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Dispersion analyses and resource utilization of aphid parasitoids in a non‐depletable environment
Author(s) -
Trumble John T.,
Oatman Earl R.
Publication year - 1984
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/bf02515512
Subject(s) - biology , aphid , parasitoid , ecology , host (biology) , index of dispersion , population , crowding , dispersion (optics) , population density , agronomy , demography , neuroscience , poisson regression , physics , optics , sociology
Summary Dispersions and resource utilization of primary and secondary parasitoids developing in non‐depletable primary host populations were determined for an aphid‐parasitoid community occurring on strawberries. Analyses of dispersions based on Green 's coefficient and Lloyd 's Patchiness Index indicated parasitized aphids were highly aggregated initially, became less aggregated as density increased, and remained aggregated following collapse of the aphid populations. The “index of aggregation” values calculated using Taylor 's Power Law concurred with results from the other indices, and the similarity of the regression coefficients from both seasons suggests that the index of aggregation may be characteristic for communities as well as species. Analysis with Iwao 's regression of mean crowding on the mean generated similar results when population data were stratified temporally, and also indicated that the individual was the basic unit of the population. In a non‐depletable environment, oviposition of individuals exhibiting an aggregated dispersion pattern within clumps of hosts provides primary parasitoids with a suitable trade‐off between energy utilization or genetic potential, and losses associated with hyperparasitism.