Effect of Light on the Development of the Angoumois Grain Moth, Sitotroga Cerealella Olivier (Lepidoptera: Gelechiidae)

Abstract

The effect of light on the development of the angoumois grain moth, Sitotroga cerealella, was studied. Three different light conditions, i.e. continuous light (LL), continuous darkness (DD) and antural illumination (LD), were used. Eggs bred under LL system showed the shortest mean incubation period, 3.27 and 4.66 days after one and four generations, respectively. The light had no effect on egg hatchability. The number of larvae that reached the adult stage under LL was less (33–36%) than under LD (37–40%) or DD (38%). The fertile females begin egg laying within 0.9 to 2.3 days after mating under all light systems. The shortest period (0.9) was shown under continuous light. The least oviposition period 4.4 and 4.5 was obtained under LL, while the longest period (6.4 and 5.7 days) was obtained under LD, after one and four generations, respectively. The light has no effect on the post-oviposition period. The longest life span of adults was recorded under LD and the shortest under LL. The females bred under LL, laid the least number of eggs (85–87 eggs), while those bred under LD and DD laid the highest number (128–130 for LD and 113–146 for DD, respectively).