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A Simulation Model for Testing the Dynamics of a Grasshopper Population
Author(s) -
Gyllenberg Goran
Publication year - 1974
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1935155
Subject(s) - grasshopper , orthoptera , acrididae , population , biomass (ecology) , forage , ecology , biology , grassland , environmental science , demography , sociology
Energy flow of a Chorthippus parallelus (Zett.) (Orthoptera) population was studied for 6 yr (1966—71) on a meadow at Tvarminne, Finland. A difference—equation model, based on biomass and energy, was constructed. The transfer coefficients were functions mainly of two environmental factors, temperature and rainfall. The model, constructed from 1969 data, was tested with values from 1967, 1970, and 1971. Heavy infection with the fungus Entomophthora grylli in 1967 and drought in 1971 resulted in poor fit to the model. The drought caused a sparse food supply and forced the grasshoppers to forage extensively for food. An activity box was therefore introduced to the model, converting animal behavior quantitatively into energy.