The Role of Birds in a Spruce Budworm Outbreak in Maine

Dowden, Philip B.; Jaynes, H. A.; Carolin, V. M.

doi:10.1093/jee/46.2.307

Cited by 28 publications

(8 citation statements)

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“…Their stomach contents were mostly fully mature larvae and pupae but rarely younger‐instar larvae (Mitchell , Dowden et al. , Mook ). It was also reported, albeit unrelated to spruce budworm, that tortricoid pupae in particular were extremely vulnerable to bird predation (Royama ).…”

Section: Part Ii: Evaluation and Analysis Of Mortality Factors In Posmentioning

confidence: 99%

“…During the previous outbreaks, many warblers of the family Parulidae were reported to be major vertebrate predators. Their stomach contents were mostly fully mature larvae and pupae but rarely younger-instar larvae (Mitchell 1952, Dowden et al 1953, Mook 1963. It was also reported, albeit unrelated to spruce budworm, that tortricoid pupae in particular were extremely vulnerable to bird predation (Royama 1970).…”

Section: Probable Sources Of Predationmentioning

confidence: 99%

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Mechanisms underlying spruce budworm outbreak processes as elucidated by a 14‐year study in New Brunswick, Canada

Royama

Eveleigh

Morin

et al. 2017

Ecological Monographs

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We conducted a 14‐yr intensive study of spruce budworm (Choristoneura fumiferana (Clem.)) survivorship at three study plots in largely balsam fir (Abies balsamea (L.) Mill.) stands in New Brunswick, Canada, to elucidate certain key mechanisms underlying spruce budworm outbreak cycles. The study covered a peak‐to‐declining phase (from 1981 and 1994) of the budworm outbreak cycle that had started in the early 1960s. Frequent sampling was carried out in each plot‐year to construct a practically continuous survivorship curve, and the annual variation in population density was estimated. We found a high level of correlation between the studied phase of the outbreak cycle and annual variations in the survivorship over the postdiapause period, suggesting that postdiapause survivorship was the chief determinant of the cycle. We found the annual changes in population density in the present study to be closely similar in pattern to those from the provincial budworm surveys conducted in much larger areas. This implies that the mechanism underlying the population process found in the few study plots in largely balsam fir stands also applies to the process in much larger areas of diverse stand types. The main source of postdiapause mortality is found to be natural enemies. The impacts of parasitoids and disease are evaluated by rearing budworm samples in the laboratory. Hymenopteran and dipteran parasitoids are by far the major sources of mortality, and microsporidians are the most prevalent pathogen. Occurrences of other entomopathogenic fungi and viruses were insignificant throughout the study. Seasonal changes in laboratory survivorship are compared with the corresponding field survivorship to estimate the effect of predation. No major mortality factor is found to singly play a predominant role in determining the outbreak cycle. Conversely, some minor factors are shown to have played significant roles. Thus, the importance of recognizing the action of natural enemies as a complex is emphasized for understanding the budworm outbreak cycle. Finally, centered on the roles played by the chronological succession of natural enemies in the present study, the results of budworm research in New Brunswick since the mid‐1940s are synthesized to outline basic mechanisms underlying the outbreak processes as a guide for further studies.

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Section: Part Ii: Evaluation and Analysis Of Mortality Factors In Posmentioning

confidence: 99%

Section: Probable Sources Of Predationmentioning

confidence: 99%

Mechanisms underlying spruce budworm outbreak processes as elucidated by a 14‐year study in New Brunswick, Canada

Royama

Eveleigh

Morin

et al. 2017

Ecological Monographs

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“…Forty percent of a potential 15,000 gives 6,000 budworms per acre as a closer estimate of actual consumption per breeding pair, or very roughly 20,000 per acre for all the bird species that feed largely on foliage insects. Dowden et at. ( 1953) estimated actual consumption at about 36,000 per acre in northern Maine.…”

Section: Discussionmentioning

confidence: 99%

The Numerical Response of Avian and Mammalian Predators during a Gradation of the Spruce Budworm

Morris¹,

Cheshire²,

Miller³

et al. 1958

Ecology

115

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“…Since we are using a continuous time model, we set erg = 5, and conclude that r, = 1.6/year. p The value of j3 has been estimated in the literature using the most general information on size of birds, their maximum daily consumption, the proportion of budworm in their diet, and their ranges of densities (Kendeigh 1947;George & Mitchell 1948;Mitchell 1952;Dowden, Jaynes & Carolin 1953;Morris et al 1958). These estimates of the maximum consumption range from 20 000 to 36 000 larvae per acre per year.…”

Section: Te2 +E 'mentioning

confidence: 99%

Qualitative Analysis of Insect Outbreak Systems: The Spruce Budworm and Forest

Ludwig¹,

Jones²,

Holling³

1978

The Journal of Animal Ecology

873

510

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(1) A procedure has been described for the qualitative analysis of insect outbreak systems using spruce budworm and balsam fir as an example. This consists of separating the state variables into fast and slow categories. (2) The dynamics of the fast variables are analysed first, holding the slow variables fixed. Then the dynamics of the slow variables are analysed, with the fast variables held at corresponding equilibrium values. If there are several such equilibria, there are several possibilities for the slow dynamics. (3) In the case of the budworm, this analysis exhibits the possibility of 'relaxation oscillations' which are familiar from theory of the Van der Pol oscillator. In more modern terminology, the jumps of the system are governed by a cusp catastrophe. (4) Such an analysis can be made on the basis of qualitative information only, but additional insight emerges when parameter ranges are defined by the kind of information typically available from an experienced biologist. (5) At the least this can be a guide to assess subsequent priorities for both research and policy. * In an effort to make the bibliography as current as possible, we have cited many works available at present only as publications of the International Institute for Applied Systems Analysis (IIASA)

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The Role of Birds in a Spruce Budworm Outbreak in Maine

Cited by 28 publications

References 0 publications

Mechanisms underlying spruce budworm outbreak processes as elucidated by a 14‐year study in New Brunswick, Canada

Mechanisms underlying spruce budworm outbreak processes as elucidated by a 14‐year study in New Brunswick, Canada

The Numerical Response of Avian and Mammalian Predators during a Gradation of the Spruce Budworm

Qualitative Analysis of Insect Outbreak Systems: The Spruce Budworm and Forest

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