[Biological characteristics and spatial distribution of Chorthippus dubius population on high mountain grassland]

Based on rearing observations and surveys in Ganjia High-Mountain Grassland, Xiahe County, Gansu Province, the occurrence period, ingestion capacity, spatial pattern, and dynamics of Chorthippus dubius were studied. The results showed that this grasshopper had only one generation in a year. Its eggs wintered in the soil, and in the next year, they began to hatch from the last ten days of May to the first ten days of June. The hatching peak took place from the middle ten days to the last ten days of June. The majority of the nymphs possessed 4 instars, and about 23% of them possessed 5 instars. The developmental duration of the nymphs underwent about 70 days, and the longevity of the adults lasted for 42 days. The ingestion capacity of the nymphs was 368. 3 mg, and that of the adults was 743.8 mg. The spatial pattern of 1-2 instars belonged to an aggregated distribution, and that of 3-5 instars belonged to even and random distribution.