Studies on developmental stages of the horse chestnut scale insect,Pulvinaria regalis Canard (Hom., Coccidae), in the open land and in the laboratory

In the presented paper the development of horse chestnut scale insect,Pulvinaria regalis Canard, was studied a on red horse chestnut (Aesculus x carnea) in the urban area of Bonn. Secondly, the scale insect growth was determined on sycamore maple (Acer pseudoplatanus) and horse chestnut (Aesculus hippocastanum) at different temperatures in the laboratory.The field population displayed an insignificant linear increase in body length between July and beginning of December. No growth was observed between December and March but between mid of March and beginning of May the body size increased exponentially. By setting up a frequency distribution of the anal plate length and by simultaneous measurement of new and old anal plate during molting it was possible to separate different developmental stages. The length of the anal plates of first instar crawlers/settlers ranged between 0.030 and 0.054 mm, that of the second and third instar nymphs between 0.066 and 0.090 mm and 0.102 to 0.150 mm, respectively. The anal plate length of fourth instar adult females differed between 0.162 and 0.246 mm, whereas those of male puparians ranged between 0.075 and 0.098 mm. Since the cuticula ofP. regalis is very extensible, the separation of different developmental stages was only reliable by using the measure of the strongly sclerosed anal plate. Until 12. August first instar crawlers/settlers and till 29. September second instar nymphs were observed on red horse chestnut in the field. Female third instar nymphs were noticed between 9. September and 28. April and fourth instar adult females from 31. March on.In the laboratoryP. regalis individuals on horse chestnut and sycamore maple did only growth at 18°C and fluctuating temperature of 20/14°C (16/8 h). The growth was heavily affected at warm temperatures of 26°C and scale insects lived only a few weeks. Only at the fluctuating temperature of 20/14°C (16/8 h) some females laid eggs on horse chestnut and sycamore maple from the 49. and 48. week on.

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Untersuchungen über Entwicklungsstadien der Wolligen NapfschildlausPulvinaria regalis Canard (Hom., Coccidae) im Freiland und Labor

Zusammenfassung In der vorliegenden Arbeit wurden die Entwicklungsstadien der Wolligen NapfschildlausPulvinaria regalis Canard im Freiland an einer Rotblütigen Roßkastanie (Aesculus x carnea) im Stadtgebiet von Bonn, sowie das Körperwachstum an Bergahorn (Acer pseudoplatanus) und Roßkastanie (Aesculus hippocastanum) bei unterschiedlichen Temperatubedingungen im Labor untersucht.Die Freilandpopulation zeigte von Juli bis Anfang Dezember eine geringe lineare, von Mitte Dezember bis Anfang März nahezu keine und von Mitte März bis Anfang Mai eine exponentielle Zunahme der durchschnittlichen Körperlänge. Durch das Aufstellen einer Häufigkeitsverteilung der Analplattenlänge sowie durch das gleichzeitige Messen von neuen und noch nicht abgestreiften alten Analplatten während der Häutungsphase konnte ein Maß zur Abgrenzung der Entwicklungsstadien ermittelt werden. Die Analplattenlänge von Crawlern/Settlern (=erstes Larvenstadium) lagen im Bereich von 0,030–0,054 mm, des ersten und zweiten Nymphenstadiums im Bereich von 0,066–0,900 mm und 0,102–0,150 mm. Bei adulten Weibchen lag die Analplattenlänge zwischen 0,162 und 0,246 mm und bei männlichen Präpuppen zwischen 0,075 und 0,098 mm. Da die Cuticula vonP. regalis sehr dehnbar ist, war eine sichere Stadienzuordnung nur mit Hilfe der stark sklerotisierten Analplatte möglich. Bis zum 12. August waren Crawler/Settler und bis zum 29. September Erstnymphen zu beobachten. Weibliche Zweitnymphen traten vom 9. September bis 28. April und adulte Weibchen ab dem 31. März in Erscheinung.Im Labor konnte auf den Versuchspflanzen Roßkastanie und Bergahorn ein Wachstum der Körperlänge vonP. regalis-Individuen bei Konstanttemperatur von 18°C und bei Wechseltemperatur von 20/14°C (16/8 h) gemessen werden. Bei einer Konstanttemperatur von 26°C war das Wachstum auf beiden Wirtspflanzenarten gestört und ein Überleben nur für wenige Wochen möglich. Nur in der Temperaturvariante 20/14°C (16/8 h) legten einige Weibchen ab der 49. Woche auf Roßkastanie und ab der 48. Woche auf Bergahorn Eier ab.

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With 2 tables and 4 figures

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Dedicated to Prof. Dr.W. Schwenke for 75th birthday 22.3.1996.     

Heavy Metal–Mineral Associations in Coeur d’Alene River Sediments: A Synchrotron-Based Analysis

Nearly a century of mining activities upstream have contaminated Lake Coeur d’Alene and its tributaries with Pb, Zn, and other heavy metals. Heavy metal concentrations in sediments of the Coeur d’Alene watershed have been shown to be inversely proportional to the sediment size fraction; thus, analysis on a very small scale is essential to determine the mobility and stability of heavy metals in this environment. Micron-scale synchrotron-based methods were used to determine the association of heavy metals with solid phases in sediments of the Coeur d’Alene River. Bulk X-ray diffraction (XRD), extended X-ray absorption fine structure spectroscopy, and synchrotron-based microfocused XRD combined with microfocused X-ray fluorescence mapping indicate the presence of crystalline Pb- and Zn-bearing mineral phases of dundasite [Pb₂Al₄(CO₃)₄(OH)₈·3H₂O], coronadite [PbMn₈O₁₆], stolzite [PbWO₄], mattheddleite [Pb₁₀(SiO₄)_3.5(SO₄)₂Cl₂], bindheimite [Pb₂Sb₂O₇], and smithsonite [ZnCO₃]. Likely phases for Zn and Pb adsorption were ferrihydrite, diaspore [AlO(OH)], manganite [Mn^(III)O(OH)], muscovite [KAl₂(Si₃Al)O₁₀(OH,F)₂], biotite [K(Fe,Mg)₃AlSi₃O₁₀(F,OH)₂], and montmorillonite [Na_0.3(Al,Mg)₂Si₄O₁₀(OH)₂·8H₂O]. The large predominance of Fe and Mn (hydr)oxides over other sorbent minerals suggests that the metal sorption behavior is dominated by these (hydr)oxide phases.     

Investigation of pharmacokinetic interaction between ivermectin and praziquantel after oral administration in healthy dogs

The purpose of this study was to determine the pharmacokinetic interaction between ivermectin (0.4 mg/kg) and praziquantel (10 mg/kg) administered either alone or co‐administered to dogs after oral treatment. Twelve healthy cross‐bred dogs (weighing 18–21 kg, aged 1–3 years) were allocated randomly into two groups of six dogs (four females, two males) each. In first group, the tablet forms of praziquantel and ivermectin were administered using a crossover design with a 15‐day washout period, respectively. Second group received tablet form of ivermectin plus praziquantel. The plasma concentrations of ivermectin and praziquantel were determined by high‐performance liquid chromatography using a fluorescence and ultraviolet detector, respectively. The pharmacokinetic parameters of ivermectin following oral alone‐administration were as follows: elimination half‐life (t_1/2λz) 110 ± 11.06 hr, area under the plasma concentration–time curve (AUC_0–∞) 7,805 ± 1,768 hr^.ng/ml, maximum concentration (C_max) 137 ± 48.09 ng/ml, and time to reach C_max (T_max) 14.0 ± 4.90 hr. The pharmacokinetic parameters of praziquantel following oral alone‐administration were as follows: t_1/2λz 7.39 ± 3.86 hr, AUC_0–∞ 4,301 ± 1,253 hr^.ng/ml, C_max 897 ± 245 ng/ml, and T_max 5.33 ± 0.82 hr. The pharmacokinetics of ivermectin and praziquantel were not changed, except T_max of praziquantel in the combined group. In conclusion, the combined formulation of ivermectin and praziquantel can be preferred in the treatment and prevention of diseases caused by susceptible parasites in dogs because no pharmacokinetic interaction was determined between them.