A device for preventing houseflies from copulating

The construction and use of a device the virgin chamber, for preventing houseflies, Musca domestica L., from copulating are described. The flies emerge between two horizontal plates kept at a distance of 5 or 4 mm and may be kept in this chamber for 1–3 days before the sexes are separated. The method is regularly used at the Danish Pest Infestation Laboratory for providing unmated flies for selection for resistance to insecticides. Original tests showed that all eggs produced by flies that stayed 1–3 days in the device were infertile, but in recent experiments a small proportion of fertile eggs were found.

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Résumé La construction et l'utilisation d'une chambre de virginité, pour empêcher la copulation de M. domestica L. est décrite. Les mouches émergent entre deux plaques horizontales séparées par 4 à 5 mm et sont maintenues dans cette chambre pendant 1 à 3 jours jusqu'à la séparation des sexes. Il s'agit d'une méthode de routine du Laboratoire Danois des Animaux Nuisibles qui fournit des mouches vierges en vue de la sélection pour la résistance aux insecticides. Les tests originels ont montré que tous les ufs pondus par les mouches qui avaient séjourné de 1 à 3 jours dans le dispositif étaient stériles, mais dans des expériences récentes une faible proportion d'ufs fertiles a été observée dans quelques tests.

     

温度对家蝇广州种群成虫繁殖力及卵黄蛋白发生的影响

研究了不同温度对家蝇(Musca domestica L.)广州种群繁殖力及卵黄蛋白发生的影响,旨在为利用家蝇广州种群大规模高效养殖提供技术支持。选同一天刚羽化的健康雌、雄蝇,分别置于20、24、28、32和36℃环境下单对饲养,重复6次。每天测定成虫日产卵量、卵孵化率及死亡数等,统计家蝇单雌产卵量、卵孵化率、成虫寿命、产卵前期和产卵期;同时自雌蝇羽化第一日起,连续15 d,每天每个温度处理下取雌蝇3头,采用间接酶联免疫(indirect enzyme-linked immunosorbentassay,ID-ELISA)法测定5种温度下雌蝇每日卵黄蛋白合成量及羽化后前15 d卵黄蛋白合成总量。结果表明,温度对家蝇成虫繁殖力影响显著。产卵量以24℃环境下最高(1 921.17粒/雌),24～28℃时产卵量显著下降。28℃时卵孵化率最高(93.48%),高或低于此温度,卵孵化率显著下降,当温度达36℃时,孵化率仅为60.78%。雌蝇在20～28℃范围内产卵期差异不显著,32℃及以上温度下,雌蝇产卵期显著缩短。产卵前期以20℃最长(9.83 d),28℃最短(3.00 d),高于28℃产卵前期又显著延长。雌、雄蝇寿命均随着温度升高而显著缩短。温度对广州种群雌蝇羽化后前15 d的卵黄蛋白合成影响显著,24℃下前15 d合成的总卵黄蛋白最高(1 683.15μg/雌),其次为28℃(1 591.95μg/雌),20℃最低(232.81μg/雌)。家蝇广州种群在24～28℃繁殖效率最高。     

A look into the cock-pit of the fly

Summary An anatomical investigation has been carried out on the third optic ganglion of the fly, Musca domestica. Two systems of giant units, the dendritic arborizations of which are arranged orthogonally relative to each other, dominate the neuropile of this ganglion. The elements of the two systems have been reconstructed using a graphical procedure based on histological sections. One system branches predominantly in the dorsoventral direction, the other one in the anterior-posterior direction. Both systems of the giant units have a twin system composed of elements smaller in diameter and strictly parallel to the main units. The two systems have been termed the Vertical and Horizontal Systems.The elements of the two systems of fibers project into the periesophageal region where they come into contact with other descending elements. Electron microscopic investigations show that the two systems are post-synaptic at the level of the ganglion from which they originate. The horizontal system has been shown to be post and pre-synaptic in nature during its course in the mid-brain and ultimately presynaptic at its endings in the periesophageal ring. The peculiar geometric arrangement of the two anatomical systems of fibers suggests a precise function in relation to the visual world and in particular to the detection of the direction of motion. The accuracy of the structural pattern displayed by the giant units in the lobular plate seems to suggest that this optic ganglion represents the ultimate orderly projection of the external world in the brain of the fly.A short review of the electrophysiological data concerning this ganglion has been tentatively correlated with some behavioral data related to the visual orientation and fixation in insects.     

The effects of laboratory culturing on (Z)-9-tricosene (muscalure) quantities on female houseflies

Using gas chromatography the relative amounts of (Z)-9-tricosene (muscalure) and some other hydrocarbons on the cuticle of 1- to 20-day-old houseflies (Musca domestica L.) from different strains were determined. Flies from a WHO strain, in culture since 1961, and first-generation laboratory-cultured flies from two wild-type strains from a poultry breeding and a cow-house with pigsty, respectively, were compared. On WHO females hydrocarbons with 23–25 C atoms constituted about 65% of the total hydrocarbons, whereas on wild-type females less than 2% of these compounds was present. (Z)-9-tricosene comprised up to 20–30% of the total hydrocarbons on 5- to 20-day-old WHO females, whereas less than 0.5% (Z)-9-tricosene was present on the wild-type females. We also compared the amounts of (Z)-9-tricosene and some other hydrocarbons on female houseflies, kept in culture in the laboratory for several generations. It appeared that whereas on first-generation wild-type females hardly or no (Z)-9-tricosene could be detected, the amounts of this substance had increased considerably after some tens of generations in the laboratory. It is suggested that this was due to selection in subsequent generations of high-density populations. Production of (Z)-9-tricosene and of tricosane was shown to be closely linked. Selection did not affect the production of other cuticular hydrocarbons by the females. It is suggested that in mixed populations (both sexes together in a cage) in the course of time (Z)-9-tricosene is transferred from females to males and (Z)-9-heptacosene from males to females. It is concluded that reproductive ability of houseflies does not primarily depend on the amounts of (Z)-9-tricosene on females, although higher amounts of this substance may increase contacts between males and females.     

世界古老果树榅桲在中国的归化及其种群动态——以湖南省褒忠山种群为例

外来植物归化因其对本地生态系统有潜在的入侵风险而受到生态学家的广泛关注。群落和种群结构反映植物的环境适应性、种群地位、稳定性和发展趋势,可为判定外来植物归化提供可靠依据。榅桲(Cydonia oblonga)为在全球广泛引种栽培达4000多年的古老果树,引入中国已有2500多年,但关于其野外逸生种群的生存状态未见报道。以目前中国唯一逸生地——湖南省褒忠山的榅桲种群为对象,在其所在群落物种组成和群落结构分析的基础上,采用时空替代法,运用静态生命表、生存曲线和时间序列预测模型对榅桲种群动态进行了定量分析。结果表明：(1)群落内共有维管束植物20科28属31种,其中木本植物16种,草本植物15种;区系以温带成分为主,占群落内非世界分布总属数的75%;(2)群落具有明显层次结构,可分灌木层和草本层,灌木层个体集中于0—1.5 m高度级,占总个体数的81.81%;(3)种群龄级结构呈近倒“J”型,存活曲线趋近于Deevey-Ⅱ型,具有稳定的更新潜力;(4)生存分析表明榅桲种群具有前期优势、中期减少、后期稳定的特点;时间序列预测表明该种群个体数量未来能够持续增长,但幼苗及小树个体基本保持稳定,其种...     

Influence of sex and prior protein feeding on preferences by the housefly, Musca domestica, between sucrose solutions and solutions of l-leucine or sodium phosphate buffer

Comparisons were made of the preferences shown by non-protein-fed females, protein-fed gravid females, and non-protein-fed males of the house fly, given choices between sucrose solution and either l-leucine or sodium phosphate buffer.In choice tests where non-protein-fed females showed little preference, protein-fed females and males both showed a strong preference for the sucrose solution. The findings suggest that l-leucine and sodium phosphate buffer are recognised by non-protein-fed females as indicators of nutrients for ovarian development.

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Résumé Les choix alimentaires de 3 catégories de M. domestica: femelles n'ayant pas consommé de protéines, femelles à ovaires développés alimentées sur protéines, mâles n'ayant pas consommé de protéines, ont été examinés par leur absorption de solutions dans une paire de potomètres.Elles avaient le choix entre, d'une part une solution de sucrose et, d'autre part une solution de L. leucine ou d'un tampon de phosphate de soude.Pour les expériences où les femelles non préalablement alimentées sur protéines ne présentent aucune préférence, les femelles alimentées sur protéines et les mâles préfèrent nettement la solution de sucrose.Les résultats montrent que les femelles non alimentées sur protéines répondent plus que les femelles mûres et les mâles à la fois à la solution de L. leucine et au tampon de phosphate qu'au sucrose. Ceci suggère que l'impulsion sensorielle provoquée par ces deux breuvages est perçue par les femelles n'ayant pas consommé de protéines comme un indicateur d'aliments indispensables au développement ovarien.

     

The <Emphasis Type="Italic">transformer2</Emphasis> gene in <Emphasis Type="Italic">Musca domestica</Emphasis> is required for selecting and maintaining the female pathway of development

We present the isolation and functional analysis of a transformer2 homologue Mdtra2 in the housefly Musca domestica. Compromising the activity of this gene by injecting dsRNA into embryos causes complete sex reversal of genotypically female individuals into fertile males, revealing an essential function of Mdtra2 in female development of the housefly. Mdtra2 is required for female-specific splicing of Musca doublesex (Mddsx) which structurally and functionally corresponds to Drosophila dsx, the bottom-most regulator in the sex-determining pathway. Since Mdtra2 is expressed in males and females, we propose that Mdtra2 serves as an essential co-factor of F, the key sex-determining switch upstream of Mddsx. We also provide evidence that Mdtra2 acts upstream as a positive regulator of F supporting genetic data which suggest that F relies on an autocatalytic activity to select and maintain the female path of development. We further show that repression of male courtship behavior by F requires Mdtra2. This function of F and Mdtra2 appears not to be mediated by Mddsx, suggesting that bifurcation of the pathway at this level is a conserved feature in the genetic architecture of Musca and Drosophila.Edited by D. Tautz     

A simple and nondestructive method for estimation of worker population size in Myrmica ant nests

A method to estimate the number of workers in Myrmica ant nests on abandoned meadows was developed based on removal of workers. Ant workers have a tendency to climb up on wooden sticks put into their nests, therefore, assuming that the number of workers removed on sticks is related to the total number of workers within the nests, regression models for Myrmica rubra, M. ruginodis and M. scabrinodis may be built. We used a general regression model to perform a backward stepwise elimination of explanatory variables. These were the number of workers removed on sticks, temperature at the nest and site (a categorical variable). In case of each species the final model contained only the number of workers removed as a significant variable. The method is apparently non-destructive as we did not observe decreased survival of nests surveyed as compared to control nests. The method can be a very useful tool in population studies of ants as well as in biodiversity projects, where ants are used as bioinidcators. Received 10 February 2005; revised 4 August 2005; accepted 24 August 2005.     

Asynchronous mitotic domains during blastoderm formation inMusca domestica L. (Diptera)

Summary We describe the mitotic cleavage patterns during blastoderm stage of the house flyMusca domestica L. Nuclear divisions up to mitotic stage 11 are apparently synchronous. Beginning with stage 12, nuclear divisions in the posterior third of the embryo lag behind, resulting first in a parasynchronous and finally in an asynchronous cleavage pattern. Thus a stage exists where all nuclei in the anterior region have completed 14 nuclear division cycles, while those in the posterior region have completed only 13 cycles. The border region between these nuclei is well defined and lies at 35% EL (egg length), the expression border of a gap gene. This border region is about 4–5 nuclei wide and shows a specialized mitotic behaviour.     

不同来源家蝇幼虫蛋白粉的水解与抗氧化性

本研究比较不同来源、不同酶解物浓度的家蝇幼虫蛋白及其抗氧化活性。以来自猪粪源和鸡粪源家蝇幼虫为原料制备蛋白粉,用胰蛋白酶水解蛋白粉制备水解产物,以·OH和O_2~-·清除率为指标评价两种蛋白酶解物的抗氧化活性。结果显示,家蝇幼虫蛋白水解物在4 h达水解度最高值,其水解物的·OH清除率在5 h达到最大为59.02%,其水解物的O_2~-·清除率在4 h达到最大为73.24%;随着两种水解物浓度增加,其抗氧化效果越强,当猪粪源和鸡粪源家蝇幼虫酶解物浓度为10 mg/mL时,两者O_2~-·清除率达到最大分别为70%和80%;·OH清除率分别为45%和52%。由此可见,家蝇幼虫酶水解物对超氧阴离子、羟自由基均有清除能力,鸡粪源家蝇幼虫酶解物优于猪粪源。     

Fine structure of the terminal organ of the house fly larva,Musca domestica L.

Summary The terminal organs of the cephalic lobes of the house fly larva, Musca domestica L., were studied by scanning and transmission electron microscopy. Six different types of sensilla were found: (1) papilla sensillum, (2) pit sensillum, (3) spot sensillum, (4) modified papilla sensillum, (5) knob sensillum, and (6) scolopidium. The papilla, pit, spot, and modified papilla sensilla have the essential structure of contact chemoreceptors, i.e., the unbranched dendritic tips are exposed externally through a single opening. However, a tubular body, which is a characteristic structure of tactile setae, is also present in some of the dendritic tips. We assume these sensilla serve a dual function—contact chemo- and mechanoreception. The role of the knob sensilla is obscure. The scolopidia present in the dorsal and the terminal organ are probably stress detectors. Two basal bodies occur in the dendritic ciliary region of all sensilla. Both of the basal bodies (except in the scolopidia) give rise to the distal ciliary microtubules as well as the proximal rootlets.This research was supported in part by the Office of Naval Research, PHS Research Grant EC-246 and NIH Training Grant ES-00069. Paper No. 3608 of the North Carolina State University Agricultural Experiment Station journal series. The advise of R. A. Steinbrecht is gratefully acknowledged.     

The effect of acidification in enclosures on the biomass and population size structure of Bosmina longirostris

An in situ enclosure experiment was performed from June to September, 1982, in Lake O'Woods, West Virginia (pH7.0), to examine the effects of acidification on the Bosmina longirostris population. Treatments were two control enclosures and two enclosures acidified from an initial pH of 7.2 to pH 4.2 over a 44 day period, using H₂SO₄. B. longirostris was not adversely affected by the acidification. In fact, its abundance, biomass, and mean body size increased in the acid treatment, as compared withe control. This positive response was probably not a direct consequence of the altered water chemistry, but instead may have occured due to reduced competition for food, and also reduced predation pressure. Acidification resulted in a decreased abundance of other herbivores, and elimination of the dominant carnivore, Mesocyclops edax.     

Survey of Mariner-Like Elements in the Housefly, Musca Domestica

The presence of mariner-like elements in four strains of the housefly, Musca domestica, was surveyed by PCR. Using the inverted terminal repeat (ITR) sequences of the Mos 1element as primers, DNAs were successfully amplified from all strains of the housefly. Southern blot analysis indicated that these amplified DNAs were repetitive sequences in the genome of M. domestica. Sequence analyses of cloned PCR products showed that they were 45% identical to the Mos 1element. These fragments appeared to be nonfunctional, because they contained no intact open reading frame (ORF) capable of encoding transposase. We conclude that these DNAs are degraded mariner-like elements (MLEs) in M. domestica. Because these endogenous MLEs in M. domesticado not encode any functional proteins, they probably would not affect the behavior of mariner-based vectors if such were introduced into this species as transformation vectors.     

Fine structure of the ventral organ of the house fly larva,Musca domestica L.

Summary The ventral organs of the cephalic lobes of the house fly larvae, Musca domestica L., were studied by scanning and transmission electron microscopy. Four sensilla were found. Three of them are each innervated by a single dendrite whose ending possesses a tubular body and communicates to the exterior through an opening. These sensilla are assumed to be mechanoreceptors. The 4th sensillum is supplied by 2 bipolar neurons with the unbranched dendritic tips (without tubular bodies) exposed to the exterior through a single opening and is probably a contact chemoreceptor.This research was supported in part by the Office of Naval Research and NIH Training Grant ES-00069. Paper no. 3724 of the North Carolina State University Agricultural Experiment Station journal series.     

The use of triflumuron on sugar-baited targets for autosterilization of the housefly, Musca domestica

A target system, capable of delivering an effective transovarial dose of the chitin synthesis inhibitor triflumuron to the house flyMusca domestica Linnaeus (Diptera: Muscidae), is described. A single 15×5 cm polyester target, dipped in triflumuron 10% suspension concentrate (s.c.) and 50% W/V sucrose solution and suspended in 30×30×30 cm cages of approximately 400 adultM. domestica for 24 h, reduced mean egg hatch to 47%. Egg hatch was reduced to 35% by allowing flies access to similar targets for 7 d. Exposure to triflumuron also interrupted the developmental cycle at the larval stage. After adultM. domestica had been exposed for 24 h to a target baited with 10% triflumuron s.c. and a 50% W/V sucrose solution, only 6% of eclosed larvae pupariated; longer exposure times prevented any pupariation. However, beyond pupariation, there appeared to be no further effect of triflumuron. The age of the flies at first exposure also affected the extent of the ovicidal and larvicidal effects induced, younger adults being more susceptible. However, effects were shown to decrease with time after exposure to triflumuron. A target dosed with 3% triflumuron s.c. resulted in a greater ovicidal effect than a target dosed with 10% triflumuron, suggesting that the higher doses were detected and elicited some negative response from the flies. Effects on females via the treatment of males were demonstrated. The results suggest that utilization of sugar-baited targets dosed with a low concentration of triflumuron may be a useful step in the development of autosterilizing systems for house fly control.     

Genetic diversity at electrophoretic loci in the house fly,Musca domestica L.

Vertical polyacrylamide gel electrophoresis was used to separate enzyme proteins at 73 putative loci in natural house fly populations sampled in central Iowa. Thirty-nine of the loci were polymorphic (53%). The mean effective number of alleles per polymorphic locus was 1.93 and 1.47 alleles among 68 scored loci. Observed and expected heterozygosities at 34 house fly loci were 0.1628 and 0.1834, respectively. No statistically significant differentiation was detected among nine central Iowa fly populations in 1989 or among nine Iowa and three Minnesota populations in 1990. Journal Paper No. J-14125 of the Iowa Agriculture and Home Economics Experiment Station, Ames. Project No. 2949.     

Mitochondrial DNA variation, effective female population size and population history of the endangered Chinese sturgeon, Acipenser sinensis

The anadromous Chinese sturgeon (Acipenser sinensis), mainly endemic to the Yangtze River in China, is an endangered fish species. The natural population has declined since the Gezhouba Dam blocked its migratory route to the spawning grounds in 1981. In the near future, the completion of the Three Gorges Dam, the world's largest hydroelectric project, may further impact this species by altering the water flow of the Yangtze River. Little is currently known about the population genetic structure of the Chinese sturgeon. In this study, DNA sequence data were determined from the control region (D-loop) of the mitochondrial genome of adult sturgeons (n = 106) that were collected between 1995–2000. The molecular data were used to investigate genetic variation, effective female population size and population history of the Chinese sturgeon in the Yangtze River. Our results indicate that the reduction in abundance did not change genetic variation of the Chinese sturgeon, and that the population underwent an expansion in the past. AMOVA analysis indicated that 98.7% of the genetic variability occurred within each year's spawning populations, the year of collection had little influence on the diversity of annual temporary samples. The relative large effective female population size (N _ef) indicates that good potential exists for the recovery of this species in the future. Strikingly, the ratio of N _ef to the census female population size (N _f) is unusually high (0.77–0.93). This may be the result of a current bottleneck in the population of the Chinese sturgeon that is likely caused by human intervention. This revised version was published online in July 2006 with corrections to the Cover Date.     

Temporal and spatial trends in allozyme frequencies in house fly populations,Musca domestica L.

Summary Allelic and genotypic frequencies were sampled from a single age class of the common house fly, Musca domestica L., at five farms on six dates from July 6 to October 12, 1982. Allozymes at six loci were resolved with vertical polyacrylamide gel electrophoresis. No consistent departures from random mating were detected. No consistent linkage disequilibrium was observed. Allele frequencies at the farms changed in independent and unpredictable ways. Gene frequencies at the five farms were initially divergent, converged in midsummer, and then progressively diverged. The divergence occured in mid-August when fly populations were large. Variation in gene frequencies at adjacent farms accounted for a large proportion of the variance in allele frequencies among all farms. These observations are consistent with the hypothesis that allele frequencies in young adult flies reflected the habitat in which they matured as larvae.Journal Paper No. 11718 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, Project No. 2411