Bioacoustic variation in Wren Troglodytes troglodytes populations on Welsh islands

ABSTRACT

Capsule: Duration and peak frequency of Wren Troglodytes troglodytes songs differ between Welsh islands (Skokholm, Flat Holm, and Sully Island) and a mainland site, suggesting random or cultural divergence.

Aims: The study tests for differences in bioacoustic traits in Wren song between four breeding sites.

Methods: Songs from breeding male Wrens were recorded from three Welsh islands and a representative location on the local mainland. Each sonogram was measured for six variables from the whole song and two distinct phrases from the beginning and middle. The variables were measured manually using an open source acoustic tool and compared between sites using generalized linear mixed-effects models.

Results: There was significant variation in song variables between island sites and the mainland. Skokholm Wren songs were significantly longer in duration than all other sites by up to 66%. Peak frequency was significantly different across all sites with Sully Island having the highest peak frequency and Skokholm the lowest.

Conclusion: The differences in song duration and frequency do not directly suggest a trend associated with selective pressures such as habitat or noise, but instead may be explained by non-selective drivers such as cultural drift or local dialect formation.     

Developmental stage of failed eggs in the red-legged partridge <Emphasis Type="Italic">Alectoris rufa</Emphasis>

Understanding whether egg failure occurs more frequently during laying or during incubation is important for determining the most vulnerable period of the egg phase in bird species with long laying and incubation periods. However, most studies compare nest failure during the egg stage and the hatchling stage. In this study we examined whether egg failure was higher during the laying period and early development than during the final stages of development in a population of red-legged partridge (Alectoris rufa) from northeast Spain. We collected 216 abandoned eggs in the field. Only 12% (n = 26) of the eggs were sufficiently intact to enable direct assessment of developmental stage, showing that 81% of 26 eggs were lost during early stages. The majority of eggs were depredated (n = 154, 71%), as evidenced by an opening hole. To take advantage of information contained in these eggs, we propose a simple method to assess their developmental stage by measuring the size of the opening of their hole. Based on this method, we estimated that the proportion of eggs lost during early stages ranged from 72 to 83%. We validated this result of a high percentage of egg failure during early developmental stages with a larger experimental sample. Nest losses in the partridge are higher during the laying period or early development. This result is important in that the direction of conservation efforts and their seasonal application should be adjusted to account for the most important factors affecting egg failure.     

Comparative Genomics of Phylogenetically Diverse Unicellular Eukaryotes Provide New Insights into the Genetic Basis for the Evolution of the Programmed Cell Death Machinery

Programmed cell death (PCD) represents a significant component of normal growth and development in multicellular organisms. Recently, PCD-like processes have been reported in single-celled eukaryotes, implying that some components of the PCD machinery existed early in eukaryotic evolution. This study provides a comparative analysis of PCD-related sequences across more than 50 unicellular genera from four eukaryotic supergroups: Unikonts, Excavata, Chromalveolata, and Plantae. A complex set of PCD-related sequences that correspond to domains or proteins associated with all main functional classes—from ligands and receptors to executors of PCD—was found in many unicellular lineages. Several PCD domains and proteins previously thought to be restricted to animals or land plants are also present in unicellular species. Noteworthy, the yeast, Saccharomyces cerevisiae—used as an experimental model system for PCD research, has a rather reduced set of PCD-related sequences relative to other unicellular species. The phylogenetic distribution of the PCD-related sequences identified in unicellular lineages suggests that the genetic basis for the evolution of the complex PCD machinery present in extant multicellular lineages has been established early in the evolution of eukaryotes. The shaping of the PCD machinery in multicellular lineages involved the duplication, co-option, recruitment, and shuffling of domains already present in their unicellular ancestors. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Overriding Semiosis: The Catastrophe of the Ambrym Eruption of 1913

ABSTRACT

The 1913 volcanic eruption on the island of Ambrym (Vanuatu) struck both groups composing the island’s population at the time, the Islanders and the British Presbyterians who had come to ‘civilise’ them. Through the lens of Peirce’s semiosis, particularly his notion of the ‘indexical sign’, this article examines the chronological development of the two groups’ divergent, and also at times convergent interpretations of the eruption as a sign. This semiotic analysis is then extended into the island’s socio-historical context, from the Presbyterians’ first attempts at missions to the catastrophic upheaval that decimated the island’s population until the 1940s, to study how the two groups interpreted themselves, each other, Western Christianity and the traditional Ambrymese belief and authority system.     

Tolerant versus sensitive genomes: The impact of deleterious mutation on fitness and conservation

Using two alternative mutational models, Iinvestigate equilibrium diffusion predictionsfor population fitness. In the classical``sensitive model', fitness is highly sensitiveto mutations, these usually having mildlydetrimental effects. In the ``tolerant model',most mutations have only tiny deleteriouseffects, but a small proportion is considerablydetrimental. When the same relationship betweenthe degree of dominance and the homozygousdeleterious effect of mutations is assumed,both models predict important inbreedingdepression after bottlenecking in largepopulations, although the sensitive oneaccounts for a higher average degree ofdominance. Under the sensitive model, the rateof fitness decline due to deleterious fixationis large for effective population sizes in the tens, and could be important in thelong term for effective sizes about 100, inagreement with previously published results.This suggests that conservation programs shouldact to avoid mutational meltdown. Under thetolerant model, however, the fitness declinedue to deleterious fixation is generally low,indicating that conservation programs shouldgive priority to avoid quick inbreeding, lossof genetic variability and adaptation tocaptive conditions, even if this reduces thestrength of selection against new mutations.     

The anticoagulant effect of prolame, N-(3-hydroxy-1,3,5(10)estratrien-17 beta-yl)-3-hydroxypropylamine, a novel amino-estrogen

The anticoagulant and estrogenic effects of prolame, N-(3-hydroxy-1,3,5(10)-estratrien-17 beta-yl)-3-hydroxypropylamine, are described. A single subcutaneous injection of prolame in male mice, ovariectomized mice, adult and infant male rats, produced dose-dependent increases of blood clotting time, which could be observed with the larger doses even after 4 days. In ovariectomized mice, prolame produced vaginal cornifications of shorter duration than those produced by estradiol-17 beta. The evidence suggests that, in contrast with currently used estrogens, prolame would not generate cardiovascular accidents if used for the treatment of prostatic carcinoma; it could also be exceptionally effective for the prevention of thrombosis.     

Fretting about FRET: Failure of the Ideal Dipole Approximation

With recent growth in the use of fluorescence-detected resonance energy transfer (FRET), it is being applied to complex systems in modern and diverse ways where it is not always clear that the common approximations required for analysis are applicable. For instance, the ideal dipole approximation (IDA), which is implicit in the Förster equation, is known to break down when molecules get “too close” to each other. Yet, no clear definition exists of what is meant by “too close”. Here we examine several common fluorescent probe molecules to determine boundaries for use of the IDA. We compare the Coulombic coupling determined essentially exactly with a linear response approach with the IDA coupling to find the distance regimes over which the IDA begins to fail. We find that the IDA performs well down to roughly 20 Å separation, provided the molecules sample an isotropic set of relative orientations. However, if molecular motions are restricted, the IDA performs poorly at separations beyond 50 Å. Thus, isotropic probe motions help mask poor performance of the IDA through cancellation of error. Therefore, if fluorescent probe motions are restricted, FRET practitioners should be concerned with not only the well-known κ² approximation, but also possible failure of the IDA.     

A female compound heterozygote (pre- and full mutation) for the CGG FMR1 expansion

Fragile X syndrome is the most common cause of inherited mental retardation. The incidence has been estimated to be 1 in 1250 males and 1 in 2000 females. Molecular studies have shown that 95% of fragile X syndrome cases are caused by the expansion of a CGG triplet in the FMR1 gene with hypermethylation of the adjacent CpG island. In spite of the high incidence of this syndrome, a female with both FMR1 genes in the expanded form has never been reported. We present here a female from the Canary Islands presenting mental retardation and attention problems. Molecular analysis has revealed that both of her FMR1 genes have the CGG expansion, one with a premutation and the other with a full mutation. We have studied the CGG repeat in the FMR1 gene in 64 members of her family and detected 33 normal individuals, 14 carriers with the premutation (1 male and 13 females), and 18 individuals with full mutations (8 males and 10 females). The index case illustrates that the possibility of both parents being carriers of the fragile X syndrome premutation should be considered in consanguineous families or in small communities. Received: 4 April 1996 / Revised: 3 May 1996     

Conjugal transfer of R plasmids to and from Enterobacteriaceae isolated from sewage

A. FERNANDEZ-ASTORGA, A. FERNANDEZ DE ARANGUIZ, M. POCINO, A. UMARAN AND R. CISTERNA. 1992. The potential of the transfer of natural plasmids between sewage strains has been studied. In vitro transfer was conducted at 37°C in tryptone soya broth and sterile raw sewage as mating media. In situ transfer was carried out in sterile raw sewage within membrane diffusion chambers at 10.6°C. When the recipient was a laboratory strain of Escherichia coli K-12, the in situ frequency values were significantly lower ( P < 0.001) than those obtained in vitro for the same mating pair. When the laboratory recipient was replaced with recipients from the same sewage source, frequency values decreased progressively from the optimum conditions to the most adverse. However, in situ frequency values were higher than those for the same donors mated with a laboratory recipient.