Study On The Effects Of Hydrolyzed Protein On The Physiological Mechanism Of Bactrocera Dorsalis (Hendel)

At present, the application of protein bait is one of the important measures for thecontrol of Bactrocera dorsalis(Hendel), but the mechanism of protein bait for fruit fly isnot clear. In order to explore the effects of protein bait on the physiological mechanismof B. dorsalis, the differences were studied in adults under the three different nutritionconditions in the period from new eclosion to sexual maturity of B. dorsalis, and thestudy maily included the measure of some important physiological indicators and theobservation of the female reproductive system of the adults, the three different nutritionconditions were: fed artificial die (group1), fed sugar+hydrolyzed protein (group2) andfed sugar+water (only fed sugar, group3). The results were as follows:(1)Measurement results of physiological indicators between the tteatments:Body size: For the same-day-old B. dorsalis under different nutrient conditions thesize of the adults’ body length were: group1> group2> group3but there were nosignificant differences among the three groups. The growth of the female and maleadults’ body was also not obvious in the period from new eclosion to sexual maturity ofB. dorsalis. And the female and male adults’ body could grow up to more than7mmwhether or not fed protein.Weight: For the same-day-old B. dorsalis under different nutrient conditions theweight of the adults were: group1> group2> group3, and there were significantdifferences among the three groups. The weight of female and male adults underdifferent nutrient conditions all gained fast before3days old, later there were someincrease in the weight of group1and group2, the weights of female adults and maleadults of group1were respectively19.93mg and17.21mg, the ones of group2wererespectively17.45mg and15.75mg. The gain of the adults’ weight of group3was notsignificant, the female and male adults’ weight both maintained at about12mg.Fat content: The situation changes in the fat content of the B. dorsalis adults ofgroup1and group2were consistent, and analysis of variance showed that there weresignificant differences in the one of group3and the fomers. The adults’ fat content ofgroup1and group2increased continuously or was at a high level before5days old,and the ones were drastically reduced at7days old, especially the males’ fat contentonly about1.7%, which was seriously lower than the one of group3(it is3.89%). The female and male adults’ fat content of group3respectively maintained at around2.5%and4%after5days old, the changes of their fat content were more stable than group1and group2.Free amino acids content: The free amino acids contents reduced after eclosion ofB. dorsalis adults, and the ones of group1and group2could continuously increase afterseveral days, the maximums of the female adults’ free amino acids content of group1and group2could respectively reach to2.45mg/g and1.66mg/g, the increasingamplitudes were more1time than their own, the maximums of the ones of the males’ ofgroup1and group2could respectively reach to2.00mg/g and1.30mg/g, theincreasing amplitudes were about0.5times than their own. But the free amino acidscontent of group3almost couldn’t change after reducing to3days old, the ones of thefemale and male adults respectively maintained at around0.57mg/g and0.55mg/g,compared with B. dorsalis had been fed protein they were showed lower levels.Glycogen content: The glycogen contents increased after eclosion of B. dorsalisadults, the ones of the females and the males reached to the maximums respectively at5days old and7day s old. The female adults’ glycogen contents were continuouslyreduced after5days old, and the one of group3was more than the ones of group1andgroup2. The male adults’ glycogen contents of group1and group2were steadilydecreased after7days old, they were respectively13.00mg/g and19.67mg/g at the endof experiment, but the male adults’ glycogen contents of group3began to decrease at7days old, and it increased to29.36mg/g from9days old to the end of experiment,compared with the fist two groups it was significant different.Trehalose content: The trehalose contents of group1and group2were similar: thetrehalose contents of the females and the males of the two groups reached themaximums respectively at5days old(group1and group2were respectively10.56mg/gand10.09mg/g) and3day s old(group1and group2were respectively8.36mg/g and10.09mg/g), and that reached the minimum at9days old(female: group1and group2were respectively3.64mg/g and5.90mg/g, male: group1and group2wererespectively3.07mg/g and10.75mg/g). The ones of group3reached to the maximumswere both at5days old(female and male were respectively11.83mg/g and13.95mg/g),after decreasing to7days old it began to increase to9days old, and then it reached theminimum at11days old(female and male were respectively6.72mg/g and4.10mg/g),so they were showed that the dynamics of glycogen contents of group3were not unstable, and the contents were significantly more than the first two groups from5to9days old. These results were illustrated that protein was very important to maintaintrehalose dynamics of B. dorsalis.Trehalase activity: The situation changes in the trehalase activity of group1andgroup2were consistent: the ones of the females of group1and group2was verysimilar at5days old, and they were increased0.4units at7days old, then they weredecreased, and they maintained at about0.36μmol/(L mg pro min); the ones of themales of group1and group2decreased o.1units from3to5days old, and theymaintained at around o.5μmol/(L mg pro min) from7to11days old, so they wereshowed the trehalase activity of the two groups was relatively stable. The trehalaseactivity of the females of group3is0.45μmol/(L mg pro min) at5days old, then itincreased0.5units at7days old, which is almost1.6times than the the first two groups,later it was always fluctuated above0.66μmol/(L mg pro min), it was significantlyhigher than the previous two groups; the one of the males of group3significantlyfluctuated between0.39μmol/(L mg the pro min), and0.91μmol/(L mg pro min)from5-11days old, it was higher than the previous two groups after7days old, so theywere showed the trehalase activity of the group3was relatively high and unstable.These results were illustrated that protein was very important to maintain trehalaseactivity homeostasis of B. dorsalis.(2) the measurement results of the female reproductive system:Ovarians areas: there were significant difference in different groups after5daysold of B. dorsalis under different nutritional conditions. The B. dorsalis’ ovarian areasof group1and group2increased rapidly after7days old. The ovarian areas of the twogroups increased to the maximum at11days old, which were2.82mm~2and2.35mm~2respectively, which were also more than10times than them at3days old. The B.dorsalis’ ovarian areas of group3were not almost increased during the period ofexperiment.Developmental level of ovarians: the three time when the three groups’ ovariansdeveloped to levelⅠ、Ⅱ、Ⅲ were different, the time of B. dorsalis of group1were5、7、11days old, the time of the ones of group2were5、7、11days old. The developmentof the two groups was almost identical. The ovarians of B. dorsalis of group3werestuck at levelⅠ, they could not develop regularly. The amount of spawned egg and the hatch rate: B. dorsalis of group3couldn’t layeggs, B. dorsalis of group1and group2were able to lay eggs, and the spawn amountsof the two groups were very similar, which were both between0.11mL and0.14mL;their hatch rates were also very simiar, which were both about85%.