Inter-locality variation in reproductive success of the citril finch Serinus citrinella

Habitat quality is generally thought to affect breeding success. We tested this effect comparing differences in clutch size and reproductive success between citril finch Serinus citrinella sub-populations closely located (<5 km) but differing in habitat quality, within the Port del Comte mountain, in the Catalonian Pre-Pyrenees. We found that birds in the low quality area (Bofia) showed significantly lower hatching, breeding and nesting success than finches in the high quality area (Vansa). These differences in reproductive success fit well with recently found differences in citril finch body mass, fat score, diet, survival rate and speed of moult between these two localities.     

Urogonimus macrostomus (Digenea: Leucochloridiidae) from the rustic bunting, Emberiza rustica, in Japan

Some trematodes were found in the cloaca of a rustic bunting (Emberiza rustica) captured in Tsushima Islands, Japan. From their morphological characters and distribution, the flukes were identified as Urogonimus macrostomus. The phylogenetic relationship between this fluke and related species was inferred from the 28S rRNA gene sequences, and the gene sequence of the fluke was found to differ at only 4 nucleotide positions from that of U. macrostomus reported from Ukraine. This is the first report of this species in Japan.     

Male extraterritorial forays, age and paternity in the socially monogamous reed bunting (Emberiza schoeniclus)

Genetic studies have shown that extra-pair paternity is widespread among socially monogamous bird species. Yet, the role of males and females and their behavior leading to this mixed reproductive strategy is poorly understood. Here, we analyze paternity in relation to male age and mating behavior in the socially monogamous reed bunting (Emberiza schoeniclus). We report a positive relation between male extraterritorial forays and success in obtaining extra-pair fertilizations. Extraterritorial forays tended to increase in frequency with male age and older males sired a larger number of extra-pair offspring than young males. Identified extra-pair sires were old in nine out of ten cases. The likelihood of being cuckolded was not affected by male age. Although based on correlative data, our results highlight age-dependent explorative male behavior as a key determinant for the understanding of extra-pair mating in the reed bunting. We do, however, emphasize the need for further studies to reveal the role of females in extra-pair copulations and fertilizations.     

Signal value of alternating and overlapping singing in the Yellowhammer<Emphasis Type="Italic"> Emberiza citrinella</Emphasis>

Interactive playback experiments were used to study the signal value of alternating and overlapping singing in the Yellowhammer Emberiza citrinella. We carried out interactive playback experiments in which 13 males were subjects of two treatments that differed in temporal pattern of playback song delivery (alternating vs overlapping). We measured 12 parameters of males' response, belonging to three categories: song output, call output and mobility (distance from loudspeaker and flights). The results do not confirm the hypothesis that the overlapping pattern is a signal of stronger threat, as compared to the alternating pattern. Overlapping and alternating playbacks generally elicited a similar response, characteristic for highly aroused males. The only significant difference found concerned latency of approach to the loudspeaker during the playback stage. When playback alternated with songs of males, the birds gained higher scores on the axis of that response measure. Such a result was linked to differences in how the alternating and overlapping playbacks affect detection and localisation of simulated rivals, rather than to the signal's threat value itself. The strong response of Yellowhammer males is consistent with the high intrusion rate and possibility of extra-pair copulation in this species, which probably simplifies close-range communication towards more aggressive and unequivocal repelling of rivals irrespective of the temporal patterning of song.     

Macrogeographic variations in food choice of mainland citril finches Carduelis [citrinella] citrinella versus insular Corsican (citril) finches Carduelis [citrinella] corsicanus

We studied variations in diet composition in sub-populations of mainland citril finches Carduelis [citrinella] citrinella in European mountain chains, compared to closely related insular Corsican (citril) finches Carduelis [citrinella] corsicanus on several Mediterranean Islands with a special emphasis on key food plants used during the breeding period. We found that citril finch sub-populations of the Pre-Pyrenees and the Black Forest rely mostly on mountain pine and dandelion seeds as main food resources during the breeding season. In contrast, insular Corsican finches on the Mediterranean islands of Capraia and Corsica fed mainly on various herb species. Finches in Corsica fed predominantly on shepherd’s purse, while birds from Capraia were choosing rosemary as their main food plant during the breeding period. These observations confirmed the previously expected difference in food choice between the two forms due to the observed increased niche breadth on Corsica. However, Corsican finches on Sardinia showed a food choice more similar to that of the citril finch populations, in that they fed predominantly on black pine seeds during breeding season. Thus we were not able to find clear behavioural differences in diet composition between all studied sub-populations of citril and Corsican finches. To conclude, food choice of both forms is highly adaptive and, in the different breeding areas, distinct key plants may be of special importance during the breeding season. The preference for these plants is likely to be linked to their abundance and their energetic and nutritional content.     

Song repertoires and seasonal song in the yellowhammer, Emberiza citrinella

Songs were recorded from male yellowhammers, Emberiza citrinella, in England and West Germany. Sonagraphic analysis revealed three major types of song structure in both populations. Most males had a repertoire of two distinct song types, and sharing between individuals was extremely rare. Most song is produced late in the breeding season, and playback experiments confirmed that it is correlated with an increase in territorial aggression at this time. Some speculations are advanced concerning the origins and functions of song repertoires in the yellowhammer.     

A spatially explicit model for integrating species assessments into landscape planning as exemplified by the Corn Bunting (Emberiza calandra)

The integration of spatial information concerning animal species into static, rule-based spatially explicit non-probabilistic models for decision-making regarding the planning of landscapes and regions provides generalised habitat-described landscape-structural parameters. As a basis for an individually developed model, a discussion is first of all presented which involves general data and parametric requirements, necessary for the development of a species-referenced, spatially explicit model for analysis and evaluation. The parameters necessary for an assessment of habitat characteristics of birds in Central Europe will be discussed on the basis of landscape and structural information, using the Corn Bunting (Emberiza calandra) as an example. A spatial analysis and assessment procedure supported by geographical information system (GIS) for this species has been developed for the definition of regulations and assessment categories and subsequently applied to the example of an open agricultural landscape in Saxony-Anhalt. Within the area of examination of approximately 42.4 km², 56 songbird perches were located (density of 1.34 territories/km²). A comparison with the 45 mapped territories from the year 2004 indicated a good correlation with the model assumptions. Indeed, 16 of these 45 territories were only briefly occupied and the establishment of breeding pairs was ascertained in only 17 territories. The analysis and assessment model as presented yielded reality-based results after the utilisation of relatively little landscape-structural entry data, and is well suited for support of the decision-making process for spatial planning. The model framework presented in this paper can be modified and transferred to other species.     

Song dialects on the Atlantic islands: goldcrests of the Azores ( Regulus regulus azoricus, R. r. sanctae-mariae, R. r. inermis)

Territorial songs in island populations of songbirds are often highly divergent from those of neighbouring continental relatives. This is shown for the three goldcrest subspecies (Regulus regulus azoricus, R. r. sanctae-mariae and R. r. inermis) endemic on six islands of the Azorean archipelago. All investigated populations display a high intra- and inter-individual acoustic variation. On each island, up to six different song types have been found; and a single male sings up to three types. In contrast, all northwestern European populations of R. r. regulus and R. r. anglorum share only a single song type. In playback experiments, none of 18 tested dialect songs of Azorean goldcrests evoked notable territorial reaction in German and Czech goldcrest males (ssp. regulus). Two differing dialect groups of the goldcrest can be distinguished on the Azores. Populations of the eastern islands, São Miguel and Santa Maria, share common song types which are not found on the islands of the central and western groups. Dialect repertoires on the westernmost islands, Flores, Faial and Pico, are dominated by a different song type. In the geologically younger western crater of São Miguel, both western and eastern song types coexist. Acoustic similarities to a population from neighbouring Terceira suggest the western part of São Miguel as the origin for the westward expansion of R. regulus on the Azores.     

The phylogenetic placement of Ostropales within Lecanoromycetes (Ascomycota) revisited

Results of molecular studies regarding the phylogenetic placement of the order Ostropales and related taxa within Lecanoromycetes were thus far inconclusive. Some analyses placed the order as sister to the rest of Lecanoromycetes, while others inferred a position nested within Lecanoromycetes. We assembled a data set of 101 species including sequences from nuLSU rDNA, mtSSU rDNA, and the nuclear protein-coding RPB1 for each species to examine the cause of incongruencies in previously published phylogenies. MP, minimum evolution, and Bayesian analyses were performed using the combined three-region data set and the single-gene data sets. The position of Ostropales nested in Lecanoromycetes is confirmed in all single-gene and concatenated analyses, and a placement as sister to the rest of Lecanoromycetes is significantly rejected using two independent methods of alternative topology testing. Acarosporales and related taxa (Acarosporaceae group) are basal in Lecanoromycetes. However, if the these basal taxa are excluded from the analyses, Ostropales appear to be sister to the rest of Lecanoromycetes, suggesting different ingroup rooting as the cause for deviating topologies in previously published phylogenies.     

Doc and copia instability in an isogenic Drosophila melanogaster stock

A high degree of heterogeneity and an overall increase in number of insertion sites of the mobile elements Doc and copia were revealed in one substock of an isogenic Drosophila melanogaster stock, while in two other substocks the distribution of copia sites was highly homogenous, but that of Doc sites was again heterogenous. We therefore concluded that copia was unstable in one of the substocks and Doc was unstable in all. Doc instability presumably arose earlier than copia instability. Doc and copia transpositions were directly observed in experiments with one substock. An abundance of copia insertions was revealed in the X chromosome where insertions with deleterious effects are exposed to selection in hemizygous condition. The locations of many other mobile elements (mdg1, mdg2, mdg3, mdg4, 297, B104, H.M.S. Beagle, I, P, BS, FB) were found to be conserved in each substock and did not differ between them, indicating that these mobile elements were stable. This homogeneity is a strong argument against any possibility of inadvertent contamination.     

Ac/Ds transposon mutagenesis in Arabidopsis thaliana: mutant spectrum and frequency of Ds insertion mutants

Using a two-component Ac/Ds system consisting of a stabilized Ac element (Ac_c1) and a non-autonomous element (Ds_A), 650 families of plants carrying independent germinal Ds_A excisions/transpositions were isolated. Progenies of 559 of these Ac_c1/Ds_A families, together with 43 families of plants selected for excision/transposition of wild-type (wt)Ac, were subjected to a broad screening program for mutants exhibiting visible alterations. This resulted in the identification of 48 mutants showing a wide variety of mutant phenotypes, including embryo lethality (24 mutants), chlorophyll defects (5 mutants), defective seedlings (2 mutants), reduced fertility (5 mutants), reduced size (3 mutants), altered leaf morphology (2 mutants), dark green, unexpanded rosette leaves (3 mutants), and aberrant flower or shoot morphology (4 mutants). To test whether these mutants were due to transposon insertions, a series of Southern blot experiments was performed on 28 families, comparing in each case several mutant plants with others showing the wild-type phenotype. A preliminary analysis revealed in 4 of the 28 families analyzed a common, novel Ds_A fragment in all mutant plants, which was present only in heterozygous plants with wt phenotype, as expected for Ds_A insertion mutations. These four mutants included two showing embryo lethality, one with dark green, unexpanded rosette leaves and stunted inflorescences, and one with curly growth of stems, leaves and siliques. Further evidence for Ds_A insertion mutations was obtained for one embryo lethal mutant and for the stunted mutant, while in case of the second embryo lethal mutant, the Ds_A insertion could be separated from the mutant locus by genetic recombination.     

Physiological characteristics of several rumen protozoa grown in vitro with observations on within and among species variation

When fed equal amounts of substrate, two Epidinium caudatum clone cultures of markedly different size produced similar volumes of microbial protoplasm. Addition of up to 50% volume of 72 h culture medium had no inhibitory effects on growth of Epidinium. Two clone cultures of Epidinium caudatum from Australia had longer generation times and showed less substrate attachment when compared to Ohio clones of this same species. Substitution of alfalfa for orchardgrass in the normal substrate increased Epidinium concentrations, while feeding only ground orchardgrass or alfalfa resulted in a marked decrease or disappearance of the protozoa. Eudiplodinium impalae, isolated from rumen contents of a steer in Australia, was successfully cultured, with generation times for this species averaging 11.3 h. Reducing particle size of the substrates by ball-milling was detrimental for growth of Entodinium and Epidinium; however, Eudiplodinium increased in concentration. Significant concentration differences were observed among six clone cultures of Epidinium obtained from Europe. A generation time of 18.7 h was measured for Enoploplastron triloricatum when the culture was transferred every 12 h. Lowering the incubation temperature to 34 °C completely inhibited protozoal growth of Epidinium and Entodinium exiguum after 12 days, but not for Entodinium caudatum.     

Interactions within and between species at different densities of the bark beetleIps typographus and its predatorThanasimus formicarius

Interactions between the bark beetleIps typographus and one of its predators,Thanasimus formicarius, were investigated in caged spruce logs containing both species in eight different density combinations. Productively (offspring per female) ofIps was adversely affected by highIps gallery density as well as highThanasimus density.Thanasimus productivity was enhanced by highIps gallery density but negatively affected by highThanasimus density.Ips productivity andThanasimus developmental rate differed between tree individuals, probably owing to tree-related differences in phloem thickness. Relative predator-causedIps mortality was ca 20% higher at high gallery density (ca 300 egg galeries per m²) than at low gallery density (ca 100 egg galleries per m²), indicating that mortality was density dependent. This difference was due to the fact thatThanasimus larval density was positively related toIps gallery density. Mortality increased by ca 0.4% with each additionalThanasimus larva per m², independently of gallery density. Relative population levels ofIps andThanasimus were monitored with pheromone traps in two regions differing in theirIps typographus outbreak history. Absolute catch as well as theThanasimus/Ips catch ratio were ten times greater in the outbreak region than in the non-outbreak region. Coupled with the results in the caging experiment, this indicates thatT. formicarius responds numerically to changes inI. typographus numbers per unit bark area as well as toIps population changes at the regional level. The findings suggest that predation under bark may be a significant factor in supressingI. typographus outbreaks.     

Functional interactions between the gene tetanic and the Shaker gene complex of Drosophila

Different phenotypes associated with the tetanic (tta) mutation such as appendage contraction, maternal effect and low viability and fertility are enhanced by one extra dose of the Shaker gene complex (ShC). The tta mutation is lethal with two extra doses of ShC. In addition, tta embryos have a defective nervous system. In this paper, I analyse the interaction between tta and ShC to gain insight into their relationship. Aneuploid analysis suggests that the lethality is due to an interaction of the tta mutation with the maternal effect (ME) region of this gene complex. Mutations in the ME region of ShC partially suppress this interaction. Trans-heterozygous combinations of MEI[l(1)305] and MEIII [l(1)459] mutations causes dominant lethality in a tta background. Trans-heterozygous combinations of an MEII [l(1)1359] mutation with the cited MEI and MEIII mutations are lethal in a tta background. Double mutant combinations and gene dosage experiments, suggest that tta also interacts with the viable (V) region of ShC. These specific genetic interactions indicate that tta and the ME and V regions of ShC are functionally related. These results, together with the previous electrophysiological, molecular and biochemical studies on these mutants suggest an interaction at the protein level. Thus, in the case of the V region, the tta gene product may modulate the activity of the K⁺ channels encoded in this region. Furthermore, the extreme dosage sensitivity of the interaction between tta and ShC suggests a stoichiometric requirement for the different gene products involved, which might be physically associated and form heteromultimers.     

Trichoderma species form endophytic associations within Theobroma cacao trichomes

Trichoderma species are usually considered soil organisms that colonize plant roots, sometimes forming a symbiotic relationship. Recent studies demonstrate that Trichoderma species are also capable of colonizing the above ground tissues of Theobroma cacao (cacao) in what has been characterized as an endophytic relationship. Trichoderma species can be re-isolated from surface sterilized cacao stem tissue, including the bark and xylem, the apical meristem, and to a lesser degree from leaves. SEM analysis of cacao stems colonized by strains of four Trichoderma species (Trichoderma ovalisporum-DIS 70a, Trichoderma hamatum-DIS 219b, Trichoderma koningiopsis-DIS 172ai, or Trichoderma harzianum-DIS 219f) showed a preference for surface colonization of glandular trichomes versus non-glandular trichomes. The Trichoderma strains colonized the glandular trichome tips and formed swellings resembling appresoria. Hyphae were observed emerging from the glandular trichomes on surface sterilized stems from cacao seedlings that had been inoculated with each of the four Trichoderma strains. Fungal hyphae were observed under the microscope emerging from the trichomes as soon as 6 h after their isolation from surface sterilized cacao seedling stems. Hyphae were also observed, in some cases, emerging from stalk cells opposite the trichome head. Repeated single trichome/hyphae isolations verified that the emerging hyphae were the Trichoderma strains with which the cacao seedlings had been inoculated. Strains of four Trichoderma species were able to enter glandular trichomes during the colonization of cacao stems where they survived surface sterilization and could be re-isolated. The penetration of cacao trichomes may provide the entry point for Trichoderma species into the cacao stem allowing systemic colonization of this tissue.     

Phylogeny, biogeography, and species boundaries within the Alexandrium minutum group

The geographic range and bloom frequency of the toxic dinoflagellate Alexandrium minutum and other members of the A. minutum group have been increasing over the past few decades. Some of these species are responsible for paralytic shellfish poisoning (PSP) outbreaks throughout the world. The origins of new toxic populations found in previously unaffected areas are typically not known due to a lack of reliable plankton records with sound species identifications and to the lack of a global genetic database. This paper provides the first comprehensive study of minutum-group morphology and phylogeny on a global scale, including 45 isolates from northern Europe, the Mediterranean, Asia, Australia and New Zealand.Neither the morphospecies Alexandrium lusitanicum nor A. angustitabulatum was recoverable morphologically, due to large variation within and among all minutum-group clonal strains in characters previously used to distinguish these species: the length:width of the anterior sulcal plate, shape of the 1′ plate, connection between the 1′ plate and the apical pore complex, and the presence of a ventral pore. DNA sequence data from the D1 to D2 region of the LSU rDNA also fail to recognize these species. Therefore, we recommend that all isolates previously designated as A. lusitanicum or A. angustitabulatum be redesignated as A. minutum. A. tamutum, A. insuetum, and A. andersonii are clearly different from A. minutum on the basis of both genetic and morphological data.A. minutum strains from Europe and Australia are closely related to one another, which may indicate an introduction from Europe to Australia given the long history of PSP in Europe and its recent occurrence in Australia. A minutum from New Zealand and Taiwan form a separate phylogenetic group. Most strains of A. minutum fit into one of these two groups, although there are a few outlying strains that merit further study and may represent new species. The results of this paper have greatly improved our ability to track the spread of A. minutum species and to understand the evolutionary relationships within the A. minutum group by correcting inaccurate taxonomy and providing a global genetic database.     

Interspecific competition between the braconid endoparasitoids Glyptapanteles porthetriae and Glyptapanteles liparidis in Lymantria dispar larvae

The effect of interspecific competition between the solitary endoparasitoid Glyptapanteles porthetriae Muesebeck (Hymenoptera: Braconidae) and the gregarious Glyptapanteles liparidis Bouché (Hymenoptera: Braconidae), was investigated in larvae of Lymantria dispar L. (Lepidoptera: Lymantriidae). Host larvae were parasitized by both wasp species simultaneously in premolt to the 2^nd or the 3^rd host instar or in an additional approach with a 4-day delay in parasitization by the second wasp species. Host acceptance experiments revealed that both wasp species do not discriminate between unparasitized host larvae and larvae parasitized previously by the same or the other species. In more than 90% female wasps parasitized the larva they encountered first. During the period of endoparasitic development, larvae of the competing parasitoid species never attacked the egg stage of the other species. When host larvae were parasitized simultaneously by both wasp species, the rate of successful development of both species depended on the age of the host larva at the time of its parasitization; G. liparidis emerged successfully from 44% of host larvae parasitized during the premolt to 2^nd instar, G. porthetriae from 28%, and in 20% of the hosts both parasitoid species were able to develop in one gypsy moth larva. However, when host larvae were parasitized simultaneously during premolt to the 3^rd instar, G. liparidis was successful in 90% of the hosts, compared to 8% from which only G. porthetriae emerged. In the experiments with delayed oviposition, generally the species that oviposited first succeeded in completing its larval development. Larvae of the species ovipositing with four days delay were frequently attacked and killed by larvae of the first parasitizing species or suffered reduced growth. As the secondary parasitoid species, G. porthetriae-larvae were never able to complete their development, whereas G. liparidis developed successfully in at least 12,5% of the multiparasitized host larvae. Thus, multiparasitism of gypsy moth larvae by both Glyptapanteles species corresponds to the contest type; however, G. porthetriae is only able to develop successfully as the primary parasitoid of young host larvae.     

Genetic evidence of a relationship between two maize transposable element systems: Cy and Mutator

Summary The Cy transposable element system is composed of two genetically defined elements: an rcy receptor element inserted at the Bronze-1 locus; and an independently segregating regulatory element, Cy. The Cy system is not functionally homologous to any of the non-Mutator transposable element systems. Evidence is presented that supports a relationship between the Cy system and the family of Mu1-homologous transposable elements that are responsible for the Mutator phenomenon. Although related, Cy elements and the Mu1-homologous elements are not identical; Cy is inherited in a near-Mendelian fashion, in contrast to the non-Mendelian inheritance of the Mu1-homologous elements.     

Interaction between the Tam1 and Tam2 transposable elements of Antirrhinum majus

Summary Two stable derivatives of the highly unstable niv-53::Tam1 allele of Antirrhinum majus were analysed. In both derivatives the Tam1 element is integrated at the same site and in the same orientation as in the parental niv-53::Tam1 allele. In both cases the Tam1 element was found to carry a 5 bp deletion (CACTA) in one of its termini. This explains the excision deficiency of these two alleles of Tam1, niv-53::Tam1-46 and niv-53::Tam1-49. Niv-44::Tam2, another stable nivea mutation, carries the 5 kb element Tam2, which is not a derivative of Tam1 but possesses identical terminal inverted repeats. When the stable lines 46 and 49 were corssed with line 44, suprisingly, a high number of the flowers in the F₁ displayed a variegated phenotype. Sequence analysis of two germinal revertants isolated from the heterozygote niv-53::Tam1-46/niv-44::Tam2 shows excision of the Tam2 element. This indicates that Tam2 is a defective element, which can be complemented by an active Tam1 element. However, the variegated F₁ phenotype observed is not inherited monofactorially. Variegation is seen only at particular times of development of the F₁ plants. These phenomena seem to involve both the Tam1 and Tam2 transposable elements.     

Morphological variation in Planococcoides njalensis occurring on cocoa in Ghana

A study was made to determine the extent of morphological variation in Planococcoides jalensis (Laing), the most important mealybug vector of cocoa swollen shoot virus (CSSV) in West Africa, and to resolve if more than one Planococcoides species is present. Fourteen populations of P. njalensis collected on cocoa from different localities in Ghana and one population each on Gliricidia sepium (Jacq.) Steud and Coffea canephora Pierre were compared by measured and meristic female characters using two types of morphometric analysis, Discriminant Functional Analysis and Principal Component Analysis. The analyses showed that P. njalensis exhibited a wide range of intraspecific morphological variation, particularly in meristic characters, but failed to identify new Planococcoides species. The results are discussed in relation to the control of the mealybug vectors of CSSV and to the suitability of Gliricidia as a shade tree for cocoa.