A new entomopathogenic nematode (EPN), described here as Steinernema beddingi n. sp., was recovered from a single soil sample collected from a cabbage field in the suburb of Kunming, Yunnan province, China, during an EPN survey in 2002. DNA sequences of both the D3 domain of 28S and the ITS regions of rDNA showed congruently that S. beddingi n. sp. clustered with S. affine and S. intermedium but was clearly distinguished from both. The new species can be separated from all other described species of Steinernema, including the two most closely related species mentioned above, by morphological characters of various stages of the nematode, including lateral field pattern and tail shape of infective juvenile, the spicule and gubernaculum shape of the first generation male, and the tail morphology of the first generation female. Steinernema beddingi n. sp. can also be separated from S. affine and S. intermedium by cross-breeding tests.
Grassland restoration, which utilizes agricultural practices (e.g., ploughing, harrowing, and fertilization), can not only change ecosystem processes to support the survival of native plants but can also affect soil microbial biomass and activity. In an artificial grassland established to restore a degraded meadow, parameters including coverage, species richness, diversity, and biomass (including above- and below-ground biomass) generally increased after four years of restoration. Likewise, soil organic matter (SOM), total nitrogen (N), available N, total phosphorus (P), and available P exhibited the same trend. The activities of selected enzymes decreased with soil depth (P < 0.05) and increased during the successional process associated with restoration. Soil enzyme activities were related to the physico-chemical characteristics of the soil and plant primary production. After four years of restoration, the plants and soils were resilient to the grassland restoration process. The results of the present study suggest a significant positive impact of artificial grassland establishment on soil quality. Artificial grassland establishment was an effective measure for restoring heavily degraded alpine meadows in the Qinghai–Tibetan Plateau region. The rapid establishment of vegetative cover and plant functional group composition after artificial grassland construction are fundamental for limiting soil erosion and restoring the initial ecosystem function. As soil is a fundamental component of every terrestrial ecosystem, soil restoration is a vital process during ecological restoration. Thus, an increase in the nutrient status of the soil is important for the sustainable development of alpine meadows. The long-term accumulation of SOM, the retention of nutrients, and the buildup of microbial biomass are ultimately attributed to labile carbon input from plant primary production.
The pine wood nematode (PWN), Bursaphelenchus xylophilus, is able to produce hundreds of thousands of offspring in a short time. Its mating behaviour might play a basic role in this marked fecundity. We investigated the features of the mating behaviour of B. xylophilus using long-time microscope video and repeated observations. The mating behaviour of B. xylophilus could be separated into a series of sequential sub-behaviours, including cruising, approaching, encountering, touching, hooping, locating, attaching, ejaculating, separating, quiescence and roaming. Overall, the process of mating behaviour could be divided into four different phases, searching, contacting, copulating and lingering; the mean times for these different phases varied significantly with 21.8 ± 2.0 min, 28.0 ± 1.9 min, 23.6 ± 0.7 min and 7.2 ± 0.5 min for each of the four phases, respectively. Attraction between the sexes was observed, indicating that sex pheromone(s) might be involved in mating behaviour of B. xylophilus. In addition, when one female was placed with three males, male-male competition was observed, which might be caused by mating-choice pressure from the female. Intra-sexual competition of females was also occasionally observed.