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To be suspended or to be cut off? Differences in the performance of two types of leaf‐rolls constructed by the attelabid beetle Cycnotrachelus roelofsi
Author(s) -
Kobayashi Chisato,
Kato Makoto
Publication year - 2004
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/s10144-004-0179-7
Subject(s) - biology , parasitism , botany , ecology , horticulture , zoology , host (biology)
The attelabid beetle Cycnotrachelus roelofsi constructs two types of leaf‐rolls (cradles): one is suspended from leaves (suspended type), and the other is severed from the leaves (cut‐off type). To evaluate differences in performance between these two cradle types, we monitored densities, survival rates, and mortality factors throughout the active season, from April to June. The proportions of the two cradle types changed over time; the suspended type was dominant early in the season but was gradually replaced by the cut‐off type. Irrespective of differences in mortality factors between the two cradle types, the survival rate was always higher in the cut‐off type than in the suspended type. Beetle mortality tended to be highest at the egg stage, and the predominant cause of mortality was parasitism by two minute trichogrammatid wasp species, Poropoea morimotoi and P . sp.1. Parasitism by P. morimotoi was significantly higher in cut‐off cradles than in suspended cradles, when cut‐off cradles were abundant, whereas parasitism by P . sp.1 tended to be higher in suspended cradles when suspended cradles were abundant. These results suggest opposed frequency‐dependent attacks by P. morimotoi and P . sp.1. We discuss how these egg parasitoids maintain coexistence of these two cradle types.