Melanin-based colorations signal strategies to cope with poor and rich environments

One hypothesis for the maintenance of genetic variation states that alternative genotypes are adapted to different environmental conditions (i.e., genotype-by-environment interaction GxE) that vary in space and time. Although GxE has been demonstrated for morphological traits, little evidence has been given whether these GxE are associated with traits used as signal in mate choice. In three wild bird species, we investigated whether the degree of melanin-based coloration, a heritable trait, covaries with nestling growth rate in rich and poor environments. Variation in the degree of reddish-brown phaeomelanism is pronounced in the barn owl (Tyto alba) and tawny owl (Strix aluco), and variation in black eumelanism in the barn owl and Alpine swift (Apus melba). Melanin-based coloration has been shown to be a criterion in mate choice in the barn owl. We cross-fostered hatchlings to test whether nestlings sired by parents displaying melanin-based colorations to different extent exhibit alternative growth trajectories when raised by foster parents in poor (experimentally enlarged broods) and rich (experimentally reduced broods) environments. With respect to phaeomelanism, barn owl and tawny owl offspring sired by redder parents grew more rapidly in body mass only in experimentally reduced broods. With respect to eumelanism, Alpine swift offspring of darker fathers grew their wings more rapidly only in experimentally enlarged broods, a difference that was not detected in reduced broods. These interactions between parental melanism and offspring growth rate indicate that individuals display substantial plasticity in response to the rearing environment which is associated with the degree of melanism: at least with respect to nestling growth, phaeomelanic and eumelanic individuals are best adapted to rich and poor environments, respectively. It now remains to be investigated why eumelanism and phaeomelanism have a different signaling function and what the lifelong consequences of these melanism-dependent allocation strategies are. This is important to fully appraise the role played by environmental heterogeneity in maintaining variation in the degree of melanin-based coloration.

Melanin-based coloration in juvenile kestrels (Falco tinnunculus) covaries with anti-predatory personality traits

Recent studies have shown that melanin-based coloration is associated with the ability to cope with stressful environments, potentially explaining why coloration covaries with anti-predator behaviours, boldness and docility. To investigate whether these relationships are consistent across species, we performed a study in the European kestrel (Falco tinnunculus). Similar to our results found previously in the barn owl (Tyto alba), nestling kestrels displaying a larger sub-terminal black tail band stayed on their back longer (tonic immobility test) and breathed at a lower rate than individuals with a smaller black band when handled. However, in contrast to barn owls, nestling kestrels with a larger black tail band were more aggressive and more agitated. Our results strengthen the hypothesis that melanin coloration is related to stress response and in turn to the reaction to predators, a very important personality trait (i.e. boldness).

The farmer's lung disease : occupational medicine input

Background: Although there has been an abundant literature in recent years about farmer's lung disease, few addressed occupational measures able to maintain the farmer in his work. Nevertheless we know now that most of the farmers can be kept at the workplace by the way of occupational preventive measures. Methods: This matter is discussed from a case report. A farmer affected by the farmer's lung disease was sent to us by his pneumologist, in order to estimate the possibility of maintaining him in his job and to determine relevant changes at his workplace to minimize risk of exposure to dust antigen. This approach required a visit to the workplace by occupational physician and hygienist. Results: The visit of the workplace pointed out different habits and architectural particularities which were potential sources of exposure. The two main proposed measures to reduce the risk, were to wear respiratory masks while working inside the barn, such as preparing hay, feeding the cattle or sweeping the floor, and to build a direct access from the bathroom (shower and toilet) to the outside, allowing to go out of the barn after taking a shower and changing, without risk of being contaminated again. Although upgrading the shower-toilet is not yet completed to date, the already performed modifications led currently to significant clinical improvements, despite the risk of exposure was high since the animals were in the barn for more than two months. Conclusion: The treatment of the farmer's lung disease must be multidisciplinary involving general practitioner, pneumologist, occupational hygienist and occupational physician.

Temporal variation in glucocorticoid levels during the resting phase is associated in opposite way with maternal and paternal melanic coloration.

Sex-dependent selection can help maintain sexual dimorphism. When the magnitude of selection exerted on a heritable sex trait differs between the sexes, it may prevent each sex to reach its phenotypic optimum. As a consequence, the benefit of expressing a sex trait to a given value may differ between males and females favouring sex-specific adaptations associated with different values of a sex trait. The level of metabolites regulated by genes that are under sex-dependent selection may therefore covary with the degree of ornamentation differently in the two sexes. We investigated this prediction in the barn owl, a species in which females display on average larger black spots on the plumage than males, a heritable ornament. This melanin-based colour trait is strongly selected in females and weakly counter-selected in males indicating sex-dependent selection. In nestling barn owls, we found that daily variation in baseline corticosterone levels, a key hormone that mediates life history trade-offs, covaries with spot diameter displayed by their biological parents. When their mother displayed larger spots, nestlings had lower corticosterone levels in the morning and higher levels in the evening, whereas the opposite pattern was found with the size of paternal spots. Our study suggests a link between daily regulation of glucocorticoids and sex-dependent selection exerted on sexually dimorphic melanin-based ornaments.

How siblings adjust sib-sib communication and begging signals to each other

Parents allocate food resources to their offspring in proportion to the intensity of begging behaviour. Begging encompasses several activities including vocalizations that should honestly signal need and jostling for the position in the nest where parents predictably deliver food items. Although siblings are known to adjust begging level to each other, the underlying mechanism remains unknown. We examined this issue in experimental two-chick broods of the barn owl, Tyto alba, a species in which siblings communicate vocally with each other in the prolonged absence of parents. The function of sib-sib vocal communication, so-called sibling negotiation, is to resolve conflicts over which individual will have priority of access to the next delivered indivisible food item. We found that when a nestling produced longer negotiation calls and stood closer to the nestbox entrance in the absence of parents, its sibling vocally negotiated at a lower rate. Additionally, when an individual produced more negotiation calls in the absence of parents, its sibling begged less intensely at the parent's return, with begging being the key factor that determined which nestling obtained a food item. We conclude that position in the nest and the duration of negotiation calls produced in the absence of parents influence the rate of producing negotiation calls, which in turn influences the rate at which siblings beg for food from their parents. Adjusting begging behaviour could therefore depend on complex sib-sib interactions taking place in the prolonged absence of parents.

Covariation between eumelanic pigmentation and body mass only under specific conditions.

Identifying the factors that mediate covariation between an ornament and other phenotypic attributes is important to determine the signaling function of ornaments. Sign and magnitude of a covariation may vary across environments if the expression of the ornament or of its linked genes regulating correlated phenotypes is condition-dependent. I investigated in the barn owl Tyto alba whether sign and magnitude of covariation between body mass and two heritable melanin-based plumage ornaments change with food supply, along the reproductive cycle and from the morning to the evening. Using a dataset of 1,848 measurements of body mass in 336 breeding females, I found that females displaying large black spots were heavier than conspecifics with smaller spots in the afternoon (i.e., a long time after the last feeding) but not in the morning (i.e., a short time after the last feeding). This is consistent with the recently proposed hypothesis that eumelanin-based ornaments are associated with the ability to maintain energy balance between food intake and energy expenditure. Thus, covariation between melanin-based coloration and body mass can be detected only under specific conditions potentially explaining why it has been reported in only ten out of 28 vertebrate species. The proposition that ornamented individuals achieve a higher fitness than drab conspecifics only in specific environments should be tested for other ornaments.

Information retention during competitive interactions : siblings need to constantly repeat vocal displays

Memory is essential to adjust behaviour according to past experience. In societies where animals interact on numerous occasions, memory of previous social interactions may help optimise investment in competition. How long information about the resource holding potential and motivation to compete of conspecifics is retained depends on how fast the value of this information fades, but also on the cost and benefit of retaining information. Information retention has never been investigated in the context of interactions prevailing within the family and more specifically sibling competition. In the absence of parents, barn owl (Tyto alba) nestlings vocally compete for priority of access to the next indivisible food item brought by a parent. The finding that owlets eavesdrop on vocal interactions between siblings to adjust investment in vocalization once competing with them suggests that they memorize siblings' vocal interactions. Playback experiments showed that owlets take into account the past siblings' vocal performance that signals hunger for at least 15 min, but only if the performance was witnessed during a sufficiently long period of time (30 min). Moreover, using natural vocal exchanges in another set of individuals, we showed that sibling signalling was no more taken into account after a few minutes. This suggests that young barn owls need to continuously display their motivation to trigger siblings' withdrawal from the current competition. Repeating a vocal display may ensure its honesty. Studying the extent to which individuals retain past information is important to understand how individuals adjust their competitive investment over resources.

Eumelanin- and pheomelanin-based colour advertise resistance to oxidative stress in opposite ways.

The control mechanisms and information content of melanin-based colourations are still debated among evolutionary biologists. Recent hypotheses contend that molecules involved in melanogenesis alter other physiological processes, thereby generating covariation between melanin-based colouration and other phenotypic attributes. Interestingly, several molecules such as agouti and glutathione that trigger the production of reddish-brown pheomelanin have an inhibitory effect on the production of black/grey eumelanin, whereas other hormones, such as melanocortins, have the opposite effect. We therefore propose the hypothesis that phenotypic traits positively correlated with the degree of eumelanin-based colouration may be negatively correlated with the degree of pheomelanin-based colouration, or vice versa. Given the role played by the melanocortin system and glutathione on melanogenesis and resistance to oxidative stress, we examined the prediction that resistance to oxidative stress is positively correlated with the degree of black colouration but negatively with the degree of reddish colouration. Using the barn owl (Tyto alba) as a model organism, we swapped eggs between randomly chosen nests to allocate genotypes randomly among environments and then we measured resistance to oxidative stress using the KRL assay in nestlings raised by foster parents. As predicted, the degree of black and reddish pigmentations was positively and negatively correlated, respectively, with resistance to oxidative stress. Our results reveal that eumelanin- and pheomelanin-based colourations can be redundant signals of resistance to oxidative stress.

Efficiency and significance of multiple vocal signals in sibling competition

Animals can compete for resources by displaying various acoustic signals that may differentially affect the outcome of competition. We propose the hypothesis that the most efficient signal to deter opponents should be the one that most honestly reveals motivation to compete. We tested this hypothesis in the barn owl (Tyto alba) in which nestlings produce more calls of longer duration than siblings to compete for priority access to the indivisible prey item their parents will deliver next. Because nestlings increase call rate to a larger extent than call duration when they become hungrier, call rate would signal more accurately hunger level. This leads us to propose three predictions. First, a high number of calls should be more efficient in deterring siblings to compete than long calls. Second, the rate at which an individual calls should be more sensitive to variation in the intensity of the sibling vocal competition than the duration of its calls. Third, call rate should influence competitors' vocalization for a longer period of time than call duration. To test these three predictions we performed playback experiments by broadcasting to singleton nestlings calls of varying durations and at different rates. According to the first prediction, singleton nestlings became less vocal to a larger extent when we broadcasted more calls compared to longer calls. In line with the second prediction, nestlings reduced vocalization rate to a larger extent than call duration when we broadcasted more or longer calls. Finally, call rate had a longer influence on opponent's vocal behavior than call duration. Young animals thus actively and differentially use multiple signaling components to compete with their siblings over parental resources.

La Guerra del francès a Lleida (1808-1814)

Este estudio histórico está dedicado a analizar la ocupación del territorio ilerdense por las tropas francesas, la repercusión y la reacción negativa que provocó en la población de Lleida, sobre todo se hará hincapié en el “Motín del Femeret”, un intento de subversión del poder fáctico tradicional por parte de una muchedumbre enfurecida ante la indolencia de las autoridades locales. También se examinará la organización de la resistencia interior de la ciudad para evitar ser conquistada, su asedio ulterior por parte de los soldados galos, la posterior conquista de Lleida por el ejército napoleónico en el año 1810 y la brutal represión que ejercieron sobre sus habitantes, causando notables daños tanto materiales como personales. Asimismo se hará referencia al gobierno francés del barón Henriod (1810-1812) como también al mandato de Alban de Villeneuve (1812-1814). Además se expondrá la reconquista a principios del año 1814 y finalmente se hará referencia a las consecuencias demográficas, económicas y sociales que produjo la Guerra de la Independencia en la ciudad de Lleida.

Aberrant features of the Messinian coral reefs, Spain

Se describen someramente los principales arrecifes del Messiniense en España, haciendo hincapié en el conjunto de 'anomalias' presentan los arrecifes del Neógeno inferior en comparación con las asociaciones arrecifales actuales. Se discute la importancia y significado de Porites sp. como coral claramente dominante, y a menudo exclusivo, en la construcción de edificios arrecifales.

Effect of the MC1R gene on sexual dimorphism in melanin-based colorations.

Variants of the melanocortin-1 receptor (MC1R) gene result in abrupt, naturally selected colour morphs. These genetic variants may differentially affect sexual dimorphism if one morph is naturally selected in the two sexes but another morph is naturally or sexually selected only in one of the two sexes (e.g. to confer camouflage in reproductive females or confer mating advantage in males). Therefore, the balance between natural and sexual selections can differ between MC1R variants, as suggest studies showing interspecific correlations between sexual dimorphism and the rate of nonsynonymous vs. synonymous amino acid substitutions at the MC1R. Surprisingly, how MC1R is related to within-species sexual dimorphism, and thereby to sex-specific selection, has not yet been investigated. We tackled this issue in the barn owl (Tyto alba), a species showing pronounced variation in the degree of reddish pheomelanin-based coloration and in the number and size of black feather spots. We found that a valine (V)-to-isoleucine (I) substitution at position 126 explains up to 30% of the variation in the three melanin-based colour traits and in feather melanin content. Interestingly, MC1R genotypes also differed in the degree of sexual colour dimorphism, with individuals homozygous for the II MC1R variant being 2 times redder and 2.5 times less sexually dimorphic than homozygous individuals for the VV MC1R variant. These findings support that MC1R interacts with the expression of sexual dimorphism and suggest that a gene with major phenotypic effects and weakly influenced by variation in body condition can participate in sex-specific selection processes.

Sosiaalityö ja maahanmuuttajat. Lastensuojelun ammattilaisten ja asiakkaiden vuorovaikutus ja tulkinnat

Tutkimuksen tavoitteena oli tuottaa tietoa siitä, mitä maahanmuuttajia koskevat erityiskysymykset suomalaisessa lastensuojelun sosiaalityössä ovat ja miten näitä kysymyksiä lastensuojelussa käsitellään. Teoreettismetodologisena viitekehyksenä on sosiaalinen konstruktionismi. Etnisten suhteiden tutkimusperinteessä työ paikantuu keskusteluun, jossa kulttuuri ja etnisyys nähdään sosiaalisesti rakentuvina ja muuntuvina. Analyysissä sovelletaan diskurssianalyyttistä metodologiaa. Tutkimus rakentuu yhteenveto-osiosta ja neljästä artikkelista. Maahanmuuttajasosiaalityötä ja lastensuojelua tarkastellaan sosiaalityöntekijöiden, muiden ammattilaisten ja asiakkaiden kielenkäytön kautta. Aineisto koostuu 11 lastensuojelun asiakaskeskustelusta ja niiden jälkeen keskustelun osapuolille tehdyistä haastatteluista, joita on yhteensä 35. Tutkimuksessa analysoidaan seuraavia kysymyksiä: Miten sosiaalityöntekijät tulkitsevat maahanmuuttajasosiaalityön erityisyyttä oman ammatillisen tehtävänsä näkökulmasta? Minkälaisia ominaisuuksia sosiaalityöntekijät rakentavat maahanmuuttaja-asiakkaille? Miten lastensuojelun keskusteluissa puhutaan monikulttuurisuuteen liittyvistä teemoista, kuten erilaisuudesta ja samanlaisuudesta sekä kulttuuri- ja rasismikysymyksistä? Miten maahanmuuttajalasten ja -nuorten osallisuus lastensuojelun asiakaskeskusteluissa rakentuu aikuisten ja lasten itsensä tuottamana? Mitä ja miten maahanmuuttajalapset ja -nuoret puhuvat kokemuksistaan lastensuojelussa ja suomalaisessa yhteiskunnassa? Maahanmuuttajien erityiskysymyksiä ovat kieleen, kulttuuriin ja valtayhteiskunnan toimintaan liittyvät ymmärtämisvaikeudet, kokemukset arkipäivän rasismista sekä perheen ja yhteisön merkittävä, osin ristiriitainen rooli. Lapsilla ja nuorilla kulttuuri on muuntuvaa ja jatkuvien neuvottelujen kohteena. Aineiston lastensuojelutilanteiden taustalla on usein kouluympäristöön liittyviä vaikeuksia. Haastatteluissa lapset kertovat kokemuksistaan ja toimijuudestaan perheeseen, yhteisöön ja kouluun paikantuvissa tilanteissa. Asiakaskeskusteluissa lasten puhuja-asema on usein heikko, jos aikuiset eivät aktiivisesti vahvista sitä. Jotkut lapset ottavat itse vahvan puhuja-aseman. Asiakaskeskusteluissa maahanmuuttajien erityiskysymyksistä puhutaan harvoin eksplisiittisesti. Haastatteluissa sosiaalityöntekijät enemmän tai vähemmän tietoisesti paikantavat maahanmuuttajasosiaalityötä vieraannuttavaan, sopeuttavaan, tasa-arvoistavaan, kulttuuritietoiseen, rasismitietoiseen ja osallistavaan kehykseen. Kehykset nostavat sosiaalityön tavoitteista, menetelmistä ja asiakkaasta keskeisiksi erilaisia asioita. Tulkinnat ovat muuntuvia, vaikka osoittavat myös tiettyä säännönmukaisuutta. Kulttuuri on keskeinen käsite erilaisuuden ja samanlaisuuden ymmärtämiseksi. Sekä työntekijät että asiakkaat perustelevat toivottavia elämäntapoja "omalla kulttuurillaan" ja selittävät ongelmia ”erilaisella kulttuurilla”. Kulttuurin käsitettä voidaan myös käyttää työvälineenä asiakaskeskusteluissa avattaessa asiakkaan omaa näkökulmaa korostavaa dialogia. Perheen ja kulttuurisen yhteisön merkitys on tärkeää arvioida lapsen ja nuoren hyvinvoinnin ja kulttuurisen identiteetin kehittymisen näkökulmasta. Sosiaalityöntekijöillä on merkittävä välittäjän rooli yhtäältä valtayhteiskunnan ja maahanmuuttaja-asiakkaiden, toisaalta vanhempien, yhteisöjen sekä lasten ja nuorten välillä. Lastensuojelussa haasteena on arkipäivän rasismin tiedostaminen sekä siihen pureutuvien työmenetelmien kehittäminen.