Song Differentiation and Population Structure: the Example of the Whistled Songs in an Introduced Population of European Starlings Sturnus vulgaris in Australia

Whistled songs of male starlings were studied in Australia and results compared with previous ones in Europe. Starling whistle sonograms can be divided into general classes according to certain criteria. All or most males sing five whistled types (“species-specific” themes), plus other (“individual”) themes. The basic repertoire of species-specific themes is almost the same in Europe and Australia with the same characteristics and similar variation ranges. In both continents each male has a certain number of individual themes, but Australian repertoires tend to be smaller, with two species-specific themes less and fewer individual themes. In all study areas dialects were based on local variations in species-specific theme structure, but the Australian dialectal system is simpler than in Europe. Therefore basic characteristics seem to have been similarly transmitted across generations in both continents. But some of the differences (individual characteristics, repertoire size, frequencies) may stem from different habitat characteristics and also social structure, which could have greatly affected song differentiation.     

THE WHISTLED SONGS OF THE EUROPEAN STARLING STURNUS VULGARIS AND THE SPOTLESS STARLING STURNUS UNICOLOR IN NORTH-EAST SPAIN

ABSTRACT

This paper describes the whistled songs of two allopatric populations of the European starling and spotless starling in NE Spain. The results show that European starlings in NE Spain sing the same whistled themes found earlier in other European populations and confirm the universal character of these themes. There are some differences between European starlings from NE Spain and other populations: rising phases appear for Inflection theme high-form, Inflection theme and Simple theme, and also differences of rate of emission appear for others (Rhythmic theme). Harmonic theme has not been found. Likewise, the first analysis of the spotless starling's whistled song shows that it shares the same general whistled song structure with the European starling; whistles have similar structural parameters (modulation, duration, frequency) and can be classified in the same categories or themes; a new theme appears, the Trilled theme, which has not been found to date in the European starling. Dialectal areas have been found in both species for the same themes (Inflection theme, Simple theme). The males of both studied populations have larger repertoires in comparison to other studied populations of the European starling.     

Vocalizations and morphology: interpreting the divergence among populations of Chough Pyrrhocorax pyrrhocorax and Alpine Chough P. graculus

Capsule Differences in vocalizations among populations are mostly explained on morphological bases, but historical factors may have played a significant role in differentiation processes.

Aims To investigate the relationships among vocal and morphological variation in two corvids: Chough and Alpine Chough.

Methods We used data from 11 populations of Chough and seven populations of Alpine Chough spanning the Palearctic distribution of the two species. Three data sets (morphometry, spectrotemporal parameters of trill calls and acoustic repertoire) were analysed and their variation compared with uni- and multivariate techniques.

Results In both species, morphological differences among populations were correlated to spectro-temporal variation of trills; in particular, frequencies of calls were negatively correlated to wing length (an indicator of body size). By considering only co-existing populations of the two species, the magnitude of morphological and spectrotemporal divergence was similar.

Conclusions In both species, birds from populations with similar morphology uttered similar call types and trills with close spectrotemporal features. In particular, larger-sized populations, as expressed by wing length, emitted lower pitched calls. However, the fact that dissimilarities in repertoire and morphology were correlated cannot be explained only by appealing to functional explanations, as the observed intraspecific morphological variability does not seem to be high enough to promote consistent changes in the pool of calls. In this case, historical factors might have contributed to the present pattern of differentiation.     

THE VOCAL REPERTOIRE OF THE GREY CROWNED CRANE BALEARICA REGULORUM GIBBERICEPS. I: THE TONAL AND THE NON-HARMONIC CALLS

ABSTRACT

The study describes the vocal repertoire of the Grey Crowned Crane Balearica regulorum gibbericeps and speculates on the purpose the calls serve. The repertoire consists of 4 tonal and 7 non-harmonic calls. Chicks have 3 different vocalizations.     

Structure,syntax and “small-world” organization in the complex songs of California Thrashers (Toxostoma redivivum)

We describe songs of the California Thrasher (Toxostoma redivivum), a territorial, monogamous species whose complex songs are composed of extended sequences of phonetically diverse phrases. We take a network approach, so that network nodes represent specific phrases, and links or transitions between nodes describe a subgroup structure that reveals the syntax of phrases within the songs. We found that individual birds have large and largely distinct repertoires, with limited phrase sharing between neighbours and repertoire similarity decaying between individuals with distance apart, decaying also over time within individuals. During song sequences, only a limited number of phrases (ca. 15–20) were found to be actually “in play” at any given time; these phrases can be grouped into themes within which transitions are much more common than among them, a feature contributing to a small-world structure. It appears that such “small-world themes” arise abruptly, while old themes are abandoned more gradually during extended song sequences; most individual thrashers switch among 3–4 themes over the course of several successive songs, and some small-world themes appear to have specific roles in starting or ending thrasher songs.     

XIVth SYMPOSIUM OF THE INTERNATIONAL BIOACOUSTICS COUNCIL

ABSTRACT

This is the first reported study of corixid water bugs examining whether all species of a genus in one locality can be distinguished by their sounds. More extensive analysis than has been reported for any corixids revealed that, although some species are difficult to distinguish morphologically, inter-species sound differences are very clear.

The sounds of all nine species of Micronecta in the study area near Melbourne, Australia were recorded. Male sounds were recorded in the laboratory, over a minimum water temperature range of 15 to 25°C. Females do not produce sounds. Signals consisted of groups of pulse-trains, except for one species with signals of usually one pulse-train. Signals were species-specific; pulse-train rate alone was sufficient to distinguish between species. There were also species differences in other signal parameters. Males also produced clicks (single pulse-trains) and low-amplitude sounds; there were some species differences in the latter. Similar signals occurred between only one pair of species, which were from different habitats (ponds and rivers). Pulse periods and pulse-train periods were negatively correlated with temperature, with curves of best fit being quadratic. Five species were also recorded in ponds; the sounds and effect of temperature were compared with laboratory recordings.     

Past and future climate-driven shifts in the distribution of a warm-adapted bird species,the European Roller Coracias garrulus

ABSTRACT

Capsule: The distribution range of the European Roller Coracias garrulus has undergone large changes over geological times, but although the species is warm-adapted, the human induced climate change is predicted to affect negatively the range of the currently large populations.

Aim: Information on species-specific vulnerability to climate change is crucial not only for designing interventions and setting conservation goals, but also to inform conservation decision-making. Our goal was to map climate suitability for the European Roller in the Western Palaearctic under current climate, and for past (last glacial maximum and mid-Holocene) and future (2050 and 2070) climate scenarios.

Methods: We used MaxEnt for species distribution modelling based on the reconstructed distribution map of the species.

Results: Our results suggest that during glacial periods Rollers persisted in small southern refugia, and then spread and colonized northern latitudes during the mid-Holocene. In the future, our models forecast a shift in climatically suitable range towards northern latitudes and an overall small range contraction (4.5–5.5%). Warmer temperatures will increase climate suitability in northern countries where the species is currently declining or became locally extinct. On the other hand, wide suitable areas under current climatic conditions are predicted to become unsuitable in the future (35–38% by 2050 and 2070, respectively), significantly impacting large populations such as those in Romania, Spain, Bulgaria and Hungary. French and Italian populations are identified to be future key populations for Roller conservation.

Conclusions: Our findings suggest that future climate changes will likely amplify the impacts of existing threats on the majority of large European Roller populations in Europe.     

LETTER TO THE EDITOR

SUMMARY

A two-year limnological survey between 1973 and 1975 showed that the Roodeplaat Dam is a warm monomictic impoundment which has stable thermal stratification during summer. Oxygen supersaturation of the surface waters and anaerobic conditions in the hypolimnion were encountered during summer. Water transparency was seasonal and related to existing phytoplankton populations and allochthonously-introduced clay material. Chemical stratification during summer was prominent and appeared to be caused not only by mineralization processes in the hypolimnion, but also by dilution in the surface layers during summer flooding. Because of the morphometry of the impoundment and the fact that sewage effluents are discharged into the major inflow, considerable horizontal variation in most chemical and biological characteristics was found. On the basis of the nutrient content of the waters and the magnitude of the phytoplankton populations observed, Roodeplaat Dam may be classified as a highly eutrophic water body.     

Assessing cell-specific effects of genetic variations using tRNA microarrays

Background

Short-read resequencing of genomes produces abundant information of the genetic variation of individuals. Due to their numerous nature, these variants are rarely exhaustively validated. Furthermore, low levels of undetected variant miscalling will have a systematic and disproportionate impact on the interpretation of individual genome sequence information, especially should these also be carried through into in reference databases of genomic variation.

Results

We find that sequence variation from short-read sequence data is subject to recurrent-yet-intermittent miscalling that occurs in a sequence intrinsic manner and is very sensitive to sequence read length. The miscalls arise from difficulties aligning short reads to redundant genomic regions, where the rate of sequencing error approaches the sequence diversity between redundant regions. We find the resultant miscalled variants to be sensitive to small sequence variations between genomes, and thereby are often intrinsic to an individual, pedigree, strain or human ethnic group. In human exome sequences, we identify 2–300 recurrent false positive variants per individual, almost all of which are present in public databases of human genomic variation. From the exomes of non-reference strains of inbred mice, we identify 3–5000 recurrent false positive variants per mouse – the number of which increasing with greater distance between an individual mouse strain and the reference C57BL6 mouse genome. We show that recurrently miscalled variants may be reproduced for a given genome from repeated simulation rounds of read resampling, realignment and recalling. As such, it is possible to identify more than two-thirds of false positive variation from only ten rounds of simulation.

Conclusion

Identification and removal of recurrent false positive variants from specific individual variant sets will improve overall data quality. Variant miscalls arising are highly sequence intrinsic and are often specific to an individual, pedigree or ethnicity. Further, read length is a strong determinant of whether given false variants will be called for any given genome – which has profound significance for cohort studies that pool datasets collected and sequenced at different points in time.

     

Identifying important bird habitats in a sub-arctic area undergoing rapid land-use change

Capsule Habitats in lowland South Iceland sustain bird populations of international importance, with highest densities in wet habitats.

Aims In areas important for biodiversity there is an urgent need to assess large-scale variation in the biodiversity value of habitats to inform management. We carried out a large-scale survey to assess the conservation value of sub-arctic, Icelandic bird habitats.

Methods Bird counts were carried out on 200 transects in the five most common vegetated habitat types in South Iceland. Based on these counts, breeding bird density and diversity were compared between habitats and total population sizes of common species in these habitats were calculated.

Results Overall, eight species (seven waders and Meadow Pipit) composed over 95% of all birds counted. The combined density of those species exceeded 275 birds/km² in all habitats. The two wettest habitat types had the highest density of birds.

Conclusion Wet habitats in lowland South Iceland held particularly high densities of breeding birds, notably waders, which constitute populations of international importance. Wet habitat types are generally of higher value for more species, than dryer ones.     

A bryophyte flora of Handa Island Sutherland

ABSTRACT

Background: Hybridization is a key driver of plant speciation, and understanding ongoing hybridization provides insights into the underlying process. We studied a hybrid complex in Mediterranean Cyclamen between common C. repandum and rare C. balearicum on Sardinia.

Aims: We analyzed variation in the frequency and morphology of different floral types to assess the degree of hybridization and analyze the ecological niche to better understand factors that influence the maintenance of hybrid populations.

Methods: We recorded the frequency of the different flower color-types in 45 populations and measured floral traits in 10 of them. We characterized the spatial extent and climatic niche of this hybrid complex. We analyzed floral type variation in four traits (flower size, style and anther length, herkogamy).

Results: Hybrid populations occupy a wide area on the NW coast of the island (~1000km2). Sites dominated by hybrid floral types are ecologically marginal for the common parent. The C. repandum-like type is present in all populations and shows a decrease in style and anther length and herkogamy in populations containing a greater proportion of hybrids.

Conclusions: This hybrid complex provides an ideal situation to examine reproductive isolation due to variation in the ecological niche of different floral types.     

CHANGES IN THE ABUNDANCE AND MORTALITY RATE OF TIGERFISH IN THE EASTERN BASIN OF LAKE KARIBA

SUMMARY

Tigerfish populations increased in the eastern basin of Lake Kariba following the successful invasion of the pelagic clupeid Limmothrissa miodon. Strong year-classes persisted for several years but the number of young tigerfish declined, a phenomenon which cannot be accounted for. The influence of these year classes on different fisheries was demonstrated. The mortality rate of the younger fish was related to the rate at which their numbers were changing with mortality rates being highest when numbers were declining most rapidly. Concern about the future of this fish was expressed because of increased fishing in its main breeding area.     

Individualgeschichte und Gesangsauspr?gung beim Star (Sturnus vulgaris) in einer Kolonie

Zusammenfassung Die Lautäußerungen der Stare können in Gesangsstrophen und Pfeiflaute unterteilt werden. Pfeiflaute sind kurz (bis 2 s) und einfach gebaut, während die Strophen wesentlich länger andauern (meist über 20 s) und sich aus zahlreichen komplex gebauten Untereinheiten zusammensetzen. In einer Kolonie bei Frankfurt am Main, in der die Individuen durch Farbringe gekennzeichnet sind, wurde der individuelle Variationsspielraum der Lautäußerungen analysiert. In den Feinstrukturen der Pfeifthemen glichen sich die Koloniemitglieder weitgehend aneinander an. In den Feinstrukturen der Motivtypen der Gesangsstrophen traten dagegen große individuelle Unterschiede auf. , die während Jahren in der gleichen Kolonie brüteten, sangen nur sehr wenige gemeinsame Motivtypen. Die Repertoiregröße variierte zwischen 17–39 Motivtypen. Im Herbstgesang traten 5 bisher noch nicht beobachtete Motivtypen auf. Es gibt somit deutliche Hinweise darauf, daß auch der adulte Star neue Laute erlernen kann.

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Individual history and song structure of Starlings (Sturnus vulgaris) living in a colony

Summary Starling's song can be divided into warbling and whistles. Whistles have a short and simple structure, whereas warbling is sung in long sequences (most often more than 20 s). In the warbling one can distinguish many different subunits (repetition of motifs). The individual variability of songs was studied in a colony near Frankfurt/Main in West Germany, where starlings were colour banded since 1969. The following results were obtained:Birds from the same colony uttered nearly identical or very similar microstructures in the species-specific whistle themes. Different to the whistle themes very distinct individual differences characterized the warbling. Only a few motif types were common among colony members. The individual repertoire size ranged from 17 to 39 motif types. Comparison of the song of one individual between the breeding season and the following autumn shows that motifs, which were not observed during spring occurred in the autumn. This observation is a hint that starlings are capable to learn new motif types even as adults.

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Stipendium der Alexander-von-Humboldt-Stiftung     

VOCAL BEHAVIOUR AND CALL DEVELOPMENT IN THE BULLFINCH (PYRRHULA PYRRHULA)

ABSTRACT

A sonagraphic analysis of the vocalizations of bullfinches Pyrrhula pyrrhula is presented and their behavioural contexts and functions noted. The vocal repertoire of the bullfinch is compared to that of other finches with particular attention to repertoire size and sexual specificity; the repertoire of 14–17 vocal categories is comparatively greater than that of most carduelines and the majority of vocalizations were given by both sexes. The development of nestling, fledgling and some adult calls is described. Early vocal ontogeny in the bullfinch was similar to that previously described for the chaffinch. The earliest recorded calls of nestling bullfinches showed a single fundamental. The independent use of two sound sources became apparent on the second day after hatching and the major elements of the three best studied call types were all derived from the lower fundamental of the nestling begging call.     

Nuclear and Wolbachia-based multimarker approach for the rapid and accurate identification of tsetse species

Background

Tsetse flies (Diptera: Glossinidae) are solely responsible for the transmission of African trypanosomes, causative agents of sleeping sickness in humans and nagana in livestock. Due to the lack of efficient vaccines and the emergence of drug resistance, vector control approaches such as the sterile insect technique (SIT), remain the most effective way to control disease. SIT is a species-specific approach and therefore requires accurate identification of natural pest populations at the species level. However, the presence of morphologically similar species (species complexes and sub-species) in tsetse flies challenges the successful implementation of SIT-based population control.

Results

In this study, we evaluate different molecular tools that can be applied for the delimitation of different Glossina species using tsetse samples derived from laboratory colonies, natural populations and museum specimens. The use of mitochondrial markers, nuclear markers (including internal transcribed spacer 1 (ITS1) and different microsatellites), and bacterial symbiotic markers (Wolbachia infection status) in combination with relatively inexpensive techniques such as PCR, agarose gel electrophoresis, and to some extent sequencing provided a rapid, cost effective, and accurate identification of several tsetse species.

Conclusions

The effectiveness of SIT benefits from the fine resolution of species limits in nature. The present study supports the quick identification of large samples using simple and cost effective universalized protocols, which can be easily applied by countries/laboratories with limited resources and expertise.

     

DO THE SIBERIAN TITS PARUS CINCTUS IN SCANDINAVIA AND SIBERIA SPEAK THE SAME LANGUAGE?

ABSTRACT

The vocabulary of Siberian tits Parus cinctus in South Norway and East Siberia is compared by means of tape recordings and spectrograms. The species has many different calls that are greatly confused in the literature. In this paper ten main call types are examined. On the whole, the equivalent utterings are geographically so similar that a distinction is usually impossible or questionable. This similarity also applies to the contextual use of the calls. Consistent structural differences in certain calls were nevertheless found. The sit foraging call embraced on average a broader frequency range and was of a slightly longer duration in Siberia than in Norway. The complex ‘gargle’ system could at both places be divided into three main groups equally represented in the populations: (1) trilled, (2) tonal and (3) simple gargles. The tonal gargles are characterized by a terminal tonal element (T) that varies in shape. In Norway, tonal gargles terminating with an even or upslurred T dominated, in Siberia those with a chevron-formed T. Historically, the west-east distribution throughout Eurasia was apparently continuous until quite recently, allowing an effective gene flow. Considering the huge distance from Norway to East Siberia and the markedly resident behaviour of the Siberian tit, it is nevertheless somewhat unexpected that so few vocal differences have evolved. Several of the calls of the Siberian tit are structurally very similar to equivalent (most likely homologous) calls in other species belonging to the subgenus Poecile, e.g. the willow tit Parus montanus and the black-capped chickadee P. atricapillus, suggesting that the multicall repertoire of their common ancestor remained largely intact despite Poecile's differentiation into different species.     

Sex-specific Activity Patterns in Periplaneta americana and their Relation to Mate-finding

The comparison of local song variations between a migratory and a sedentary population of starlings shows the species-specificity of the basic categories and of their variation range. Local variations were studied for different themes in the repertoire, near Kaiserslautern (West Germany) during the reproductive season of 1982. Results were compared with those previously obtained in Brittany (France). In the study area in Germany, 80 % of the individuals migrate in autumn whereas the Breton starlings remain near the colony all year. To compare the whistles of individuals of different regions, by examing the important variations in their frequency modulation, it is necessary to know the general basic features of the whistles. Using sonograms, the whistles of starlings can be divided into 8 general classes according to particular criteria: rhythmicity, modulation etc. Five themes, among these 8 classes, are sung by all or most of the individuals (“specific themes”). The analyses of whistles give us the following results:

• 1 The songs of the migratory population studied in W. Germany contain basic features corresponding to those known in the sedentary French population.
• 2 Like the Breton starlings, those in Germany show a “theme-specific” dialect distribution: the rhythmic theme shows several variants in an area of a few km², whereas the uniform simple theme presents only one variant over several 100 km². For the five themes, the dialectal mosaic is totally different: two birds can have the same variant of one given theme and sing different dialects of another.
• 3 The themes which, in France, show a great number of variants over a small area present the same tendency towards strong subdivision in dialects in Germany. In the two study areas, no correlation could be found between dialectal boundaries and ecological factors.
• 4 Considering that two starling populations with very different characteristics show such similarities in their basic song structures and also in their pattern of local variation (in the parameters concerned and in the sizes of the dialect areas) we may suppose that the basic structure of the specific themes could be determined by a genetic program. Some characteristics, like the precise details of the frequency modulation, may be due more to learning and may conform to the local dialect.

     

Effects of nutrient amendments on modular growth,flowering effort and reproduction of snowbed plants

Background: There have been few studies on the effects on alpine flora and vegetation of an increase in nutrient availability. Two main potential sources of increased nutrient availability in alpine ecosystems are enhanced mineralisation caused by climate warming and atmospheric nitrogen deposition. Little is known on how life history traits of different species are related at individual and community levels to enhanced nutrient availability.

Aims: We investigated the effects of nitrogen and phosphorus addition on the modular growth, flowering and germination of four species: two snowbed specialists and two alpine generalists.

Methods: We established in a late snowbed at the Gavia Pass, Italian Alps, a factorial experiment with four fertiliser treatments (N, P, Low N+P, and High N+P) and an unfertilised control. Nutrients were applied in 2003–2006 and we recorded the number of modules per individuals, total number of flowers, number of flowers per flowering module, and calculated the percentage of flowering modules in 2005 and 2006, and counted the number of seedlings in 2006.

Results: The modular growth and flowering effort of the species appeared to be co-limited by N and P. The alpine generalists showed greater responses to fertilization in vegetative growth and flowering compared with snowbed specialists. The number of seedlings recorded indicated species-specific responses to nutrient addition.

Conclusions: Our results suggest that enhanced nutrient availability stimulates modular growth and flowering effort in responsive alpine generalist species. This, in turn, could lead to an increase in their abundance, leading to changes in community structure in snowbeds with enhanced nutrient availability.     

Microvesicles as promising biological tools for diagnosis and therapy

ABSTRACT

Introduction: Shed by most cells, in response to a myriad of stimuli, extracellular vesicles (EVs) carry proteins, lipids, and various nucleic acids. EVs encompass diverse subpopulations differing for biogenesis and content. Among these, microvesicles (MVs) derived from plasma membrane, are key regulators of physiopathological cellular processes including cancer, inflammation and infection. This review is unique in that it focuses specifically on the MVs as a mediator of information transfer. In fact, few proteomic studies have rigorously distinguished MVs from exosomes.

Areas covered: Aim of this review is to discuss the proteomic analyses of the MVs. Many studies have examined mixed populations containing both exosomes and MVs. We discuss MVs’ role in cell-specific interactions. We also show their emerging roles in therapy and diagnosis.

Expert commentary: We see MVs as therapeutic tools for potential use in precision medicine. They may also have potential for allowing the identification of new biomarkers. MVs represent an invaluable tool for studying the cell of origin, which they closely represent, but it is critical to build a repository with data from MVs to deepen our understanding of their molecular repertoire and biological functions.