Survey of insect growth regulator (IGR) resistance in house flies (Musca domestica L.) from southwestern Turkey

Insect growth regulators (IGRs) are currently the fastest‐growing class of insecticides, and in Turkey these products represent a new approach to pest control. In recent years, several IGRs were also registered for the control of the house fly, Musca domestica L. (Diptera: Muscidae), in Turkey. A field survey was conducted in the summers of 2006 and 2007 to evaluate resistance to some agriculturally and medically used IGRs on house flies from livestock farms and garbage dumps in the greenhouse production areas (Merkez, Kumluca, Manavgat, and Serik) of Antalya province (Southwestern Turkey). The results of larval feeding assay with technical diflubenzuron, methoprene, novaluron, pyripoxyfen, and triflumuron indicate that low levels (RF<10‐fold) of resistance to the IGRs exist in the house fly populations from Antalya province. Exceptions, however, were two populations, Guzoren and Toptas, from the Kumluca area which showed moderate resistance to diflubenzuron with 11.8‐fold in 2006 and 13.2‐fold in 2007, respectively. We found substantial variation in susceptibility of field‐collected house fly populations from year to year and from product to product. We generally observed an increase in resistance at many localities sampled from 2006 to 2007. The implications of these results to the future use of IGRs for house fly control are discussed. It will be critically important to continue monitoring efforts so that appropriate steps can be taken if resistance levels start to increase.     

Electrophoretic analysis of genetic variability in the house fly (Musca domestica L.)

Methods are described for the resolution of house fly, Musca domestica L., enzymes by vertical polyacrylamide gel electrophoresis. An electrophoretic survey in Ames, Iowa, of 51 loci distributed among 26 enzyme systems revealed that 40% of the loci are polymorphic. Observed and expected heterozygosities measured at 33 loci were 0.0981 and 0.1148, respectively. A significant deficiency of heterozygotes was noted at certain loci.Journal Paper No. J-11423 of the Iowa Agriculture and Home Economics Experiment Station, Ames. Project No. 2411.     

Ovarian suppression by DDT and resistance in the house fly (Musca domestica L.)

Suggested by immunological theory, this study was initiated to test an hypothesis on physiological induction of resistance to insecticides. The hypothesis was proved untenable in the test system, but from the experimentation emerged evidence for a chronically toxic action of DDT expressed in reduced fecundity in female house flies fed sub-lethal amounts of this insecticide. This action can be a strong selective force, promptly revealing tolerant genotypes in the population. The usual selection for resistance does not necessarily also select for ovarian tolerance; even DDT-resistant flies can show ovarian suppression when fed DDT-contaminated food.It is possible that the route of administration of the DDT is important as the means by which the physiologic events described can occur as a chronic intoxication without the usual acutely toxic effects.

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Zusammenfassung Der vorliegenden Arbeit liegt die Frage zugrunde, ob Stubenfliegen, die bereits im Embryonalstadium DDT ausgesetzt werden, diesem gegenüber Resistenz erwerben können. Fütterung erwachsener Stubenfliegen mit C¹⁴-markiertem DDT führt zu dessen Inkorporation schon in den Eiern der Ovarien; die Inkorporation konnte in den schlüpfenden Larven weite verfolgt werden.In Versuchen, in denen je Versuchsglied stets nur die Nachkommenschaft eines Elternpaares (ein Eigelege) verwendet wurde, spalteten sich zwei gleichgrossen Populationen heraus: Während die eine die gleiche Anfälligkeit gegenüber DDT (0,12 g/Fliege) aufwies wie die Nachkommenschaft DDT-ungefütterter Eltern, war die andere Population dieser Dosis gegenüber tolerant.Die Ergebnisse von weiteren Versuchen belegen eindeutig, dass die durch DDT-Behandlung im Embryonalstadium hervorgerufene DDT-Toleranz primär nicht physiologisch bedingt ist, sondern primär auf genetischen Ursachen beruhen muss: Wurden DDT-gefütterte Weibchen mit DDT-anfälligen bzw. DDT-resistenten Männchen, denen kein DDT zum Futter gemischt worden war, gekreuzt, so war die gesamte Nachkommenschaft DDT-anfällig bzw. DDT-resistent.Es ergibt sich die Frage, welches Prinzip diese genotypisch verankerte Toleranz phänotypisch in Erscheinung treten lässt. Die in den Versuchen verwendeten DDT-Dosen waren ohne wesentlichen Einfluss auf den Eischlupf und die Mortalität von Larven und Fliegen. Dagegen senkte die Fütterung deutlich die Anzahl der zur Eiablage befähigten Weibchen und die Anzahl der von den anderen Weibchen gelegten Eier.

     

Visual targets for capture and management of house flies, Musca domestica L.

House flies and stable flies were collected on a Florida dairy farm using a commercial Alsynite sticky cylinder trap that was either used alone or covered with white, blue, or black outdoor awning fabric. Collections of both species of flies were highest on exposed Alsynite (house flies, 506.2 flies/day; stable flies, 19.1) followed by blue fabric (house flies, 308.1 flies/day; stable flies 12.5). Responses of both species to white and black fabric were 70% lower than to either of the former materials. When blue fabric was used to cover 50% of the surface area of Alsynite cylinders, house fly responses were significantly higher (290.2 flies/day) than to blue fabric alone (165.2); stable fly responses to the bi-colored target were significantly higher (152.6) than to Alsynite alone (93.8). Comparison of fly counts in the blue-covered versus uncovered Alsynite with traps of a single material indicated that house fly attraction to blue fabric was enhanced by the presence of clear Alsynite, whereas stable fly attraction to Alsynite was enhanced by the presence of blue fabric. The presence of blue+Alsynite visual targets increased collections of house flies in pans of dry fly bait but not in baited jug traps. Visual targets treated with 1.2% bifenthrin controlled >50% and 90% of house flies in large cages by days two and four after placement, respectively.     

Autosomal interactions and mechanisms of pyrethroid resistance in house flies, Musca domestica

Five BC? lines and 16 house fly mass-cross homozygous lines were generated from crosses of the pyrethroid resistant ALHF (wild-type) and susceptible aabys (bearing recessive morphological markers on each of five autosomes) strains. Each of the resulting homozygous lines had different combinations of autosomes from the resistant ALHF strain. Levels of resistance to permethrin were measured for each line to determine the autosomal linkage, interaction and, possibly, regulation in pyrethroid resistance of house flies. Results indicated that factors on autosome 4 are not involved in the development of resistance in house flies, while factors on autosomes 1, 2, 3 and 5 play important roles in pyrethroid resistance. The sodium channel gene has been mapped on autosome 3 and multiple cytochrome P450 genes overexpressed in resistant ALHF house flies have been genetically mapped on autosome 5, suggesting that P450 mediated detoxification and sodium channel-mediated target site insensitivity located on autosomes 3 and 5, respectively, are major factors related to resistance development in house flies. However, neither the factors on autosome 3 or 5 alone, nor the factors from both autosomes 3 and 5 combined could confer high levels of resistance to pyrethroid. In addition, strong synergistic effects on resistance was obtained when autosomes 1 and 2 interact with autosome 3 and/or 5, suggesting that the trans factors on autosomes 1 and 2 may interact with factors on autosomes 3 and 5, therefore, playing regulatory roles in the development of sodium channel insensitivity- and P450 detoxification-mediated resistance.     

Superoxide dismutase in the housefly,Musca domestica (L.)

Four superoxide dismutase (SOD) (E.C. 1.15.1.1) isozymes were present in whole tissue homogenates of Musca domestica when examined by polyacrylamide gel electrophoresis. One of the isozymes contained manganese, and the other three contained copper and zinc. All were observed in each of the body tagma (head, abdomen, and thorax) and at each developmental stage (egg to adult). The copper- and zinc-containing isozymes purified from newly emerged, adult M. domestica had a relative molecular weight of 34,800 as determined by gel filtration chromatography but consisted of two equal-size subunits of 16,000 as measured by sodium dodecylsulfate polyacrylamide gel electrophoresis. An isoelectric point between 4.8 and 5.1 was measured. Approximately 2 mol each of copper and zinc were present per dimer. The three copper, zinc isozymes were identified as charge variants. The amino acid composition of the enzyme was similar to that of copper, zinc-containing superoxide dismutases from other sources. Purified housefly copper, zinc superoxide dismutase was neither deactivated nor able to protect lactic dehydrogenase against deactivation in the presence of light and rose bengal, a known generator of singlet oxygen. The role of SOD in the phototoxic reaction involving rose bengal is discussed.     

拟除虫菊酯对家蝇Ca—ATPase和Ca—Mg—ATPase的抑制作用

通过对家蝇神经系统的Ca-ATPase、Ca-Mg-ATPase性质的研究,表明Ca-ATPase、Ca-Mg-AT-Pase反应的适宜pH值分别为7.0-8.5和6.5。适温皆为35-40℃;底物（ATP）最适浓度均为0.5mmol/L。比较测定了家蝇三个品系中两种ATPase的活性及拟除虫菊酯对该酶的抑制作用,实验证明,敏感与Del-R、2Cl-R品系间Ca-ATPase、Ca-Mg-ATPase活力无明显的差异。溴氰菊酯、氯菊酯可部分地抑制敏感品系家蝇Ca-ATPase活性,而对拟除虫菊酯抗性品系Ca-ATPase无抑制作用,从而证明,Del-R、2Cl-B品系Ca-ATPase对拟除虫菊酯的敏感性已明显降低,这可能能是击倒抗性机制之一。实验还表明,拟除虫菊酯对Ca-Mg-ATPase基本上无抑制作用,这说明在家蝇中,Ca-Mg-ATPase并不是拟除虫菊酯的一个靶标位点。     

House Fly (Musca domestica L.) Attraction to Insect Honeydew

House flies are of major concern as vectors of food-borne pathogens to food crops. House flies are common pests on cattle feedlots and dairies, where they develop in and feed on animal waste. By contacting animal waste, house flies can acquire human pathogenic bacteria such as Escherichia coli and Salmonella spp., in addition to other bacteria, viruses, or parasites that may infect humans and animals. The subsequent dispersal of house flies from animal facilities to nearby agricultural fields containing food crops may lead to pre-harvest food contamination with these pathogens. We hypothesized that odors from honeydew, the sugary excreta produced by sucking insects feeding on crops, or molds and fungi growing on honeydew, may attract house flies, thereby increasing the risk of food crop contamination. House fly attraction to honeydew-contaminated plant material was evaluated using a laboratory bioassay. House flies were attracted to the following plant-pest-honeydew combinations: citrus mealybug on squash fruit, pea aphid on faba bean plants, whitefly on navel orange and grapefruit leaves, and combined citrus mealybug and cottony cushion scale on mandarin orange leaves. House flies were not attracted to field-collected samples of lerp psyllids on eucalyptus plants or aphids on crepe myrtle leaves. Fungi associated with field-collected honeydews were isolated and identified for further study as possible emitters of volatiles attractive to house flies. Two fungal species, Aureobasidium pullulans and Cladosporium cladosporioides, were repeatedly isolated from field-collected honeydew samples. Both fungal species were grown in potato dextrose enrichment broth and house fly attraction to volatiles from these fungal cultures was evaluated. House flies were attracted to odors from A. pullulans cultures but not to those of C. cladosporioides. Identification of specific honeydew odors that are attractive to house flies could be valuable for the development of improved house fly baits for management of this pest species.     

Reversed selection responses in small populations of the housefly (Musca domestica L.)

We compared the efficacy of artificial and natural selection processes in purging the genetic load of perpetually small populations. We subjected replicate lines of the housefly (Musca domestica L.), recently derived from the wild, to artificial selection for increased mating propensity (i.e., the proportion of male–female pairs initiating copulation within 30 min) in efforts to cull out the inbreeding depression effects of long-term small population size (as determined by a selection protocol for increased assortative mating). We also maintained parallel non-selection lines for assessing the spontaneous purge of genetic load due to inbreeding alone. We thus evaluated the fitness of artificially and ‘naturally’ purging populations held at census sizes of 40 individuals over the course of 18 generations. We found that the artificially selected lines had significant increases in mating propensity (up to 46% higher from the beginning of the protocol) followed by reversed selection responses back to the initial levels, resulting in non-significant heritabilities. Nevertheless, the ‘naturally’ selected lines had significantly lower fitness overall (a 28% reduction from the beginning of the protocol), although lower effective population sizes could have contributed to this effect. We conclude that artificial selection bolstered fitness, but only in the short-term, because the inadvertent fixation of extant genetic load later resulted in pleiotropic fitness declines. Still, the short-term advantage of the selection protocol likely contributed to the success of the speciation experiment since our recently-derived housefly populations are particularly vulnerable to inbreeding depression effects on mating behavior.     

麦麸饲料中细菌对家蝇幼虫生长发育的影响

从饲料用麦麸中分离出的12种细菌均能支持无菌家蝇Musca domestica L．幼虫在胰化酪蛋白大豆卵黄琼脂（TrypticaseSoy EggYolkAgar,TSEYA）培养基中完成整个生长发育过程。1）幼虫在接种香味类香味菌Myroidesodoratimimus的TSEYA培养基中生长时间最短,仅需97．61&#177;1．14h;2）幼虫在接种醋酸钙不动杆菌Acinetobacter calcoaceticus的TSEYA培养基中的化蛹率可达到86．81％;3）从接种嗜水汽单胞菌Aeromonas hydrophila的TSEYA培养基中得到的蝇蛹重量最高,达到20．15&#177;0．23mg／个;4）除铜绿假单胞菌Pseudomonasaeruginosa饲养的家蝇羽化率较低（60．87％）外,其余各种细菌饲养的羽化率在84．33％～97．47％之间。此外,枯草芽孢杆菌Bacillus subtilis、香味类香味菌、聚团肠杆菌Enterobacter agglomerans以及成团肠杆菌Pantoeaagglomerans可作为单一营养来源支持幼虫完成整个生长发育过程。对枯草芽孢杆菌、金黄色葡萄球菌Staphylococcusaurous、成团肠杆菌、大肠杆菌Escherichiacoli、奇异变形杆菌Proteusmirabilis以及香味类香味菌中各种营养成分进行分析,结果发现,6种细菌均能提供大量的维生素如（0．105～1．08g／kg）。在氨基酸方面,香味类香味菌和枯草芽孢杆菌中的10种昆虫必需氨基酸含量与总氨基酸含量之比（Essential amino acid／Totalaminoacid,EAA／TAA）最高,而金黄色葡萄球菌最低。这个比例与蛹重呈正相关（p=0．031）。在脂肪酸相对含量方面,金黄色葡萄球菌具有最高的饱和脂肪酸含量（76．38％）,香味类香味菌含有56．79％的不饱和脂肪酸,而枯草芽孢杆菌则具有最高的支链脂肪酸含量（42．16％）。     

Ordered membrane particles in rhabdomeric microvilli of the housefly (Musca domestica L.)

Rhabdomeric microvilli of the housefly were freeze-fractured (FF) and thin sectioned (TS) for ultrastructural examination. Ordered files of closely packed membrane particles (82 Å wide, 250 Å long) were seen (FF) on the microvillar membrane (usually E face). The long axis of each particle was canted about 45° to that of the microvillus. Occasionally particles in this array appeared on the P face. It is hypothesized that ordered particles may represent either a photopigment precursor stock, a second photolabile pigment, or the newly discovered sensitizing, UV-absorbing, photostable visual pigment. In the underlying membrane leaflet (P face) were found spherical (85 Å diameter) unoriented particles in a concentration of about 6,000/μm². The size, shape and density of these structures are compatible with those of rhodopsin particles. These particles also covered the basal area of each microvillus. The findings from TS material were difficult to correlate with those from FF replicas. At high magnification the former showed that the plasma membrane of the transected microvillus is composed of spherical, hollow subunits (averaging 43 Å diameter), sometimes fused to form double, 86 Å units. These substructures were closely packed and continuous around the microvillus. This beaded plasma membrane, in rare cases, was doubled around the microvillus. In other instances the plasma membranes were continuous between neighboring microvilli. The physiological implications of these ultrastructural features are discussed.     

Occurrence and metabolism of prostaglandins in the housefly,Musca domestica (L.)

Prostaglandins (PGs) of the E and F series were quantified in the housefly by radioimmunoassay (RIA). Whole insects and reproductive tissues from both sexes contained PGE₍₁₊₂₎ and PDG_2α which increased in amount with age. PGF_2α levels were higher than PGE series in extracts of whole male and female insects and in ovaries. Male reproductive tissues contained higher amounts of PGE₍₁₊₂₎ than PGF_2α. Gas chromatographic-mass spectrometric (GC-MS) analyses of the products formed after injection of arachidonic acid (20:4) and eicosatrienoic acid (20:3, n-6) into male and femal insects demonstrated the conversion of 20:4 to PGF_2α and 20:3 to PGF_1α. Radiolabeled 20:4 injected into houseflies was rapidly converted to PGE₂ and PGF_2α. The catabolism of PGE₂ was more rapid than PGF_2α in males, whereas in females, PGE₂ and PGF_2α were converted to more polar products at similar rates. Radiolabeled 20:4 injected in the hemolymph was incorporated into the reproductive tracts of male insects. About 2.1% of the total radioactivity from [³H]20:4 injected into males just prior to mating was transferred to females during mating. Thus, PG are formed from 20:4 in male and female houseflies. During mating, 20:4 is transferred from males to females where it can be metabolized to PGF_2α.     

Evaluation of commercial and field‐expedient baited traps for house flies,Musca domestica L. (Diptera: Muscidae)

A comparison of nine commercial baited fly traps on Florida dairy farms demonstrated that Terminator traps collected significantly more (13,323/trap) house flies (Musca domestica L.) than the others tested. Final Flight, Fly Magnet, and FliesBeGone traps collected intermediate numbers of flies (834‐2,166), and relatively few were caught with ISCA, Advantage, Fermone Big Boy, Squeeze & Snap, or OakStump traps (<300). Terminator traps collected about twice as many flies (799.8/trap) as FliesBeGone traps (343.8) when each trap was baited with its respective attractant, but when the attractants were switched between the two trap types, collections were significantly lower (77‐108) than was observed with traps baited with their respective attractant. Solutions of molasses were significantly more attractive to house flies than honey, maple syrup, or jaggery (date palm sugar). Field‐expedient traps constructed from discarded PET water bottles were much less effective than commercial traps, but painting the tops of such traps with black spray paint resulted in a six‐fold increase in trap capture.     

Molecular Polymorphism of Head Acetylcholinesterase from Adult Houseflies (Musca domestica L.)

Acetylcholinesterase (AChE) from housefly heads was purified by affinity chromatography. Three different native forms were separated by electrophoresis on polyacrylamide gradient gels. Two hydrophilic forms presented apparent molecular weights of 75,000 (AChE1) and 150,000 (AChE2). A third component (AChE3) had a migration that depended on the nature and concentration of detergents. In the presence of sodium deoxycholate in the gel, AChE3 showed an apparent molecular weight very close to that of AChE2. Among the three forms, AChE3 was the only one found in purified membranes. The relationships among the various forms were investigated using reduction with 2-mercaptoethanol or proteolytic treatments. Such digestion converted purified AChE3 into AChE2 and AChE1, and reduction of AChE3 and AChE2 by 2-mercaptoethanol gave AChE1, in both cases with a significant loss of activity. These data indicate that the three forms of purified AChE may be classified as an active hydrophilic monomeric unit (G1) plus hydrophilic and amphiphilic dimers. These two components were termed G2s and G2m, where "s" refers to soluble and "m" to membrane bound.