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The Energy Storage Of Diapause Pupae Of Hyphantria Cunea Drury Before Overwintering And The Influence Of Temperature Change On Its Energy Consumption During Overwintering

Posted on:2021-02-18Degree:MasterType:Thesis
Country:ChinaCandidate:W WangFull Text:PDF
GTID:2393330611495431Subject:Forest Protection
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Diapause is highly advantageous for seasonal adaptation by insects,but insects normally feed very little in diapause;thus,the energy consumed by insects during long-term diapause is a highly challenging problem.Hyphantria cunea Drury(Lepidoptera: Arctiidae)is a major invasive pest in China.Hyphantria cunea enters diapause as a pupa.Subsequently,the adult loses its ability to feed due to the degeneration of its mouthparts so the energy reserves stored before diapause determine the survival rate and fitness of the adults after emergence.In addition,in the process of spreading from north to south,Hyphantria cunea is constantly facing the pressure of temperature rising during overwintering.Therefore,it is of great theoretical value to study the energy storage mode before overwintering of diapause pupa of Hyphantria cunea and the influence of temperature rising during overwintering on its safe overwintering,so as to understand the diffusion adaptation mechanism of invasive pests.In this paper,the overwintering mechanism of Hyphantria cunea was discussed from two aspects: the energy reserve before overwintering and the energy consumption during overwintering.The main research results are as follows:1.Diapause-destined pupae will reserve more energy by increase feeding efficiency during the preparation phase of diapause compared with non-diapause pupae.The body size,body mass,lipid and carbohydrate contents,as well as the efficiency of converting digested food into body matter and efficiency of converting ingested food into body matter were significantly higher in the diapause pupae and diapause-destined larvae than the counterparts.We also observed higher lipase,amylase and lower protease activity in diapause-destined larvae,as well as lower protein content in diapause pupae than the non-diapause-destined larvae and non-diapause pupae,respectively.We concluded that the diapause pupae reserve greater energy than non-diapause pupae by increasing feeding efficiency,and the diapause-destined larvae increased the lipids and carbohydrates reserves by increasing the lipase and amylase activities,whereas the destined non-diapause larvae increased the protein reserves in the non-diapause pupae by elevating the protease activity.2.When the diapause induction period of Hyphantria cunea is under the short photoperiod(L:D 10:14)and the long photoperiod(L:D 13:11),the doomed diapause larva that feels the short photoperiod increases the energy storage of the diapause preparation period by increase feeding efficiency.We found that the body size,body mass,lipid and carbohydrate contents of diapause pupae in short photoperiod were significantly higher than those in long photoperiod,and the ECI of diapause larvae in short photoperiod was significantly higher than that in long photoperiod.At the same time,we found that the activities of lipase and amylase in the midgut of diapause larvae under short photoperiod were significantly higher than those under long photoperiod.We conclude that the short photoperiod predestined diapause larva can increase the energy storage by improving the feeding efficiency,while the short photoperiod predestined diapause larva can increase the lipid and carbohydrate storage by increasing the lipase and amylase activities in the midgut.3.Different temperatures in the early overwintering period had significant effects on the body size,body mass and energy consumption of diapause pupae.We found that in the early stage of overwintering,the content of lipid generally increased with the increase of temperature,mainly for synthetic storage,while the content of carbohydrate and protein generally decreased with the increase of temperature,mainly for consumption.We conclude that carbohydrates,especially glycogen,are consumed as early energy sources in diapause pupae,while protein is used as the second energy source.When glycogen supply is insufficient,protein is transported as a supplement.Lipid is not consumed as early energy sources,but continues to be stored for the long winter.The effects of constant temperature and fluctuating temperature of energy materials in the early winter are also different.At 15 ?,20 ? and 25 ?,high temperature accelerates the synthesis and consumption of energy materials.The influence of different temperature fluctuation amplitude is different.The small fluctuation amplitude of 20±5 ? has little effect on the energy synthesis and consumption compared with the constant temperature of 20 ?,but the large fluctuation amplitude of 20±5 ? generally has significant effect.
Keywords/Search Tags:Hyphantria cunea Drury, diapause, photoperiod, energy reserve, energy consumptio
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