Natural Regulation of Innocuous Gypsy Moth 1 Populations 2
| Autor: | Ronald J. Sloan, Robert W. Campbell |
|---|---|
| Rok vydání: | 1977 |
| Předmět: | |
| Zdroj: | Environmental Entomology. 6:315-322 |
| ISSN: | 1938-2936 0046-225X |
| DOI: | 10.1093/ee/6.2.315 |
| Popis: | Preliminary studies on the determinants of numerical stability among a series of sparse gypsy moth, Lymantria dispar (L.), populations studied between 1965 and 1970 led to the hypothesis that year-to-year numerical stability among these populations was determined largely by a combination of predaceous birds, which tended to concentrate on instar IV–VI larvae, and small mammals, especially Peromyscus leucopus , which tended to concentrate on the pupae. Test results in 1971 both supported the above hypothesis and emphasized the importance of selective predation on the female pupae by mammals in maintaining these sparse populations at innocuous levels. These same results also indicated that vertebrate predators were consuming about one-half of the parasitized instar IV–VI larvae and most of the parasitized pupae in the sites studied. Thus, the percentage of the gypsy moth population that contains parasites may often be much higher than the percentage that is actually killed by these same parasites. These results suggest not only that the activities of vertebrate predators may have been critically important in maintaining these sparse gypsy moth populations at innocuous levels, but also that the role of parasites in the dynamics of such populations in North America may be considerably more constrained by the activities of these predators than has previously been reported. Conversely, parasites may play their most important role within outbreak foci, since these foci are characterized, in part, by sparse gypsy moth populations that exhibit exceptionally low rates of vertebrate predation. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|