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Demographic attributes of an introduced herbivorous lady beetle
Author(s) -
Ohgushi Takayuki,
Sawada Hiroichi
Publication year - 1995
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/bf02515758
Subject(s) - biology , overwintering , fecundity , coccinellidae , hibernation (computing) , intraspecific competition , population , instar , larva , herbivore , ecology , mortality rate , longevity , competition (biology) , population growth , population density , reproduction , demography , zoology , predation , predator , sociology , computer science , state (computer science) , genetics , algorithm
Demographic attributes of the adults of an introduced herbivorous lady beetle Epilachna niponica (Coleoptera: Coccinellidae) were investigated from 1975 to 1981 in the Botanical Garden of Kyoto University. Population growth rate varied from 4.8 to 16.8 throughout the study period. Fecundity and mortality in the late larval period contributed most to annual changes in the population growth rate. Population growth rate was negatively correlated with the density of overwintering adults. Adult survival from emergence to the reproductive season, which varied from 0.03 to 0.36 throughout the study, was almost completely determined by survival during the pre‐hibernation period. Adult survival to the preproductive season changed in a size‐ and sex‐dependent manner. Larger adults survived better than smaller individuals; male‐biased mortality occurred from adult emergence to the reproductive age. Severe intraspecific competition among late instar larvae due to host plant defoliation produced a higher proportion of small‐sized adults, resulting in lower adult survival to hibernation. The introduced population had a higher population growth rate and a lower adult survival to the reproductive season than the source population.