Fourth-stage Juveniles Research Articles

マツノザイセンチュウ分散型4期幼虫のマツノマダラカミキリ成虫気管からの離脱行動

マツノザイセンチュウ分散型4期幼虫のマツノマダラカミキリ成虫気管からの離脱行動

A cladistic analysis of the tribe Labiostrongylinea Beveridge, 1983 (Nematoda: Cloacinidae) parasitic in macropodoid marsupials (Marsupialia: Macropodoidea), with a redescription of Parazoniolaimus collaris Johnston & Mawson, 1939.

Morphological characters of both adult and juvenile representatives of the genera comprising the Labiostrongylinea (Strongylida: Cloacinidae: Cloacininae) were examined to prepare an amended description of Paralabiostrongylus bicollaris, a redescription of Parazoniolaimus collaris and a cladistic analysis of the tribe. A cluster of Wallabinema spp., with a fleshy collar on which amphids and deirids are borne, was used as the outgroup for the analysis. The 50% consensus tree, bootstrapped through 1000 replicates, derived from the cladistic analysis had a basal polytomy of Dorcopsinema and Paralabiostrongylus; and a crown polytomy of Labiosimplex, Labiomultiplex, Parazoniolaimus, Labiostrongylus and Potorostrongylus. This analysis provided reasonable evidence for considering all 7 clades as being of generic status and amended diagnoses were prepared. The morphology of the cephalic end of fourth stage juveniles, cephalic papillae and amphids lying posterior to the lips, gave support to the contentions that a fleshy collar is a plesiomorphic character and that Dorcopsinema is the most primitive genus within the group. There was, however, insufficient support from morphological data to provide a robust resolution of generic relationships. Host and biogeographical data were indicative of Paralabiostrongylus and Labiosimplex having been derived from ancestral Dorcopsinema, then Labiostrongylus, Labiomultiplex and Parazoniolaimus derived from ancestral Labiosimplex, and Potorostrongylus from ancestral Labiomultiplex. Additional data, derived from molecular sequencing, is needed to help resolve the relationships within the tribe.

Habitat quality and prey size as determinants of survival in post-larval and early juvenile instars of the blue crab Callinectes sapidus

Habitat structure and prey size are important determinants in the outcome of predator-prey interactions. We investigated the role of simulated habitat type and density (simulated Zostera marina [hereafter referred to as 'Zostera']: 500 and 1500 shoots m -2 , and simulated Spartina alterniflora [hereafter referred to as 'Spartina']: 97 and 291 shoots m -2 ) in mediating predator-prey interactions. Proportional survival during predation by the piscene predator Fundulus heteroclitus on 2 successive life-history stages (post-larvae and first juvenile instars) of the blue crab Callinectes sapidus (Rathbun), was quantified under laboratory conditions that closely approximated field conditions. We also examined the effects of juvenile crab size (equal biomass and equal numbers of 2 or 3 prey-size categories, respectively) on survival during adult F. heteroclitus predation in the absence of vegetation. Crab size categories included small (first juvenile instars; 2.1 mm carapace width [cw]), medium (fourth and fifth crab stage juveniles; 6.0 to 9.1 mm cw), and large (sixth and seventh stage juveniles; 9.2 to 12.6 mm cw) in the equal numbers experiments and small and medium crabs for the equal biomass experiment. Mean proportional survival was higher for both life-history stages in simulated Zostera, with first-instars exhibiting higher proportional survival than post-larvae at the experimental densities tested (post-larvae: no grass = 0.23, low-density grass = 0.44, high-density grass = 0.57; first-instars: no grass = 0.47, low-density grass = 0.87, high-density grass = 0.87). Mean proportional survival did not differ significantly among life-history stages in the simulated Spartina treatments, although proportional survival between treatments was higher for first-instars than post-larvae (post-larvae: no Spartina = 0.17, low-density Spartina = 0.18, high-density Spartina = 0.19; first-instars: no Spartina = 0.46, low-density Spartina = 0.43, high-density Spartina = 0.48). Finally, size-refuge experiments with equal numbers or biomass of prey demonstrated significant differences between each size or/and biomass category tested. Crabs exhibited increasing proportional survival with increasing crab size (small = 0.34, medium = 0.66, large = 0.97) or weight (small = 0.18, medium = 0.67) in the presence of F. heteroclitus, suggesting that C. sapidus attains a refuge in size from predation by adult F. heteroclitus at approximately 9.2 to 12.6 mm. Our findings suggest that the influence of habitat structure on crab survival (possibly as a function of surface area) varies with simulated habitat type, crab density and crab stage (post-larvae versus first-instar), providing additional evidence of the importance of seagrasses in the early life-history stages of blue crabs.

Effects of the biological nematicide, DiTera®, on movement and sensory responses of second stage juveniles of Globodera rostochiensis, and stylet activity of G. rostochiensis and fourth stage juveniles of Ditylenchus dipsaci

AbstractDiTera® (Valent BioSciences Corp.), a novel biological nematicide obtained from fermentation with a hyphomycete fungus, adversely affected activity and movement through sand columns of second stage juveniles (J2) of Globodera rostochiensis. Electrophysiological tests demonstrated that exposure to 1% DiTera® prevented sensory perception of potato root diffusate. Electropharyngeograms of stylet protractor muscle activity showed that prior exposure of fourth stage juveniles of Ditylenchus dipsaci and J2 of G. rostochiensis to 1% DiTera® significantly reduced stylet thrusting when nematodes were transferred to artificial tap water or 10 mM serotonin, respectively. The modes of action and the control potential of this biological nematicide are discussed.

平底角型培養瓶を用いたマツノザイセンチュウとマツノマダラカミキリの共存培養と分散型IV期幼虫の生起

平底角型培養瓶を用いたマツノザイセンチュウとマツノマダラカミキリの共存培養と分散型IV期幼虫の生起

New records of Criconematoidea (Nematoda) from South Africa, with the description of Criconema zantene n. sp.

AbstractCriconema zantene n. sp., found in the rhizosphere of a Podocarpus sp. tree, is described and illustrated. Females are characterised by having 46-56 body annuli covered with tile-like scales, stylet 101-122 μm long, one lip annulus with a greater diameter than first body annulus, distinct submedian lobes, tooth-like lobes on posterior body annuli with a double row of lobes on first annulus directly posterior to vulva, a sigmoid vagina and an overhanging anterior vulval lip. Second, third and fourth stage juveniles with varying numbers of longitudinal rows of filamented scales on cuticle. Criconema princeps (Andrássy, 1962) Raski & Luc, 1985, Mesocriconema dherdei (De Grisse, 1967) Loof & De Grisse, 1989 and Paratylenchus straeleni (De Coninck, 1931) Oostenbrink, 1960 are reported from South Africa for the first time. These species are briefly discussed, illustrated and morphometrics given. Additional data is given for C. pauciannulatum Van den Berg, 1992.

Population dynamics of Paratylenchus nanus in soil under pasture: 2. Biotic factors and population modelling

AbstractSeasonal and monthly sampling of a Paratylenchus nanus population showed that trends in biomass were similar to those for abundance. A Population Age Index (proportional contribution of each life stage multiplied by stage biomass) showed population age increased from a minimum in spring to maximum in winter. From mid-spring to mid-summer, population age was greater in 0-10 than 10-20 cm depth; this may have been due to a greater proportion of juveniles developing over this period at the deeper depth. The populations at 10-20 cm deep included a greater proportion of fourth stage juveniles than those at 0-10 cm. This may reflect the smaller root resource at 10-20 cm depth limiting population development. Monthly sampling of patches of high vs low P.nanus density indicated that such patches retain their densities relative to each other in most months. Evidence is presented for density-dependence in the P. nanus population at 0-10 cm and density-independence at 10-20 cm depth. Multiple regression models were fitted, taking into account all factors (abiotic and biotic) which were significantly associated with P.nanus abundance, and results are discussed to highlight areas still requiring investigation before a complete model of the population dynamics of this nematode can be achieved.

Host Range of a California Sting Nematode Population

Recently, sting nematodes were discovered associated with dying turfgrass in several golf courses in Coachella Valley, Calif. Based on their morphology and internal transcribed spacer (ITS) rDNA restriction pattern, the pests were identified as Belonolaimus longicaudatus Rau. This study was undertaken to determine the host status of 60 different plant species and cultivars for a California population of B. longicaudatus. The host range tests were conducted under greenhouse conditions at 25 ± 2 °C and ambient light. At the second-leaf stage, each pot was infested with 55 ± 12 adults or fourth-stage juveniles per 150 g of blow sand. The population densities determined after 7 weeks of incubation qualified >80% of the plants tested as good hosts with a reproduction factor (Rf = Pf/Pi) > 4. The majority of those were grasses, although reproduction was best on Gossypium hirsutum L. with Rf = 58.6. While Capsicum annuum L., Medicago sativa L., Arachis hypogaea L., Euphorbia glyptosperma Engelm., Cucumis sativus L., and Daucus carota L. were less suitable host plants with Rf < 4, only Abelmoschus esculentus (L.) Moench, Citrullus lanatus Thunb., and Nicotiana tabacum L. were nonhosts among the tested species. This sting nematode population had a high reproductive fitness on a majority of species tested and must be considered a major threat for most agricultural and horticultural crops grown in sandy soils.

Electrophysiological activity during recovery from anhydrobiosis in fourth stage juveniles of Ditylenchus dipsaci

AbstractUpon immersion in water, anhydrobiotic nematodes display a period of apparent inactivity, the lag phase, before they commence spontaneous movement. Following a period of desiccation of the fourth stage juveniles of the plant-parasitic nematode Ditylenchus dipsaci, electrical activity during rehydration was recorded using glass microelectrodes inserted into individual nematodes. The pattern observed was a period of no electrical activity, followed by low amplitude electrical events and then also high amplitude events. Movement of the nematode was associated with the high amplitude events, whose recordings formed trains of spikes that coincided with the activity of the nematode. The lag phase represents a period during which the physiological functions of the nerves and muscles are restored. This may involve the restoration of ionic gradients between the inside and the outside of the cells, which is reflected in an increase in spike amplitude in those nematodes where a sustained period of high amplitude activity was recorded. Activité électrophysiologique durant la sortie d'anhydrobiose chez le quatrième stade juvénile de Ditylenchus dipsaci - Immergés dans l'eau, les nématodes anhydrobiotiques passent par une période d'inactivité apparente - la phase de latence - avant que des mouvements spontanés ne débutent. Pendant la réhydratation qui suivait une période de dessication l'activité électrique de juvéniles de quatrième stade de Ditylenchus dipsaci a été enregistrée grâce à des microélectrodes de verre implantées dans le nématode. La courbe observée correspondait à une période sans activité électrique, suivie par des phénomènes électriques de faible amplitude, combinés ensuite à des phénomènes de forte amplitude. Les mouvements des nématodes étaient associés aux phénomènes de forte amplitude dont le tracé consiste en une suite de pics coïncidant avec l'activité du nématode. La phase de latence correspond à la période pendant laquelle les fonctions physiologiques nerveuses et musculaires sont restaurées. Cela peut englober la restauration des gradients ioniques à l'intérieur et à l'extérieur des cellules, phénomène reflété par une augmentation des pics chez ceux des nématodes où une période soutenue d'activité de forte amplitude a été notée.

Developmental expression of secretory beta-1,4-endoglucanases in the subventral esophageal glands of Heterodera glycines.

Two beta-1,4-endoglucanases (EGases), Hg-eng-1 and Hg-eng-2, were recently cloned from the soybean cyst nematode, Heterodera glycines, and their expression was shown in the subventral esophageal glands of hatched second-stage juveniles (J2). We examined the expression of these EGases in the subventral glands of all post-embryonic life stages of H. glycines by in situ hybridization and immunolocalization. The first detectable accumulation of EGase mRNAs occurred in the subventral glands of unhatched J2. EGase transcripts remained detectable in J2 after hatching and during subsequent root invasion. However, in late parasitic J2 and third-stage juveniles (J3), the percentage of individuals that showed EGase transcripts decreased. In female fourth-stage juveniles and adult females, EGase transcripts were no longer detected in the subventral glands. EGase hybridization signal reappeared in unhatched males coiled within the J3 cuticle, and transcripts were also present in the subventral glands of migratory adult males. Immunofluorescence labeling showed that EGase translation products are most abundantly present in the subventral glands of preparasitic J2, migratory parasitic J2, and adult males. The presence of EGases predominantly in the migratory stages suggests that the enzymes are used by the nematodes to soften the walls of root cells during penetration and intracellular migration.

The first isolated collagen gene of the root-knot nematode Meloidogyne javanica is developmentally regulated

The nematode's surface comprises a multilayered cuticle, which consists mainly of collagen proteins. We identified, cloned and characterized the first cuticular collagen gene, Mjcol-3, of the plant-parasitic nematode Meloidogyne javanica. The gene putatively encodes a 32.4-kDa collagen protein, including a propeptide which possesses a subtilisin-like protease-cleavage site. Six introns were identified in the gene sequence, with three slightly different acceptor-splicing sites. The basic structure of the predicted MJCOL-3 protein sequence is highly similar to that of the Caenorhabditis elegans DPY-7, with 65.9% identity between the two amino acid sequences. Relative to DPY-7, the putative MJCOL-3 protein has a shorter carboxy-terminus. This non-conserved feature may indicate different contributions of DPY-7 and MJCOL-3 collagens to the structure of the cuticle. Mjcol-3 is developmentally regulated: transcripts were found mainly in preparasitic developing eggs, less in parasitic third- and fourth-stage juveniles and young females shortly after the fourth molt, and much less in females before egg-laying.

Meloidogyne javanica Development in Three Clover Populations

Root‐knot nematodes (RKN), Meloidogyne spp., cause damage to red clover (Trifolium pratense L.) which affects water and nutrient uptake and may predispose plants to other soil‐borne pathogens. Penetration and development of M. javanica (Treub) Chitwood three clover populations differing in resistance levels were evaluated in two greenhouse experiments conducted during 1994 and 1995. The RKN susceptible red clover cultivar ‘Kenstar’, a red clover breeding selection designated FLMR6 with moderate RKN resistance, and a highly RKN resistant species T. stoloniferum Mublenburg, running buffalo clover (RBC), were grown in Cone‐tainers and inoculated with 450 second‐stage juveniles (J2) 21 d after germination. Responses measured were numbers of J2, J3/J4 (third‐stage or fourth‐stage juvenile nematodes) and adults at 1, 2, 4, 8, 16, 24, 36, 48, 60, 80 (Exp. 2), and 120 (Exp. 1) days after inoculation (DAI). Fecundity was evaluated by counting number of egg‐masses and total number of eggs per plant at 80 and 120 DAI. More J2 were found in Kenstar roots than in FLMR6 and RBC roots at 4, 8, 36, 60, 80, and 120 DAI. More third or fourth stage juveniles (J3/J4) were found Kenstar and FLMR6 roots than in RBC at 16, 24, 36, 48, 60, 80, and 120 DAI, and Kenstar J3/J4 numbers were higher than FLMR6 at 60 and 120 DAI. Fewer adults were found in FLMR6 roots than in Kenstar at 36, 48, 60, 80, and 120 DAI, but adult numbers in RBC roots were signiftcantly lower than in FLMR6 at these same dates. At 80 and 120 DAI, number of egg masses and total number of eggs were greater on Kenstar roots than on FLMR6a, nd total egg numbers on RBC were lower than on FLMR6. The resistance mechanisms in FLMR6 and RBC hindered normal M. javanica development because of a combination of slower maturation to later growth stages and fewer J3/J4 maturing to adults, which produced fewer J2 for secondary infection.

Cotton Resistance to Root‐Knot Nematode: II. Post‐Penetration Development

Root‐knot nematode (RKN), Meloidogyne incognita (Kofoid and White) Chitwood, damages cotton, Gossypium hirsutum L., roots, affecting water and nutrient uptake and predisposing the plants to other soilborne pathogens. Post‐penetration development of RKN was compared on three genotypes. Susceptible M‐8, moderately resistant M‐78, and highly resistant M‐315, were grown in a greenhouse in a Wickham sandy soil (a fine, loamy, mixed thermic, Typic Hapludult) and inoculated with second‐stage juveniles. RKN in each of 7 developmental stages were counted every 2 d for 44 d. At 18 DAI, 70, 45, and 6% of RKN present were adults in M‐8, M‐78, and M‐315, respectively. In addition to slower development of RKN in M‐315, resistance is expressed by significantly fewer developing third and fourth stage juveniles at 8 DAI and fewer developing to mature females at about 24 DAI. Most RKN that penetrated M‐315 failed to establish and/or maintain giant cells. However, a few females established giant cells. At 44 DAI, the numbers of egg‐laying females on M‐8, M‐78, and M‐315 were 299, 144, and 5, respectively. There were significantly fewer root galls on M‐315 than on M‐78 or M‐8 beginning 10 DAI, and significantly fewer on M‐78 than on M‐8 at 40 DAI. Galls were significantly smaller on M‐315 than on M‐78 or M‐8 beginning 8 DAI, and significantly smaller on M‐78 than on M‐8 beginning 18 DAI. Thus, the post‐penetration development of root‐knot nematode was slower, fewer developed to adult females, and root galls were fewer and smaller on the resistant genotypes than on the susceptible M‐8.

Description and Biology of Subanguina Chr Ysopogoni Sp. N. (Nematoda), a Parasite of Chrysopogon Ful Vus (Gramineae) in Haryana, India

Subanguina chrosopogoni sp. n. forming galls on inflorescence of Chrysopogon fulvus (Spreng.) Chiov. in Ambala district of India is described. The main distinguishing features of this new species are: Female: L = 1.653 ±0.166 mm; V = 92.2 ± 1.3; stylet = 7.5 ±0.3 μm; MB = 57.9 ± 4.7 μm; excretory pore = 106 ± 5.3 μm; ovary usually with one flexure, oocytes arranged in multiple rows, crustaformeria in form of four rows of 20-22 cells each; tail ending in a mucronate process. Male: L = 1.186 ± 0.109 mm; a = 41.8 ± 6.1; lateral lines 7-8; stylet = 8.97 ± 0.31 μm; MB = 55.3 ± 6.2 μm; spicule = 31.6 ± 1.4 μm; tail ending in a digitate process. Quiescent third-stage juvenile: L = 0.782 ± 0.0356 mm; MB = 53.2 ± 2.2 μm; tail length = 57.04 ± 3.36 μm, ending in a pointed terminus. Quiescent and infective being different stages of development. Studies on life cycle of this nematode reveal that quiescent third-stage juveniles can survive for more than nine months in a desiccator, refrigerator or at room temperature in air dried galls. They emerge instantly out of galls in water at 0-37°C and moult to fourth-stage juveniles in soil and penetrate growing points of Chrysopogon seedlings. The final moult occurs inside the floral galls. Sexes are separate and reproduction is by amphimixis. The first moult occurs inside the egg and second-stage juveniles moult to third-stage quiescent juveniles inside the gall. Only one generation is completed in a year. Incidence of galls in natural habitats was found to be 2%. Infested plants exhibit no symptoms during the vegetative phase.

Quantification of parasitism of the soil-borne nematode Criconemella xenoplax by the nematophagous fungus Hirsutella rhossiliensis

A “dilution plate assay” was developed to quantify parasitism of C. xenoplax by H. rhossiliensis. Aliquots of C. xenoplax in suspension (treated with 0.5% NaOCl after extraction from soil by wet sieving and centrifugation) were spread onto 1.5% water agar plates supplemented with 200 parts 10 −6 streptomycin sulfate. After 5 days at 22 ± 2°C, the numbers of C. xenoplax with or without sporulating H. rhossiliensis were determined using a dissecting microscope. The assay was used to measure the rate of decay (disappearance) of parasitized C. xenoplax in field samples incubated in the laboratory. Time required for 50% reduction in number of parasitized nematodes (averaged across all life stages) incubated at −33 kPa soil water potential and at 10,15 or 20°C was 61, 26 or 16 days, respectively. Rate of decay was much faster for parasitized second- and third-stage juveniles than for parasitized fourth-stage juveniles and adults. Rate of infection can be estimated if the number of parasitized nematodes and rate of decay of such nematodes are known.

Influence of Food and Temperature On the Development and Moulting of Goodeyus Ulmi (Nematoda: Rhabditida)

Cultures of Goodeyus ulmi were established on the bacterium Escherichia coli and the fungus, Botrytis cinerea. At 20°C the compete life cycle took 6 days and required c. 108 day° above a threshold for development of c. 1.3°C. Food supply affected the rates of development and of population increase. When fourth stage juveniles were allowed to feed on E. coli for different durations they began moulting after 29 hours but were still able to moult even if they had fed for only 23-24 hours.

Survival of Pterotylenchus Cecidogenus Following Storage in Galls of Desmodium Ovalifolium, Desiccation and Exposure To High Osmotic Pressure

Galls on Desmodium ovalifolium plants caused by Pterotylenchus cecidogenus were stored in either paper (low humidity) or sealed plastic (high humidity) bags at constant 10, 24, 30 or 35°C or at temperatures fluctuating between 18 and 22°C for 4 weeks. The total number of P. cecidogenus and of females subsequently extracted was reduced by increasing temperature, fluctuating temperature and high humidity. Isolated nematodes were very intolerant of desiccation. Motility of nematodes was diminished with increasing osmotic pressure and time of exposure when treated with solutions of 0, 0.1, 1.0 and 2.0 M NaCl for 6 or 24 hours. By using frequency distributions of body lengths it was shown that the fourth-stage juveniles were best able to survive desiccation and high temperature in plant galls and high osmotic pressure, followed by J3 with J2 and adult females having similar ability.

Ultrastructural changes during recovery from anabiosis in the plant parasitic nematode, Ditylenchus

Ultrastructural changes after desiccation and rehydration of the anabiotic fourth-stage juveniles of the plant parasitic nematode Ditylenchus dipsaci (Kuhn) Filipjev are described and quantified. Anabiotic juveniles retain their structural integrity, although the cuticle decreases in thickness and the muscle cell sarcoplasm condenses. In contrast the structure of the non-anabiotic nematode Panagrellus silusae is completely disorganized by desiccation. Following rehydration of D. dipsaci there is a lag phase of 2–3 hr before the nematodes become active. During this period the juveniles undergo an ordered series of morphological changes. The lipid droplets within the intestinal cells coalesce and the cuticle increases in thickness. The muscle cell sarcoplasm expands, the spacing of the thick myofilaments increases and the mitochondria swell before recovering a more normal appearance. These morphological changes, together with earlier metabolic studies, indicate that repair occurs during the lag phase prior to recovery. This may involve membrane repair and the re-establishment of the ionic gradients essential for normal muscle and nerve function.

A New Criconematid Nematode, Pseudocriconema japonicum n. gen. et n. sp. (Tylenchida : Criconematidae) from Japan

The designation Pseudocriconema n. gen. is proposed with a type species of P.japonicum n. sp. for the nematode from soil around roots of Pieris japonica, Hydrangea paniculata, and Lindera triloba in Mt. Aso, Kumamoto Prefecture. This genus resembles Seriespinula, but differs from it in the distinct submedian lobes, and tri-and/or rectangular shaped body scales. This is also similar to the Ogma, but distinguished from it by the larger first-head-annule and body scales with fringes on extremities. The type species, P.Japonicum is characterized by 400-504 μm body length, ten longitudinal rows of scales, 77-90 body annules, stylet 63.2-69.5 μm long, and vulva located at the 15th to 18th annule from the terminus. Male has three incisures in the lateral field, acute and 46.0-54.0 μm long spicules, and a small gubernaculum. Third-and fourth-stage juveniles have 10-12 longitudinal rows of round scakes with fine and sharp spines on their tip.

Comparisons of Invasion and Development of Globodera Spp. and European Potato Cyst-Nematode Pathotypes in Roots of Resistant Solanum Sg. Leptostemonum Spp

Populations of Globodera species from the Americas and potato cyst-nematodes G. pallida pathotype Pa2 and G. rostochiensis pathotype Rol from Europe were compared by their relative abilities to invade and develop in roots of eight wild Latin American Solanum sg. Leptostemonum spp. resistant to Globodera and in susceptible S. prinophyllum from Australia. All resistant plants were invaded by second stage juveniles. G. tabacum, a G. rostochiensis population from Bolivia, G. solanacearum and G. virginiae in that order had the greatest invasion rates and development into the third and fourth stages. G. rostochiensis Ro1 and G. pallida Pa2 invaded less numerously and few developed to the third stage. In all combinations fourth stage juveniles were mostly males. Only in Ro1 and Pa2 did males fail to reach adulthood in any plant species. S. quitoense and S. sisymbriifolium, which differentiate Globodera populations and appear to have specific resistance, were most heavily invaded, allowed greatest development of juveniles and produced most adult males. In strongly resistant S. torvum and S. viarum, which appear to have nonspecific resistance, and in S. hirtum juveniles invaded less numerously and rarely developed beyond the early third stage.