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.