Journal ArticleDOI
The effect of spruce cone insects on seed production in Switzerland
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TLDR
It is indicated that site and tree conditions contributed more to the variability of seed yield than insect presence in a cone, and the model predicted significant effects of insect attack mainly for cones with total seed numbers that were higher than the average.Abstract:
In 1989 and 1990, spruce cones were harvested at 29 sites distributed over the five main geographic regions of Switzerland, i.e. Jura, Central Plateau, North, Central and South Alps. The presence of insects and the species-spe- cific consumption of seeds was determined for each cone by examination of the median longitudinal section. Seven seed-feeding species (Assara terebrella, Cydia strobilella, Dioryctria abietella, Eupithecia abietaria, Megastigmus strobi- lobius, Plemeliella abietina, Strobilomyia anthracina) and the spruce cone gall midge Kaltenbachiola strobi were found in the samples. The proportions of infested cones ranged from 36 to 100%. The regions did not show significant dif- ferences in terms of infestation rates, whereas differences between sites within the regions were highly significant. Seed loss ranged from 2 to 100%, its geographical distribution exhibiting a similar pattern to the infestation rates. Considering the number of infested cones, C. strobilella was the most abundant species, followed by K. strobi and P. abietina. Cones infested by conospermatophagous species (C. strobilella, D. abietella, E. abietaria) showed higher seed losses than those infested by spermatophages (M. strobilobius, P. abietina). Due to the ubiquitous occurrence of C. strobilella, its high infestation rates and the resulting seed losses caused by its offspring, this species has to be con- sidered as the most important insect seed predator in Switzerland. A multiple linear regression analysis was carried out for each region to simultaneously explore the impact of site and tree variables as well as the effect of insect attack on the yield of viable seeds. The results indicate that site and tree conditions contributed more to the variability of seed yield than insect presence in a cone. The model predicted significant effects of insect attack mainly for cones with total seed numbers that were higher than the average.read more
Citations
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Journal ArticleDOI
Ecological and evolutionary consequences of spatial and temporal variation in pre-dispersal seed predation
TL;DR: It is known that seed predators can have important, and often variable, effects on plant population dynamics and trait evolution, however, it still remains to assess how important they are across study systems and relative to other aspects of the plant's biotic and abiotic environment.
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Changes in biotic interactions and climate determine recruitment of Jeffrey pine along an elevation gradient
TL;DR: This article examined how climate influences Jeffrey pine (Pinus jeffreyi ) recruitment, mortality, and species interactions at three elevation zones (low, mid, high) across its elevation range (1550-2470m) in the semi-arid Carson Range of western Nevada.
Journal ArticleDOI
Intra-specific density dependence is required to maintain species diversity in spatio-temporal forest simulations with reproduction
Heike Lischke,Thomas J. Löffler +1 more
TL;DR: A submodel of the spatio-temporal forest model TreeMig for simulating seed production, seed dispersal, seed bank dynamics and sapling development is presented and interactions of different factors that can influence species diversity in a forest are examined.
Journal ArticleDOI
Invertebrate predation of postdispersal seeds and juvenile seedlings of black spruce (Picea mariana) in the boreal forest of eastern Canada
TL;DR: An extensive vertebrate exclosure experiment was used to evaluate black spruce postdispersal seed and seedling predation by invertebrates in three boreal habitats of Eastern Canada: recent burn, sprucemoss, and lichen woodland.
Journal ArticleDOI
Biology and management of North American cone-feeding Dioryctria species
TL;DR: The development of integrated pest management programs targeting Dioryctria species will benefit from a conceptual framework on which to base future research, and it is recommended that factors that mediate population distribution at landscape, local, and temporal scales are identified.
References
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Book
Multiple Regression: Testing and Interpreting Interactions
Leona S. Aiken,Stephen G. West +1 more
TL;DR: In this article, the effects of predictor scaling on the coefficients of regression equations are investigated. But, they focus mainly on the effect of predictors scaling on coefficients of regressions.
Journal ArticleDOI
Multiple Regression: Testing and Interpreting Interactions
TL;DR: In this article, multiple regression is used to test and interpret multiple regression interactions in the context of multiple-agent networks. But it is not suitable for single-agent systems, as discussed in this paper.
Journal ArticleDOI
Insect Fauna of Coniferous Seed Cones: Diversity, Host Plant Interactions, and Management
TL;DR: Insects are considered the most important seed predators during the predispersal phase of seed development, and this review deals exclusively with those exploiting seed cones prior to seed dispersal.
Journal ArticleDOI
The entomofauna of the cones of spruce, Picea abies (L.) Karst. in Poland
TL;DR: In the years 1978–1981 a number of 46 species (a total of 4,593 individuals) of insects were obtained from cones of spruce, Picea abies (L.) Karst, Poland.
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