DIFFERENCES IN OVARIAN DEVELOPMENT BETWEEN AUSTRACRIS PROXIMA (WALKER) AND A. GUTTULOSA (WALKER) (ORTHOPTERA: ACRIDIDAE)

Abstract

Ovarian development is observed throughout the year in Austracris proxima in the field whereas in A. guttulosa it is restricted to mid‐summer and for the remainder of the year females of this species remain immature. In the laboratory variations in day length did not affect the ovarian development of A. proxima but long day treatments were necessary to induce the ovaries of A. guttulosa to develop. The former species is largely confined to temperate, coastal areas where, as a result of the evenly distributed relatively abundant rainfall, conditions are favourable for breeding throughout the year when two generations may occur. The latter species is commonest in the tropical inland where breeding is restricted to the short rainy season and only one generation occurs annually.