Chapter 3 Field Biologists and the Collection of Data {#field}}

One definition of a stochastic process is the description of how data are gathered. We briefly describe the monumental effort of Yu and Luck (1988) to collect and analyze data on the structure and dynamics of California red scale (Aonidiella aurantii (Maskell) Homoptera: Diaspididae), its related parasites-Aphytis, Comperiella, Encarsia-and associated predators. Data collected reflect their understanding at that time, and the type of data change over the three-year period as their understanding evolved. Data focused on individuals found at sampling are by necessity sparse, representing limited snapshots of a dynamic biological system.

The study of populations involves knowledge of how abundance and distribution of individuals change over time. We can count individuals by state as a continuous function of time using quantitative population ethology. This gives life-table and interaction data that does not require synchronous generations. We illustrate this with an on-going study of a host-parasite system involving the California red scale and Aphytis species.