Persistence of conidia of Entomophthora muscae in relation to age, temperature, and humidity

In this paper, the effect of age, humidity, and temperature on the conidial survival of Entomophthora muscae was evaluated. E. muscae was obtained from Musca domestica in a dairy in Itatiba (São Paulo, Brazil) and maintained in the laboratory by continuous passage through flies. Furthermore, the ability of conidia to infect flies at three temperatures (17, 21, and 27 °C), four ages of conidia (12, 72, 96, and 154 hours) and two humidities (100 and 60% RH) was evaluated. The temperature of 21 °C was the most favorable for the infection of house flies. Humidity was a cause of variation at 27 °C when the conidia were up to 12 hours old, but had no effect at lower temperatures. Conidia held at 100% RH and aged 72 hours caused no infection at 17 °C, but were infective at 21 °C. In the present study, conidia retained viability much longer than previously observed. Finally, the effect of humidity, temperature, and conidial age is discussed.     

家蝇卵巢中的信息化学物质引诱雌蝇产卵的研究

产卵期家蝇MuscadomesticaL .卵巢中的信息化学物质诱引家蝇产卵。行为试验表明 ,雌蝇产卵时优先选择被成熟卵巢污染过的发酵麦麸 ,诱集的产卵百分率依次为 :发酵麦麸 + 1对卵巢 >湿麦麸+ 1对卵巢 >发酵麦麸 >湿麦麸 ;卵巢提取物同样对产卵雌蝇有诱集活力。产卵雌蝇卵巢正己烷、二氯甲烷以及乙酸乙酯的提取物均能诱集雌蝇产卵 ,诱集的产卵百分率依次为 :雌蝇卵巢正己烷提取物 >乙酸乙酯提取物 >二氯甲烷提取物。推测家蝇卵巢中的信息化学物质可能含有家蝇产卵聚集信息素的组分。     

家蝇幼虫血淋巴中抗真菌肽的诱导方法比较及抗真菌活性

以未诱导组作为空白对照研究比较真菌诱导、超声诱导和热诱导家蝇Musca domestica 幼虫血淋巴初提液的抗真菌肽效果,比较各种诱导方法诱导后的幼虫存活率;用凝胶层析法和高效液相分离纯化热诱导家蝇3龄幼虫抗真菌肽,检测其抗白假丝酵母菌Candida albicans和新生隐球菌Cryptococcus neoformans活性;SDS-PAGE分析抗真菌肽的蛋白分子量范围。结果表明：3种诱导方法诱导后家蝇幼虫均产生具有明显抗真菌作用的抗真菌肽,其初提液抑菌圈大小没有明显差别;真菌诱导组和热诱导组幼虫存活率低于对照组,而超声诱导组与对照组相比则无明显差别。经分离纯化后,抗真菌肽仍具有较好的抗真菌活性;SDS-PAGE分析表明该抗真菌肽有效成分的蛋白分子量在14.4 kD以下。结果提示热诱导家蝇幼虫产生抗真菌肽是一种方便、有效的诱导方式。     

An evaluation of (Z)-9-tricosene and food odours for attracting house flies, Musca domestica, to baited targets in deep-pit poultry units

Field trials investigating the effect of food baits on catches of Musca domestica at toxic targets impregnated with the female sex pheromone, (Z)-9-tricosene, were conducted in a caged-layer deep-pit poultry unit in southern England. Targets treated with an Alfacron-sugar mixture and baited with 2.5 g of 40% (Z)-9-tricosene beads caught significantly greater numbers of both male and female M. domestica than control targets. Egg and milk-baited targets were less attractive than controls, while brewers yeast slightly increased the numbers of M. domestica attracted. However, the inclusion of brewers yeast in (Z)-9-tricosene-impregnated targets produced a significant reduction in the number of male M. domestica attracted. Increased female attraction was elicited by baiting the targets with 2-phenylethanol, at the quantities of 1 mg and 10 mg. However, 2-phenylethanol had no effect on female attraction when presented in conjunction with (Z)-9-tricosene. The implications of these results in relation to the control of M. domestica populations in poultry units are discussed.     

不同细菌对家蝇幼虫抗菌蛋白/肽的诱导效应

利用抑菌圈测量法和毛细管电泳研究、比较不同细菌对家蝇Musca domesticaL.幼虫抗菌蛋白/肽的诱导效应。结果表明,家蝇幼虫受细菌诱导后抗菌活性比对照都有不同程度的增加,同时不同细菌诱导表达样品对于相应的诱导菌均表现很高的抗菌活性。毛细管电泳图谱表明鼠伤寒沙门氏菌Salmonella typhimurium50013诱导后抗菌蛋白/肽表达强度增加了50倍,其它细菌诱导后抗菌蛋白/肽表达强度增加了1～40倍。与G+细菌相比,G-细菌具有更强的诱导效应。结论:家蝇幼虫对不同的细菌刺激有特异性反应,即不同细菌诱导抗菌蛋白/肽的强度、种类和数量都不一致。     

家蝇和大头金蝇在麦麸和猪瘦肉上的产卵选择和发育差异

在中国许多地区, 大头金蝇Chrysomya megacephala F.已侵入过去由家蝇Musca domestica L.占绝对优势的垃圾生态位, 逐渐成为城市蝇类的优势种. 为了解单独和混合饲养时食物种类对家蝇和大头金蝇幼虫生长发育的影响, 在室内观察了野外大头金蝇和家蝇F1代在湿麦麸、猪瘦肉以及两者混合物上的产卵选择和生活史. 结果显示: (1)大头金蝇嗜在含有猪瘦肉的基质上产卵, 而家蝇嗜在含有麦麸的基质上产卵;(2)初孵家蝇和大头金蝇幼虫都能在含有瘦肉的食物上发育至成虫. 在麦麸上, 初孵家蝇幼虫能发育至成虫, 而初孵和2龄大头金蝇幼虫在进入下一龄期前全部死亡, 但少数3龄大头金蝇幼虫能发育至成虫;(3)等量初孵家蝇与大头金蝇在含有猪瘦肉的食物上共同生长时, 与家蝇相比, 大头金蝇的发育历期较短、存活率较高. 与家蝇在麦麸上共同生长时, 与在麦麸上独立生长的同龄大头金蝇相比, 大头金蝇的发育历期较短、存活率较高. 这些结果表明, 共生时家蝇可促进大头金蝇对植物质营养的利用, 这也许是大头金蝇能成功侵入家蝇占绝对优势的垃圾生态位的一个重要原因.     

The influence of oviposition phenology on survival in host races of Eurosta solidaginis

Phenological differences between host plants can contribute to allochronic isolation of host races of phytophagous insects. Host races of the gallmaking fly, Eurosta solidaginis, that live on different species of goldenrod (Solidago altissima and S. gigantea) exhibit different emergence phenologies. These differences could result from adaptation to corresponding phenological differences between the hosts in periods of optimal suitability for gall formation and survival to adulthood. In order to test this, some flies of each host race were allowed to emerge naturally while the emergence times of others were manipulated to correspond to the emergence and oviposition periods of the other host race. Percent gall formation and survival to adulthood were examined for three oviposition periods: the peak time of emergence and oviposition of the earlier-emerging host race (that from S. gigantea), that of the later-emerging host race (that from S. altissima), and a week after the peak emergence of the host race from S. altissima. Flies of both host races were allowed to ovipuncture plants of the appropriate species during each of these periods. Plant relative growth rates were measured during each of these periods. The experiment was repeated twice over a two-year period. Relative growth rates of both host species were highest during the earliest oviposition period (the period during which the host race from S. gigantea normally emerges). Percent gall formation was significantly correlated with plant relative growth rate, but the coefficient of determination was low. In both years of the study, percent gall formation of both host races was highest during the earliest oviposition period (the period during which the host race from S. gigantea normally oviposits). Likewise, percent survival to adulthood in both host races was highest during the earliest oviposition period. There was no significant effect of oviposition period on the percent of larval death due to parasitism by Eurytoma gigantea or predation by Mordellistena unicolor. These results suggest that the host race from S. altissima does not emerge at the time that its host is optimally suited for gall formation or survival to adulthood. Therefore, differences in emergence phenologies do not appear to be due to corresponding phenological differences between the host species in suitability for gall formation or survival to adulthood.     

Search orientation of Musca domestica in patches of sucrose drops

ABSTRACT. The searching tactics of the housefly, Musca dormestica L. (Diptera: Muscidae), have been delineated from digitized pathways of flies walking in patches of sucrose drops arranged in linear (ROW) and hexagonal (HEX) arrays. The areas covered by flies in ROW and HEX patches are distinctly different, but flies seem not to employ different tactics for the two types of resource arrays. The number of drops located, if at least one drop is found, does not differ between ROW and HEX. Most quantitative measures of local search remain constant after the first interdrop interval, although feeding time decreases as flies sample successive drops. Local search intensifies after each drop is ingested, with locomotory rate decreasing and turning rate increasing, followed by decay of both measures toward ranging levels. Searching can be characterized by two movement tendencies resulting from specific, definable, locomotory functions: a forward-moving tendency is expressed by the fly as it leaves a resource in approximately the same direction as it arrives; and local search is characterized by looping, rather than straight walking, with a variable turning rate that generates a rough ‘zigzag’ superimposed on looping. The two movement tendencies, combined, allow flies to locate resources in a linear arrangement, because of the forward-moving tendency, and to locate resources not arranged in a linear array because of the ‘noisy’ loop. M. domestica does not appear to retain and use information gained from one patch of drops in another, so the search tactic of the fly seems therefore to be a compromise between straight movement and circular movement that may be adaptive for an environment subject to frequent changes in the spatial distribution of resources. Giving-up-time, the period between ingesting the last drop and leaving the patch, is a function of the rate of change in the transition from local search to ranging, which is constant in our experiments. If a fly does not encounter another drop while ranging, during which it walks relatively straight, the fly moves out of and away from the patch.     

家蝇蛆抗菌肽提取工艺研究

蝇蛆抗菌肽多有广谱抗菌、抗癌等功能,是很好的天然抗菌药物来源,但由于得率较低,目 前对其产品开发的研究较少。以家蝇Musca domestica干蝇蛆为原料,利用加热-层析法和海藻酸吸附法2种工艺提取蝇蛆抗菌肽。结果表明：加热-层析法快速、简便,抗菌肽提取得率达0.26％,是海藻酸吸附法提取抗菌肽得率的5.2倍。提取的家蝇抗菌肽主要是分子量6.2～17.2 kD、等电点5.59～5.91的弱酸性小分子多肽,其热稳定性高,能杀灭枯草杆菌Bacillus subtilis等多种革兰氏阳性菌。加热-层析法能有效去除外源性蛋白酶,保证肽类产品的稳定性,同时还能提取出非蛋白类的抗菌成分,提示其对开发具有高附加值的抗菌产品将会有良好的应用前景。     

家蝇幼虫肠道细菌对其取食选择性和生长发育的影响

目的探究家蝇幼虫肠道细菌对幼虫取食与发育的影响,进而明确肠道细菌的部分功能。方法取3日龄家蝇幼虫,采用细菌传统分离法分离纯化其肠道内可培养细菌并进行分子鉴定,利用这些肠道细菌进行家蝇幼虫爬行选择实验,测定幼虫对不同细菌的选择性;利用这些肠道细菌发酵液与麦麸混合饲养家蝇幼虫,记录家蝇幼虫发育过程中的生物学参数,分别以LB培养原液与麦麸混合饲养的幼虫为阴性对照,以无菌水与麦麸混合饲养的幼虫为空白对照。结果在家蝇幼虫肠道中共分离出9个属10种细菌,分别为霍氏肠杆菌(Enterobacter hormaechei)、肺炎克雷伯菌(Klebsiella pneumoniae)、铜绿假单胞菌(Pseudomonas aeruginosa)、别雷斯不动杆菌(Acinetobacter bereziniae)、斯氏普罗威登斯菌(Providencia stuartii)、阴沟肠杆菌(Enterobacter cloacae)、乳酸乳球菌(Lactococcus lactis)、纺锤形赖氨酸芽胞杆菌(Lysinibacillus fusiformis)、居幼虫普罗威登斯菌(Providencia vermicola)和沙福芽胞杆菌(Bacillus safensis)。其中,除铜绿假单胞菌和斯氏普罗威登斯菌外,其余8种细菌对幼虫有显著吸引作用;除铜绿假单胞菌对家蝇生长有明显抑制作用以外,其余9种细菌对家蝇幼虫生长均有一定的促进作用,其中霍氏肠杆菌和别雷斯不动杆菌对其生长有显著促进作用。结论明确了家蝇幼虫肠道细菌的组成,确定了8种家蝇幼虫肠道细菌对其取食有吸引作用,9种细菌对其生长发育有促进作用。霍氏肠杆菌和别雷斯不动杆菌可作为添加剂用于家蝇的规模化饲养,以提高养殖效率。铜绿假单胞菌可作为生长抑制剂用于家蝇幼虫的防治。