Effects of short-term heat shock of eggs on the development and fecundity of Plutella xylostella (L.) (Lepidoptera: Plutellidae)

It has been hypothesized that the survival, development, fecundity and population of insects are affected significantly by high temperatures. The diamondback moth, Plutella xylostell (L.) (Lepidoptera: Plutellidae), is a serious and economically important pest of cruciferous crops throughout the word. In this research, the adult longevity and fecundity of P. xylostella were studied in laboratory conditions. After applying heat shock stress, (۳۰, ۳۵ and ۴۰ °C) for ۲, ۴, ۶ and ۸h, the experiments were conducted at ۲۵ ± ۱ °C, ۶۵ ± ۵% RH, and a photoperiod of ۱۶:۸ (L: D)h on Brassica napus. The developmental time of immature stages were significantly affected by heat shock temperatures (۳۰ to ۴۰ °C) compared to the ۲۵ °C (control), but the developmental time of larvae did not differ significantly at ۴۰ °C. The pupal development time differed significantly at heat shock temperatures, which was longest (۶.۱۳ ± ۰.۰۵ days) at ۳۰ °C for ۲h. Heat shock temperature also had significant impact on adult longevity and fecundity of diamondback moth. The longest adult longevity for females and males was determined to be ۱۴.۴۷ ± ۱.۰۴ and ۱۱.۰۴±۰.۹۵ days respectively at ۳۵ °C for ۲h. The fecundity of females fluctuated significantly with increasing temperature stress. Our findings provide useful information on the potential of this insect in response to environmental temperature changes.

Keywords:

Plutella xylostella , fecundity , longevity , heat shock temperature