Natural Causes and Rates of Early Larval Mortality in Gypsy Moths (Lepidoptera: Lymantriidae) Sampled from Field Populations in Different Density States
| العنوان: | Natural Causes and Rates of Early Larval Mortality in Gypsy Moths (Lepidoptera: Lymantriidae) Sampled from Field Populations in Different Density States |
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| المؤلفون: | Ellen H. Yerger, Marycarol Rossiter |
| المصدر: | Environmental Entomology. 25:1002-1011 |
| بيانات النشر: | Oxford University Press (OUP), 1996. |
| سنة النشر: | 1996 |
| مصطلحات موضوعية: | education.field_of_study, Ecology, Population, Zoology, Outbreak, Biology, Gypsy moth, medicine.disease, biology.organism_classification, Population density, Lepidoptera genitalia, Insect Science, Lymantria dispar, medicine, education, Ecology, Evolution, Behavior and Systematics, Epizootic, Entomophaga maimaiga |
| الوصف: | There was significant variation in early survival among gypsy moth, Lymantria dispar (L.), populations across the northeastern United States. The test individuals were collected as new eggs from field populations representing 5 regions, which differed in their history of gypsy moth establishment. Within each region, 2 populations were sampled: one in the building phase and the other in the outbreak phase of the gypsy moth population density cycle. We measured hatch success and incidence of early death (up to day 12 after feeding initiation) and identified the cause of death (viral, fungal, or poor quality). These data were used to test the following 2 hypotheses: (1) young larvae from high density populations experience greater mortality because of disease and poor quality than those from building populations, and (2) early stage survival is greater at the leading edge of gypsy moth range expansion than in populations from established regions. We found that mortality patterns differed in relation to density of the sampled population: populations in the outbreak stage were of poorer quality, showing lower hatch success and higher mortality among hatchlings. Mortality caused by a nucleopolyhedrosis virus was greatest among neonates from outbreak populations relative to neighboring building populations in all regions where there was no history of Entomophaga maimaiga (Humber) fungal infection. Despite the presence of E. maimaiga infection in field populations of several regions before the egg laying period, there was no evidence of infection by the fungus E. maimaiga in neonates hatched from any field collected egg masses. In neonates who were collected as eggs from populations with a history of E. maimaiga infection, the virus was curiously absent, despite its characteristic presence in building and outbreak populations and usual role in ending an outbreak. These results suggest that it is important to determine whether this fungus interferes with replication and transmission of the virus and inadvertently prevents the initiation or development of a viral epizootic. Finally, regions with the longest history of gypsy moth establishment had lower overall early survival. However, this relationship may be confounded by the presence of the new fungal microbe, E. maimaiga , in the 2 regions of oldest establishment. In these 2 regions, 48% of the egg masses had very poor hatch compared with 9% for the other 3 regions. But, if only post-hatch survival is considered, there was no relationship between early stage mortality and time after gypsy moth establishment in a region. |
| تدمد: | 1938-2936 0046-225X |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::a33cd16efb6cd3c5c226ad2a83b98ff9 https://doi.org/10.1093/ee/25.5.1002 |
| رقم الأكسشن: | edsair.doi...........a33cd16efb6cd3c5c226ad2a83b98ff9 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 19382936 0046225X |
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