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Humid microenvironment prerequisite for the survival and growth of nymphs of the rice brown planthopper, Nilaparvata lugens (Stål) (Homoptera: Delphacidae)
Author(s) -
Isichaikul Somchai,
Fujimura Koichi,
Ichikawa Toshihide
Publication year - 1994
Publication title -
population ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 59
eISSN - 1438-390X
pISSN - 1438-3896
DOI - 10.1007/bf02515081
Subject(s) - delphacidae , nymph , homoptera , cage , brown planthopper , biology , relative humidity , zoology , moulting , instar , population , rice plant , horticulture , botany , pest analysis , larva , biochemistry , mathematics , physics , demography , combinatorics , sociology , gene , thermodynamics
Nymphs of Nilaparvata lugens were experimentally reared from the 2nd instar in a cage covering part of the leaf sheath of an individual rice plant grown in a Wagner pot. Plants were covered with the cage from the water surface of the pot to 10 cm above the surface (lower cage‐group) or from 10 cm to 20 cm above the surface (upper cage‐group). Temperatures measured at three different parts of the cage remained fairly constant in both groups at around 25°C (23.7–25.2°C in mean value). In the lower cage‐group, relative humidities measured at the three heights in the cage in (76.3–90.5% in mean value) markedly increased with the approach to the water surface. The nymphs of this group, particularly during the molting period, aggregated close to the surface. Eighty‐two percent of the released nymphs emerged in this group. Relative humidities measured at three heights of the upper cage‐group were 69.5–72.7% in mean value, and all the nymphs in this group died within 3 days after their release although half of them stayed on the rice plants within 6 h after their release. The role of relative humidity as a limiting factor on the range of the microhabitat and the population density of N. lugens in rice fields was discussed on the basis of the results.