THE EFFECTS OF METHODS OF SEWAGE APPLICATION ON THE ECOLOGY OF BACTERIA BEDS

Two difficulties in treating sewage in bacteria beds—namely, the choking of the beds by excessive growths of micro-organisms and the nuisance from flies breeding in the beds—are considered as one ecological problem. The effect of the manner in which the sewage is applied to the bed through different types of distributor nozzle on the film and fauna populations was studied. It was found that nozzles which provided a strong flushing action on the surface did not prevent excessive growth of film below the surface but did limit the grazing fauna, as a result of which the amount of film was greater than under jets in which the flushing action was reduced. Where this reduction was effected by allowing the sewage jet to first impinge on a splash plate, uniform conditions were produced in the medium below, where the species were in direct competition for food in the one ecological niche. As a result the fly larvae ( Anisopus fenestralis and Psychoda sp.) suppressed the population of Achorutes subviaticus (Collembola) during the winter. Where the flushing action was reduced by allowing the sewage to flow through an increased number of holes of smaller bore, two niches were provided, one wet region, subject to some flow of sewage, and the other drier region between the jets. Under this method, two populations existed side by side, Achorutes being present throughout the year in the drier zone and A. fenestralis larvae occupying the sub-jet zones.     

The ecology of the British species of Psychoda (Diptera; Psychodidae)

A study of the dispersal of the sewage-filter Psychodids requires a knowledge of the breeding haunts and seasonal incidences of the local species of the genus. Field dung, decaying vegetable matter and organic mud form the breeding places to one of which some species confine themselves, whilst others, e.g. Psychoda seuerini Tonn., breed in a variety of materials. P. alternata Say is more restricted in its choice of breeding grounds and proved the best indicator of dispersal from sewage filters. With this fly, invasion of farms and woodland was apparent at a distance of 1/4 and 1 mile respectively from the filters, but not at a distance of 1 1/2 miles in the direction of the prevailing wind.     

A STUDY OF THE BIOLOGY AND CONTROL OF ANISOPUS FENESTRALIS (SCOPOLI, 1763), A FLY ASSOCIATED WITH SEWAGE FILTERS

In work on the control of the sewage fly Anisopus fenestralis (Scopoli, 1763), it was shown that the larval phase was considerably lengthened by limiting the food supplied. The effects of food supply and temperature are considered in relation to the incidence of the adult fly in the filters. The assessment of the fly population of sewage filters by tray traps, as previously used by other workers, was investigated. Both light and temperature were found to affect the number of A. fenestralis entering the trays: it is concluded that although the trays do not accurately assess the A. fenestralis population of a bed, nor measure the rate of emergence from the bed, they are of value in assessing the relative effect of different control measures. In the filters the period of maximum abundance was during the spring, followed by a period of reduced numbers throughout the summer, with a recovery in the autumn giving relatively high numbers throughout the winter. Emergence of A. fenestralis from the filters is influenced by climatic factors, especially temperature and light; a diurnal variation in the rate of emergence was also observed. Because of this effect of temperature on emergence, the flies were only present above the filters in the warmer periods of the year; and because of the reduced numbers in the filters in the summer, the flies were only abundant above the beds during the spring and early summer and in the autumn. BHC applied as a water-dispersible powder was more effective than in the form of an emulsion. It was also most effective when used against the larval phase.     

Epithelial moulds on the shells of the early Palaeozoic brachiopod Lingulella

A fine hexagonal network of microscopic ridges has been discovered on the internal shell surface of the cosmopolitan Lower Palaeozoic inarticulate genus Lingulella. The micro-ornamentation has been recognised on all well-preserved specimens examined, from Cambrian and Ordovician successions in Ireland, North America, Gt. Britain, Spitzbergen, and China. Examination of the mantle of the related Recent genus Lingula revealed that the outer epithelial cells are arranged in a hexagonal close-packed pattern comparable in size and form to the micro-ornamentation in the fossil shells. This fact, along with the discovery of a polygonal pattern on some organic layers in the Lingula shell, suggests that the micro-ornamentation in fossil Lingulella is the mould of the outer epithelium responsible for shell secretion. No trace of epithelial moulds has yet been found in specimens of Lingula from younger Palaeozoic successions. This difference may prove to be a useful diagnostic feature in distinguishing linguloid inarticulates from one another. Epithelial moulds , Lingulella, Palaeoglossa, Lingula, Cambrian, Ordovician, Recent.     

THE ECOLOGY OF ANISOPUS FENESTRALIS SCOP. (DIPTERA) IN SEWAGE BACTERIA BEDS

The assessment of populations of Anisopus fenestrate (Scopoli, 1763) in sewage bacteria beds by the trapping of adults at the surface has been previously proved to be unsatisfactory. Methods were therefore developed for determining the numbers of egg masses, larvae and pupae as well as the total organic matter in a unit volume of bed. The relative larval populations of three areas under investigation were related to the loading of the beds as measured by the sewage strength and rate of application. In the upper 2 ft. 6 in. the numbers of larvae and pupae per unit volume of bed decreased with depth. There was no evidence of any vertical migration of the larvae before pupation. The horizontal distribution of larvae was found to be affected by the method of distribution. In beds served with fixed spray jets larvae are more abundant nearer the jets than at some distance away. In beds served with travelling distributors the larvae are more abundant in the zones below the jets than in the drier intermediate zones. In both cases relatively higher percentages of pupae in the drier zones might indicate a horizontal migration of larvae before pupating or of the pupae themselves.
The incidence of the larvae throughout 1949 in all three beds showed recurring peaks. In the following year a more intensive investigation on one area showed that this was due to successive generations of the fly; the proximity of the peaks is determined mostly by temperature and their size by the amount of food available in the bed during the larval grazing phase.
In the area not treated with insecticide intraspecific competition during a period when food was limiting, due to depletion by the previous generation, resulted in a natural reduction in the population. In the area treated with insecticide the food was retained and this natural control was thereby delayed.     

An investigation into the variations in the fine surface details of the eggs of five species of Delia (Diptera: Anthomyiidae)

The eggs of five species of Delia have been examined for the external chorionic patterning, the size and shape of the micropyle and the number, characteristics and distribution of the aeropyles using the scanning electron microscope. The species concerned are the cabbage root fly Delia radicum , the onion fly Delia antiqua , the seed corn maggot Delia platura , the wheat bulb fly Delia coarclata and the turnip fly Delia floralis.
Each species has its own clear characters and this, coupled with a significant difference in egg size, enables one species to be distinguished from another.     

Discontinuity surfaces recorded in shallow-marine platform carbonates: an example from the Early Jurassic of the Velebit Mt. (Croatia)

Discontinuity surfaces of different types and scales are common in successions of shallow-marine carbonate platforms because sediments there are deposited close to the sea level and therefore are sensitive to any significant physico-chemical changes of environmental factors. Discontinuity surfaces indicate breaks in sedimentation under subaqueous or subaerial conditions. Most discontinuities in shallow-marine carbonate successions are on a bed-scale, and can be determined only by analysis of sedimentologic, diagenetic, taphonomic, and ichnologic features of the rock. The study of small-scale discontinuities has been carried out on two Lower Jurassic successions of the Velebit Mt. Depending upon their common features and environment of formation, three groups of discontinuities are distinguished on simple bedding planes: subaerial exposure surfaces, erosion surfaces, and omission surfaces. The distribution of discontinuity types in both successions is evaluated. Exposure surfaces prevail in both sections, and four units (relatively thin intervals of the sedimentary record) with abundant subaerial exposures are recognized. Dated by biostratigraphy, these units are of earliest Sinemurian, middle Early Sinemurian, earliest Pliensbachian, and late Early Pliensbachian age. Omission surfaces are the least common type of discontinuity. Thickness variations of high-frequency peritidal and shallow subtidal shallowing-upward cycles, highlighted by the Fischer plots show a very similar long-term trend for the two sections. The units with common subaerial exposure surfaces coincide with the falling limb of the Fischer plots and the section with common omission surfaces coincides with the rising limb of the plots. The studied discontinuities are formed by autocyclic and/or allocyclic processes operating on the shallow platform, but the units with abundant subaerial exposures invoke allogenic forcing of the sedimentary record. The use of the units with abundant discontinuities instead of a single surface has proven useful for the correlation of the studied shallow-platform deposits because one type of discontinuity may change laterally into another type or features of different discontinuity types can be superimposed.     

Reproductive biology of Arum italicum (Araceae) in the south of France

The reproductive success of Arum italicum in south-western France showed a positive relationship with plant vigour at both the plant (number of inflorescences) and inflorescence (number of seeds) levels. However, the infructescence and berry numbers were not related to the number of inflorescences, and two-fold more seeds were produced by individuals flowering several times than by those flowering just once. Moreover, the reproductive success of this species appeared to be limited by the high abortion rate (50%), strong predation pressure on the inflorescences (34%), and low seed set rate of nonpredated inflorescences (36%), suggesting pollination limitation. Nevertheless, a positive relationship was found between the mean number of Psychoda trapped per inflorescence and the number of maturing infructescences, particularly for the most abundant species, Psychoda crassipenis . Therefore, pollinator availability appeared to be an important limiting factor for fructification in the studied population, by contrast with other studies in which the fruit set appeared to be related more strongly to the density of inflorescences. Such different results may have been caused by the relatively low abundance of Psychoda in the present study.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 43–49.     

Internal extraocular photoreceptors in a dipteran insect

Within the head capsule of the moth-fly Psychoda cinerea, underlying each of the two compound eyes, are two internal ocelli of different sizes. There are seven photoreceptor cells in Ocellus I and two in Ocellus II. The internal Ocellus I appears clearly different from the retina of the compound eye, by different rhabdom structure, different size of pigment granules and different stability of these pigments to solvents. Ocellus II does not contain any pigment granules. The physiological activity of these photoreceptors is indicated by their well-developed axons, the rhabdom structure, organelles produced by membrane reorganization, and Actaptation phenomena. The internal ocelli are former larval stemmata that have been displaced inward during metamorphosis. Presumably they have a stimulatory action on the CNS, in analogy with the dorsal ocelli, which are lacking in Psychoda. It is plausible to credit the internal ocelli with a photosensitive role in the functional complex of pacemakers and circadian rhythm.     

Genetic diversity of populations of Old World screwworm fly, Chrysomya bezziana, causing traumatic myiasis of livestock in the Gulf region and implications for control by sterile insect technique

Abstract.  Fly larvae were collected from 181 cases of traumatic myiasis in livestock in 10 regions of four countries in the Middle East Gulf region: Iran, Iraq, Saudi Arabia and Oman. The predominant fly species responsible for cases was the Old World screwworm (OWS) fly, Chrysomya bezziana Villeneuve (Diptera: Calliphoridae). In cases from Iran and Oman, which included non-OWS fly species, OWS fly was found solely responsible for 67.6% of cases and jointly with other fly species for a further 12.7% of cases. The major hosts were sheep and goats, together comprising 84.6% of the total, which reflects their predominance among the livestock of these Gulf countries. The major site of wounding on sheep and goats was the tail (40.3%), followed by female genitalia (14.0%). The 3' terminal 715 nucleotides of the mitochondrial cytochrome b gene were sequenced for 178 larvae of OWS. Five haplotypes were identified: three had been recorded previously in the region (two were common throughout and one was unique to Oman), and two were newly identified, one from southern Iraq and the other from Saudi Arabia, both in regions sampled for the first time. The haplotypes varied from one another only at one or two nucleotide sites, equivalent to an intraspecific difference of 0.14–0.28% across the entire 715-bp fragment. There was a single statistically significant association between host species and haplotype in Saudi Arabia, a first such record for OWS fly. The small degree of genetic diversity between geographical populations of OWS fly within the Gulf region suggests that a single Gulf colony could be used to implement the sterile insect technique within an integrated control programme.     

H.A. Hawkes—A pioneer of field ecology

This article outlines the life and career of H.A. (Bert) Hawkes, who has been referred to as one of the founders of field ecology, due to the work he conducted in the late 1940s and 1950s, investigating the fly nuisance emanating from biological filters. Following an overview of his life, there is a focus on his core research, carried out over a period of some 50 years, on two aspects of river pollution control—the prevention of pollution by sewage biological filtration and the monitoring of river pollution by biological surveillance.     

Synthesis of Indicator Strains and Density of Ribonucleic Acid-Containing Coliphages in Sewage

Escherichia coli strains freshly isolated from natural sources are inefficient indicators of coliphages present in sewage. Four E. coli strains recently isolated from clinical specimens were mutagenized to obtain lac(-) mutants. Such mutants were infected with an F'lac(+) sex factor of E. coli K-12. Pairs of isogenic lac(-) and lac(-)/F'lac(+) strains were used as indicators of coliphages present in sewage, and it was found that such strains can be effectively used for a direct and almost selective enumeration of F-specific coliphage contents of sewage samples. Serological tests were applied to a number of F-specific phages isolated. All the isolates that were tested fell into two distinguishable antigenic classes: members of one class being related to ribonucleic acid (RNA) phage MS2 and those of the other being related to another RNA phage, namely, Qbeta. MS2-related phages have been found to be more widely distributed than the Qbeta related phages. Most habitats sampled were found to yield only one or the other kind of phage. Single-stranded deoxyribonucleic acid-containing F-specific phages were not detectable by the methods employed by us.     

Extremely small genomes in two unrelated dipteran insects with shared early developmental traits

We discovered extremely small genomes (1C ~100 Mb) in the dipteran insects Coboldia fuscipes (Scatopsidae) and Psychoda cinerea (Psychodidae). The small genomes of these species cannot be explained by a fast developmental rate, which has been shown to correlate with small genome sizes in animals and plants but might accommodate the combined effects of other developmental traits, including small egg size, thin blastoderm layer, and long-germ development.     

Variation in the proportion of flower visitors of Arum maculatum along its distributional range in relation with community‐based climatic niche analyses

Because species–specific interactions between plants and insects require considerable physiological adaptations to establish and be maintained through time and space, highly specialized interactions are rare in nature. Consequently, even if some one‐to‐one interactions might appear locally specialized, additional partners may be involved at a wider scale. Here, we investigate the geographical constancy in the specificity level of the specialized lure‐and‐trap pollination antagonism involving the widespread European Arum maculatum and its associated Psychodid pollinators. Until now, studies concurred in demonstrating that one single insect species, Psychoda phalaenoides, efficiently cross‐pollinated plants; researches were, however, performed locally in western Europe. In this study we characterize for the first time the flower visitors’ composition at the scale of the distribution range of A. maculatum by intensively collecting plants and insects throughout the European continent. We further correlate local climatic characteristics with the community composition of visiting arthropods. Our results show that flowers are generally visited by P. phalaenoides females, but not over the whole distribution range of the plant. In some regions this fly species is less frequent or even absent and another species, Psycha grisescens, becomes the prevailing visitor. This variability is geographically structured and can be explained by climatic factors: the proportion of P. grisescens increases with higher annual precipitations and lower precipitations in the warmest trimester, two characteristics typical of the Mediterranean zone. Climate thus seems driving the specificity of this interaction, by potentially affecting the phenology of one or both interacting species, or even of volatile and heat production in the plant. This result therefore challenges the specificity of other presumably one‐to‐one interactions covering wide distribution ranges, and provides an example of the direct effect that the abiotic environment can have on the fate of plant–insect interactions.     

Dicarboximide resistance in field isolates of Alternaria alternata is mediated by a mutation in a two-component histidine kinase gene

Isolates of Alternaria alternata collected from a field site which had previously been treated with the dicarboximide fungicide iprodione were found to demonstrate a high level of resistance to iprodione and the phenylpyrrole fungicide, fludioxonil in plate assays. In order to determine the genetic basis for this fungicide resistance a partial length clone of a two-component histidine kinase (HK) was isolated from genomic DNA of a fungicide-sensitive A. alternata isolate using degenerate primers by PCR. Analysis of the AaHK1 gene structure indicates the presence of six 90 amino acid repeat domains upstream of a kinase domain as found in the homologous HK genes from other fungal species. Comparison of nucleic acid sequences from the fungicide-sensitive and fungicide-resistant A. alternata isolates confirmed the presence of mutations leading to premature termination of the translated HK protein. The possible role of the two-component HK in the development of dicarboximide resistance in A. alternata is discussed.     

Genome, evolution, Drosophila and beyond: the new dimensions

A century ago a little fly with red eyes was first used for genetic studies. That insignificant fly, called at that time Drosophila ampelophila, revolutionized biology while becoming the model we know today under the name of Drosophila melanogaster. Since then its study has never ceased, but the field of interest has somewhat changed during the century. To caricature a little, today we essentially learn from Drosophila meetings that the fly has a brain! It is true that the fly is a tremendous model organism for neurobiology. But this fly is, in fact, an appropriate and recognized model for the whole of biology. Indeed, Drosophila meetings are exceptional opportunities to gather biologists of diverse backgrounds together. There we not only learn about the latest improvements in our field of interest, but surely appreciate learning another bit of biology. From this biological melting pot has emerged a culture very specific to the fly community. Thus besides neurobiology, cell biology and development, a diversity of other research fields exist; they all have their own place in the cultural and historical dimension of the "drosophila" model. Several communications from those diverse research fields were presented at the 8th Japanese Drosophila Research Conference (JDRC8) and are briefly covered here. We believe it more judicious to call the model "drosophila" without a capital initial, as the model has never really been limited to only the Drosophila genus. The vernacular name "drosophila" is currently used to designate any fly of the Drosophilidae family and we believe the term more appropriate than "small fruit fly" or "vinegar fly" to better include the species and ecological diversity of the model.     

Mould biodiversity in homes II. Analysis of mattress dust

Fungal species from 130 samples of mattress dust have been identified. The number of moulds varies from one mattress to another with extreme values ranging from less than 1000 to more than 70 000 000 CFU/g of dust (median value of 30 000 CFU/g).Eurotium repens is undoubtedly the most frequent species detected in mattress dust.Aureobasidium pullulans, Alternaria alternata, Penicillium chrysogenum, Aspergillus penicilloides andAspergillus restrictus, which were frequently isolated and/or revealed important concentrations in dust samples, are the other main occurring species. Fungal flora in mattresses are more numerous in winter, the peak period being December-January. The most important contaminations by xerophilic species occurred during that peak period, whereas non-osmophilous species were constantly present during the year. The qualitative conditions of the habitat have an influence on the abundance of moulds in mattresses. Mattresses from damp houses could be a source forAlternaria throughout the year. No significant difference has been detected between the contamination level of men and women's mattresses (P=0.651). Children's mattresses are less contaminated than adults (P=0.025). The level of contamination could be affected by perspiration.     

Genetic mutation affects the energy status of <Emphasis Type="Italic">Drosophila</Emphasis>

Conditional dominant lethals (CDL) represent a special class of genetic mutations observed in Drosophila. Mutation manifests as a dominant lethal in one genotype, but lethality is not expressed in another genotype. CDL mutants exhibit a set of traits discriminating them from classic mutations. We observed unusually high mobility of flies and high sexual activity of males carrying these mutations. We used special tests for evaluation of energy metabolism of CDL mutants. Indirect calorimetry (CO₂ excretion measurement) has been used for estimation of energy exchange in four mutant and two control fly lines. A special device has been used for evaluation of locomotor activity of these fly lines. Energy exchange and locomotor activity in CDL mutants were significantly higher than in control lines. We conclude that some genetic mutations are capable of increasing energy dissipation in their carriers.     

Changes in the energy status of Drosophila as a result of genetic mutation

Conditional dominant lethals (CDL) represent a special class of genetic mutations observed in Drosophila. Mutation manifests as a dominant allele in one genotype, but lethality is not expressed in another genotype. CDL mutants exhibit a set of traits discriminating them from classic mutations. We observed unusually high mobility of flies and high sexual activity of males carrying these mutations. We used special tests for evaluation of energy metabolism of CDL mutants. Indirect calorimetry (CO2 excretion measurement) has been used for estimation of energy exchange in four mutant and two control fly lines. A Special device has been used for evaluation of locomotor activity of these fly lines. Energy exchange and locomotor activity in CDL mutants were significantly higher than in control lines. We conclude that some genetic mutations are capable of increasing energy dissipation in their carriers.     

Hidden diversity of endophytic fungi in an invasive plant

Fungal endophytes are important in plant ecology and common in plants. We attempted to test cointroduction and host-jumping hypotheses on a community basis by comparing endophytes isolated from invasive spotted knapweed (Centaurea stoebe, Asteraceae) in its native and invaded ranges. Of 92 combined, sequence-based haplotypes representing eight classes of Fungi, 78 occurred in only one of the two ranges. In the native range of C. stoebe, one haplotype of Alternaria alternata was clearly dominant, whereas in the invaded range, no haplotype was dominant. Many haplotypes were closely related to one another and novel. For example, six putative, new species of Botrytis were discovered as endophytes of C. stoebe, which has never been reported to have Botrytis spp.. Apparent differences between the two communities of endophytes were significant according to an analysis of similarity, but phylogenetic community structure did not differ significantly between the ranges. Both host-jumping and cointroduction of fungal endophytes likely took place during the spotted knapweed invasion.