1 Hit in 0.044 sec


Akira TAKAI, Yosiaki ITO, Kazuyoshi MIYASHITA, Kazuo NAKAMURA
1963 Nihon Seitai Gakkaishi  
Orthoptera : Acrididae ) . Jap. J. EcoL l3,196 − 204 ( 1963 ) . Alocal outbreak of the grasshopper ハfecostethus magister occurred in 19610n a marshy grass 艮 and , 5 ha in area , Thi8 species completes its life ・ cycle 三 n / lfiscanthus sinen5is ・ community , excepting at the tirne of the outbreak when 皿 any individuals invaded into culti − vated land. The popuIation dynamics of this species from 1961 to 1963 was described briefly in the present paper . Number of adults emerged in this grassla 且
more » ... d in this grassla 且 d was ( 25-50 ) x104 i旦 1961,and 3 . 5 × 104 in 1962 , A key − factor for this decrease was suggested to be fioodi 且 g . As the grassland wa3 sub 皿 erged during ∫ uly of 1961, most of females died having no time to ovipo8it their egg ・ pods . About le to 20 per cent of eggs were killed by predat 至 on , while no egg ・ parasite has been discovered so far. Nymphal mortality was high from the first to third instar but reduced after the fourth in8tar, The uumber of egg ・ pods laid in 1962 was remarkably larger than tha 目 丑 1961, because of 旦 o 且ooding a ロ d low adult mortality . Soil pro 丘1e showed that this grassland was gradually drying up due to artificial drainage of surrounding basin , offering good conditions for the gras8hoPPe ビ s propagation . 緒 言
doi:10.18960/seitai.13.5_196 fatcat:vf2cqvhqhfc7ldsmezeb7wkqli