Introduction to the Study of Animal Populations -- The Sampling Programme and the Measurement and Description of Dispersion -- Absolute Population Estimates using Marking Techniques -- Absolute Population Estimates by Sampling a Unit of Habitat -- Air, Plants, Plant Products and Vertebrate Hosts -- Absolute Population Estimates by Sampling a Unit of Habitat -- Soil and Litter -- Absolute Population Estimates by Sampling a Unit of Habitat -- Freshwater Habitats -- Relative Methods of Population Measurement and the Derivation of Absolute Estimates -- Estimates based on Products and Effects of Insects -- Observational and Experimental Methods for the Estimation of Natality, Mortality and Dispersal -- The Construction, Description and Analysis of Age-specific Life-tables -- Age-grouping of Insects, Time-specific Life-tables and Predictive Population Models -- Systems Analysis and Modelling in Ecology -- Diversity, Species Packing and Habitat Description -- The Estimation of Productivity and the Construction of Energy Budgets

The virtual impossibility of extracting the many different species from a habitat with equal efficiency by a single method (e.g. Nef, 1960). 1.1 Population estimates Population estimates can be classified into a number of different types; the most convenient classification is that adopted by Morris (1955), although he used the terms somewhat differently in a later paper (1960). 1.1.1 Absolute and related estimates The animal numbers may be expressed as a density per unit area of the ground of the habitat. Such estimates are given by nearest neighbour and related techniques (Chapter 2), marking and recapture (Chapter 3), by sampling a known fraction of the habitat (Chapter 4-6) and by removal sampling and random walk techniques (Chapter 7). Absolute population The number of animals per unit area (e.g. hectare, acre). It is almost impossible to construct a budget or to study mortality factors without the conversion of population estimates to absolute figures, for not only do insects often move from the plant to the soil at different developmental stages, but the amount of plant material is itself always changing. The importance of obtaining absolute estimates cannot be overemphasized