Cricket Life Cycles

Abstract

The life cycles of crickets can be divided into two basic categories, one with seasonality and the other without it (Alexander, 1968). Since adult crickets live a relatively long time and continue to lay eggs, this distinction may become vague in warm climates. Even in such cases, however, the two categories can be recognized when the underlying developmental characteristics are experimentally analyzed. A life cycle that shows a more or less fixed phase relationship with the seasonal cycle of environment usually involves physiological responses that buffer the life cycle from perturbing fluctuations in external conditions. Such responses form a coordinated system of seasonal homeostasis, in which diapause and photoperiodism are principal components. When development is controlled by this system, its rate is not always a simple function of temperature. The thermal coefficient Q10 is often shifted from an ordinary value of 2--3 to a lower or even a negative one by intervention of diapause or other photoperiodic responses. The life cycle thus includes thermally heterogeneous phases. This situation may be described by the classical though not widely used word heterodynamic (Roubaud, 1922). When there is no such switching of developmental phases, the cricket responds to heat summation in more or less similar ways throughout the entire life cycle, so that its development is homodynamic These words are used here because of their convenience and adequacy.