【作者】 郑俊丽；

【导师】 雷朝亮；

【作者基本信息】 华中农业大学 ， 农业昆虫与害虫防治， 2011， 硕士

【摘要】 在自然界有很多昆虫具有趋光行为,尽管人类很早就开始利用昆虫的趋光性防治害虫,但有关昆虫趋光的光谱特性、感光生理等方面的研究仍不能阐明昆虫趋光的根本原因。黑腹果蝇(Drosophila melanogaster)是具有趋光性的日行性昆虫,对UVA有强烈趋性。本文以黑腹果蝇为实验材料,研究了不同UVA强度(200±25μw/cm2,10±μw/cm2)和不同时间(1h、2h、3h)的照射对其成虫寿命、繁殖力和子代生长发育等生物学特性的影响,测定了不同UVA照射及不同日龄黑腹果蝇体内脂质过氧化、总抗氧化能力及抗氧化酶活性的变化,以期从生物学和生理学方面探讨昆虫趋光的本质。主要研究结果如下：1.UVA照射对黑腹果蝇成虫寿命和繁殖力的影响黑腹果蝇成虫寿命UVA组高于对照组,不同照射强度间差异显著(p<0.001),其中,高强度短时间和低强度有利于果蝇存活,而高强度长时间照射导致寿命缩短；在繁殖力测定中,不同UVA强度和照射时间下的总产卵量差异不显著,但经UVA照射的产卵量均高于对照组,而且随着照射时间的延长产卵量不断增加,低强度3h处理组的产卵量增加最多。总之,低强度的UVA照射有利于黑腹果蝇成虫的存活和繁殖。2.UVA照射对黑腹果蝇F1代存活率和发育历期的影响果蝇成虫经受UVA不同强度和时间照射后,其子代的存活率(从卵到成虫)没有显著差异,只有低强度2h处理组存活率显著高于对照；不同UVA强度对黑腹果蝇雌雄虫发育时间有显著影响(p<0.001),不同照射时间没有显著影响(p=0.097),但二者的交互作用显著(p<0.001),经UVA照射的果蝇,其子代的发育时间均显著延长。这表明UVA照射对果蝇F1代的生长发育存在一定不利的影响。3.不同UVA强度和照射时间对黑腹果蝇成虫抗氧化反应的影响雌雄虫在丙二醛(MDA)、总抗氧化能力、过氧化氢酶(CAT)和过氧化物酶(POD)四个生理指标上存在显著的性别差异；总抗氧化能力(p<0.001)和CAT活性(p=0.004)在高低两个强度间存在显著差异；对各指标的影响在照射时间上均没有显著差异,但时间和照射强度之间存在一定的交互作用。雄虫在高强度30min时MDA含量显著高于对照组,总抗氧化能力显著低于对照,POD活性显著高于60min组；在低强度120min时CAT和谷胱甘肽S转移酶(GST)活性显著高对照。雌虫在高强度只有60min时的总抗氧化能力显著低于30mmin组；在低强度60mmin和120mmin处理组MDA含量均显著高于对照,总抗氧化能力和超氧化物歧化酶(SOD)活性在60mmin时显著高于对照,CAT活性均显著高于对照,其他均无显著差异。4.UVA照射对不同日龄黑腹果蝇成虫抗氧化反应的影响雌雄果蝇体内MDA含量和SOD活性均在前期维持在稳定水平,28或42日龄时显著下降后又恢复到之前的水平；POD活性逐渐下降到42日龄的最低水平,随后略有升高；雄虫CAT活性先显著提高而后急剧下降到之前水平,GST先显著下降而后升高到前期水平,雌虫CAT和GST活性均随日龄增加出现持续升高,有利于延长寿命；而总抗氧化能力先显著下降又显著升高,雄虫更是出现显著上升又下降的反复波动,这是SOD、CAT、POD、GST综合作用的结果。以上研究表明,UVA照射延长子代发育历期,低强度比高强度更有利于增加黑腹果蝇成虫寿命和繁殖力,果蝇体内各种抗氧化酶综合作用能将UVA照射所产生的活性氧维持在较低水平,在果蝇生命后期内持续高强度UVA照射降低酶活性而加速衰老,UVA照射对昆虫影响与辐射强度和时间有关。更多还原

【Abstract】 Phototaxis is a common phenomenon in insects, and many insects exhibit positive response to light, which has been used widely to control populations of many types of insect pest. The spectral preferences, physiologic perception of light had been well studied all over the world. However, the mechanism of phototaxis is also not clear. The fruit fly, Drosophila melanogaster, is a diurnal insect display a conspicuous positive photo tactic behavior to light stimuli, especially to black light (UVA). To elucidate the phototaxis mechanism, we test the lifehistory fitness and physiolical responses. We use the high (200±25μw/cm2) and low (10±5μw/cm2) intensity of UVA light to irradiate Drosophila melanogaster for different exposure times (1h,2h,3h), and the effects on adult longevity and fecundity, F1 generation development were reflected. We also test responses of the lipid peroxidation, total antioxidant capacity, and antioxidant enzymes of adult flies under different UVA radiation and during different ages of flies. The main results are as follows:1. The effects of UVA radiation on lifespan and fecundity of fruit fly adults.The lifespan showed that the longevity by UVA radiation was longer than the control, and there were significant differences in intensity (p<0.001). The mean lifespan of flies in short exposure time was longer than that of longer exposure time, in the high intensity of UVA. While, in the low intensity, the lifespan both female and male were increasing with the exposure time extending. The fecundity tests showed that there were no significant effects on the lifetime fecundity neither in intensity nor exposure time of UVA radiation. However, all the UVA irradiation assays have more egg production than the ck. With exposure time prolonging, the lifetime reproduction were increasing in both UVA intensity, especially the 3h traits in low UVA intensity increased more. All in all, the low UVA intensity was of benefit to adults’fitness.2. The effects of UVA radiation on survivorship and development time of F1 generation of D. melanogaster.The survivorship from egg to eclosion showed that there were no significant effects of neither intensity nor the exposure time, only the 2h assay in low UVA had higher survivorship than the control. The development time data revealed a significant effect of main effect of UVA intensity (p< 0.001), but no difference among the exposure times (p =0.097), whereas the differences were reflected in a significant UVA intensity×Exposure time interaction. The flies in all the UVA irradiations developed slower than the control, significantly, among light regimes in high and low intensity. The results of survivorship and development time revealed that the UVA radiation was harmful to pre-adult’s fitness, at least a partial effect.3. The effects of different intensity and exposure time of UVA radiation on antioxidant responses of D. melanogaster.There were significant differences on malonaldehyde (MDA) content, total antioxidant capacity, catalase (CAT) and peroxidases (POD) activity between the sexes. And the total antioxidant capacity (p< 0.001) and CAT (p= 0.004) activity were different between the intensities of UVA. No difference among the exposure time, while the interactions of UVA intensity×Exposure time were existed. To the male, in 30min high UVA radiation, the MDA content was higher, but the total antioxidant capacity was lower than those of ck, POD activity higher than 60min’s. And in the low UVA radiation, CAT and glutathione-S-transferase (GST) activity were higher than the ck, which was in 120min. To the female, only 60min of high radiation was lower in total antioxidant capacity than 30min’s. And in low intensity, MDA content was higher than ck in 60min and 120min, total antioxidant capacity and superoxide dismutase (SOD) activity were higher in 60min, all the CAT maintain higher activity, compared with ck.4. The effects of UVA radiation on antioxidant responses of D. melanogaster in different ages.In fly adults, Age-related changes in MDA content and SOD activity followed a bell-shaped trend, with increase during the first 2 or 4 weeks of life followed by a sharp decrease during the latter part of life, whereby the level of activity was similar in the very young and the very old flies. The POD activitie was linearly decline during 42 days, and then slightly increased. The CAT and GST activity were different changes in male and female, and both of them in female were increase with age of the flies, which relate to long life span. But CAT activity tends to slightly increase during young age and sharply decrease in the latter, in contrast GST activity declined first and then increased. The total antioxidant capacity tend was undulate, especially in the male, which is combination of all the antioxidant defenses.The above research showed that, the development time of F1 generation was longer in the UVA radiation, and the longevity was longer and egg production was more in UVA radiation, especially in low intensity, but The activity of SOD, CAT, POD and GST were contributing to control the low level of ROS, which caused by UVA radiation. In the old age, the continual high UVA radiation reduced activity of antioxidant enzymes, which was bad work in slowing the senescence down. In total, the effects of UVA radiation are depending on the intensity and exposure time.更多还原