The objective of this study was to assess the effect of different constant temperatures (20, 25, 30, and 35C) at a constant relative humidity (70 5% R.H.) on some biological aspects of the peach fruit fly Bactrocera zonata (Saund.). Results clearly revealed that the embryonic development of B. zonata declined gradually as the temperature increased from 20 to 35 C. The highest percentage of egg hatch was 90.33 at 30C and the lowest rate was 71.18% at 35C. Temperatures of 25 and 30C were considered the favorable zone for egg hatching. The developmental rate of larvae gradually increased with the increase of temperature .The same trend was also observed for pupation rate. The pupal duration declined as temperature increased. The highest rate of adult emergence was 97.42% at 30C and the lowest rate was 83.54% at 20C. The sex ratio of emerged adults was female biased at all temperatures except at 30C. The average pre-oviposition periods were 29.4, 22.8, 20.4, and 17.18 days at 20, 25, 30, and 35C, respectively. On the other hand, an inverse effect was observed in oviposition periods. The optimum and favorable temperatures for female fertility ranged between 25 and 30C, where the average of egg hatching was 186 and 174.8, respectively. No significant differences were observed between the averages of pre-oviposition period relative to copulation types. On the other hand, the oviposition period was affected by the type of copulation. Repeated copulation induced the female to deposit remarkably higher number of eggs than the other two copulation types (delayed copulation and copulated once). The average of egg hatching of the deposited eggs in the three different types of copulation, i.e., repeated copulation, delayed copulation and copulated once was 73.90, 60.33, and 63.02, respectively.
Key words: Bactrocera zonata threshold temperature-thermal units (degree-days)-biological aspects-mating types
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