Photoperiodic control of protogyny in the lawn ground cricket, Polionemobius mikado (Orthoptera: Trigonidiidae)

Abstract

Sexual dimorphism in timing of adult emergence is common in insects. In most insects, males emerge before female (protandry), however, some insects show earlier female emergence (protogyny). Here, I report the effects of photoperiod on protogyny in the lawn ground cricket (Polionemobius mikado). Upon exposure to different photoperiods at 26 C, P. mikado females were found to emerge earlier than the males in the short-day photoperiod. However, no difference in the nymphal development duration was observed between the sexes in the long-day photoperiod. Protogynous development is expected to be more pronounced in the crickets that eclosed later in the year than those that eclosed earlier; therefore, its adaptive significance is closely associated with environmental seasonality that is encountered by the eclosed females.