THE ROLE OF JUVENILE-HORMONE AND JUVENILE-HORMONE ESTERASE IN WING MORPH DETERMINATION IN MODICOGRYLLUS-CONFIRMATUS

The role of juvenile hormone (JH) and juvenile hormone esterase (JHE) in regulating wing morph determination was studied in the cricket Modi cogryllus confirmatus. JHE activities were significantly higher in nas cent long-winged (LW) vs short-winged (SW) crickets during the latter half but not during the first half of the last stadium. The magnitude and direction of the activity differences were similar to those previo usly documented between wing morphs of the cricket, Gryllus rubens, In contrast, activities of general esterase, an enzyme or group of enzym es with no demonstrated role in regulating the JH titer in insects, sh owed no or only minor differences between morphs, The magnitude and di rection of the JHE activity variation is consistent with a regulatory role for this enzyme in some aspect of wing dimorphism, However, the t iming of the differences (exclusively during the last half of the last stadium) argue against a role in regulating wing length development p er se, Single or multiple applications of juvenile hormone-III to nasc ent LW individuals during the first few days of the last stadium signi ficantly redirected development from long to short wings, Multiple app lications of acetone, by itself, also increased the production of shor t-winged adults, For most treatments, all individuals with shortened w ings also had undeveloped flight muscles, These data suggest that JH m ay play a role in wing morph determination in M. confirmatus but that it affects a different aspect of the polymorphism from JHE. Copyright (C) 1996 Elsevier Science Ltd