Sur la biologie deMicrophthalma europaea Egg., tachninaire parasite des larves deScarabaeidae

Zusammenfassung Die Laborzucht aufeinanderfolgender Generationen vonMicrophthalma europaea egg. hat es uns m?glich gemacht, die Entwicklung dieser Tachinide bei 25°C festzustellen. Die Dauer der Stadien ist 3–4 Tage für das erste, 4–7 Tage für das zweite und 8–12 Tage für das dritte Larvenstadium, 14 Tage für die Nymphe, 14–18 Tage für die Reifungsperiode der Weibchen. Die mittlere Lebensdauer für die weiblichen Fliegen ist 25 Tage und 20 Tage für die m?nnlichen. Auch über den Einfluss der Umwelt hat man Erfahrungen gesammelt und zwar über den Einfluss der Temperatur und der Feuchtigkeit auf die Fruchtbarkeit dieser Zweiflügler, die selten h?her ist als 300–400 Planidia pro Weibchen und über die M?glichkeiten im Boden zu überleben, ehe sie in die Wirtslarve eindringen. Unter den Umst?nden dieses Versuches ist die Entwicklung nur in den Larven vonCetoniinae und vonDynastinae m?glich; die Larven vonMelolonthinae werden nicht, oder sher wenig parasitiert. Unter den empfindlichen Arten variiert die Menge der angegriffenen Individuen mit der Art ebenso wie die Anzahl und das Gewicht der pro Wirtslarve geformten Puppen. Die Larven vonPotosia cuprea F. und vonPhyllognathus silenus F. sind güstiger für die Entwicklung als z.B. die Larven vonOryctes nasicornis L. oder vonOxythyrea funesta Poda. Die Vervollkommnung der Zuchttechnik erlaubt es, die für einen biologischen Bek?mpfungsversuch gegen Scarabeiden-Larven n?tige Anzahl Parasiten zu produzieren.

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Cette étude préliminaire a été effectuée en liaison avec.E. Biliotti, Directeur de la Station de Lutte biologique et de Zoologie agricole d'Antibes, spécialiste en la matière. Nous l'en remercions vivement.     

Beobachtungen Beim Züchten VonPerillus Bioculatus (Fabr.) (Heteropt., Pentatomidae), Einem Aus Nordamerika Importierten Räuber des Kartoffelkäfers

Zusammenfassung Die PentatomidePerillus bioculatus (Fabr.), ein natürlicher Feind vonLeptinotarsa decemlineata (Say) in Nordamerika, wurde 1956 bis 1958 aus Kanada (Belleville) nach Deutschland (Darmstadt) geschickt und hier für eine sp?tere Verwendung zur biologischen Bek?mpfung des Kartoffelk?fers aufgezogen. Nach einer Schilderung der Lebensweise der einzelnen Entwicklungsstadien wird die Methode beschrieben, die sich beim Import der Wanzeneier aus Amerika und bei deren Versand nach Polen und Ungarn 1959 bew?hrt hat. Die bei der Durchführung von Gruppenzuchten und Massenzuchten erprobten K?figtypen und Verfahren werden geschildert. — Als mittlerer Nahrungsverbrauch eines Individuums w?hrend der Entwicklung zur Imago wurden entweder 285 Kartoffelk?fer-Eier oder 3,7 L₄ oder 5,1 K?fer dieser Art ermittelt. Das letzte (5.) Larvenstadium verbraucht dabei 69% der angegebenen Menge (Abb. 10). Für Erstlarven ist Saugen an Pflanzenstengeln lebenswichtig. Imagines nach der überwinterung verbrauchten meist 0,7–0,8 Kartoffelk?fer oder 0,5 L₄ am Tag. Ohne grosse Verluste k?nnen die Wanzen im Sommer 1–2 Monate hungern; gelegentlich tun sie das sogar spontan. Das Geschlechterverh?ltnis der Imagines betrug 1∶1. Die durchschnittliche Eizahl eines begatteten Weibchens wurde bei Ern?hrung mit Eiern oder Larven vonL. decemlineata mit 95–98 im Monat und mit sch?tzungsweise 100–120 im ganzen Leben ermittelt. Unbegattete oder nur mit K?fern ern?hrte Weibchen legten viel weniger Eier. Die Larvenentwicklung wird durch ungünstige Ern?hrung verlangsamt. Die Mortalit?t in den Zuchten war niedrig, wenn eine günstige Temperatur (tags über 25°C), eine hochwertige Ern?hrung (Eier und Larven des Kartoffelk?fers) und reichlich Versteckpl?tze in den K?figen zur Verfügung standen. Die praktische Durchführung einer Massenzucht wird geschildert, deren Ausbeute in 123 bzw. 91 Tagen das 45- bzw. 67 fache des Ausgangsbestandes war. Die überwinterung vonP. bioculatus ist unter allen bisher bekannten Bedingungen sehr verlustreich. Im Freiland konnte die Art bisher zweimal in Darmstadt überwintern. Obwohl warme Tage sie aus den Verstecken locken, gelang es in zahlreichen Versuchen bei hoher Temperatur und st?ndigem Futterangebot nicht, die Wanzen den Winter über sich fortpflanzen zu lassen; auch die Nahrung wurde monatelang nahezu ganz verweigert. Die Tiere sind im Winter nicht erstarrt, sondern nur lethargisch. — Als Vorbereitung für eine Freilassung der Raubwanze durchgeführte Versuche mit Pflanzenschutz-Mitteln, die auf Kartoffelfeldern weiterhin notwendig sein werden, wurde die verschiedenartige Empfindlichkeit vonP. bioculatus gegenüber einigen Insektiziden und Fungiziden bestimmt (Tab. 6). Besonders schonend waren Kalkarsen und die Phytophthora-Mittel Dithane, Maneb und Kupferoxydul.

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Summary The pentatomidPerillus bioculatus (Fabr.), a predator ofLeptinotarsa decemlineata (Say) in North America, was sent to Germany (Darmstadt) from Canada (Belleville) in 1956–1958 and reared there for later use in biological control against the Colorado potato beetle. After outlining the life history of the different instars a method of shipment is described which was successfully employed in transferring the eggs from America and to Hungary and Poland. Cages and methods used in group- and in mass-rearings are depicted. — The average food intake of one individual ofP. bioculatus during its development from the egg to the adult stage was either 285 eggs or 3,7 fourth instar larvae (L₄) or 5,1 adults ofL. decemlineata. The last larval instar (L₅) consumed approx. 69% of it (Fig. 10). For first instar larvae sucking on plants is obligatory. Adults after hibernation use mostly 0,7–0,8 adult potato beetle or 0,5 L₄ of the prey per day. The predator is able to starve without great losses 1–2 months during summer time; occasionally, this is done spontaneously. The sexual index of adultP. bioculatus was 1∶1. The average egg number per mated female was 95–98 per month when fed with eggs or larvae ofL. decemlineata amounting to approx. 100–120 eggs during lifetime. Unmated females or such fed with beetles only produced much less eggs. Larval development is retarded through unfavourable nourishment. Mortality in the rearings was low when favourable temperature (day-time above 25°C), good food (eggs and larvae ofL. decemlineata) and enough hiding places were available. A practical mass rearing method is described which yielded in 123 or 91 days an 45- or 67- fold increase respectively of the start population. Hibernation ofP. bioculatus results under all conditions so far studied in high mortality. The species hibernated successfully twice in Darmstadt. Although warm temperatures activate them in the field it was not possible to obtain permanent reproduction and food intake in the laboratory at high temperatures and long day conditions (after end of August). The bugs are not motion-less but only lethargic during winter. — In field experiments using pesticides which remain to be necessary on potato fields the differential susceptibility ofP. bioculatus was tested (Tab. 6). Most selective properties were shown by the stomac insecticide calcium arsenate and the fungicides Dithane, Maneb and cuprous oxide.

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Herr Dr.A. Szmidt vom Forstschutz-Institut in Posen (Katedra Ochrony Lasu, Poznań, Polen) arbeitete von M?rz bis Oktober 1959 als Stipendiat der Rockefeller-Foundation in Darmstadt.     

Utilisation des larves dePlutella maculipennis [Lep.: Hyponomeutidae] comme insecte-Test de divers hyphomycètes entomopathogènes [Fungi imperfecti]

Résumé La sensibilité dePlutella maculipennis Curt. à divers hyphomycètes entomopathogènes est définie par des essais biologiques en conditions standardisées. La contamination est réalisée par pulvérisation sous tour de traitement de rondelles de chou calibrées; les chenilles au 3^e stade, venant de muer, sont placées pendant 48 h sur les rondelles traitées. Le calcul des droites logarithme de la dose-probit de la mortalité et des DL 50 le 6^e j après le traitement, montre que les larves deP. maculipennis sont sensibles aux différents types de propagules fongiques quelle que soit la formulation: conidiospores, blastopores non formulées, lyophilisées ou enrobées dans l'argile. La pathogénie de diverses souches deBeauveria bassiana (Bals.) Vuill.,B. brongniartii (Sacc.) Petch.,Nomuraea rileyi (Farl.) Sams.,Metarhizium anisopliae (Metch.) Sor.,M. flavoviride Gams. & Rozsypal, etPaecilomyces fumosoroseus Wize (Brown & Smith) est étudiée. Les résultats montrent dans quelles conditionsP. maculipennis est utilisé à La Minière comme insecte-test pour vérifier la qualité des préparations à base d'hyphomycètes.

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Summary Bioassays of entomopathogenic hyphomycetes were conducted with 3rd instar larvae ofPlutella maculipennis Curt. at controlled conditions. Contaminations were carried out by spraying fungal suspension on small cabbage foliage discs in a spray tower. Newly molted larvae were placed on contamined discs during 48 h. The LD 50 dosages showed a high susceptibility of insects to differentBeauveria propagules such as conidiospores, not formulated blastospores, lyophilized blastospores or clay-coated blastospores. Moreover some strains ofBeauveria bassiana (Bals.) Vuill.,B. brongniartii (Sacc.) Petch.,Nomuraea rileyi (Farl.) Sams.,Metarhizium anisopliae (Metch.) Sor.,M. flavoviride Gams & Rozsypal andPaecilomyces fumoso-roseus (Wize) Brown & Smith were tested for specificity toP. maculipennis larvae. The results indicated that Lepidoptera larvae are interesting as test insects to measure the potency of some hyphomycetes biopreparations. It was established that a 6 days delay after treatment is sufficient when the fungal strain is pathogenic toP. maculipennis.

     

Zur Isolierung und Kultur insektenpathogener Entomophthoraceen

Zusammenfassung Massenvermehrungen wirtschaftlich wichtiger Schadinsekten k?nnen durch Pilze aus der Familie der Entomophthoraceen in wenigen Tagen zusammenbrechen. Ihre Isolierung und Kultur bereitet oft Schwierigkeiten. Hier wird als einfache und erfolgreiche Methode die Isolierung mittels Hühnerei-Dotter, der bei 80°C 40–50 Min. im Heissluftsterilisator (Trockenschrank) in schr?g liegenden R?hrchen koaguliert wurde, empfohlen. Die Technik der Isolierung — ausgehend von Konidien—wird beschrieben. Der koagulierte Dotter eignet sich ebenso für die laufende Kultur von Entomophthoraceen-St?mmen. Weiterimpfungen der bei Zimmertemperatur gehaltenen Kulturen müssen alle 3–4 Wochen vorgenommen werden. Will man gelegentlich seltener weiterimpfen, k?nnen die St?mme in Kultur-R?hrchen gehalten werden, die 3–4 cm hoch Vollmilch enthalten und dreimal bei 100°C 20 Min. oder einmal bei 110°C 15 Min. sterilisiert wurden. Die Entomophthoraceen wachsen hier vor allem in dem oben abgeschiedenen Milchfett. Solche Kulturen waren noch nach 1 1/2 Monaten, bei manchen Arten auch noch nach 4 Monaten lebensf?hig. Für die Kultivierung eigneten sich auch Milch-Agar, Milch-Hafermehl-Agar, Fleischextrakt-Pepton-Dotter-Agar und manchmal Kartoffelkeile, wenn das Wachstum auf ihnen allen auch nicht so gut war wie auf koaguliertem Dotter. N?hrb?den, die mit 25 I.E. Penicillin und 50 Gamma Streptomycin/l ccm zubereitet waren, hemmten den Wuchs vonEmpusa aulicae Reich. und einer vonAphis fabae scop. isoliertenEmpusa sp. nicht. — Isolierung und Kultur insektenpathogener Entomophthoraceen erscheinen für Versuche zur biologischen Bek?mpfung ebenso n?tig wie zur Kl?rung taxonomischer und biologischer Fragen.

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Summary An outbreak of an insect pest may be controlled in a few days by fungi of the familyEntomophthoraceae. Isolation and culture of such fungi is often difficult. A simple and successful method is herein recommended, utilizing a substrate of hen's egg yolk previously coagulated 40–50 minutes at 80°C in a hot air oven. The medium is prepared in tubes in a slanted position. The culture technique, starting with conidia is described. Coagulated yolk is also a suitable medium for successive transfer and maintenance ofEntomophthoraceae cultures. Stock cultures maintained at room temperature must be transferred once every three or four weeks. If desirable, subcultures ofEntomophthoraceae fungi may be held in test tubes at greater intervals. For this purpose tubes are filled with whole milk 3–4 cm in depth and sterilized at 100°C three times or autoclaved at 110°C for 15 minutes. The fungi grow essentially in the top layer of milk fat. Such cultures live up to 1 1/2 months, some species survive 4 months. Milk agar, milk oatmeal agar, beef extract pepton yolk agar, and potato pieces are also suitable for cultivation. The growth on such substrates is not as good as on the coagulated yolk. Media with 25 international units of penicillin and 50 gamma of streptomycin per ml did not influence the growth ofEmpusa aulicae Reich. and oneEmpusa sp. isolated fromAphis fabae scop. Isolation and cultivation of entomophagousEntomophthoraceae are considered to be as important for experiments in biological control as for studies on taxonomy and biology of distinct species.

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Nach einem Vortrag im Kolloquium der C.I.L.B. über Insektenpathologie und mikrobiologische Bek?mpfung, Paris, Oktober 1958.     

Effect of temperature on the in vitro radial growth of Zoophthora radicans and Pandora blunckii, two co-occurring fungal pathogens of the diamondback moth Plutella xylostella

The effect of four different temperatures (15, 20, 25 and 30°C) on the in vitro growth of 19 isolates of Pandora blunckii and 14 isolates of Zoophthora radicans from Plutella xylostella larvae was investigated. Both species grew more at 20 and 25°C than the other two temperatures. However, Z. radicans grew more than P. blunckii at 20 and 25°C. Within each species there were differences amongst: all isolates regardless of geographical origin, isolates from different countries and isolates from Mexico. No relationship was found between optimal growth temperature and geographical origin. This represents the first report of the relationship between temperature and the in vitro growth of P. blunckii. The ecological role of this large variability amongst isolates within each species is discussed.     

Absence de résistance aBacillus thuringiensis,chez la teigne des crucifères,Plutella maculipennis [Lep.: Hyponomeutidae]

Résumé Une forte pression de sélection (DL 90) est exercée pendant 10 générations consécutives sur une lignée dePlutella maculipennis Curt., à l'aide du complexe cristaux-spores d'unBacillus thuringiensis (standard E 61). Les survivants de chaque génération sont soumis à la pression sélective au début du 4^e et dernier age larvaire, en pulvérisant la préparation bactérienne en suspension aqueuse sur l'aliment végétal. A la 11^e génération, comparativement à la lignée de référence, aucune différence significative de sensibilité n'est constatée entre les deux lignées.

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Summary A strain ofPlutella maculipennis was held under high selection pressure (LD 90) byBacillus thuringiensis spore-crystal complex (standard E 61) for 10 generations. The survivors of each generation were subjected to selective pressure by feeding the fourth-instar larvae on cabbage leaves sprayed withBacillus thuringiensis in aqueous suspension. At the 11th generation, no significant difference of susceptibility was observed when compared to the control strain.

     

Der Einfluss der Temperatur auf die Anstichaktivität beiNasonia vitripennis undSpalangia nigra [Chalcid.: Pteromalidae]

Zusammenfassung Bei den 2Pteromalidae Nasonia vitripennis (Walker) undSpalangia nigra latreille wird gezeigt, wie die Temperatur w?hrend des Anstichs die Zahl der abgelegten Eier beeinflusst. Die Anstichaktivit?t beginnt bei beiden Arten bei etwa 12,5°C, hat bei 25°C ihr Optimum und nimmt bis 40°C wieder ab. Bei dem Greg?rparasitenN. vitripennis ist bei 25°C in Folge gesteigerter lokomotorischer Aktivit?t die Zahl der parasitierten Puppen am h?chsten, die Zahl der Nachkommen pro Puppe jedoch niedriger als bei 20°C und 30°C. Die niedrigere Eizahl pro Puppe bei 25°C führt zu einer Verschiebung des Geschlechtsverh?ltnisses zugunsten der ♀♀. Beide Parasiten k?nnen in einem breiten Temperaturbereich anstechen. Die weite Potenz dieser plurivoltinen Arten wird als eine Anpassung an ein breites Wirtsspektrum angesehen.

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Summary Experiments with the 2 PteromalidsNasonia vitripennis (Walker) andSpalangia nigra Latreille show in which way the number of eggs depends on the temperature prevalent during the stinging. The stinging activity starts at about 12,5°C, has its optimum at 25°C, has its optimum at 25°C to 30°C and decreases from 30°C to 40°C. withN. vitripennis the number of parasitized pupae is largest at 25°C the number of offsprings, however, smaller than at 20°C and 30°C. Thus at 25°C the sex ratio is changed in favour of the ♀♀. Both parasites can sting within a broad scope of temperature. This great capacity of the two plurivoltine species is regarded as an adaptation to a borad spectrum of hosts.

     

Die motorische aktivität der endoparsitischen Larven vonPimpla turionellae L. undPimpla flavicoxis Ths. [Hym., Ichneum.] in der wirtspuppe

Zusammenfassung Die endoparasitischen Larven der beiden nahe verwandten PuppenparasitenartenPimpla turionellae undPimpla flavicoxis legen w?hrend ihrer Larvenentwicklung in der Wirtspuppe eine charakteristische Wanderung zurück. Unabh?ngig von der Lage des Parasiteneies in der Puppe wandert die Junglarve sofort nach dem Verlassen des Eies zum Kopfende der Puppe und zerst?rt dort das Gehirn und die umliegenden Organe. Anschliessend kriecht sie ins Abdomen, w?hrend sie gleichzeitig die Wirtsgewebe aufl?st und Nahrungsbrei zu sich nimmt. Im Abdomen dreht sie sich abermals um, so dass ihr Kopf zum Vorderende der Puppe weist. In dieser Lage verzehrt sie den Rest des verflüssigten Puppeninhalts und verpuppt sich. Die Parasitenimagines schlüpfen durch das Vorderende der Wirtspuppe. —In superparasitierten Puppen wandern alle Junglarven zum Kopfende der Wirtspuppe und tragen dort ihre Konkurrenzk?mpfe aus, indem die überz?hligen Larven durch Bissverletzungen ausgeschaltet werden. In der Regel bleibt eine Larve am Leben und entwickelt sich weiter. — Die Junglarven werden wahrscheinlich durch chemische oder Str?mungsreize zum Vorderende der Puppe gelenkt. Dieses ausgepr?gte Orientierungsverhalten gestattet die Ausschaltung gleichalteriger Nahrungskonkurrenten zum frühest m?glichen Zeitpunkt. Die Wanderung der Larven bringt den Parasiten allem Anschein nach noch andere Vorteile.

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Summary The endoparasitic larvae of two pupal parasites,Pimpla turionellae L. andPimpla flavicowis Ths. (Hym., Ichneumonidae) move inside the host pupa (Galleria mellonella L.) in a characteristic manner during their development. Soon after hatching from the eggs the young larvae arrive in the head of the pupa (tab. 1 and 6) and destroy the organs situated here by histolysis. As is shown in tables 2, 3, 4 and in figure 2 the movement of the larvae to the head region is independent of the site of the egg in the pupa. One or two days afterwards the larvae change their position by moving into the abdomen, liquefying its contents (fig. 3). They turn again in the abdomen but remain there feeding on the rest of the liquified host tissues. The fullgrown larva lies in the abdomen occupying nearly the whole cavity of the pupa. Its head is directed towards the head part of the pupa. Pupation is usually performed in this position so that the adult emerges from the anterior end of the host pupa. When the host pupa is superparasitized byP. turionellae, all young larvae move to its anterior end. The competing larvae fight each other, using their mandibles for wounding the soft body of their competitors. These wounds seem always to be fatal and can be recognized by their rapid melanization (fig. 4). Since all young larvae have met in the head region of the pupa, the dead competitors can usually be found there in full number, the victor having moved into the abdomen next day (tab. 5). Only a single larva survives. The young larvae seem to be directed by a chemical attractant or by rheotaxis in the circulating hemolymph, since gravity and light can be excluded as factors of orientation. The behaviour of the larvae enables the parasites to eliminate competitors of the same age at the earliest possible moment and in this way to conserve all the food for the surviving larva. Further advantages are probably gained by the circulating movement of the larvae, i.e. the early elimination of the hormonal control system of the host and the final position of the fullgrown larva, which leads the emerging adult to openings in the cocoon or gallery preformed by the host larva.

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Pimpla flavicoxis Гhs=Pimpla aquiloniaCress (Aubert, 1969).     

<Emphasis Type="Italic">Haliphthoros milfordensis</Emphasis> isolated from black tiger prawn larvae (<Emphasis Type="Italic">Penaeus monodon</Emphasis>) in Vietnam

 A marine fungus was isolated from the black tiger prawn Penaeus monodon at Nha Trang, Vietnam, on March 20, 2001 and named isolate NJM 0131. The fungus was identified as Haliphthoros milfordensis from the characteristics of asexual reproduction, and its physiological characteristics were investigated. Although the optimum temperature for growth of the isolate was 25°–30°C, the fungus grew at a wide range of temperatures (15°–40°C). H. milfordensis grew well in 50%–100% seawater, but poorly in PYG agar containing 1.0%–5.0% NaCl and KCl. The fungus grew at a wide range of pH (4.0–11.0) with the optimum pH value of 7.0–9.0. The isolate also showed pathogenicity to swimming crab larvae (Portunus trituberculatus) by artificial infection, but mortality was not high. This is the first report of disease in the black tiger prawn P. monodon in Vietnam caused by H. milfordensis. Received: July 22, 2002 / Accepted: January 21, 2003 Correspondence to:K. Hatai     

Infektionsversuche mit einigenEntomophthora-arten bei den termitenCoptotermes formosanus (Shiraki) undReticulitermes lucifugus (Rossi)

Zusammenfassung MancheEntomophthora-Arten sind im Infektionsversuch nicht so wirtsspezifisch, wie oft angenommen wird. So waren die TermitenCoptotermes formosanus undReticulitermes lucifugus gegenüberEntomophthora destruens, E. thaxteriana und 2 St?mmen vonE. virulenta anf?llig; die unterschiedliche Mortalit?t erreichte 65–100%. Das Infektionsoptimum fürE. destruens lag bei 15–22°C. 3–5 Tage alte Dotterplattenkulturen brachten st?rkste Konidien-bildung und Infektionsit?t. Die Virulenz vonE. thaxteriana konnte durch geeignete Wirtspassage gesteigert werden.

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Summary The experiments have again confirmed that someEntomophthora species are under experimental conditions not so specific with regard to their host, as has often been taken for granted. Their specifity under natural conditions is also given by ecological factors. The termites ofC. formosanus were infested byE. thaxteriana (100 per cent),E. destruens (95 per cent), andE. virulenta, strain No 1 (70 per cent), while the termites ofR. lucifugus byE. destruens (80 per cent), andE. virulenta, strain No 1 (70 per cent) and strain No 2 (65 per cent). The two termite species have shown a different response to the three fungi. The optimum temperature for the development of mycosis caused byE. destruens ranges in the two termite species between 15° and 22°C; in artificial nests of termites, however, both termite species have been cultivated successfully at 26°–28°C. The most vigorous formation of conidia on coagulated yolk apparently takes place between the 3rd and the 5th day of cultivation. Such cultures may give a high percentage infection of termites. The strains ofE. thaxteriana which were freshly isolated from a closely related or identical host, have proved to be much more virulent with regard to this host as compared with strains from a long-term cultivation in vitro or such which were reisolated from a less closely related host. The studied material of conidia showed that not only individual species but also individual strains of the same species which had been cultivated for a long period of time in the same way on the same medium differed by their pathogenicity.

     

Gut morphology,feeding rate and gut clearance in five species of caddis larvae

Feeding rate, the rate of movement of food through the gut and gut morphology of large larvae of five caddis species (Halesus radiatus, Hydropsyche instabilis, Polycentropus kingi, Rhyacophila dorsalis and Potamophylax cingulatus) were investigated in the laboratory. Following 72 hr starvation, P. cingulatus and H. radiatus larvae became satiated (refused prey offered directly to the mouthparts) after consuming 8–11 and 9–13 mayfly nymphs (Baetis rhodani, 3.5–4.6 mm) respectively. Hunger level affected prey consumption. In P. cingulatus, the number of prey consumed over 24 h (at 9.5–12 °C) increased with starvation periods from 0–72 h, but declined following longer starvation periods. Six clearly recognisable gut states (defined by the position of food material in various parts of the gut) can be identified at different times since commencement of a meal. As environmental temperature increased (from 8–12 °C to 15–17 °C), the rate of change of the gut state increased and the food retention time decreased in all species. Feeding periodicity (i.e. nocturnal/diurnal activity) in the field was estimated based on the evacuation rate and the gut state and environmental temperature at the known time of collection. Initiation of consumption of prey appeared to coincide with emptying of the foregut and proximal midgut, whereas actual feeding continued until complete satiation when some threshold fullness of the foregut had been reached. The length of time food was held in the foregut was positively correlated with increasing specialisation of the foregut (particularly elaboration of the proventriculus).     

A thermostable α-galactosidase from Lenzites elegans (Spreng.) ex Pat. MB445947: purification and properties

An α-galactosidase was isolated from a culture filtrate of Lenzites elegans (Spreng.) ex Pat. MB445947 grown on citric pectin as carbon source. It was purified to electrophoretic homogeneity by ammonium sulfate precipitation, gel filtration chromatography and anion-exchange chromatography. The relative molecular mass of the native purified enzyme was 158 kDa determined by gel filtration and it is a homodimer (Mr subunits = 61 kDa). The optimal temperature for enzyme activity was in the range 60–80 °C. This α-galactosidase showed a high thermostability, retaining 94 % of its activity after preincubation at 60 °C for 2 h. The optimal pH for the enzyme was 4.5 and it was stable from pH 3 to 7.5 when the preincubation took place at 60 °C for 2 h. It was active against several α-galactosides such as p-nitrophenyl-α-d-galactopyranoside, α-d-melibiose, raffinose and stachyose. The α-galactosidase is a glycoprotein with 26 % of structural sugars. Galactose was a non-competitive inhibitor with a Ki = 22 mM versus p-nitrophenyl-α-d-galactoside and 12 mM versus α-d-melibiose as substrates. Glucose was a simple competitive inhibitor with a Ki = 10 mM. Cations such as Hg²⁺ and p-chloromercuribenzoate were also inhibitors of this activity, suggesting the presence of –SH groups in the active site of the enzyme. On the basis of the sequence of the N-terminus (SPDTIVLDGTNFALN) the studied α-galactosidase would be a member of glycosyl hydrolase family 36 (GH 36). Given the high optimum temperature and heat stability of L. elegans α-galactosidase, this fungus may become a useful source of α-galactosidase production for multiple applications.     

Facteurs de limitation des populations d'Aphis fabae dans l'ouest de la France III. Répartition et incidence des différentes espèces d'Entomophthora dans les populations

Résumé Plusieurs espèces d'Entomophthora participent à la régulation des populations d'Aphis fabae Scop. sur féverole dans l'Ouest de la France. Les r?les respectifs de chaque espèce ont été évalués en 1971 et de 1973 à 1975. Entomophthora fresenii Nowak. est l'espèce qui se dissémine le plus rapidement et le plus complètement dans les parcelles, et qui est la plus agressive au niveau des colonies. Ces deux caractères en font l'agent pathogène dominant d'A. fabae dans l'Ouest, 3 années d'observations sur 4.Entomophthora aphidis Hoffman, bien que présent tous les ans n'est le pathogène le plus efficace qu'en 1973.Entomophthora thaxteriana Petch etEntomophthora planchoniana Cornu n'apparaissent pas chaque année et, lorsqu'ils sont présents, n'interviennent que pour une faible part dans le développement des mycoses. Des facteurs inhérents à l'agent pathogène (spécificité, caractères du cycle) ainsi que des facteurs écologiques (climatiques) sont évoqués pour expliquer la prédominance d'E. fresenii.

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Summary Several species ofEntomophthora take part in the natural control ofAphis fabae Scop. on field beans (Vicia faba) in the West of France. The respective importance of each species was assessed in 1971 and from 1973 to 1975. Entomophthora fresenii Nowak. is the species that most completely and quickly spreads in the fields, and the most efficient in the colonies. For both reasonsE. fresenii is the main pathogen ofA. fabae in the West of France 3 years over 4. AlthoughEntomophthora aphidis Hoffman occurs every year, this species was the most efficient pathogen in 1973 only.Entomophthora thaxteriana Petch just occurred in 1974 and 1975 and, these years, its contribution in the total sum of infected aphids was low.Entomophthora planchoniana Cornu appeared in 1975 only, very late in the season, which makes its pathogenicity difficult to assess. Factors inherent to the pathogen (specificity ofE. fresenii, nature of its cycle, dependence of the aggregation of aphids) and ecological factors such as response to climate variations, may at least to a great extent explain the predominance ofE. fresenii. All these factors must be studied for a good understanding of this species.

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Les 2 premiers mémoires de cette étude ont été publiés dans Entomophaga respectivement parRobert et al. (18, 1973, 61–75) etRabasse & Robert (20, 1975, 49–63)     

L'efficacité d'un mélange deBacillus thuringiensis Berl. et de DDT contreAgrotis ypsilon Rott. (Noctuidae)

Zusammenfassung Mit dem Ziele, die biologische Wirkung einer Mischung zwischen einem Handelspr?parat vonB. thuringiensis Berl. (Bakthan) und DDT (Gesarol 75) gegen die Raupenstadien vonAgrotis ypsilon Rott. abzukl?ren, wurden eine Serie Laborversuche duchgeführt. Beschreibung der Versuchsmethode und Darstellung der für die verschiedenen Larvenstadien erhaltenen Resultate. Die Kombination der beiden Mittel kann den allein schlecht wirksamenB. thuringiensis Berl. “aktivieren”. Diese Erscheinung konnte jedoch nur bei Larven des 4 Stadiums beobachtet werden und nur wenn der DDT-Zusatz in sehr schwachen Konzentrationen erfolgte. Weitere Versuche werden zu unternehmen sein, um das wirksamste Mischungsverh?ltnis n?her zu bestimmen.      

Die Wirkung von Kernpolyedern (Baculovirus spec.) ausMamestra brassicae aufTrichogramma cacoeciae [Hym.: Trichogrammatidae] undChrysopa carnea [Neur.: Chrysopidae]

Zusammenfassung Kernpolyeder vonMamestra brassicae (L.) wurden auf Nebenwirkungen an zwei Entomophagen-Arten in der Basis- Konzentration (LC₁₀₀ für den natürlichen Wirt) sowie der 5- und 10 fachen Konzentration geprüft. Schadwirkung durch Kontakt mit frisch angetrocknetem Belag bzw. durch Verfüttern eines kontaminierten N?hrsubstrates auf den EiparasitenTrichogramma cacoeciae Marchal konnte nicht nachgewiesen werden. Ebenso wurde die Entwicklung vonT. cacoeciae in parasitierten Wirtseiern durch eine Tauchbehandlung mit der Kernpolyeder-Suspension in verschiedenen Intervallen nach der Parasitierung nicht gest?rt. Im Wahl- und Nichtwahlversuch konnte keine Repellentwirkung von Wirtseiern festgstellt werden, die in eine Kernpolyeder-Suspension getaucht worden waren. Die r?uberischen Larven vonChrysopa carnea Steph. waren gegenüber der 10fachen Basiskonzentration bei direktem Bespritzen der Larven, Kontakt mit einem frisch angetrockneten sprit zbelag sowie bei peroraler Aufnahme unempfindlich, wie die Frassleistung der Larven, die Fekundit?t der Imagines sowie die Schlüpfrate der Eier zeigte. Bei praktischen Eins?tzen von Kernpolyeder-Pr?paraten zur Bek?mpfung der Kohleule sind im Gegensatz zu den üblichen Anwendungen von Phosphors?ureestern keine direkten Nebenwirkungen auf die untersuchten Nutzinsekten zu erwarten.

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Summary The side effect of a water suspension of polyhedral inclusion bodies of nuclnear polyhedrosis virus (NPV) fromMamestra brassicae (L.) in a concentration of 1-, 5-, and 10-fold of the LC₁₀₀ for the natural host was tested on two beneficial insects. No reduction in the parasitization capacity ofTrichogramma cacoeciae Marchal (Hym.: Trichogrammatidae) was recorded when adults were exposed to a fresh dry film, or fed on contaminated honey-agar. The development of the parasite inSitotroga cerealella Oliv. host eggs was not affected when these were dipped in a suspension of the NPV at different time intervals after parasitization. In additional tests, it was shown that deposit of the NPV suspension had no repellent effect onTrichogramma. The feeding capacity of the predatory larve ofChrysopa carnea Steph., fecundity of the adults as well as viability of the eggs were not affected when the larvae were directly sprayed with the highest tested concentration of the suspension, exposed to fresh dry film or fed on contaminated diet. These experiments indicate that, in contrast to the use of the conventional organophosphorus insecticides, no hazard to the tested beneficial insects should be expected when the preparation of the polyhedral inclusion bodies will be used in the field.

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Nr. 2 der Serie: Wirkung von Insektenpathogenen auf Entomophagen. Als Nr. 1 gilt:S. Hassan & A. Krieg: über die schonende Wirkung vonBacillus thuringiensis-Pr?paraten auf den ParasitenTrichogramma cacoeciae (Hym.: Trichogrammatidae). — Z. Pfl. Krankh. Pfl. Schutz, 82, 515–521, 1975.     

Characterization of a recombinant cellobiose 2-epimerase from <Emphasis Type="BoldItalic">Caldicellulosiruptor saccharolyticus</Emphasis> and its application in the production of mannose from glucose

A putative N-acyl-d-glucosamine 2-epimerase from Caldicellulosiruptor saccharolyticus was cloned and expressed in Escherichia coli. The recombinant enzyme was identified as a cellobiose 2-epimerase by the analysis of the activity for substrates, acid-hydrolyzed products, and amino acid sequence. The cellobiose 2-epimerase was purified with a specific activity of 35 nmol min^–1 mg^–1 for d-glucose with a 47-kDa monomer. The epimerization activity for d-glucose was maximal at pH 7.5 and 75°C. The half-lives of the enzyme at 60°C, 65°C, 70°C, 75°C, and 80°C were 142, 71, 35, 18, and 4.6 h, respectively. The enzyme catalyzed the epimerization reactions of the aldoses harboring hydroxyl groups oriented in the right-hand configuration at the C2 position and the left-hand configuration at the C3 position, such as d-glucose, d-xylose, l-altrose, l-idose, and l-arabinose, to their C2 epimers, such as d-mannose, d-lyxose, l-allose, l-gulose, and l-ribose, respectively. The enzyme catalyzed also the isomerization reactions. The enzyme exhibited the highest activity for mannose among monosaccharides. Thus, mannose at 75 g l^–1 and fructose at 47.5 g l^–1 were produced from 500 g l^–1 glucose at pH 7.5 and 75°C over 3 h by the enzyme.     

Control and possible applications of a novel carrot-spoilage basidiomycete, Fibulorhizoctonia psychrophila

A novel cold-tolerant fungus, Fibulorhizoctonia psychrophila, was isolated from a refrigerated carrot storage facility and identified as an anamorph of Athelia, often classified in Rhizoctonia s.l. Growth of this fungus was observed between 0 and 20°C with an optimum at 9–12°C, while incubation of mycelium grown at 15–32°C resulted in absence of growth even after the fungus was transferred back to 15°C. Growth was inhibited in the presence of the antifungals sorbic acid or natamycin, in particular when the fungus was incubated at 18°C. F. psychrophila produces polysaccharide degrading enzymes that, when compared to enzymes from the ascomycete fungus Aspergillus niger, retain a larger proportion of their activity at lower temperatures. This indicates that F. psychrophila could be used as a source for novel industrial enzymes that are active at 4–15°C.     

Cynipoidea undIchneumonidae [Hym.] Als Parasiten vonBoriomyia subnebulosa (Steph.) [Neur., Hemerobiidae]

Zusammenfassung Boriomyia subnebulosa hat in NW-Deutschland 2 Generationen.B. subnebulosa (Steph.) erscheint so sp?t im Frühjahr, dass sie die frühschlüpfenden Blattl?useRhopalosiphum insertum (Wlk) in den Obstanlagen nicht wirksam dezimieren kann. 27 bzw. 52% der Larven vonB. subnebulosa waren 1966 und 1967 in Obstanlagen bei Kiel parasitiert. Als Parasiten traten auf: die CynipidenAegilips striolata Cam undAe. petiolata Kief (zusammen: 12,3/34,0%),Ae. bicolorata Cam (1,8/2,1%),Anacharis ensifera Wlk (4,1/8,3%),A. immunis Wlk (2,0/4,2%),A. typica Wlk (0,5/0,4%) und die IchneumonideHemiteles brunneus Morl (5,9/1,5%).

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Summary In NW-GermanyBoriomyia subnebulosa has 2 generations. The photoperiod (short day) induces a facultative larval diapause. The larva hibernates as pre-pupa.B. subnebulosa appears as late in spring that it cannot efficiently reduce the early emerging aphidRhopalosiphum insertum in the orchards. In orchards near Kiel in 1966 and 1967 27% resp. 52% of the larvae ofB. subnebulosa were parasitized. As parasites appeared: the CynipidsAegilips striolata andAe. petiolata (together 12.3/34.0%),Ae. bicolorata (1.8/2.1%),Anacharis ensifera (4.1/8.3%),A. immunis (2.0/4.2%),A. typica (0.5/0.4%) and the IchneumonidHemiteles brunneus (5.9/1.5%). Aegilips andAnacharis are solitary endoparasites. Their last-instar larvae leave the host and then completely eat it up from the outside.Aegilips andAnacharis are polyvoltin and have a facultative larval diapause. They hibernate as larva in their host.Anacharis and the solitary ectoparasiteHemiteles brunneus can also hibernate as pre-pupa in the cocoon ofBoriomyia. Aegilips striolata andAnacharis ensifera develop at 45–100% air humidity at a temperature from 8–28°C. The morphology of eggs and larvae ofAegilips andAnacharis is described.

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Herr Dr. P.Ohm, Zoologisches Institut Kiel, half mir freundlicherweise bei der Einarbeitung in die Taxonomie vonBoriomyia, Herrn Dr.J. Quinlan, Museum of Natural History London, verdanke ich die Bestimmung derCynipoidea, Herrn. Dr.K. Horstmann, Institut für Angewandte Zoologie Würzburg, die Bestimmung derIchneumonidae, und Herrn Dipl. Biol.H. Gleiss, Institut für Pflanzenschutz G?ttingen, die Bestimmung vonRhopalosiphum insertum (Wlk).     

Effects of extreme changes of sea water temperature and salinity on the development of the sand dollar <Emphasis Type="Italic">Scaphechinus mirabilis</Emphasis>

The combined effects of temperatures of 14, 17, 20, 22, and 25°C and salinities of 36–12‰ on embryos and larvae of the sand dollar Scaphechinus mirabilis was studied. Embryonic development is the most sensitive stage in the early ontogenesis of S. mirabilis. It is completed at a temperature of 14–20°C in a salinity range of 36–24‰ and at temperature of 22°C to 26‰. The fertilization proceeds in wider ranges of temperature and salinity. Among the swimming larvae, blastulae showed the greatest resistance to variations of these environmental factors. All the larvae survived at a temperature of 14–22°C and a salinity of 36–20‰, and more than 70% of them at 18‰. The pluteus I is the most vulnerable stage; probably this is related to the formation of the larval skeleton and transition to phytoplankton feeding. The survival of larvae at the age of 20 days was 100% at 14–22° C and a salinity of 36–24‰, most of them survived at 14–20°C and a salinity 18‰. The temperature 25 ° C is the most damaging for early development of S. mirabilis. The duration of development of that species lasts 28.5–29 days at 20°C and a salinity of 32.2–32.6‰. At 20 and 22°C, the larvae settled and completed metamorphosis more quickly if sand from the parental habitat was present. The larvae did not settle during the experiment (14 days) at 14 ° C and in the absence of sand.     

Développement endoparasitaire et croissance pondérale larvaire du parasitoïdeLixophaga diatraeae [Dip.: Tachinidae] dans un hôte de substitution:Galleria mellonella [Lep.: Pyralidae]

Résumé L'étude du développement endoparasitaire deLixophaga diatraeae (Towns.) dans un h?te de substitutionGalleria mellonella L. a été effectuée par dissections d'h?tes hébergeant des parasito?des d'age connu. Les résultats mentionnés sont obtenus avec en movenge 2.6 parasito?des par h?te. Les élevages ont lieu à 22.5±0.5°C et 85±5 % H.R. avec une photophase de 12 h pourL. diatraeae et à 28±1°C à l'obscurité pourG. mellonella. La croissance pondérale larvaire suit une loi exponentielle et correspond à un temps de doublement du poids de 0,65 j pour les stades 1 et 2 et environ 0,8 j pour le stade 3. Le développement larvaire complet requiert 7,5 j en moyenne. Les stades 1,2 et 3 durent en moyenne respectivement 2,9, 2,5 et 2,1 j. La mue larvaire L₁–L₂ intervient vers 0,23 mg et la mue L₂–L₃ vers 3,2 mg. La larve nouvelle née pèse 12,3 μg et la croissance larvaire représente un facteur multiplicatif maximum d'environ 2 500 fois. Le poids moyen des pupes obtenues est de 14,2 mg.

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Summary Endoparasitic development ofLixophaga diatraeae (Towns.) reared in a substitution hostGalleria mellonella L. was studied by dissections of hosts containing known aged parasitoids. The exposed results are obtained with an average of 2,6 parasitoids per host. Rearing ofL. diatraeae was performed at 22.5±0.5°C and 85±5% R.H. with 12 light hours and rearing ofG. mellonella at 28±1°C in darkness. The larval weight growth is exponential and exhibits a doubling time of 0.65 day for the 1st and 2nd stages and around 0.8 d. for the 3rd stage. Mean complete larval development time is 7.5 days. The 1, 2 and 3 stages last respectively 2.9, 2.5 and 2.1 days. Larval moulting 1–2 happens around 0.23 mg and moulting 2–3 around 3.2 mg. New hatched larva weights 12.3 μg and during larval growth multiplicates its weight by about 2,500. The mean pupal weight is 14.2 mg.

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Nous remercionsColette Ogier pour sa collaboration technique,P. Laviolette etG. Bonnot pour leur lecture critique du manuscrit.