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Population dynamics of Malacosoma neustria testacea (Lepidoptera: Lasiocampidae): Stabilizing process in a field population

1977; Wiley; Volume: 18; Issue: 2 Linguagem: Inglês

10.1007/bf02510854

1438-390X

Masakazu Shiga,

Plant and animal studies

Summary Stabilizing mechanism in population of Malacosoma neustria testacea was investigated in a central part of Japan based on eight year survey. Population fluctuation in each developmental stage in the experimental field was rather small, i.e., 5.9 times in egg and 85.0 times in female adult. Pupal weight negatively correlated with the densities of 5th instar larvae and prepupae (cocoons) and correlation coefficient was highly significant in females. Population density was stabilized by density‐dependent dispersal of female moths in preovipositional period. Comparison between fecundity of emerged moths and that of actually oviposited ones in the experimental field suggested that density‐dependent dispersal took place as the result of density‐dependent size variation, i.e., small‐sized female months have higher flying ability. This hypothesis was supported by the experiment in which flying ability of newly emerged female moth was measured. Similar stabilizing mechanism is expected to occur in semelparous or pro‐ovigenic insects.