ANAGASTA KUEHNIELLA مطالعه رفتارهاي تغذيه اي لاروها، دو شكلي جنسي در لاروها و شفيره ها و مراحل مختلف نشو و نمايي شب پره مديترانه اي آرد

The Study of Larval Feeding Behaviours, Sexual Dimorphism in Larvae and Pupae and Different Developmental Stages of the Mediterranean Flour Moth, Anagasta kuehniella (Zeller)

The larval feeding behaviours, sexual dimorphism in 5th instar larvae and pupae, different developmental stages and head capsule width were studied during 1998-1999, by rearing the larvae of Anagasta kuehniella moth on four food regimes (wheat flour and wheat flour + bran in proportions of 75%: 25%, 50%:50% and 25%:75%) with two moisture contents of 13.9% and 8.7% under laboratory conditions. The Mediterranean flour moth larvae gave high infestations to food substrates by spinning silky fibers, depositing molting skins and their feces. Larvae have cannibalistic behaviour and in the absence of food materials, stronger larvae eat other larvae and pupae. Male 5ʹh instar larvae bear a red dot on dorsal surface of their 5th abdominal segment, but females do not bear that dot. The sex of pupae could be easily distinguished by considering morphological characteristics. 26% of pupae, when taken out of their concoons and exposed to smooth surfaces had difficulties in normal adult emergence. In all treatments, embryonic development lasted 4-5 days. The shortest larval stage duration (31-32 days) was observed on moistend regime of wheat flour. An increase in bran content caused elongation of larval stages which were 40-41, 41-42, 49-51 and 56-63 days in rearings on dry foods and 31-32, 33-34, 43-45 and 56-60 days in rearings on moistend foods, with 0%, 25%, 50% and 75% bran contents, respectively. 4th and 5th instar larvae showed significantly different head capsule width. An increase in bran content caused reduction of head capsule width. The means of head capsule width was less on dry foods. It was also found that the head capsules of the 5th instar of female larvae were somewhat larger than that of males.