Machinery of Environmental Response Mechanisms in Insects

Abstract

Any attempt to discuss the high abundance and ecological success patterns of insect species in tropical environments must, in my view, take into account two major sorts of driving forces that have contributed to the elaboration of insects as a group and to the elaboration of the multiplicity of life styles represented within the group. I define life style in this context as the population parameters and habitat associations of particular genera and species within families of insects. Population parameters include age-specific fecundity and mortality schedules, developmental rate, and patterns of dispersion. The habitat is that portion of the overall environment of a region that supports breeding populations of particular species. The habitat may also include a large spectrum of “transient” species that do not breed there. I assume that insect species settle into those habitats that permit them to maintain levels of population abundance that usually prevent extinctions. Much of this book is devoted to discussions of various aspects of such patterns. In the present chapter, however, we examine some of the major properties of the generalized insect phenotype that have preadapted insects in general to the patterns and structure of environments. Thus an understanding of insectan success in terms of adapting to various kinds of environments warrants an appreciation for the vast evolutionary history of the group as well as contemporaneous ecological factors affecting phenotypic diversification at generic and species levels.