A mid-Cretaceous ambrosia fungus, Paleoambrosia entomophila gen. nov. et sp. nov. (Ascomycota: Ophiostomatales) in Burmese (Myanmar) amber,and evidence for a femoral mycangium

An ambrosia fungus is described from filamentous sporodochia adjacent to a wood–boring ambrosia beetle (Coleoptera: Curculionidae: Platypodinae) in mid-Cretaceous Burmese amber. Yeast-like propagules and hyphal fragments of Paleoambrosia entomophila gen. nov. et sp. nov. occur in glandular sac mycangia located inside the femur of the beetle. This is the first record of a fossil ambrosia fungus, showing that symbiotic associations between wood–boring insects and ectosymbiotic fungi date back some 100 million years ago. The present finding moves the origin of fungus-growing by insects from the Oligocene to the mid-Cretaceous and suggests a Gondwanan origin.     

Aposymbiotic interactions of three ambrosia beetle fungi with avocado trees

Interactions between the fungal symbionts of the polyphagous shot hole borer (PSHB) Euwallacea nr. fornicatus and avocado host trees of cultivars 'Hass' and 'Ettinger' were studied, with emphasis on the three symbiotic fungi of the beetle. Fusarium euwallaceae did not spread far from the beetle galleries and remained viable in live xylem for 25 months; Graphium euwallaceae and Paracremonium pembeum disappeared from the live tissue 2 months after inoculation, but remained viable in dead xylem. The role of F. euwallaceae as a pathogen that contributes to typical wilting symptoms of PSHB-colonized avocado branches was assessed. The enhanced resistance of 'Ettinger' than of 'Hass', as manifested in its fewer beetle attacks was not reflected in the interaction of these cultivars with the symbiotic fungi. The specific pseudo-pathogenic interaction of F. euwallaceae with the xylem may be the key to understanding the different susceptibility between attacked hosts.     

Ambrosia beetle Premnobius cavipennis (Scolytinae: Ipini) carries highly divergent ascomycotan ambrosia fungus,Afroraffaelea ambrosiae gen. nov. et sp. nov. (Ophiostomatales)

Ambrosia beetles and fungi represent an interesting and economically important symbiosis, but the vast majority of ambrosia fungi remain unexplored, hindering research, management of pathogens, and mitigation of invasive species. Beetles in the subtribe Premnobiini are one example of an entire beetle lineage whose fungal symbionts have never been studied. Here, we identify one dominant fungal symbiont of Premnobius cavipennis by using fungus culturing, community sequencing, microtome sectioning and micro-CT scanning of mycangia. Phylogenetic analyses of combined 18S and 28S rDNA and β-tubulin sequences revealed a highly divergent fungal lineage within Ophiostomatales, Afroraffaelea ambrosiae gen. nov. et sp. nov. The newly described fungal lineage represents another origin of the symbiosis within the Kingdom Fungi, adding to our understanding of the geographic ancestry of ambrosia fungi. P. cavipennis possesses pharyngeal mycangia which appear restrictive in fungus selection. This ambrosia beetle-fungus association has remained stable even after invasions into non-native regions.     

Raffaelea quercivora sp. nov. associated with mass mortality of Japanese oak, and the ambrosia beetle (Platypus quercivorus)

 A hyphomycete consistently isolated from dead oak trees (Quercus serrata and Q. mongolica var. grosseserrata) attacked by the ambrosia beetle Platypus quercivorus in Japan is described and illustrated as Raffaelea quercivora sp. nov. The new species is characterized by having small obovoid to pyriform sympodioconidia and slender, long conidiophores that taper to a point. The fungus has been isolated from the body surfaces and mycangia of the beetle. It is likely that the fungus was transferred to oak trees by P. quercivorus. Received: August 20, 2001 / Accepted: March 14, 2002     

Identification of the ambrosia fungus of <Emphasis Type="Italic">Xyleborus monographus</Emphasis> and <Emphasis Type="Italic">X. dryographus</Emphasis> (Coleoptera: Curculionidae,Scolytinae)

The scolytid ambrosia beetles Xyleborus monographus and X. dryographus were investigated to identify their nutritional ambrosia fungi. The examination of the oral mycetangia of the beetles, the specialized organs for fungal transport, revealed the dominant occurrence of Raffaelea montetyi, a fungus that was also predominant in the beetle tunnels in the immediate vicinity of the feeding larvae. R. montetyi was previously known only as the ambrosia fungus of the platypodid ambrosia beetle, Platypus cylindrus. These beetle species inhabit the same habitat, mainly trunks of oaks in the Western Palaeartic. The possibility of an exchange of the symbiotic fungus between the ambrosia beetles within their common breeding place is discussed. Consequently, the previous hypothesis of a species-specific association of a single ambrosia fungus with a single beetle species is questioned. A phylogenetic analysis based on DNA sequences classified R. montetyi within the Ophiostomatales of the ascomycetes. The investigation of conidiogenesis of R. montetyi by SEM supported this taxonomic placement and showed the development of the conidia by annellidic percurrent proliferation, identical to the conidiogenesis reported for many anamorph states of the Ophiostomatales.     

<Emphasis Type="Italic">Ambrosiella</Emphasis><Emphasis Type="Italic">beaveri,</Emphasis> sp. nov., Associated with an exotic ambrosia beetle, <Emphasis Type="Italic">Xylosandrus mutilatus</Emphasis> (Coleoptera: Curculionidae,Scolytinae), in Mississippi,USA

Xylosandrus mutilatus is an Asian ambrosia beetle that has recently established in Mississippi, Texas, Alabama, and possibly Florida, USA. We investigated the fungi associated with the mycangia (specialized fungus-transporting structures) of X. mutilatus in Mississippi. Mycangia consistently yielded an Ambrosiella sp. which was subsequently found to be closely related to, but distinct from, other Ambrosiella species affiliated with Ceratocystis. This Ambrosiella is described herein as Ambrosiella beaveri sp. nov. Also isolated were Geosmithia lavendula, G. obscura, and a yeast, Candida homelintoma. It is likely Ambrosiella beaveri was introduced along with the beetle into North America.     

Microbial symbiotes of the ambrosia beetleXyloterinus politus

Progression in the understanding of the microecology of ambrosia beetles and their associated microorganisms is briefly reviewed. Between the 1840s and the early 1960s the concept of one ambrosial fungus per ambrosia beetle was emphasized. Some subsequent research has supported the view that each ambrosia beetle plus several associated microorganisms constitute a highly co-evolved symbiotic community. It was hypothesized in this study that such a community of symbiotic microbial species, not just one ambrosial fungus, is actively cultivated and perpetuated by the ambrosia beetleXyloterinus politus. Experimental results indicated that bacteria, yeasts, a yeastlike fungus, and ambrosial fungi compose such a symbiotic microbial complex in association withX. politus. The microecology of the ectosymbiotic microorganisms in relation to this insect is discussed.     

Volatiles from the symbiotic fungus Raffaelea lauricola are synergistic with Manuka lures for increased capture of the Redbay ambrosia beetle Xyleborus glabratus

相似文献   

Four new Ophiostoma species associated with hardwood-infesting bark beetles in Norway and Poland

Ophiostoma spp. (Ophiostomatales, Ascomycota) are well-known fungi associated with bark and ambrosia beetles (Curculionidae: Scolytinae, Platypodinae). Fungi in the Ophiostomatales include serious tree pathogens as well as agents of timber blue-stain. Although these fungi have been extensively studied in the northern hemisphere, very little is known regarding their occurrence on hardwoods in Europe. The aims of the present study were to identify and characterize new Ophiostoma spp. associated with bark and ambrosia beetles infesting hardwoods in Norway and Poland, and to resolve phylogenetic relationships of Ophiostoma spp. related to the Norwegian and Polish isolates, using multigene phylogenetic analyses. Results obtained from five gene regions (ITS, LSU, β-tubulin, calmodulin, translation elongation factor 1-α) revealed four new Ophiostoma spp. These include Ophiostoma hylesinum sp. nov., O. signatum sp. nov., and O. villosum sp. nov. that phylogenetically are positioned within the Ophiostoma ulmi complex. The other new species, Ophiostoma pseudokarelicum sp. nov. reside along with Ophiostoma karelicum in a discrete, well-supported phylogenetic group in Ophiostoma s. stricto. The results of this study clearly show that the diversity and ecology of Ophiostoma spp. on hardwoods in Europe is poorly understood and that further studies are required to enrich our knowledge about these fungi.     

New sharks of the genus Abdounia (Carcharhiniformes: Carcharhinidae) from the Upper Eocene of the Trans-Ural Region

Two new species of carcharhinid sharks from the Late Eocene deposits (Tavda Formation) of the southern Trans-Urals, Abdounia vassilyevae sp. nov., previously determined as A. aff. beaugei, and A. lata sp. nov., are described. To date, up to five Priabonian species of Abdounia have been recorded. New finds supplement the data on diversity, evolution, and paleobiogeography of Abdounia.     

The ambrosia symbiosis is specific in some species and promiscuous in others: evidence from community pyrosequencing

Symbioses are increasingly seen as dynamic ecosystems with multiple associates and varying fidelity. Symbiont specificity remains elusive in one of the most ecologically successful and economically damaging eukaryotic symbioses: the ambrosia symbiosis of wood-boring beetles and fungi. We used multiplexed pyrosequencing of amplified internal transcribed spacer II (ITS2) ribosomal DNA (rDNA) libraries to document the communities of fungal associates and symbionts inside the mycangia (fungus transfer organ) of three ambrosia beetle species, Xyleborus affinis, Xyleborus ferrugineus and Xylosandrus crassiusculus. We processed 93 beetle samples from 5 locations across Florida, including reference communities. Fungal communities within mycangia included 14–20 fungus species, many more than reported by culture-based studies. We recovered previously known nutritional symbionts as members of the core community. We also detected several other fungal taxa that are equally frequent but whose function is unknown and many other transient species. The composition of fungal assemblages was significantly correlated with beetle species but not with locality. The type of mycangium appears to determine specificity: two Xyleborus with mandibular mycangia had multiple dominant associates with even abundances; Xylosandrus crassiusculus (mesonotal mycangium) communities were dominated by a single symbiont, Ambrosiella sp. Beetle mycangia also carried many fungi from the environment, including plant pathogens and endophytes. The ITS2 marker proved useful for ecological analyses, but the taxonomic resolution was limited to fungal genus or family, particularly in Ophiostomatales, which are under-represented in our amplicons as well as in public databases. This initial analysis of three beetle species suggests that each clade of ambrosia beetles and each mycangium type may support a functionally and taxonomically distinct symbiosis.     

A mid-Cretaceous trichomycete,Priscadvena corymbosa gen. et sp. nov., in Burmese amber

Priscadvena corymbosa gen. et sp. nov., is described from thalli and sporangia emerging from the oral cavity of a click beetle (Coleoptera: Elateridae) in mid-Cretaceous Burmese amber. The fossil contains several features unknown in extant Trichomycetes including a click beetle (Coleoptera: Elateridae) host, spiny, aerial thalli with the entire thallus bearing numerous small uninucleate globular spores and stalks attached to the oral cavity of its host. Based on these features, P. corymbosa gen. et sp. nov. is placed in a new family, Priscadvenaceae fam. nov., and new order, Priscadvenales ord. nov. The new morphological and behavioral features of the fossil add to the diversity of the trichomycetes as currently defined.     

Microstructure of the prothoracic mycangia in the ambrosia beetle Platypus koryoensis (Coleoptera: Curculionidae: Platypodinae)

Platypus koryoensis (Murayama) (Coleoptera: Curculionidae: Platypodinae) is a minute ambrosia beetle that can cause significant damage to live oak trees (Quercus mongolica) along with its symbiotic pathogenic fungus (Raffaelea sp.). Although both sexes of the beetle have a number of cuticular depressions for carrying microorganisms, only the females have mycangia that are typical in size on the pronotum. The mycangial cavities are filled with a mass of amorphous substances including yeast-like spores. In addition, mycangial cavities are equipped with cuticular pores which release substances to support symbiotic microorganisms during storage. Small depressions of both sexes can be subdivided into two clusters according to their relative sizes and locations. Although they have a typical cuticular peg (basiconic sensillum), they also share a common morphological characteristic with the typical mycangium of female: a round outlet and an invaginated reservoir containing a mass of secretory substances. Accordingly, our fine structural data suggest that both the female mycangia and the clusters of small cuticular depressions in both sexes also have a mycangial function in common regardless of their relative size and location.     

Dispersal behaviour of Euwallacea nr. fornicatus (Coleoptera: Curculionidae: Scolytinae) in avocado groves and estimation of lure sampling range

相似文献   

Differences among avocado cultivars in susceptibility to polyphagous shot hole borer (Euwallacea spec.)

Polyphagous shot hole borer (PSHB) (Euwallacea spec.; Coleoptera: Curculionidae: Scolytinae) has recently invaded southern California, USA. Along with its associated fungi, the beetle causes branch dieback and tree mortality in more than 200 host tree species, including avocado (Persea americana Mill., Lauraceae) and many important native, urban landscape, and nursery stock trees. As PSHB spreads into the avocado‐growing regions of southern California, there is a pressing need for more information for effective management of the insect/fungus complex. The objective of this study was to examine avocado cultivars to see whether there were differences in susceptibility to attack and gallery development from PSHB. We conducted choice and no‐choice trials with cut branches in the laboratory, artificially infested avocado saplings with PSHB, and also surveyed attack rates for two cultivars of field‐grown avocado subject to natural attack by PSHB. Laboratory and field trials showed similar patterns for preference among avocado cultivars indicated by beetle attack rates and gallery formation. Among the common commercial cultivars, Fuerte, Gwen, and Bacon most often had lower attack rates and lower rates of gallery formation. Zutano most frequently indicated high attack rates and much gallery formation, indicating that it may be the most susceptible to PHSB of the commercial cultivars.     

Lecithoceridae (Lepidoptera: Gelechioidea) of New Guinea,Part V: Descriptions of two new genera,Neotimyra gen. nov. and Strombiola gen. nov.

This is the 5th part in a series on the family Lecithoceridae (Lepidoptera, Gelechioidea) of New Guinea. Two new genera, Neotimyra gen. nov. and Strombiola gen. nov. are proposed. There are five new species in the genus Neotimyra (N. senara sp. nov., N. milleri sp. nov., N. gyriola sp. nov., N. warkapiensis sp. nov., and N. nemoralis sp. nov.), and one new species in the genus Strombiola (S. papuana sp. nov.). Adults, heads, labial palpi, venations, and male genitalia are illustrated.     

Kerfornella nov. gen., Trilobite Homalonotidae de l'Ordovicien armoricain et iberique

In the Massif Armoricain, Kerfornella nov. gen. includes several trilobites from the Llanvirn and the Llandeilo:K. brevicaudata (DESLONGCHAMPS) and K. cf. brevicaudata in Normandie, K. miloni nov. sp. and K. nov. sp. aff. miloni in the Synclinorium median. All these species, previously attributed to Plaesiacomia ? brevicaudata (DESLONGCHAMPS), would belong to two distinct phyletic lines. The stratigraphical interest of K. brevicaudata, which occurs in the Lower Grès de May and in the “quartzites Botella” from eastern Sierra Morena, is confirmed.     

Mycobiota associated with the ambrosia beetle Scolytodes unipunctatus (Coleoptera: Curculionidae, Scolytinae)

Ambrosia beetles (Coleoptera: Scolytinae) are associated with strictly entomochoric and mutualistic fungi. We studied the mycobiota associated with Scolytodes unipunctatus, ambrosia beetles that infest Cecropia trees in Central America. Isolates were characterized using morphology and rDNA sequences (ITS region, LSU, and SSU rDNA). Four species are described here: Raffaelea scolytodis sp. nov. (Ophiostomatales), Gondwanamyces scolytodis sp. nov., Custingophora cecropiae sp. nov., and Graphium sp. (Microascales). The genus Custingophora is emended to include Knoxdaviesia anamorphs of Gondwanamyces based on uniformity of DNA sequences and phenotype.     

<Emphasis Type="Italic">Fusarium matuoi</Emphasis> sp. nov. and its teleomorph <Emphasis Type="Italic">Cosmospora matuoi</Emphasis> sp. nov.

A group of Fusarium isolates from slime flux similar to F. aquaeductuum produced unique, strongly curved, aseptate, C-shaped conidia. They were found to be identical to F. splendens nom. nud. Dried specimens from which F. splendens was originally isolated were reexamined and characterized as a new species of Cosmospora. Cosmospora matuoi sp. nov. is proposed for the teleomorph, and Fusarium matuoi sp. nov. is proposed for its anamorph.