大头金蝇营养成分分析

分析大头金蝇Chrysomya megacephala(Fabricius)的营养成分。结果表明,大头金蝇幼虫、蛹、成虫干粉水分含量分别是6.83,2.07和3.70%,干体粗蛋白含量分别为63.72,76.81和70.54%,粗脂肪分别为16.43,12.82和7.23%。蛋白质中氨基酸总量百分比分别为56.39,55.61和59.12%,其中必需氨基酸占氨基酸总量(E%)的48.34,53.08和43.91%,必需氨基酸与非必需氨基酸之比(E/N)分别为0.94,1.13,0.81,E/T为3.22,3.54,2.93。大头金蝇幼虫、蛹、成虫不饱和脂肪酸占总脂肪酸含量依次是68.1,61.9和65.9%。含有人和动物所必需的常量和微量元素,但没有检测到有毒重金属镉(Cd)、铅(Pb)。大头金蝇与鱼粉、舍蝇幼虫、柞蚕蛹相比,营养成分指标较高,属于理想的昆虫蛋白资源。     

不同饲料对大头金蝇生殖力的影响

研究了不同饲料对大头金蝇生殖力的影响。结果表明在25℃下,大头金蝇Chrysomyamegacephala(Fabricius)成蝇取食油菜花粉、奶粉、白砂糖、蜂蜜、白砂糖+油菜花粉,其个体死亡50%所需时间分别为15,13,90,70,50d;雌蝇平均寿命分别为13.0,17.4,74.7,54.3,45.4d;产卵期分别为1.9,1.5,38.4,40.9,29.7d;平均产卵量为2.9,1.8,717.1,439.0,513.9粒。平均寿命、产卵期、产卵量最高水平均出现在饲喂白砂糖、蜂蜜、白砂糖+油菜花粉,三者差异不显著,但与油菜花粉、奶粉有显著差异。大头金蝇雌雄成虫间的寿命稍有不同。在人工饲养大头金蝇成蝇时添加适量糖可提高其生殖力。     

大头金蝇的综合利用研究进展

大头金蝇Chrysomya megacephala是重要的法医昆虫、资源昆虫和卫生害虫。大头金蝇的各个发育阶段与人类活动关系密切。本文简要介绍了大头金蝇的分布、分类鉴定及生物学背景,着重从法医学应用、幼虫在有机废弃物转化中的应用、幼虫的活性物质及成虫传粉应用4个方面总结其在资源综合利用方面的研究进展,并讨论了大头金蝇其幼虫和成虫存在的风险及可能的控制方法。新型法医学手段的开发拓宽了大头金蝇在法医领域的应用范围;大头金蝇幼虫能够有效地转化粪便、餐厨垃圾、污泥等多种有机废弃物创造环境和经济效益;幼虫具有多种活性物质,有利于其高附加值产品的开发;虽然成虫的自然传粉效果好,但是其作为传粉昆虫人工释放仍有局限性,仅适用可控空间内。大头金蝇的病媒特性仍是限制其广泛应用的绊脚石,这一问题的解决,有赖于多种技术的有机结合。     

大头金蝇幼虫油脂对小鼠的降血脂作用

用健康昆明种小鼠建立高脂血症模型,同时用不同剂量的大头金蝇Chrysomyia megacepha la (Fabricius)幼虫油脂灌胃5周,摘除眼球取血,用试剂盒检测血脂值,光学显微镜观察小鼠肝脏病理变化。结果表明：大头金蝇幼虫油脂处理组小鼠血清胆固醇(TC)、甘油三酯（TG）、低密度脂蛋白胆固醇(LDL-C)水平显著降低,低剂量、中剂量和高剂量油脂处理组小鼠TG的浓度较高脂模型组小鼠分别下降20.70%、48.98%和56.06%;高脂模型组小鼠血清TC高达4.59 mmol/L,低剂量、中剂量和高剂量油脂处理组小鼠TC浓度较高脂模型组小鼠分别下降16.99%、23.52%和25.49%;高密度脂蛋白胆固醇（HDL-C）升高明显,低剂量、中剂量和高剂量油脂处理组小鼠HDL-C较高脂模型组小鼠升高11.74%、18.04%和18.95%,并呈现一定的剂量-效应关系;连续饲喂大头金蝇幼虫油脂对小鼠肝细胞有一定保护作用。提示大头金蝇幼虫油脂具有治疗小鼠高脂血症的作用。     

温度对大头金蝇生长发育的影响及其用于PMI推断的探讨

分别在22℃、25℃、28℃恒温下,用处死家兔的肌肉饲养大头金蝇Chrysomya megacephala初孵幼虫,研究温度对大头金蝇生长发育的影响及其在法医学中推断死者死后间隔时间(postmortem interval,PMI)方面的应用.结果显示,不同温度下,幼虫体长、体重分别与取食时间呈线性相关(R2>0.96,R2>0.92),可用于推断PMI.另外,蛹长、蛹重、发育历期可作为辅助指标,提高推断的准确性.随温度升高,大头金蝇的生长发育明显加快.不同温度的大头金蝇生长发育差异显著,28℃下的大头金蝇发育历期为187.2 h,22℃下为279 h,比22℃发育时间缩短了91.8 h;28℃下的大头金蝇幼虫、蛹的体长和体重与处于25℃、22℃的大头金蝇也有明显差异.     

用蝶啶荧光分析法推断大头金蝇成虫日龄

应用蝶啶荧光分析法分析了常见尸食性蝇类大头金蝇Chrysomyamegacephala成虫头部蝶啶含量与日龄间关系 ,以及温度、性别等对这种关系的影响。结果表明 ,日龄、温度和性别对成虫蝶啶含量均有显著影响 ,其中温度为主要影响因子。在 16℃、2 0℃、2 4℃、2 8℃和 32℃各恒温下 ,成虫头部蝶啶含量与日龄间存在显著的线性关系。雌雄成虫头部蝶啶积累速率 (或 )与温度 (t)的关系分别可用指数函数FV =0 0 12 88×e(0 2 2 41t-3 12 7) +0 36 49(r2 =0 9987)和线性函数MV =0 0 5 74t- 0 36 37(r2 =0 95 5 7)很好地加以拟合。依据恒温试验结果 ,提出了自然变温条件下成虫日龄的 3种候选估测方法 ,证实这 3种方法仅适宜雄成虫而不适于雌成虫 ,其中对雄成虫日龄估测的最小误差平均为 2 5 5d。最后实际应用中如何选用这 3种方法作了讨论。     

吗啡对大头金蝇生长发育的影响及其用于推断PMI的初步探讨

用致死剂量盐酸吗啡注射家兔,处死后用其肌肉在恒温25℃条件下饲养大头金蝇Chrysomyia megacephala初孵幼虫,研究吗啡对大头金蝇生长发育的影响,及其用于法医学中推断死者死后间隔时间(Postmortem interval,PMI)方面的初步探讨.结果 显示,在25℃下孵化64 h后,处理组大头金蝇的体长、体重及蛹长、蛹重明显大于对照组幼虫(P＜0.05),这种趋势一直持续到羽化.吗啡缩短了大头金蝇的发育历期,根据大头金蝇发育历期进行PMI推断时,吗啡可使PMI推断值缩短14.7 h.     

盐酸吗啡对大头金蝇生长发育的影响及其对死者死亡时间推断的意义

用盐酸吗啡注射家兔,处死后用家兔的不同组织饲养大头金蝇 Chrysomya megacephala初孵幼虫,研究吗啡剂量对大头金蝇幼虫生长的影响及其在法医学中推断死者死亡时间方面的应用。结果显示,在28℃下,取食处理组兔肉和肝脏的大头金蝇幼虫的体长和体重均于孵化后28 h开始在不同程度上大于对照组幼虫,这种趋势一直持续到幼虫末期。在实验的剂量范围内（2.67～10.66 mg/kg）,吗啡可促进大头金蝇幼虫的生长。根据大头金蝇幼虫体长和体重推断死者死亡时间时,吗啡的这种影响可使推断值产生的最大偏差达18h。     

五谷虫油不皂化物的提取工艺研究

许多不皂化物成分作为药效成分被应用于恶性肿瘤的临床治疗中,五谷虫不皂化物的提取分离可以充分发挥这种传统中药材的功效。通过单因素实验得到不皂化物酸值较低而产率较高的最佳工艺条件是石油醚添加量为10mL/g,碱添加过量5%,在60℃的条件下反应15min,0.5mol/L的KCl溶液添加量为50mL/g。通过响应面优化后,得到最佳的不皂化物酸值和提取率分别为70.21mg KOH/g和58.05%。     

Ultrastructure of male accessory glands of Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae)

The ultrastructure of the male accessory glands of the blow fly, Chrysomya megacephala (Fabricius), was presented using light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). A pair of accessory glands was separated at opposite sites. Morphometric results using LM yield evidenced no significant difference in the median of either length or width of the left and right glands. A significant increment in both length and width was seen to plateau between three to six days. SEM observation showed that the surface of the glands revealed a faint irregular groove pattern throughout, and it was occasionally penetrated by tracheoles. Each gland was a slender, elongated sac‐like tubule having apical rounded ends, with a slight constriction at the sub‐apical part of the gland being observed occasionally. TEM analyses of three‐day‐old males showed that the glands consisted of external capsular cells with a basement membrane underneath, glandular cells, and gland lumen. The capsular cell was flat and contained a nucleus with electron dense material in the nuclear envelope. The glandular cell, appearing as columnar, consisted of a vacuolated component that contained a large oval nucleus centrally or sub‐basally located, with dense mitochondria, numerous rough endoplasmic reticulum, and secretory vesicles containing electron‐lucent materials. In the gland lumen, the cross‐section through the middle portion revealed dense secretory materials, characterized by electron‐dense materials. Some sections revealed a large lumen where secretion accumulates within the delicate sac. The seven‐day‐old glands exhibited a remarkable change in the lumen, where the whole space contained a large amount of secretory materials, with the electron‐dense materials being characterized as similar to those observed in three‐day‐old glands. About four prominent types of secretions were observed on the basis of difference in electron‐density.     

Eicosanoids mediate nodulation reactions to bacterial Escherichia coli K 12 infections in larvae of the oriental blowfly, Chrysomya megacephala

Abstract  Nodulation is the predominant cellular defense reaction to bacterial challenges in insects. In this study, third instar larvae of Chrysomya megacephala were injected with bacteria, Escherichia coli K 12 (10⁶ CFU/mL, 2 μL), immediately prior to injection of inhibitors of eicosanoid biosynthesis, which sharply reduced nodulation response. Test larvae were treated with specific inhibitors of phospholipase A₂ (dexamethasone), cyclo-oxygenase (indomethacin, ibuprofen and piroxicam), dual cyclo-oxygenase/lipoxygenase (phenidone) and lipoxygenase (esculetin) and these reduced nodulation except esculetin. The influence of bacteria was obvious within 2 h of injection (5 nodules/larva), and increased to a maximum after 8 h (with 15 nodules/larva), and then significantly reduced over 24 h (9 nodules/larva). The inhibitory influence of dexamethasone was apparent within 2 h of injection (4 vs. 5 nodules/larva), and nodulation was significantly reduced, compared to control, over 24 h (5 vs. 8 nodules/larva). Increased dosages of ibuprofen, indomethacin, piroxicam and phenidone led to decreased numbers of nodules. Nodules continued to exist during the pupal stage. However, the effects of dexamethasone were reversed by treating bacteria-injected insects with an eicosanoid-precursor polyunsaturated fatty acid, arachidonic acid. These findings approved our view that eicosanoid can mediate cellular defense mechanisms in response to bacterial infections in another Dipteran insect C. megacephala .     

Mitochondrial genomes of the sheep blowfly, Lucilia sericata, and the secondary blowfly, Chrysomya megacephala

This paper presents complete mitochondrial genomes for the sheep blowfly, Lucilia sericata (Meigen), and the secondary blowfly, Chrysomya megacephala (Fabricius). Both L. sericata and C. megacephala had standard dipteran-type mitochondrial genome architectures and lengths of 15 945 bp and 15 831 bp, respectively. Additionally, C. megacephala possessed a tRNA duplication either side of the D-loop, as previously reported in another Chrysomya species, C. putoria; this duplication appears to be synapomorphic for the genus Chrysomya. As in other insect mitochondrial genomes, base compositions had a high AT content, with both genomes more than 76% AT-rich.     

Sexual size dimorphism decreases with temperature in a blowfly,Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae)

1. There is wide intra‐specific variation in sexual size dimorphism (SSD). Much of this variation is probably as a result of sexual differences in the selective pressure on body size. However, environmental variables could affect males and females differently, causing variation in SSD. 2. We examined the effects of two temperatures (20 and 30 °C) on SSD in six populations of the blowfly, Chrysomya megacephala. 3. We found that body size increased with temperature in all the populations studied, and the sexes differed in phenotypic plasticity of body size in response to rearing temperature. This created substantial temperature‐induced variation in SSD (i.e. sex × temperature interaction). Males were often smaller than females, but the degree of dimorphism was smaller at the higher temperature (30 °C) and larger at the lower temperature (20 °C). This change in SSD was not because of a gender difference in the effect of temperature on development time. Further studies should address whether this variation can be produced by adaptive canalisation of one sex against variation in temperature, or whether it may be a consequence of non‐adaptive developmental differences between the sexes. 4. Although most studies assume that the magnitude of SSD is fixed within a species, the present study demonstrates that rearing temperature can generate considerable intra‐specific variation in the degree of SSD.