Observations on the Feeding Ecology of Impala

The distribution, habitat preference, and diet of impala in mixed wooded savanna were studied. In the wet season impala were evenly distributed through the different vegetation types and their diet was predominantly grass, but in the dry season they concentrated in areas of Acacia savanna and changed to a mainly browsing diet. The amount of grass in the diet was related to plant moisture content and recent effective rainfall. The impala selected succulent food rich in crude protein but preferred grazing to browsing when palatable grass was available. These factors and the presence of fallen Acacia pods probably attracted impala to the Acacia areas in winter.     

Experimental infection of normal and immunosuppressed pigs with Pseudomonas pseudomallei

A single dose of 5 x 10(8) bacilli of Pseudomonas pseudomallei by intratracheal injection resulted in acute (21 cases) or chronic (19 cases) melioidosis in 40 of 48 pigs. Fifteen (10 acute and 5 chronic) had been immunosuppressed by cyclophosphamide before inoculation. The major clinical signs were initial fever, marked neutrophilia and, in the acute cases, respiratory distress. There were no signs of the nasal and ocular discharge, paresis or diarrhoea seen in acute cases in south-east Asia. The cyclophosphamide treatment caused a significant decrease in the neutrophil count by 7 d after inoculation in all 15 immunosuppressed pigs, and all were culture positive at necropsy. Eight of the 33 non-treated pigs were culture negative at necropsy. Pigs overcoming the initial phase of infection had more abscess-like nodules that were bacteriologically sterile at necropsy than the pigs with acute cases of melioidosis. P. pseudomallei was isolated predominantly from the spleen, lungs and the injection site. Although only one strain was used in this study, it is likely that Australian strains of P. pseudomallei are not as virulent as the south-east Asian isolates.     

1/25 translocations in Blonde d'Aquitaine cattle in New Zealand

A Robertsonian centric fusion between chromosomes 1 and 25 in Blonde d'Aquitaine cattle in New Zealand is reported. This fused chromosome is the same as the widely reported 1/29 translocation chromosome with the difference in the numbering arising from inconsistencies in the G and R-banded cattle karyotypes of the International System for Cytogenetic Nomenclature of Domestic Animals, 1989.     

Tracking the long-term decline and recovery of an isolated population

Effects of small population size and reduced genetic variation on the viability of wild animal populations remain controversial. During a 35-year study of a remnant population of greater prairie chickens, population size decreased from 2000 individuals in 1962 to fewer than 50 by 1994. Concurrently, both fitness, as measured by fertility and hatching rates of eggs, and genetic diversity declined significantly. Conservation measures initiated in 1992 with translocations of birds from large, genetically diverse populations restored egg viability. Thus, sufficient genetic resources appear to be critical for maintaining populations of greater prairie chickens.     

Can water disinfection prevent the transmission of infectious koi herpesvirus to naïve carp? – a case report

Hygienic measures such as disinfection are important tools for the maintenance of fish health in aquaculture. While little information is available on the disinfection of water intended for fish containment, Huwa‐San^®, a disinfectant used in food and water industries, was used for daily treatment at concentrations of approximately 60 ppm over a total period of 3 months (experiment 1) with a 3‐week treatment‐free interval after 2 months (experiment 2). During this period, koi herpesvirus (KHV) was added to the water of two aquaria, one used as a normal contact control, the other one receiving daily water disinfectant treatments that prevented KHV infection of carp. In the second experiment, Huwa‐San^® treatment was interrupted and KHV infection was prevalent. However, when naïve fish were introduced to the same aquarium after re‐application of disinfectant, KHV could not be detected in those naïve fish. Whilst KHV could not be detected in samples where disinfectant had been applied, it was present in samples of naïve fish cohabiting with infection contact control animals which had undergone no disinfectant treatment over experiments 1 and 2. The results presented here show that water treatment with a disinfectant may prevent transmission of infectious KHV to naïve carp cohabited with infected carp.     

Long‐term Effects of Pyrethrin and Cyfluthrin,a Type II Synthetic Pyrethroid,Insecticide Applications on Bull Reproductive Parameters

The objectives of this study were to determine effects of cyfluthrin and pyrethrin spray products, used in combination with cyfluthrin topical and ear tag applications, on bull reproductive parameters over 18 weeks. Angus or Angus x Simmental bulls were randomly assigned to one of three treatment groups: (i) no exposure to pyrethrins/cyfluthrin (CONT; n = 10), (ii) cyfluthrin ear tag and topical applications (ET; n = 10), or (iii) cyfluthrin ear tag, topical, premise spray and pyrethrin fog spray applications (ET+S; n = 8). Bull body weight was measured every 3 week, and body condition score and scrotal circumference were recorded on weeks 0, 9 and 18. Semen and serum were collected every 3 weeks for sperm evaluation and testosterone measurement, respectively. There was a treatment × week interaction (p < 0.01) for sperm with primary defects; bulls in CONT group had a greater (p = 0.01) percentage of sperm with primary defects than bulls treated with insecticides at week 18. Overall and progressive sperm motility, normal sperm morphology, secondary sperm defects and serum testosterone concentrations changed (p < 0.01) over time in all bulls; however, treatment did not affect (p ≥ 0.13) any of these parameters. There were also no treatment effects (p ≥ 0.08) on bull body weight, body condition score or scrotal circumference. The use of pyrethrin‐ and cyfluthrin‐based insecticides, regardless of application, did not negatively affect reproductive parameters in beef bulls when administered over 18 weeks.     

Population flushing with sexually sterile insects

In theory, populations of animals can be displaced by overloading a resource with introduced sterile animals. The theory was tested on natural populations of the Queensland fruitfly Dacus tryoni Frogg. Three of four treated populations declined sharply within 2 days after sterile flies had been introduced. This procedure may be useful both as a tool in experimental ecology and as a means of controlling pests.     

Local Control of Microdomain Orientation in Diblock Copolymer Thin Films with Electric Fields

Local control of the domain orientation in diblock copolymer thin films can be obtained by the application of electric fields on micrometer-length scales. Thin films of an asymmetric polystyrene-polymethylmethacrylate diblock copolymer, with cylindrical polymethylmethacrylate microdomains, were spin-coated onto substrates previously patterned with planar electrodes. The substrates, 100-nanometer-thick silicon nitride membranes, allow direct observation of the electrodes and the copolymer domain structure by transmission electron microscopy. The cylinders aligned parallel to the electric field lines for fields exceeding 30 kilovolts per centimeter, after annealing at 250°C in an inert atmosphere for 24 hours. This technique could find application in nanostructure fabrication.     

Die Resistenz von Insekten gegen Insektizide

Zusammenfassung Es ist offensichtlich schwer, ja gefährlich, bei einem Gegenstand dieser Art endgültige Schlußfolgerungen zu ziehen. Immerhin ist von der Theorie wie von den Vorgängen, die beide hier erörtert worden sind, genug bekannt, um gewisse Winke zu geben:I. Örtlich begrenzt auftretende gegen ein Insektizid resistente Stämme müssen sich nicht notwendigerweise weiter verbreiten, denn:a) wenn die Behandlung nicht allgemein ist, kann Rückentwicklung durch natürliche Populationen stattfinden;b) ein gegen Insektizide resistenter Stamm muß nicht notwendigerweise anderen Umweltbedingungen so gut angepaßt oder so fruchtbar sein, daß nicht bei Abwesenheit des Insektizids die natürliche Population die Tendenz hat, früher oder später zum früheren Zustand zurückzukehren, besonders wenn Berührung mit unbehandelten Populationen möglich ist.II. Wenn es sich nicht um eine Veränderung genetischer Faktoren handelt, wie z. B. das Auftreten einer Mutation, wird sich ein bestimmter Widerstandszustand einstellen, mit welchem man in einigen Fällen durch erhöhte Dosierung, Häufigkeit und größere Sorgfältigkeit der Behandlungen fertig werden kann.III. In isolierten Bezirken, in welchen sehr intensive und sorgfältige Schädlingsbekämpfungs-Maßnahmen vorgenommen worden sind, werden am ehesten resistente Stämme auftreten.IV. Bei unterschwelligen Dosen besteht die Möglichkeit individueller Anpassung.formerly Officer-in-Charge, Fumigation Laboratory, Canada Department of Agriculture, Montreal, P. Q. and new Senior Officer, Fumigation Research Unit, Science Service Laboratory, Canada Department of Agriculture, London, OntarioEine Ubersetzung von Contribution No. 78 from the Plant Protection Division, Science Service, Canada Department of Agriculture, Ottawa, Ont. Der englische Original-Artikel erschien in den September-und Oktober-Heften 1949 von PEST CONTROL. Um die Ausführungen auf das Laufende zu bringen, hat der Verfasser (im September 1950) einiges geändert und zugefügt.