Performance of polyvoltine silkworm Bombyx mori L. on different mulberry plant varieties

Five cultivated mulberry plant varieties, BSRM‐34, BSRM‐56, BSRM‐57, BSRM‐58 and BSRM‐59, were used to evaluate the effects of plant variety on larval and cocoon characteristics of mulberry silkworm Bombyx mori L. Silkworm larvae undergo their entire larval periods on leaves of mulberry varieties. Different larval characteristics of larval weight, larval length and larval breadth were measured in different growth stages. After rearing, the fifth instar larvae were transferred into a mountage (Chandraki) structure for cocoon rearing for spinning and cocoon production. The cocoons were then harvested and different cocoon characteristics like cocoon weight, shell weight and shell percentage; and other characters like pupal weight and effective rate of rearing were measured. The results showed statistically significant differences among different varieties on larval and cocoon characteristics. The highest performance was observed by feeding the variety BSRM‐34 in respect of the average weight of 10 mature larvae (40.5 g), single mature larval length (7.6 cm) and breadth (1.0 cm), single cocoon weight (1.4 g), shell weight (0.2 g) and pupal weight (1.2 g) while the average performance was recorded by feeding varieties BSRM‐57 and BSRM‐59. The poorest performance was showed by feeding the variety BSRM‐56 (in case of larval characters) and BSRM‐58 (in case of cocoon characteristics). These two varieties also showed the poorest performance for silk yield. Through comparing all the above parameters it was concluded that BSRM‐34 is the best mulberry variety and it is recommended that Bangladeshi farmers adopt that variety for better yield of silk.     

Food deprivation effects on carbohydrate levels and their relation to feeding responses of western cherry fruit fly Rhagoletis indifferens to spinosad bait

Abstract The nutritional state of tephritid fruit flies affects various behaviours. The present study aims to determine food deprivation effects on carbohydrate levels and their relation to feeding responses to spinosad bait (GF‐120^® Naturalyte^® Fruit Fly Bait; Dow AgroSciences, Indianapolis, Indiana), as measured indirectly by mortality, in western cherry fruit fly Rhagoletis indifferens Curran (Diptera: Tephritidae). Sugar levels in 1–2‐day‐old flies exposed to sugar for 1 h and then deprived of sugar for 10–24 h decrease but, in flies with access to continuous sugar and no sugar, they increase and do not change, respectively. Sugar levels in 14–15‐day‐old flies that have had free access to yeast extract and sugar and are then deprived of it for 0 and 10 h do not differ but they are lower at 24 and 30 h. Mortalities of 1–2‐day‐old flies exposed to sugar for 1 h and then deprived of it for 0–24 h progressively increase but they do not increase in flies given no sugar because the mortalities in this treatment are equally high at all times. By contrast, mortalities of 14–15‐day‐old flies deprived of food increase from 0 to 10–30 h but there are no differences from 10 to 30 h. Mortalities of 14–15‐day‐old flies deprived of food for 3 and 6 h also do not differ. Food deprivation effects on glycogen are similar, although glycogen occurs at lower levels than sugar. The results obtained suggest that R. indifferens flies need to feed multiple times on carbohydrate foods during the day to maintain their carbohydrate levels, that their responses to spinosad bait will increase if they do not, and that there may be age‐related effects on carbohydrate levels and responses to spinosad bait.     

近交对单倍体-二倍体种群平衡遗传多态性的影响

本文通过对一个双等位基因位点在产雄孤雌生殖遗传体系下不完全同胞交配的模拟 ,研究了在显性、共显性和超显性遗传模式下近交对平衡多态性的影响。结果显示 :相对于二倍体 -二倍体种群 ,不完全同胞交配会减少产雄孤雌生殖种群的遗传变异。然而 ,在各种情况下 ,近交对单倍体 -二倍体种群的总体影响不如对二倍体 -二倍体种群极端