Bursaphelenchus fagi sp. n. (Nematoda: Parasitaphelenchidae), an insect-pathogenic nematode in the Malpighian tubules of the bark beetle, Taphrorychus bicolor (Herbst.) (Coleoptera: Curculionidae, Scolytinae), in European beech, Fagus silvatica L.

Abstract

Bursaphelenchus fagi sp. n. (Nematoda: Parasitaphelenchidae), an insect-pathogenic nematode in the Malpighian tubules of the bark beetle, Taphrorychus bicolor (Herbst.) (Coleoptera: Curculionidae, Scolytinae), in European beech, Fagus silvatica L. Summary -Bursaphelenchus fagi sp. n. is described from the bark of European beech, Fagus silvatica. All propagative stages of the nematode are numerous in larval galleries of the beech bark beetle, Taphrorychus bicolor, while dauer juveniles aggregate in Malpighian tubules of adult beetles. The new species is characterised by the body length of 871 (763-1110) p m in female and 852 (718-992) /xmin male, very slender body (a = 56.8 (50.4-67.1) and 64.5 (56.5-73.8) in female and male, respectively), and spicules 15.2 (14.0-17.0) p m long. The extended anterior vulval lip in female, lateral fields with four incisures, and number (7) and arrangement of male caudal papillae may indicate that B. fagi sp. n. is closely related to the xylophilus group. It differs from this group by the relatively small, claw like spicules with narrow capitulum, indistinct condylus in almost continuous line with dorsal lamina, and lack of distinct cucullus at the spicule tip. The close relation of B. fagi sp. n. with the xylophilus group has been confirmed by DNA sequencing and phylogenetic analysis of the 28S rDNA region. Bursaphelenchus fagi sp. n. most closely resembles B. tokyoensis and B. idius, but can be separated by differences in the arrangement of the male caudal papillae, a unique feature for each species. The taxonomic separation of the new species is also confirmed by the unique molecular profile of the ITS region (ITS-RFLP). The mass presence of dauer juveniles of B. fagi sp. n. in Malpighian tubules of adult T. bicolor leads to degradation of the tubule cellular epithelium and local expansion of its basement membrane. These changes clearly indicate direct pathogenicity of the nematode to its vector insect. In laboratory rearing, B. fagi sp. n. can grow and reproduce on Botryotinia fuckeliana cultures.

Parasitic association of the mycetophagous wood nematode, Bursaphelenchus fraudulentus with the honey fungus Armillaria ostoyae

“…Two nematodes morphologically similar to B. fraudulentus , which were originally isolated from the haemocoel of adult Saperda perforata and Trypophloeus asperatus , and their larval galleries in aspen, P. tremula , after additional DNA analysis turned to be new species and described earlier as Bursaphelenchus populi and B. trypophloei , respectively (Tomalak & Filipiak, , , ). From Malpighian tubules of dissected adult beetles of T. bicolor and P. chalcographus , two other new species of Bursaphelenchus have been found and described as B. fagi and B. piceae , respectively (Tomalak & Filipiak, ; Tomalak & Pomorski, ). On the body surface and under elytra of adult S. carpini and T. bicolor , numerous dauer juveniles of B. eremus and another new Bursaphelenchus species (under description) were present, respectively.…”

“…In the forest environment, the most common and frequently specific vectors of nematodes are saproxylic insects, such as bark, long‐horned and snout beetles (Massey, ; Rühm, ; Tomalak, Welch, & Galloway, ). The nematodes are usually transmitted as resting (dauer) juveniles under elytra, in tracheas or inside body of the vectors, introduced to a new tree by the insect during construction of its parental or larval galleries, and depart from the tree on or inside emerging beetles of the new generation (Mamiya & Enda, ; Tomalak & Filipiak, ; Tomalak, Worrall, & Filipiak, ).…”

Functional roles of nematodes associated with the walnut twig beetle and eastern black walnut in the inland northwest

“…Bursaphelenchus spp. are also found in association with numerous beetle‐fungal complexes and diseases in hardwoods (Ryss et al, 2015; Tomalak et al, 2013, 2017; Tomalak & Filipiak, 2014, 2018; Tomalak & Malewski, 2014), but their significance in the aetiology of associated diseases has not been well‐characterized.…”

Preliminary survey of nematodes associated with broadleaved trees in İzmit Forest Management Directorate, Turkey

“…Some species such as B. mucronatus Mamiya & Enda, 1979, B. sexdentati Rühm, 1960 and several others are considered as minor pathogens of pine tree hosts (e.g. Braasch et al., 1999; Skarmoutsos and Michalopoulos‐Skarmoutsos, 2000; Kanzaki et al., 2011; Dayi & Akbulut, 2012) or parasites/pathogens of their insect vectors such as B. doui Braasch, Gu, Burgermeister & Zhang, 2005 (Kanzaki et al., 2013), B. fagi Tomalak & Filipak, 2014 (Tomalak & Filipak, 2014), B. tiliae Tomalak & Malawski, 2014 (Tomalak & Malawski, 2014) and B. piceae Tomalak & Pomorski, 2015 (Tomalak & Pomorski, 2015).…”