Effect of Temperature and Termite Starvation on Phagocytosis by Protozoan Symbionts of the Eastern Subterranean Termite Reticulitermes flavipes Kollar

Abstract Many termite species rely on intestinal protozoan symbionts to digest their cellulosic foods. We examined cellulose acquisition by the symbionts of the Eastern subterranean termite Reticulitermes flavipes Kollar (Isoptera; Rhinotermitidae) by following their phagocytosis of red paper fed to the termite host. The effects of termite host starvation and environmental temperature on feeding activity were studied in the zooflagellates Trichonympha agilis Leidy (Trichonymphidae), Pyrsonympha vertens Leidy, Dinenympha fimbriata Kirby, and D. gracilis Leidy (Pyrsonymphidae), which are among the largest residents in R. flavipes' hindguts. Protozoans in termites starved for 24 h ingested red paper significantly sooner than protozoans in termites with continuous access to food. Trichonympha, Pyrsonympha, and Dinenympha all ingested red paper particles at approximately the same rate. Red paper appeared significantly sooner in protozoans in termites maintained at 32°C than in those maintained at 22°C or 26°C. At 32°C, numbers of Trichonympha per gut remained constant over 96 h. Pyrsonympha and Dinenympha cells were absent or significantly reduced in number by 72 h at that temperature. These results provide insight into the environmental factors that shape the termite–protozoan symbiosis. They may aid in the development of protozoicides used to control pest termites. Received: 1 August 1997; Accepted: 26 November 1997     

Surface structures of three species of the genusEntomophthora

The surface structure of freshly discharged conidia ofEntomophthora thaxteriana Hall & Bell andE. destruens Weiser & Batko is slightly undulated and that of their papillae has elevated ridges forming a reticulation. The conidia ofZoophthora aphidis Batko are of more variable shape than those ofE. thaxteriana andE. destruens, their surface is smoother and the reticulate structure of their papillae is less distinct. The surface of germinating or older conidia of all the 3 species is gradually wrinkled, furrowed, forming deep depressions or completely broken down. The surface features of germ tubes or hyphae depend on the tubes being filled with the plasma and the resultant turgor. The plasma ofZ. aphidis conidia is capable of forming large areas of membranes of various shapes which enables it to move to a rather long distance.

---

Résumé La structure de la surface des conidies projetées deEntomophthora thaxteriana Hall & Bell etE. destruens Weiser & Batko est faiblement ondulée et celle de leurs papilles a des crêtes élevées formant un réticule. La forme des conidies deZoophthora aphidis Batko est plus variable que celle des conidies deE. thaxteriana etE. destruens, leur surface est plus unie et la structure réticulaire de leurs papilles est moins distincte. La surface des conidies en germination ou plus agées des 3 espèces est successivement ridée, sillonnée, formant des dépressions profondes ou complètement écroulée. Les caractères de la surface des tubes germinatifs ou des hyphes dépendent de la teneur des tubes en plasma et de la turgescence qui en résulte. Le plasma des conidies deZ. aphidis est capable de former de grandes surfaces de membranes de formes diverses qui lui permettent de se déplacer à une assez grande distance.

     

Harvesting rate of the termite,Drepanotermes tamminensis (Hill) within native woodland and shrubland of the Western Australian wheatbelt

The Western Australian termite,Drepanotermes tamminensis (Hill), harvests various plant materials according to biomass availability. The main litter components harvested by this termite in a woodland dominated byEucalyptus capillosa are bark and leaves of the major tree species, while in shrubland dominated byAllocasuarina campestris, shoots of this species are taken. Harvesting mainly occurs during the autumn (April–May) and spring (September–October) seasons. The commencement and duration of harvesting appears to depend partly on weather conditions, with harvesting taking place at temperatures between 15 and 25°C after periods of rain. This species of termite harvests approximately 15.6 g m⁻² year⁻¹ and 3.2 g m² year⁻¹ (dry weight of plant material) in the woodland and shrubland, respectively.     

The survival of Entomophthora spp. in mummified aphids at different temperatures and humidities

Entomophthora aphidis survived for at least 32 weeks at 0°C and 20 or 50% RH and E. thaxteriana for at least 16 weeks at 10°C and 20 or 50% RH in mummified infected pea aphids, Acyrthosiphon pisum. The fungi produced infective conidia when the aphids were moistened. This probably explains the survival of Entomophthora species infecting aphids during short periods when the weather is unsuitable for conidial discharge and host infection.     

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.

---

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.

---

---

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)     

The Non-LTR Retrotransposon R2 in Termites (Insecta,Isoptera): Characterization and Dynamics

The full-length element of the non-LTR retrotransposon R2 is here characterized in three European isopteran species: the more primitive Kalotermes flavicollis (Kalotermitidae), including two highly divergent mitochondrial lineages, and the more derived Reticulitermes lucifugus and R. urbis (Rhinotermitidae). Partial 3′ sequences for R. grassei and R. balkanensis were also analyzed. The essential structural features of R2 elements are conserved in termites. Phylogenetic analysis revealed that termite elements belong to the same clade and that their phylogeny is fully compatible with the phylogeny of their host species. The study of the number and the frequency of R2 insertion variants in four R. urbis colonies suggests a greatly reduced, or completely absent, recent element activity.     

A case for a free-running circannual rhythm in soldier developmental time of Formosan subterranean termites

The success of all insect societies relies on their ability to maintain optimal levels of different castes. Here we report on an apparent free-running circannual rhythm that optimizes the developmental time of the soldier caste of Coptotermes formosanus Shiraki. Over a 3 year period, bioassays were conducted each month (except June) with groups of 100 termite workers in a 28°C incubator in total darkness. The number of days needed for C. formosanus soldiers to develop varied depending on the time of the year (month). In March, just prior to the major swarming exodus for alates (April to June), 9 days were required before a worker molted to a presoldier. Longer times were required for such a molt in all other months, with an increasing trend from April to December (from 13 to 30 days) and a decreasing trend from January to February (from 25 to 12 days). Colony origin or the length of time that termites were kept in the laboratory under constant conditions (26 – 28°C, 70 – 80% RH) before testing (7 days – 1 year) did not affect this rhythm. This is the first demonstrated evidence of a free-running circannual rhythm in a social insect. Received 23 July 2007; revised 9 and 21 August 2007; accepted 23 August 2007.     

Hydrogen emission by three wood-feeding subterranean termite species (Isoptera: Rhinotermitidae): Production and characteristics

Abstract Hydrogen emission by wood-feeding termites, Coptotermes formosanus, Reticulitermes flavipes and Reticulitermes virginicus, was investigated upon a cellulosic substrate as their food source. The emission rates among the three species tested were significantly different and R. virginicus demonstrated the greatest H₂ emission at 4.78 ± 0.15 μmol/h/g body weight. In a sealed test apparatus, H₂ emission for each termite species showed a quick increase at the initial incubation hours (3–6 h), followed by a slower growth, possibly due to the feedback inhibition by gas accumulation. Further investigation revealed that continuous H₂ emission could be maintained by reducing the H₂ partial pressure in the sealed container. The bioconversion of cellulose to molecular H₂ by the subterranean termites tested could reach as high as 3 858 ± 294 μmol/g cellulose, suggesting that the termite gut system is unique and efficient in H₂ conversion from cellulosic substrate.     

Termites (Isoptera) in forest ecosystems of Cat Tien National Park (Southern Vietnam)

The species composition, abundance and colony sizes of terrestrial termites were studied in five forest habitats of Cat Tien National Park, Southern Vietnam. Twenty-four species belonging to Rhinotermitidae (1 species) and Termitidae (23 species, mostly Macrotermitinae), were found in mounds and in soil samples. The density of inhabited termite nests in different habitats averaged 68 per hectare (range 44–106), most nests belonged to Macrotermes spp. Six mounds of dominant species (Globitermes sulphureus, Microcerotermes burmanicus, Macrotermes carbonarius, M. gilvus, M. malacensis and Hypotermes obscuriceps) were destructively sampled. The number of termites in the nests ranged from 65 000 to 3 150 000 individuals with the biomass ranging from 185 to 2440 g live weight. The abundance of foraging termites in soil and litter averaged 60 ind./m2.The total abundance of Macrotermes species alone could conservatively be estimated as 2.5 million individuals and 20.5 kg live weight per hectare. Four species dominating in the studied habitats (M. carbonarius, M. gilvus, M. malaccensis, and H. obscuriceps) belong to active litter decomposers.     

Antitermitic effect of the Lantana camara plant on subterranean termites (Isoptera: Rhinotermitidae)

Abstract The insecticidal effects of Lantana camara L. (flowers, leaves, stems and roots) and the soil where lantana had been growing, on foraging activity and survival of the subterranean termites Coptotermes formosanus and Reticulitermes flavipes were examined in a 3-week experiment. The soil in which lantana had been growing had no effect on termite tunneling and survival. Incorporation of chipped fresh lantana leaves and stems into soil had no effect on mortality but caused significant reduction in tunneling. The 5-cm wide barrier of soil with lantana tissue incorporated effectively repelled groups of both species from penetrating the barrier and thus prevented infestation of a piece of wood on the other side of the barrier. C. formosanus was more sensitive in avoiding the barrier than R. flavipes. Leaves, stems and flowers were more repellent than roots. These results provide preliminary evidence that fresh-cut lantana leaves, stems and flowers may have use as additives to garden mulches against termites.     

Phylogenetic Analysis of the Gut Bacterial Microflora of the Fungus-Growing Termite Odontotermes formosanus

We constructed a bacterial 16S rRNA gene clone library from the gut microbial community of O. formosanus and phylogenetically analyzed it in order to contribute to the evolutional study of digestive symbiosis and method development for termite control. After screening by restriction fragment length polymorphism (RFLP) analysis, 56 out of 280 clones with unique RFLP patterns were sequenced and phylogenetically analyzed. The representative phylotypes were affiliated to four phylogenetic groups, Firmicutes, the Bacteroidetes/Chlorobi group, Proteobacteria, and Actinobacteria of the domain Bacteira. No one clone affiliated with the phylum Spirochaetes was identified, in contrast to the case of wood-feeding termites. The phylogenetic analysis revealed that nearly half of the representative clones (25 phylotypes) formed monophyletic clusters with clones obtained from other termite species, especially with the sequences retrieved from fungus-growing termites. These results indicate that the presence of termite-specific bacterial lineages implies a coevolutional relationship of gut microbes and host termites.     

A comparison of two methods for sampling assemblages of subterranean,wood-eating termites (Isoptera)

Abstract Within a 50 × 50 m area of wandoo Eucalyptus capillosa woodland in the Western Australian wheatbelt, the diversity and frequency of occurrence of wood-eating termite species was assessed at two food types. Over a 12 month period, monthly termite activity was determined: (i) at sound/undecayed artificial baits (seasoned wooden stakes of Jarrah, Karri, Pine, Batu, Oregon; Jarrah sawdust; paper rolls); and (li) at naturally occurring timber, fallen logs and branches of wandoo, in varying stages of decay. Termite diversity was 11 species at baits, 18 species at wandoo out of an overall site richness of 21 species. Karri attracted the most species (9); sawdust attracted none. At wandoo, Nasutitermes exitiosus, Coptotermes acinaciformis and Occasitermes occasus accounted for 59% of samples where termites were recorded. At baits, Heterotermes occiduus accounted for a mean of 80% of samples across bait types, but was rarely sampled at wandoo (5% of samples). Only H. occiduus, C. acinaciformis and Amitermes neogermanus ate bait. Pine, Oregon and paper rolls were most effective in attracting foraging termites in terms of highest per cent of replicates showing bait consumption and highest consumption rates. Jarrah and Batu were least attractive to foraging termites. Samples from wandoo underestimated the relative frequency of occurrence of H. occiduus within the study site. Coptotermes acinaciformis, which attack large food items, and certain species of Amitermes, which forage on subterranean food, may have been underestimated by both sampling methods. These findings indicate that a proper understanding of the structure of wood-eating termite assemblages within a given area requires a composite sampling strategy which addresses termites that eat sound or decayed wood, as well as surface and subsurface foragers.     

Upper limits of temperature for growth inChlorella (Chlorophyceae)

The upper limit of temperature for growth is a species-specific character in the genusChlorella. The limits of 14Chlorella species range from 26–30°C (C. saccharophila) to 38–42°C (C. sorokiniana), withC. fusca var.vacuolata (34°C) andC. kessleri (34–36°C) assuming an intermediate position. Thus, there is no wide gap in the temperature limits between the normal (“low-temperature”) species ofChlorella and the “high-temperature” species,C. sorokiniana.     

Behavioral Response of Two Subterranean Termites (Isoptera: Rhinotermitidae) to Vibrational Stimuli

Behavioral responses to vibrational stimuli were examined in two subterranean termite species, Coptotermes formosanus Shiraki and Reticulitermes flavipes (Kollar). Termites habituated to vibrational stimulation when in social groups, but failed to do so individually, indicating that habituation is a collective action. In assays on termite groups, both species demonstrated a similar pattern of behavioral responses to vibrational stimuli: evanescent cessation of activity and movement, followed by withdrawal from the vibration source. Groups of both species then gradually moved back toward the vibration source as a consequence of continuous exposure. However, it took a significantly shorter period for C. formosanus to return (57 s) to the test arena and to resume (80 s) normal foraging activities in the test arena compared with R. flavipes, which took 97 and 227 s, respectively, when exposed to the vibration frequency of 120 bmpm. High vibration frequency (240 bmpm) increased the time required to return (C. formosanus, 80 s; R. flavipes, 153 s) and to resume regular locomotion (C. formosanus, 186 s; R. flavipes, 263 s). Our experiments demonstrate that workers play a crucial part in adjusting groups of termites to distressful vibrations. Soldiers of R. flavipes demonstrated similar behavioral responses as workers, however, C. formosanus soldiers exhibited a transient positive response before withdrawal. An erratum to this article is available at .     

Use of Genetically Engineered Escherichia coli to Monitor Ingestion, Loss, and Transfer of Bacteria in Termites

Escherichia coli was transformed with a recombinant plasmid (pEGFP) containing the genes for ampicillin resistance and Green Fluorescent Protein (GFP). Escherichia coli expressing GFP (E. coli/GFP+) was then fed to workers of the termite Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). The transformed bacteria in the termite guts were detected by growing the gut flora under selective conditions and then checking the cultures for fluorescence. Recombinant plasmids in the termite gut were detected by plasmid extraction with subsequent restriction enzyme digest. The presence of the GFP gene in the gut of termites fed with E. coli/GFP+ was verified by PCR amplification. Transformed E. coli were ingested rapidly when workers fed on filter paper inoculated with E. coli/GFP+. After 1 day, 42% of termite guts harbored E. coli/GFP+. Transfer of E. coli/GFP+ from donor termites (fed with E. coli/GFP+) to recipients (fed with moist filter paper) occurred within 1 day. However, without continuous inoculation, termites lost the transformed bacteria within 1 week.     

Arolia in termites (Isoptera): functional significance and evolutionary loss

Summary. Termite workers from all families examined had no arolia (=adhesive pads) on their tarsi and are unable to climb smooth vertical surfaces such as glass or polypropylene plastic. This contrasts with ants where both workers and alates of most species possess arolia and are able to climb these surfaces. Arolia were present in alates of the majority of species investigated from three of the four most basal termite families (Mastotermitidae, Termopsidae and Kalotermitidae), though absent from the basal family Hodotermitidae that contains only three genera. Alates in the two kalotermitid species tested readily climbed glass walls. The complete evolutionary loss of arolia from alates in the specious two most apical termite families (Rhinotermitidae and Termitidae) suggests paedomorphosis. Very smooth surfaces probably cannot be used to completely prevent entry of rhinotermitid termites into buildings because these termites can eventually build galleries of feces and soil over these surfaces. However, an experiment with Coptotermes formosanus showed that a smoother surface significantly slows down the rate of gallery building.Received 12 February 2004; revised 17 June 2004; accepted 29 June 2004.     

Entomophthora blunckii an Kohlschaben (Plutella maculipennis): Isolierung und neue Beschreibung

Zusammenfassung Von pilzbefallenen Larven der KohlschabePlutella maculipennis Curt. wurdeEntomophthora blunckii Lakon exZimmermann isoliert. Die Art wird mit lateinischer Diagnose gültig beschrieben, die morphologischen Merkmale werden erg?nzend angegeben und erstmals durch Fotos belegt.E. blunckii w?chst gut auf koaguliertem Eidotter, weniger gut auf Sabouraud-Glucose-Agar. Mycelwachstum wurde zwischen 8° und 28°C beobachtet, dagegen nicht bei 32°C. Die Symptome infizierter Larven werden geschildert und der Pilz wird mit ?hnlichen Arten verglichen.

---

Summary Entomophthora blunckii Lakon exZimmermann was isolated from larvae of the diamondback-mothPlutella maculipennis Curt. and redescribed. The fungus is characterized by its elliptical to pear-shaped conidia (from infected larvae 13–20×7–11 μm, mostly 15–18×7–9 μm) with the outer membrane often inflated and its branched conidiophores forming a dense gray to faint greenish-yellowish covering over the body of the insect. The symptoms of larvae infected withE. blunckii are described. The species grows on coagulated egg yolk, less well on Sabouraud-Dextrose-Agar. Growth was observed between 8° and 28°C but not at 32°C. The fungus is compared with similar species.

     

Effects of antibiotics on hydrogen production and gut symbionts in the Formosan subterranean termite Coptotermes formosanus (Isoptera: Rhinotermitidae)

Abstract Symbiotic microorganisms that inhabit the gut of Coptotermes formosanus enable this termite to degrade lignocelluloses and further produce hydrogen as an important intermediate to be recycled in its hindgut or as a byproduct to be emitted to the atmosphere. Both symbiotic protists and prokaryotes in the guts of termites demonstrated some different roles with respect to hydrogen production. In this study, the effects of two antibiotics, ampicillin and tetracycline, on hydrogen emission and the gut symbionts of C. formosanus were investigated. Hydrogen emission from termite guts was significantly enhanced when termites fed on wood diets treated with either ampicillin or tetracycline. The greatest H₂ emission rates, 2 519 ± 74 and 2 080 ± 377 nmol/h/g body weight, were recorded with the treatments of ampicillin and tetracycline, respectively, which showed 6–7 times more H₂ production than that of controls. Antibiotic‐treated diets negatively affected the prokaryotic communities and reduced their abundances, particularly on those ectosymbionts inhabiting the gut walls or in the gut fluid of C. formosanus, such as spirochetes. However, no significant reductions in the counts of gut cellulolytic protists, Pseudotrichonympha grassii and Holomastigotoids hartmanni, were recorded; and with a further observation by confocal laser scanning microscopy, the endosymbionts inhabiting P. grassii generally survived the antibiotic treatments. These results suggest that some prokaryotes may serve as the main hydrogen consumers, while P. grassii, together with its endosymbionts, may function as the main contributors for hydrogen production in the hindgut of C. formosanus.     

Behavioral Interactions Between <Emphasis Type="Italic">Aphaenogaster rudis</Emphasis> (Hymenoptera: Formicidae) and <Emphasis Type="Italic">Reticulitermes flavipes</Emphasis> (Isoptera: Rhinotermitidae): The Importance of Physical Barriers

Predation pressure from ants is a major driving force in the adaptive evolution of termite defense strategies and termites have evolved elaborate chemical and physical defenses to protect themselves against ants. We examined predator–prey interactions between the woodland ant, Aphaenogaster rudis (Emery) and the eastern subterranean termite, Reticulitermes flavipes (Kollar), two sympatric species widely distributed throughout deciduous forests in eastern North America. To examine the behavioral interactions between A. rudis and R. flavipes we used a series of laboratory behavioral assays and predation experiments where A. rudis and R. flavipes could interact individually or in groups. One-on-one aggression tests revealed that R. flavipes are vulnerable to predation by A. rudis when individual termite workers or soldiers are exposed to ant attacks in open dishes and 100% of termite workers and soldiers died, even though the soldiers were significantly more aggressive towards the ants. The results of predation experiments where larger ant and termite colony fragments interacted provide experimental evidence for the importance of physical barriers for termite colony defense. In experiments where the termites nested within artificial nests (sand-filled containers), A. rudis was aggressive at invading termite nests and inflicted 100% mortality on the termites. In contrast, termite mortality was comparable to controls when termite colonies nested in natural nests comprised of wood blocks. Our results highlight the importance of physical barriers in termite colony defense and suggest that under natural field conditions termites may be less susceptible to attacks by ants when they nest in solid wood, which may offer more structural protection than sand alone.     

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.

---

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.

---

---

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