Department of Zoology, University of Calicut-673 635, Kerala (India).
Neck-ligated and thorax-ligated post feeding (day 4) last instar larvae of Spodoptera mauritia Boisd. were injected with 4 μg ecdysterone or topically treated with 1 pg of a juvenile hormone analogue (JHA) hydroprene. The effects of these treatments on the fusion of testes lobes were studied. Ligated larvae kept as controls and thorax-ligated larvae treated with 1μg JHA survived for 12 ± 1 days without showing any sign of pupal development. The testes of these larvae were seen unfused. On the other hand, neck-ligated larvae treated with 1 μg JHA and neck-/thorax-ligated larvae injected with 4 pg ecdysterone exhibited pupal cuticle secretion and fusion of testes lobes. These findings suggest that ecdysteroids are involved in the fusion of testes lobes occurring during larval-pupal metamorphosis of S. mauritia.
