Seasonal Reproduction: Patterns and Control

Abstract

The great diversity of reproductive tactics among and within vertebrate species is a testament to the many levels of biological organization at which selection acts to shape the reproductive process. In this chapter, we define seasonal reproduction as the occurrence of breeding in an individual at a specific time of year. Populations exhibit seasonal reproduction insofar as the individuals of the population breed synchronously. Seasonal reproductive cycles are not necessarily synonymous with annual reproductive cycles; for example, an individual that breeds in the spring every two or three years has a seasonal cycle, but not an annual one. Aseasonal (or nonseasonal) reproduction includes reproductive patterns in which individuals breed continuously or year around. Aseasonal reproduction may also include reproductive patterns in which individuals of species breed in response to specific yet erratic environmental cues; for example, species living in the deserts of mid-western Australia may breed only when occasional and unpredictable rains inundate an area.