Journal ArticleDOI
Comparative Population Dynamics of Two Goldenrod Aphids: Spatial Patterns and Temporal Constancy.
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Aphid dispersion was manipulated in the field to determine how the different spatial patterns of the two species influenced reproduction and mortality, and hence the relative tendencies of their populations to irrupt, and found that feeding in large colonies provided no reproductive advantage to either species.Abstract:
Two aphid species, Uroleucon nigrotuberculatum and U. caligatum, that feed on the goldenrod Solidago altissima, are similar in life histories and feeding habits, but differ markedly in their spatial distribution and temporal variability. In this study, U. caligatum typically occurred in small colonies scattered throughout goldenrod fields, and its numbers remained relatively constant through time, whereas U. nigrotuberculatum occurred in dense colonies and exhibited greater fluctuations in population size. The aggregated spatial pattern of U. nigrotuberculatum resulted from both active aggregation of alates and lack of dispersal by apterae and nymphs. Field experiments in which colony size was held constant revealed that U. nigrotuberculatum enjoyed no clear reproductive advantage that might explain its greater tendency to outbreak. In addition, U. nigrotubercultatum was more susceptible to generalist predators (such as cantharid beetles, mirid bugs, and mites) than U. Caligatum. Aphid dispersion was then manipulated in the field to determine how the different spatial patterns of the two species influenced reproduction and mortality, and hence the relative tendencies of their populations to irrupt. Feeding in large colonies provided no reproductive advantage to either species. Aggregation did, however, enhance aphid survivorship when generalist predators were the main mortality agents. The advantage was reversed later in the season when the aphids' fungal pathogen was present; aggregation then led to a decrease in survivorship. Thus, aggregation allowed a numerical escape from generalist predators but also promoted fungal epidemics, so that the temporal variability in U. nigrotuberculatum populations was largely a consequence of its spatial distribution.read more
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Aphid Ecology An optimization approach
TL;DR: The aim of this book is to provide a history of resource tracking in space and some of the techniques used have been described, as well as some new approaches, that have been proposed and tested in the laboratory.
Journal ArticleDOI
Allee effects driven by predation
TL;DR: A series of simple heuristic models were used to develop a theoretical framework for understanding predation-driven Allee effects as a function of predator functional and aggregative responses.
Journal ArticleDOI
Aggregation in Aphis Varians: An Effective Strategy for Reducing Predation Risk
Peter Turchin,Peter Kareiva +1 more
TL;DR: By quantifying the per capita population growth rates for aphid colonies of differing sizes, it is found that individual aphids benefited by being clumped together, but a predator—exclusion experiment indicated that clumping was beneficial to aphids only in the presence of predators.
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Modelling the dynamic spatio-temporal response of predators to transient prey patches in the field
TL;DR: Using Spatial Analysis by Distance Indices it is demonstrated that populations show ephemeral spatial pattern at the field scale, and a strong response by the beetle population to aphid patches is revealed.
Journal ArticleDOI
Patterns in Population Change and the Organization of the Insect Community Associated with Goldenrod
Richard B. Root,Naomi Cappuccino +1 more
TL;DR: In this paper, the authors report on the population dynamics and community-level features in a diverse, native fauna of phytophagous insects associated with goldenrod (Solidago altissima), a native perennial plant that forms a dominant, long-persisting element in old field succession.
References
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Practical Nonparametric Statistics
TL;DR: Probability Theory. Statistical Inference. Contingency Tables. Appendix Tables. Answers to Odd-Numbered Exercises and Answers to Answers to Answer Questions as discussed by the authors.
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On the Evidence Needed to Judge Ecological Stability or Persistence
Joseph H. Connell,Wayne P. Sousa +1 more
TL;DR: An analysis of census data from many long-term studies revealed a continuum of temporal variability in the dynamics of natural populations and communities, with no evidence of multiple stable states in unexploited natural populations or communities.
Journal ArticleDOI
Offensive-Defensive Interactions between Herbivores and Plants: Their Relevance in Herbivore Population Dynamics and Ecological Theory
TL;DR: It is suggested that interactions within and among species of herbivores are better understood in terms of interference and facilitation than in termsof competition.
Journal ArticleDOI
Fluctuations in Abundance of Tropical Insects
TL;DR: The data suggest that physical stability and predictability of the environment are important for determining the AV of the insects and that the wet but seasonal tropics are physically no more stable than the wet temperate zone.
Related Papers (5)
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