Releases of Spalangia nigroaenea and Muscidifurax zaraptor (Hymenoptera: Pteromalidae) increase rates of parasitism and total mortality of stable fly and house fly (Diptera: Muscidae) pupae in Illinois cattle feedlots

Weekly releases of Spalangia nigroaenea Curtis and Muscidifurax zaraptor Kogan & Legner from May through August of 1991-1993 at small, owner-operated cattle feedlots in Illinois provided weekly emergence of 100-300 parasitoids of each species per feedlot animal. In assessments based on fly and parasitoid emergence from > 47,000 stable fly and house fly puparia collected during the 3-yr period, total stable fly mortality was greater in lots where releases were made (60.7%) than in paired, untreated control lots (51.7%) (P = 0.04; paired t-test); parasitism of stable fly pupae by S. nigroaenea averaged 11.6% where releases were made and 6.4% in paired control lots (P = 0.0016). In lots where releases were made, total mortality of house fly pupae was greater (68.7 versus 56.1%; P = 0.0001); unexplained mortality was greater (55.5 versus 46.1%; P = 0.0018); and parasitism by Muscidifurax spp. was greater (2.4 versus 1.4%; P = 0.07) than in paired control lots. Parasitism, unexplained mortality, and total mortality of both fly species varied significantly from 1991 to 1992 in lots that received the same treatment each year, presumably due primarily to weather. Over the 3-yr period, releasing these species, particularly S. nigroaenea, significantly reduced production of stable fly and house fly adults in cattle feedlots. The potential value of such reductions is likely to vary as a result of feedlot conditions and weather.     

Accudosetm aerosol--an effective house fly (Diptera; Muscidae: Musca domestica L.) adulticide control system for cage type poultry houses

An automatic piped aerosol system (Accudose TM) using 0.7% synergized pyrethrin insecticide, was tested at a typical narrow cage poultry farm for the control of adult house flies, Musca domestica L. A similar narrow cage poultry farm was used as a control with all house fly control measures left up to the cooperating poultryman. AccudoseTM was compared with other house fly control methods at other similar farms which included three types of man-portable ultra volume (ULV) generators and an integrated (biological-chemical) program. Results of the five month test demonstrated that the AccudoseTM system suppressed house fly populations better than other control methods.     

Skin lesions in dogs, horses and calves caused by the stable fly Stomoxys calcitrans (L.) (Diptera: Muscidae)

Specific skin lesions caused by Stomoxys calcitrans on the feeding sites of different species are described. Skin lesions appeared on dogs, horses and calves following bites of stable flies. Necrotic dermatitis was observed in 32 dogs of various breeds at the tip of the ears. Exudative dermatitis appeared on the legs of 45 adult horses and dermatitis was diagnosed in the "hair whirlpools" on the backs of 18 white calves.     

Mortality of horn fly (Diptera: Muscidae) larvae in bovine dung supplemented with loline alkaloids from tall fescue

Larvae of arthropod ectoparasites of livestock, such as the horn fly, Haematobia irritans (L.), may be exposed to acyl-loline alkaloids in dung of ruminant livestock ingesting herbage of the tall fescue (Festuca arundinacea Schreb.)-endophyte association [Neotyphodium coenophialum (Morgan-Jones & W. Gams) Glenn, Bacon & Hanlin comb. nov.]. Biological activity of alkaloid-supplemented bovine dung was assayed by growth, development, and survival of 1st instars of horn fly. An extract from tall fescue seed, containing N-formyl loline (NFL), N-acetyl loline (NAL), and loline (59:21:20 by mass, respectively) caused 100% mortality of horn fly larvae when dung was supplemented at > or = 100 micrograms/g. Probit analysis of data corrected for natural mortality indicated a LD50 of 30 micrograms/g (95% fidicial limits: 20-49 micrograms/g). When horn fly larvae were introduced to dung supplemented with up to 50 microM of acyl-loline derivatives, mortality of larvae varied significantly between alkaloids (P < 0.0001). Probit analysis indicated that NFL [LD50: 34 microM (95% fidicial limits: 3-53 microM)] was more toxic than NAL [LD50: 46 microM (0-83 microM)], and that loline hydrochloride was not toxic.     

Comparison of core sampling and pupal traps for monitoring immature stable flies and house flies (Diptera: Muscidae) in beef feedlot pens

Core samples and cylindrical pupal traps were used to monitor immature stages of the stable fly, Stomoxys calcitrans (L.), and house fly, Musca domestica L., from 5 sample areas in beef feedlot pens: the feed apron-soil interface, the back fence, the side (pen dividing) fence, the mound, and the general lot. One feedlot was sampled during 1986, two feedlots were sampled in 1987, and three samples were taken at random from each sample area on each sample date. Core samples showed that both populations were highest from the feed apron sample area. Pupal traps tended to show the same result but differences between sample areas were not significant for immature stable flies. Both sampling methods generally indicated similar population trends of the 2 fly species over the season; correlation coefficients between the 2 sampling methods were generally significant but few correlations were strong and large divergences between population trends were present. Only approximately 69% of the total number of pupal traps placed were recovered; the loss of traps could have contributed to differences between the 2 sampling methods. Core sampling would be preferred if lower variance of samples is important; if collecting pupae of known age is important, then pupal traps may be useful if they are protected from trampling by cattle.     

Mechanical transport of rotavirus by the legs and wings of Musca domestica (Diptera: Muscidae)

BACKGROUND: Whether or not tumor response to chemotherapy-sensitized radiation therapy (CTRT) for head and neck cancer leads to an improved outcome is unknown. METHODS: Forty patients who received preoperative cisplatin plus simultaneous radiotherapy for operable stage III and IV head and neck cancer were reviewed retrospectively regarding clinical demographics, staging, and survival status. RESULTS: Twenty-one (57%) patients had a histologic complete response (HCR) and 16 (43%) had a partial (PR) (9) or clinical complete (7) response (CCR). Tumor response of N1 versus N2-3 nodal disease showed 6 (75%) HCR and 4 (25%). Five-year disease-free survival overall was 82% for HCR versus 38% for PR/CCR (P <0.05). Disease-specific 5-year survival was 100% for HCR versus 27% for PR/CCR (P <0.002). CONCLUSIONS: Histologic complete response to CTRT for head and neck cancer is associated with increased survival and encouraging disease-free status. Response to CTRT is inversely proportional to lymphatic tumor load.     

Effects of cold stress on survival and reproduction of Haematobia irritans (Diptera: Muscidae)

1. Hydroxypropyl-beta-cyclodextrin (HP-beta-CD) increases the stability of the oxazolidine prodrug toward hydrolysis. 2. The binding constant (Kb) and rate constant (Kc) for the hydrolysis of the prodrug-HP-beta-CD complex were calculated from the kinetic data. 3. Ion-spray mass spectra confirmed prodrug-HP-beta-CD complexation. 4. Mass spectral and kinetic data indicated 1:1 stoichiometry for the complex. 5. A significant elevation of locomotor activity in rats was observed when either (-)-ephedrine or the prodrug was administered by either the intraperitoneal or the oral route. 6. Addition of HP-beta-CD potentiated the central nervous system effect of both (-)-ephedrine and the prodrug when administered intraperitoneally. However, when the drugs were administered orally, HP-beta-CD caused a decrease in activity.     

Neem oil as a sand fly (Diptera: Psychodidae) repellent

The repellent action of neem oil was evaluated against sand flies under laboratory and field conditions. Concentrations of 2% neem oil mixed in coconut or mustard oil provided 100% protection against Phlebotomus argentipes throughout the night under field conditions; against Phlebotomus papatasi it repelled sand flies for about 7 h in the laboratory. Neem oil is an indigenous product and a low-cost alternative for personal protection against sand fly bites.     

Twisted rhabdomeres in the compound eye of a tipulid fly (Diptera)

The individual rhabdomeres of the outer retinular cells (R 1-6) in the tipulid fly, Ptilogyna, twist about their long axes. Proximally, the rhabdoms become partitioned off by processes from the retinular cells, so that the basal region of each rhabdomere is enclosed in a "pocket" formed by its own cell (Fig. 2). This organisation of the rhabdom enables each rhabdomere to twist while supported within its own retinular cell, and while the cell itself maintains its orientation with respect to the entire ommatidium. Theory predicts that the rhabdomeral twisting should significantly reduce the polarisation sensitivity of R 1-6, but have little effect on the efficiency with which unpolarized light is absorbed.     

Variability of the morphological traits in the blood-sucking black fly Odagmia caucasica (Diptera: Simuliidae)

Eleven morphometric and four qualitative features of larvae, as well as 6 morphometric parameters of pupae of Odagmia caucasica, which had been collected in 5 geographically remote regions of Armenia, have been studied. In this work besides absolute values of features we have used their ratios (indices) that shows forms and proportions of different organs. It was found, that larvae taken from Bzhni and Getashen had asymmetry of bilateral characteristics and that there were differences in the level of morphometric features variability; the latter fact is connected with sex and phase of the insect. Study of chronological variability of populations from Bzhni, Getashen and Martuni has revealed differences in the nature of distribution of features. It was shown that the rate of differentiation between geographically isolated populations fluctuated in the range from 20 (Getashen) to 33% (Amassiya). Differences in the qualitative alternative features and in the rate of microsporidium infection distinguish the differentiation of populations from Bzhni and Amassiya, which is caused by anthropogenic factor in Bzhni and by isolating landscape barrier in Amassiya. Species-specific morphometric features were discovered; these were the indices of proportions of larva ventral sclerite and of pupa respiratory filaments.     

The role of the house fly (Musca domestica) in the dissemination of hookworm

The effect of cooling rate, warming rate, and duration of phase transition upon survival of frozen canine kidneys was investigated. In the present study, 11 kidneys out of 14 rapidly cooled (2--4degreesC/min) to --22degreesC and thawed (70--110degreesC/min) were viable following contralateral nephrectomy. The serum creatinine and BUN levels rose to a maximum of 8.4 and 30 mg%, respectively, on the eighth day post-contralateral nephrectomy. Average survival time was 10 days; however, two of the dogs in this group were allowed to survive, one for 3 months and one for over 2 years. Eight kidneys out of 16 slowly cooled (0.25-1.0degreesC/min) and either rapidly or slowly warmed (20-30degreesC/min) had function to produce small amounts of urine; however, they did not survive more than 5 days after contralateral nephrectomy. Cooling rates of 0.1 and 10degreesC/min were too harmful to the kidney to have renal function after reimplantation. The minimum renal cell damage as assessed by LDH and GOT in the post-freeze perfusate was found in the 2-4degreesC/min cooling rate following rapid warming (70degrees-110degreesC/min). Correlation of the duration of phase transition time to renal cell damage was linear for LDH and GOT (r=0.93). This result suggests that the duration of phase transition time also is an important factor during the freezing process, affecting post-thaw survival of canine kidneys.     

Breeding structure of screwworm fly populations (Diptera: Calliphoridae) in Colima, Mexico

Starch gel electrophoresis was used to resolve gene frequencies among populations of screwworm, Cochliomyia hominivorax (Coquerel). The loci examined coded for alpha-glycerophosphate dehydrogenase, octanol dehydrogenase, and phosphoglucomutase. Flies were sampled by traps widely distributed in Colima Province, southwestern Mexico. Gene frequencies at Odh differed significantly among the 11 populations. Alleles segregating at Pgm and alpha-Gpdh were homogeneous among populations. There were significant departures from random mating within populations, but no genetic differentiation among populations was detected. The data suggest unrestricted gene flow among populations. Departures from random mating within populations were explained by the pooling of samples from separate breeding units.     

Mitotic and polytene chromosome analyses in the Queensland fruit fly, Bactrocera tryoni (Diptera: Tephritidae)

The Queensland fruit fly, Bactrocera tryoni, like the Mediterranean fruit fly, Ceratitis capitata, has a diploid complement of 12 chromosomes, including five pairs of autosomes and a XX/XY sex chromosome pair. Characteristic features of each chromosome are described. Chromosomal homology between B. tryoni and C. capitata has been determined by comparing chromosome banding pattern and in situ hybridisation of cloned genes to polytene chromosomes. Although the evidence indicates that a number of chromosomal inversions have occurred since the separation of the two species, synteny of the chromosomes appears to have been maintained.     

Evaluation of three (Z)-9-tricosene formulations for control of Musca domestica (Diptera: Muscidae) in caged-layer poultry units

A field trial comparing the effectiveness of toxic targets impregnated with different formulations of the Musca domestica L. female sex pheromone (Z)-9-tricosene was conducted in a caged-layer, deep-pit poultry unit in southern England. Targets baited with 5 g of technical grade (Z)-9-tricosene, or 5 g of a 40% polymer bead formulation, caught significantly greater numbers of M. domestica than control targets. This increase in attractiveness of the pheromone-impregnated targets persisted for at least 24 wk. However, mean daily catch rates of M. domestica at targets baited with 5 g of a 2% wettable powder formulation did not significantly differ from control levels. Technical grade and bead formulations of the pheromone attracted significantly more males than females. However, the catches of female M. domestica at these pheromone-impregnated targets were significantly greater than female catches at control targets. Monitoring with sticky cards indicated that the introduction of toxic targets successfully suppressed adult M. domestica population density for up to 13 wk. Possible hypotheses explaining the effect of (Z)-9-tricosene on female attraction are discussed.     

Sexual selection as a side-effect of sexual conflict in the seaweed fly, Coelopa ursina (Diptera: Coelopidae)

The mating system of the seaweed fly involves a premating struggle. When mounted, females violently try to remove the male. In this study 48% of premating struggles resulted in successful rejection of the male, 46% in copulation and 6% were terminated by the male. Large males had a mating advantage. However, contrary to what would be predicted if this sexual selection occurred as a result of active female mate choice, we found a positive association between the duration of premating struggles and male size. A positive association was also found between the duration of premating struggles and male mating success, suggesting that large males may benefit through their superior ability to withstand female rejection. Large females rejected males more easily than small females, suggesting that the premating struggle has not evolved to allow mate assessment by females. We conclude that sexual selection is occurring as a side-effect of the female rejection response, which has probably evolved in order to avoid costs associated with copulation. Nevertheless, a sexual size dimorphism has evolved with males being larger and much more variable in size than females. (c) 1998 The Association for the Study of Animal Behaviour.     

Larvicidal activity of the entomopathogenic fungus Tolypocladium cylindrosporum (Deuteromycotina: Hyphomycetes) on the mosquito Aedes triseriatus and the black fly Simulium vittatum (Diptera: Simuliidae)

Laboratory bioassays evaluated the pathogenicity of the entomopathogenic fungus Tolypocladium cylindrosporum against Aedes triseriatus. All larval instars were found to be susceptible at temperatures from 18 to 25 degrees C. Blastoconidia were more virulent than conidia. Mortality was proportional to exposure time in assays using blastoconidia. Blastoconidia and exposure time appear to be a more adequate method for bioassay of T. cylindrosporum virulence than the standard procedure of using conidia and continuous exposure. Tolypocladium cylindrosporum was also active against Simulium vittatum black fly larvae, but the mortality recorded was much lower than with mosquito larvae.     

Invasion genetics of the Mediterranean fruit fly: variation in multiple nuclear introns

Biological invasions generally start from low initial population sizes, leading to reduced genetic variation in nuclear and especially mitochondrial DNA. Consequently, genetic approaches for the study of invasion history and population structure are difficult. An extreme example is the Mediterranean fruit fly, Ceratitis capitata (Medfly), for which successive invasions during this century have resulted in a loss of 60% of ancestral genetic variation in isozymes and 75% of variation in mitochondrial DNA. Using Medflies as an example, we present a new approach to invasion genetics that measures DNA sequence variation within introns from multiple nuclear loci. These loci are so variable that even relatively recently founded Medfly populations within California and Hawaii retain ample genetic diversity. Invading populations have only lost 35% of the ancestral genetic variation. Intron variation will allow high-resolution genetic characterization of invading populations in both natural and managed systems, although non-equilibrium methods of analysis may be necessary if the genetic diversity represents sorting ancestral polymorphism.