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Density‐dependent regulation in populations of potato‐colonizing aphids
Author(s) -
Alyokhin Andrei,
Drummond Francis A.,
Sewell Gary
Publication year - 2005
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/s10144-005-0232-1
Subject(s) - myzus persicae , biology , macrosiphum euphorbiae , aphid , density dependence , population density , aphididae , population , botany , ecology , homoptera , pest analysis , demography , sociology
Scarcity of long‐term (over 30 years) data series represents a major challenge for an accurate estimation of the role of density‐dependent processes in population regulation. We analyzed population densities of the wingless parthenogenic morphs of buckthorn aphid (BA), Aphis nasturtii Kaltenbach, potato aphid (PA), Macrosiphum euphorbiae (Thomas), and green peach aphid (GPA), Myzus persicae (Sulzer) from 1949 to 2003 for signs of density‐dependent regulation. We found strong evidence of density‐dependent regulation, with detection of density dependence being fairly consistent among the different statistical techniques. Direct density dependence was detected for the populations of all three species. There was also evidence of delayed density dependence for PA. The periodicity of population fluctuations for BA and GPA was 6.1 years and 3.9 years, respectively. The periodicity for PA was not explicit, being highly variable throughout the time series. Effects of density‐independent weather factors were relatively minor compared to density‐dependent regulation. The BA populations experienced a significant reduction in both density and annual oscillations starting in 1995, while GPA populations experienced a similar reduction in 1991. No such change was apparent for PA. The most likely explanation for the observed phenomenon is a change in the composition of the lady beetle community following the establishment of two alien coccinellid species, and/or changes in insecticide use by commercial growers in the area of the study.