scholarly journals Barn owls display larger black feather spots in cooler regions of the British Isles

2016 ◽  
Vol 119 (2) ◽  
pp. 445-454 ◽  
Author(s):  
Alexandre Roulin ◽  
Christophe F. Randin
Keyword(s):  
British Isles ◽  
Black Feather ◽  
Barn Owls

Why barn owls in the British Isles are ghostly white

2021 ◽  
Vol 252 (3361) ◽  
pp. 20
Author(s):  
Jake Buehler
Keyword(s):  
British Isles ◽  
Barn Owls

Ultradian Rhythmicity in Sleep-Wakefulness Is Related to Color in Nestling Barn Owls

2017 ◽  
Vol 32 (5) ◽  
pp. 456-468 ◽  
Author(s):  
Madeleine F. Scriba ◽  
Isabelle Henry ◽  
Alexei L. Vyssotski ◽  
Jakob C. Mueller ◽  
Niels C. Rattenborg ◽  
...  
Keyword(s):  
Social Interactions ◽  
Rem Sleep ◽  
Period Length ◽  
Tyto Alba ◽  
Circadian Expression ◽  
Black Feather ◽  
Black Spots ◽  
Barn Owls ◽  
Save Energy ◽  
Ultradian Rhythmicity

The possession of a rhythm is usually described as an important adaptation to regular changing environmental conditions such as the light-dark cycle. However, recent studies have suggested plasticity in the expression of a rhythm depending on life history and environmental factors. Barn owl ( Tyto alba) nestlings show variations in behavior and physiology in relation to the size of black feather spots, a trait associated with many behavioral and physiological phenotypes including the circadian expression of corticosterone and the regulation of body mass. This raises the possibility that individual spottiness could be associated with rhythmicity in sleep-wakefulness. Owlets showed ultradian rhythms in sleep-wakefulness, with a period length of 4.5 to 4.9 h. The period length of wakefulness and non-REM sleep was shorter in heavily compared to lightly spotted female nestlings, whereas in males, the opposite result was found. Furthermore, male and female nestlings displaying small black spots showed strong rhythmicity levels in wakefulness and REM sleep. This might be an advantage in a stable environment with predictable periodic changes in light, temperature, or social interactions. Heavily spotted nestlings displayed weak rhythms in wakefulness and REM sleep, which might enable them to be more flexible in reactions to unexpected events such as predation or might be a mechanism to save energy. These findings are consistent with previous findings showing that large-spotted nestlings switch more frequently between wakefulness and sleep, resulting in higher levels of vigilance compared to small-spotted conspecifics. Thus, nestlings with larger black feather spots might differently handle the trade-off between wakefulness and sleep, attention, and social interactions compared to nestlings with smaller black spots.

scholarly journals Expression of glucocorticoid and mineralocorticoid receptor genes co-vary with a stress-related colour signal in barn owls

2019 ◽  
Author(s):  
Paul Béziers ◽  
Anne-Lyse Ducrest ◽  
Luis M. San-Jose ◽  
Céline Simon ◽  
Alexandre Roulin
Keyword(s):  
Glucocorticoid Receptors ◽  
Environmental Changes ◽  
Tyto Alba ◽  
Post Translational Modification ◽  
Melanocortin System ◽  
Gene Encoding ◽  
Physiological Processes ◽  
Expression Of Genes ◽  
Black Feather ◽  
Barn Owls

AbstractGlucocorticoid hormones are important intermediates between an organism and its environment. They enable an organism to adjust its behavioural and physiological processes in response to environmental changes by binding to mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) expressed in many tissues, including the integument. The regulation of glucocorticoids covaries with melanin-based colouration in numerous species, an association that might result from the melanocortin system and evolve within a signalling context. Most studies have focused on the circulating levels of glucocorticoids disregarding the receptors that mediate their action and could partly account for the covariation between the regulation of stress and melanin-based coloration. We investigated the association between melanin-based coloration and the gene expression levels of GR and MR but also of the melanocortin system and melanogenesis in the growing feathers of nestling barn owls (Tyto alba). We also considered the expression of genes related to the melanocortin system and melanogenesis to better understand the origin of the link between the expression of receptors to which corticosterone binds and melanin-based coloration. Nestling barn owls displaying larger black feather spots expressed GR and MR at lower levels than did smaller-spotted individuals. Because the expression of the GR and MR genes was positively, rather than negatively, correlated with the expression of melanogenic genes, we suggest that the link between melanin-based coloration, GR and MR is not directly associated to melanogenesis. The finding that the expression of GR and MR was positively associated with the expression of the PCSK2 gene (encoding the protein convertase responsible for post-translational modification of the proopiomelanocortin hormone) suggests that the melanocortin system may be implicated in the establishment of the covariation between melanism and the expression of receptors to which glucocorticoids bind. Together with previous studies, our results suggest that coloration is not only related to the production of glucocorticoids but also to the sensitivity of the integument to glucocorticoids.

scholarly journals Unexpected post-glacial colonisation route explains the white colour of barn owls (Tyto alba) from the British Isles

2021 ◽  
Author(s):  
Ana Paula Machado ◽  
Tristan Cumer ◽  
Christian Iseli ◽  
Emmanuel Beaudoing ◽  
Anne-Lyse Ducrest ◽  
...  
Keyword(s):  
Glacial Refugia ◽  
Species Distribution Modelling ◽  
Northern Europe ◽  
Future Research ◽  
Suitable Habitat ◽  
British Isles ◽  
Tyto Alba ◽  
Land Bridge ◽  
Barn Owls ◽  
White Colour

AbstractThe climate fluctuations of the Quaternary shaped the movement of species in and out of glacial refugia. In Europe, the majority of species followed one of the described traditional postglacial recolonization routes from the southern peninsulas towards the north. Like most organisms, barn owls are assumed to have colonized the British Isles by crossing over Doggerland, a land bridge that connected Britain to northern Europe. However, while they are dark rufous in northern Europe, barn owls in the British Isles are conspicuously white, a contrast that could suggest selective forces are at play on the islands. However, analysis of known candidate genes involved in colouration found no signature of selection. Instead, using whole genome sequences and species distribution modelling, we found that owls colonised the British Isles soon after the last glaciation, directly from a white coloured refugium in the Iberian Peninsula, before colonising northern Europe. They would have followed a yet unknown post-glacial colonization route to the Isles over a westwards path of suitable habitat in now submerged land in the Bay of Biscay, thus not crossing Doggerland. As such, they inherited the white colour of their Iberian founders and maintained it through low gene flow with the mainland that prevents the import of rufous alleles. Thus, we contend that neutral processes likely explain this contrasting white colour compared to continental owls. With the barn owl being a top predator, we expect future research will show this unanticipated route was used by other species from its paleo community.

Illustrations and the genesis of Barrett and Yonge's Collins pocket guide to the sea shore (1958)

2010 ◽  
Vol 37 (2) ◽  
pp. 274-291 ◽  
Author(s):  
P. G. Moore
Keyword(s):  
Crucial Role ◽  
British Isles ◽  
Publishing History ◽  
Biological Station ◽  
Marine Biological ◽  
Illustrated Text ◽  
History Of ◽  
The University

Twenty nine items of correspondence from the mid-1950s discovered recently in the archives of the University Marine Biological Station Millport, and others made available by one of the illustrators and a referee, shed unique light on the publishing history of Collins pocket guide to the sea shore. This handbook, generally regarded as a classic of its genre, marked a huge step forwards in 1958; providing generations of students with an authoritative, concise, affordable, well illustrated text with which to identify common organisms found between the tidemarks from around the coasts of the British Isles. The crucial role played by a select band of illustrators in making this publication the success it eventually became, is highlighted herein. The difficulties of accomplishing this production within commercial strictures, and generally as a sideline to the main employment of the participants, are revealed. Such stresses were not helped by changing demands on the illustrators made by the authors and by the publishers.

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