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  • Author or Editor: Karin Kiontke x

Karin Kiontke and Albrecht Manegold

Abstract

The life cycle of two morphologically very similar Diplogasteroides species and their association with cockchafers in southern Germany was investigated. 70-100% of cockchafer grubs and 95% of the imagines carried Diplogasteroides spp. dauer juveniles. The nematodes were almost exclusively found on the external cuticle of the insects and usually not in the body cavity or the intestine. Diplogasteroides spp. dauer juveniles embark on the grub and accumulate during its development. There was some indication that dauer juveniles are transmitted from male to female beetle during copulation. The dauer juveniles resume development only after the death of the beetle, feeding on the cadaver (necromeny). Former hypotheses, assuming the nematode species to be parasitic and to cause the death of cockchafer grubs, can be refuted.

Walter Sudhaus, Robin Giblin-Davis and Karin Kiontke

Abstract

Caenorhabditis angaria n. sp., an ectophoretic associate of the West Indian sugarcane weevil, Metamasius hemipterus (Coleoptera: Curculionidae) is described and illustrated. Data on biology (longevity, fecundity) and ecology are presented. Caenorhabditis angaria n. sp. is gonochoristic and can be differentiated from other species of Caenorhabditis by its comparatively short stoma in combination with six semicircular overlapping flaps on the lips, lack of a pharyngeal sleeve, one pair of teeth on each sector of the metastegostom, and a proximally open bursa with nine pairs of genital papillae (GP) and papilliform phasmids (ph) in a 2/2 + 2 + 3 + ph arrangement with GP4 and 7 opening dorsally. Caenorhabditis angaria n. sp. was isolated and cultured from M. hemipterus from Dade, Broward and Palm Beach Counties, FL, USA, and from Port-of-Spain, Trinidad, and from the American palm weevil, Rhynchophorus palmarum, from Trinidad. The nematode is phoretically associated with weevils as dauer juveniles without causing obvious deleterious effects. Caenorhabditis angaria n. sp. does not require the association with a weevil and can be cultured continuously on bacteria.

Walter Sudhaus, Karin Kiontke and Albrecht Manegold

Abstract

A detailed morphological description is presented of Diplogasteroides nasuensis Takaki, 1941 and D. magnus Völk, 1950, using light and scanning electron microscopy. Neoaplectana melolonthae Weiser, 1958 and Diplogasteroides (Rhabdontolaimus) berwigi Rühm, 1959 are synonymised with D. nasuensis. This gonochoristic species is distinguished from the hermaphroditic D. magnus by the dorsal metastomal decoration which consists of bristle-like protrusions instead of a more or less uniform tooth. The spermatocytes in D. nasuensis are twice as big as those in hermaphrodites of D. magnus. Dauer juveniles of D. nasuensis are considerably bigger than those of D. magnus. Dauer juveniles of both species are present on wood cockchafer (Melolontha hippocastani) larvae and adults but, on adult beetles, D. nasuensis dauer juveniles enter the genital pouch, whereas those of D. magnus are found under the hind coxae. In Germany, D. nasuensis is found only on M. hippocastani. D. magnus dauer juveniles are also found on a variety of other Scarabaeidae. Further small differences distinguish the two species. The genus Diplogasteroides is proposed to be taken in a broad sense. Several genera names are synonymised with Diplogasteroides.

Mantaro Hironaka, Karin Kiontke and Walter Sudhaus

Abstract

Caenorhabditis japonica n. sp. is described from Parastrachia japonensis from Japan. The species is closely related to species of the Caenorhabditis elegans group and shares many characters with them. It differs from these species in having blunt spicule tips of complex shape and in lacking a terminal notch in the bursa velum. Caenorhabditis japonica n. sp. is further characterised by an anterior end with the lips fused in pairs, long and pointed stegostomal teeth, long fringes on the anterior bursa margin and the form of the genital papillae (GP4 reduced). The species is integrated into the phylogenetic tree of Caenorhabditis. Some resulting consequences for character evolution within Caenorhabditis are discussed. Caenorhabditis japonica n. sp. is associated with a burrower bug, thereby adding a new component to the diverse ecology of Caenorhabditis species.

David Fitch, Koichi Soné, Natsumi Kanzaki, Fukiko Abe, Robin Giblin-Davis, Karin Kiontke and Kunihiko Hata

Abstract

Teratorhabditis synpapillata, originally described from cow dung in Bali, was isolated from the red palm weevil, Rhynchophorus ferrugineus, in Japan. Dauer juveniles were isolated from beneath the elytra of five specimens of R. ferrugineus that had emerged from a dead Canary Island date palm, Phoenix canariensis, in Kagoshima, Japan. The dauer juveniles were cultured on a NGM agar plate and the adult nematodes observed and measured with the aid of light microscopy. The full length of the ribosomal small subunit (SSU) and D2/D3 expansion segment of the ribosomal large subunit (LSU) were sequenced for molecular identification. Based upon morphology, molecular profile and a hybridisation test, the nematode was confirmed as T. synpapillata. A comparison of morphology and morphometrics suggests that the only other nematode reported from R. ferrugineus (= 'Pelodera rhynchophori') is also conspecific with T. synpapillata. A phylogenetic analysis using SSU and LSU rRNA gene sequences fully resolves the relationships of four Teratorhabditis and six outgroup species and demonstrates a sister group relationship of T. synpapillata and T. palmarum, another associate of palm weevils.