal Scomberomorus and Grammatorcynus and their parasites with seas located to the west. Only four parasites (all copepods) are shared by the East and West Pacific, and they are circum-tropical. In contrast, the West Pacific shares species of the more pelagic Scomber and their parasites with seas both to the east and west, although at the genus level, only two circum-tropical monogenean genera are shared by the E and W Pacific. We conclude that the East Pacific Barrier has been a 100% or almost 100% effective barrier to dispersal of species of Scomberomorus, Grammatorcynus and their parasites, whereas for species of Scomber and their parasites, the East Pacific has been a less effective barrier.     

Monoclonal Antibodies for the Identification of Trypanosomatids of the Genus Phytomonas

Monoclonal antibodies have been produced against culture forms of Phytomonas francai and Phytomonas serpens parasites, respectively, in cassava roots and tomato fruits. These monoclonal antibodies have been tested against 5 other Phytomonas spp. isolated from plants and 14 species of trypanosomatids of various genera. Monoclonal antibodies were found to react exclusively with Phytomonas spp., always giving negative results with other trypanosomatid genera. Thus, these monoclonal antibodies seem to be an effective tool for the identification of phytomonads among insect trypanosomatids.     

Interkingdom host jumping underground: phylogenetic analysis of entomoparasitic fungi of the genus cordyceps

Most members of the ascomycetous genus Cordyceps are endoparasitic fungi of insects and other arthropods, but about 20 of the 300 described species are parasitic to hart's truffles, Elaphomyces spp. In order to understand the evolution of host specificity and the process of interkingdom host jumping in Cordyceps, we investigated the phylogenetic relationships of 22 representatives, including 4 truffle parasites and 18 insect parasites, based on nuclear and mitochondrial rDNA sequences. Five monophyletic groups were identified in both nuclear and mitochondrial phylogenies. In three of the five clades, the members utilized hosts from the same insect group, suggesting that the endoparasite-host connections have been conserved to some extent. On the other hand, it was also shown that major host shifts between distantly related insects must have occurred repeatedly. Notably, phylogenetic analyses strongly suggested that parasites of hart's truffles originated from parasites of cicada nymphs during the evolution of the CORDYCEPS: The common habitats of cicada nymphs and hart's truffles, deep underground and associated with tree roots, suggest that the interkingdom host jumping from Animalia to Fungi might have been promoted by the overlapping ecological niche of the unrelated hosts. This finding provides an impressive case of a drastic host shift in favor of the host habitat hypothesis.     

The occurrence of broncho-pulmonary nematodes in sheep from Emilia-Romagna

In the present investigations 510 sheep have been examined for the presence of lungworm larvae: 342 (67,05%) of them proved positive. The identification of the parasites demonstrated the presence of Dyctiocaulus filaria in 18,62% of the examined animals, Muellerius capillaris in 50%, Cystocaulus ocreatus in 26,86% and Protostrongylus spp. in 12,35%. All positive flocks were positive for two or more genera of lungworms.     

Determinants of host-specificity in parasites of freshwater fishes.

Factors responsible for interspecific variability in host-specificity were investigated within 15 genera (including 176 species) of metazoan parasites found in Canadian freshwater fish. For each species in a genus, the parasite's number of known hosts was determined from published host-parasite records. The effects of the total number and mean size of potential hosts (i.e. all fish species belonging to the family or families that include a parasite's known hosts) on number of hosts of congeneric species were evaluated using multiple regressions. Since parasite species that have been recorded often tend to have greater numbers of known hosts than do seldom-recorded parasites, it was necessary to control for the confounding effect of study intensity. In all parasite genera, whether from highly specific taxa such as monogeneans or from less host-specific ones, there was a positive relationship between the number of potential hosts and the number of known hosts. However, no consistent relationships were observed between the mean size of potential hosts and number of known hosts. These results suggest that the availability of suitable host species may have been a key factor limiting the colonization of new hosts by fish parasites.     

Maternal transmission of mitochondrial DNA in ducks

Maternal transmission of mitochondrial DNA (mtDNA) has been studied in amphibians, insects and mammals, but little is known about mtDNA inheritance in the ovaripirous avian species. In this study, we have constructed the physical maps of mitochondrial genomes from two different genera of ducks (Cairina and Anas) and taken advantage of the availability of their hybrids to demonstrate that mtDNA is maternally inherited.     

The influence of interaction type and feeding location on the phylogeographic structure of the yucca moth community associated with Hesperoyucca whipplei

The interactions between herbivorous insects and their host plants have been central in generating diversification in both groups. We used a community of four yucca moth species, monophagous on the host plant Hesperoyucca whipplei (Agavaceae), to examine how the type of interaction and where insects feed within a plant influence phylogeographic structure of herbivorous insects. These four species included two fruit-feeders, one mutualistic and one commensalistic, and two commensalistic stalk-feeders. Surveys based on mtDNA cytochrome oxidase I sequence data demonstrated that the moth species differed in phylogeographic history. Populations of the mutualist pollinator, Tegeticula maculata, exhibited the most subdivision in comparison to the three commensal Prodoxus species (both genera in Lepidoptera, Prodoxidae). Feeding location was also correlated with differences in phylogeographic history through its influence on population sizes and the probability of gene flow. The results suggest that both the outcome of interactions and where insects feed may influence population structure.