Insect Life History Patterns

This volume results from a symposium entitled "Species and Ufe History Patterns: Geographic and Habitat Variation", held during the National Meeting of the Entomo­ logical Society of America in Denver, Colorado, USA in November, 1979. The stimu­ lus to assemble papers on this theme emerged from continuing discussions with col­ leagues concerning controversies in ecology and evolutionary biology, namely those associated with plant-herbivore interactions, life history theory, and the equilibrium status of communities. The study organisms used in this series of reports are all either herbivorous insects or those intimately associated with plants. In this volume we stress the variation found in life history traits and address some of the problems inherent in current life history theory. We include as life history traits not only traditional variables such as fecundity, size of young, and age to first and peak reproduction, but also diapause and migration, traits that synchronize reproduction with favorable plant resources. Because life history traits of phytophagous insects are influenced in part by spatial and temporal variation in the quality and availability of their host plants, we also consider the role that dis­ continuities in plant quality play in reducing insect fitness. Lastly, much of the tra­ ditional life history theory concerns itself with differences between the evolution of traits or constellations of traits when populations incur primarily density-independent, compared to density-dependent, mortality. Consequently, we address this issue and attempt to shed light on the equilibrium status of several phytophagous insect com­ munities.

Contenu

Introductory Chapter Considerations for the Development of a More General Life History Theory.- One Host Plant Variation and Insect Life Histories.- 1 Individual Trees as Heterogeneous Environment: Adaptation to Herbivory or Epigenetic Noise?.- 2 Responses of Black Pineleaf Scales to Host Plant Variability.- 3 Responses of Host Plants in the Speciation of Treehoppers: An Example from the Enchenopa binotata Complex.- Two Population and Species Variation in Life Histories.- 4 Geographic Variation and Behavioral Flexibility in Milkweed Bug life Histories.- 5 Latitudinal Variation in the life Histories of Insects Occupying Disturbed Habitats: A Case Study.- 6 Geographic Variation of the Diapause Response in the European Corn Borer.- 7 Natural Selection and life History Variation: Theory plus Lessons from a Mosquito.- 8 Alternative life History Patterns in Risky Environments: An Example from Lacebugs.- Three Life Histories and Nonequilibrium Populations.- 9 Organization of a Guild of Sap-feeding Insects: Equilibrium vs. Nonequilibrium Coexistence.- 10 The Possibility of Insect Communities without Competition: Hispine Beetles on Heliconia.- 11 What Makes a Good Island Colonist?.- 12 Biogeographic Patterns among Milkweed Insects.