RESUMEN
Adaptive phenotypic plasticity is an important source of intraspecific variation, and for many plastic traits, the costs or factors limiting plasticity seem cryptic. However, there are several different factors that may constrain the evolution of plasticity, but few models have considered costs and limiting factors simultaneously. Here we use a simulation model to investigate how the optimal level of plasticity in a population depends on a fixed maintenance fitness cost for plasticity or an incremental fitness cost for producing a plastic response in combination with environmental unpredictability (environmental fluctuation speed) limiting plasticity. Our model identifies two mechanisms that act, almost separately, to constrain the evolution of plasticity: (i) the fitness cost of plasticity scaled by the nonplastic environmental tolerance, and (ii) the environmental fluctuation speed scaled by the rate of phenotypic change. That is, the evolution of plasticity is constrained by the high cost of plasticity in combination with high tolerance for environmental variation, or fast environmental changes in combination with slow plastic response. Qualitatively similar results are found when maintenance and incremental fitness costs of plasticity are incorporated, although a larger degree of plasticity is selected for with an incremental cost. Our model highlights that it is important to consider direct fitness costs and phenotypic limitations in relation to nonplastic environmental tolerance and environmental fluctuations, respectively, to understand what constrains the evolution of phenotypic plasticity.
Asunto(s)
Evolución Biológica , Fenotipo , Ambiente , Modelos TeóricosRESUMEN
This study assessed the major histocompatibility complex (MHC) and neutral genetic variation and structure in two percid species, perch Perca fluviatilis and zander Sander lucioperca, in a unique brackish ecosystem, the Baltic Sea. In addition, to assess the importance of MHC diversity to disease susceptibility in these populations, comparisons were made to an introduced, disease susceptible, P. fluviatilis population in Australia. Eighty-three MHC class II B exon 2 variants were amplified: 71 variants from 92 P. fluviatilis samples, and 12 variants from 82 S. lucioperca samples. Microsatellite and MHC data revealed strong spatial genetic structure in S. lucioperca, but not P. fluviatilis, across the Baltic Sea. Both microsatellite and MHC data showed higher levels of genetic diversity in P. fluviatilis from the Baltic Sea compared to Australia, which may have facilitated the spread of an endemic virus, EHNV in the Australian population. The relatively high levels of genetic variation in the Baltic Sea populations, together with spatial genetic structure, however, suggest that there currently seems to be little risk of disease epidemics in this system. To ensure this remains the case in the face of ongoing environmental changes, fisheries and habitat disturbance, the conservation of local-scale genetic variation is recommended.
Asunto(s)
Genes MHC Clase II , Variación Genética , Genética de Población , Percas/genética , Animales , Océano Atlántico , Australia , Resistencia a la Enfermedad/genética , Ecosistema , Exones , Finlandia , Explotaciones Pesqueras , Especies Introducidas , Repeticiones de Microsatélite , Análisis de Secuencia de ADN , SueciaRESUMEN
Annual variation in flood frequency and hydroperiod during the vegetation season has ecological impacts on the floodplain biota. Although many insect groups may have a lower emergence during a flood event, it is poorly known how annual emergence of insects in temporary wetlands is related to the variation in hydrology. Between May and September, we studied the weekly emergence of 18 insect taxa over six consecutive years, 2002-2007, in six temporary flooded wetlands (four wet meadows and two forest swamps) in the River Dalälven floodplains, Central Sweden. We used emergence traps to collect emerging insects from terrestrial and aquatic parts of wet meadows and swamp forests. In all wetlands, the insect fauna was numerically dominated by the orders Diptera, Hymenoptera, Coleoptera and Homoptera. On a weekly basis, 9 out of the 18 insect taxa had lower emergence in weeks with flood than in weeks with no flood, whereas no taxon had a higher emergence in weeks with flood. Over the seasons, we related insect emergence to seasonal flood frequency and length of hydroperiod. The emergence of most studied taxa decreased with increasing hydroperiod, which suggests that emergence after floods do not compensate for the reduced emergence during floods. Only Culicidae and the aquatic Chironomidae sub-families Tanypodinae and Chironominae showed an increase in emergence with increasing hydroperiod, whereas Staphylinidae peaked at intermediate hydroperiod. We conclude that a hydroperiod covering up to 40% of the vegetation season has a significant negative effect on the emergence of most taxa and that only a few taxa occurring in the temporary wetlands are actually favoured by a flood regime with recurrent and unpredictable floods.
Asunto(s)
Inundaciones , Insectos/fisiología , Estadios del Ciclo de Vida/fisiología , Ríos , Humedales , Animales , Modelos Lineales , Dinámica Poblacional , Especificidad de la Especie , SueciaRESUMEN
Two species of arbovirus vector, Culex torrentium and Culex pipiens (Diptera: Culicidae), occur in several European countries, but difficulties in their accurate identification and discrimination have hampered both detailed and large-scale distribution and abundance studies. Using a molecular identification method, we identified to species 2559 larvae of Cx. pipiens/torrentium collected from 138 sites in 13 European countries ranging from Scandinavia to the Mediterranean coast. In addition, samples of 1712 males of Cx. pipiens/torrentium collected at several sites in the Czech Republic were identified to species based on the morphology of their hypopygia. We found that the two species occur together in large areas of Europe, and that Cx. torrentium dominates in northern Europe and Cx. pipiens dominates south of the Alps. The transition in dominance occurs in central Europe, where both species are roughly equally common. There was a strong correlation between the length of the growing season at different sites and occurrences of the two species. As the growing season increases, the proportion and detection of Cx. torrentium decrease, whereas those of Cx. pipiens increase. The present findings have important consequences for the interpretation of the results of studies on major enzootic and link-vectors of mosquito-borne bird-associated viruses (i.e. Sindbis, West Nile and Usutu viruses), especially in central Europe and Scandinavia.
Asunto(s)
Distribución Animal , Culex/fisiología , Insectos Vectores/fisiología , Animales , Arbovirus/fisiología , Culex/anatomía & histología , Culex/genética , Culex/crecimiento & desarrollo , Complejo IV de Transporte de Electrones/genética , Europa (Continente) , Proteínas de Insectos/genética , Larva/genética , Larva/fisiología , Masculino , Proteínas Mitocondriales/genética , Reacción en Cadena de la Polimerasa , Densidad de Población , Estaciones del Año , Especificidad de la EspecieRESUMEN
Natural and sexual selection shape the evolution of species but the interplay between them is poorly understood. Two phylogenetic studies on birds have suggested that species with greater sexual dichromatism have a broader habitat use. We show that in agamid lizards, species with more elaborate secondary sexual traits are also ecologically more opportunistic. Species with greater dimorphism in head size and ornamentation have greater altitudinal range and broader habitat use, respectively, and species with greater sexual dichromatism have wider microhabitat use. Body size was positively associated with sexual and ecological generalism, but associations between ecological and sexual traits remained after accounting for body size. We suggest that sexual and natural selection may be linked either because sexual selection can promote generalism at the population level by favouring 'good genes', or because higher population densities may be associated with both stronger sexual selection and broader resource use.
Asunto(s)
Lagartos/fisiología , Preferencia en el Apareamiento Animal , Animales , Tamaño Corporal/fisiología , Lagartos/genética , Caracteres SexualesRESUMEN
Species richness and species turn-over of Chironomidae was studied in irregularly flooded wetlands of the River Dalälven flood-plains in central Sweden. The chironomid fauna, sampled with emergence traps in six wetlands over six summers, contained as much as 135 species, and the cumulative species curves indicated that the regional species pool contain several more species. Recurrent irregular floods may have induced this high chironomid species richness and the high species turn-over in the temporary wetlands, as the dominance between terrestrial and aquatic species shifted between years. Half of the wetlands were treated with Bacillus thuringiensis var. israelensis (Bti) against larvae of the flood-water mosquito Aedes sticticus. These treatments had no significant effect on chironomid species richness, but there was a higher species turn-over between years of primarily low abundance species in the treated wetlands. The cumulative number of species was also higher in the Bti-treated experimental wetlands than in the untreated reference wetlands. Thus, Bti treatment against mosquito larvae seemed to have only small effects on chironomid species richness but seemed to increase the colonisation-extinction dynamics.
Asunto(s)
Biodiversidad , Chironomidae/clasificación , Chironomidae/fisiología , Humedales , Animales , Inundaciones , Dinámica Poblacional , Factores de TiempoRESUMEN
Recently, several polymerase chain reaction (PCR)-based methods for detection and genetic identification of haemosporidian parasites in avian blood have been developed. Most of these have considerably higher sensitivity compared with traditional microscope-based examinations of blood smears. These new methods have already had a strong impact on several aspects of research on avian blood parasites. In this study, we present a new nested PCR approach, building on a previously published PCR method, which has significantly improved performance. We compare the new method with some existing assays and show, by sequence-based data, that the higher detection rate is mainly due to superior detection of Plasmodium spp. infections, which often are of low intensity and, therefore, hard to detect with other methods.
Asunto(s)
Enfermedades de las Aves/diagnóstico , Haemosporida/aislamiento & purificación , Malaria Aviar/diagnóstico , Parasitemia/veterinaria , Infecciones Protozoarias en Animales/diagnóstico , Pájaros Cantores/parasitología , Animales , Enfermedades de las Aves/epidemiología , Enfermedades de las Aves/parasitología , ADN Protozoario/sangre , Eritrocitos/parasitología , Haemosporida/clasificación , Haemosporida/genética , Malaria Aviar/epidemiología , Malaria Aviar/parasitología , Parasitemia/diagnóstico , Parasitemia/epidemiología , Parasitemia/parasitología , Filogenia , Plasmodium/clasificación , Plasmodium/genética , Plasmodium/aislamiento & purificación , Reacción en Cadena de la Polimerasa/métodos , Reacción en Cadena de la Polimerasa/veterinaria , Prevalencia , Infecciones Protozoarias en Animales/epidemiología , Infecciones Protozoarias en Animales/parasitología , Reproducibilidad de los Resultados , Alineación de Secuencia/veterinariaAsunto(s)
Medicina Familiar y Comunitaria , Asignación de Recursos para la Atención de Salud , Recursos en Salud , Atención Primaria de Salud , Medicina Familiar y Comunitaria/economía , Medicina Familiar y Comunitaria/organización & administración , Recursos en Salud/economía , Recursos en Salud/organización & administración , Humanos , Atención Primaria de Salud/economía , Atención Primaria de Salud/organización & administración , SueciaRESUMEN
A fragment of the mitochondrial cytochrome b gene of avian malaria (genera Haemoproteus and Plasmodium) was amplified from blood samples of 12 species of passerine birds from the genera Acrocephalus, Phylloscopus and Parus. By sequencing 478 nucleotides of the obtained fragments, we found 17 different mitochondrial haplotypes of Haemoproteus or Plasmodium among the 12 bird species investigated. Only one out of the 17 haplotypes was found in more than one host species, this exception being a haplotype detected in both blue tits (Parus caeruleus) and great tits (Parus major). The phylogenetic tree which was constructed grouped the sequences into two clades, most probably representing Haemoproteus and Plasmodium, respectively. We found two to four different parasite mitochondrial DNA (mtDNA) haplotypes in four bird species. The phylogenetic tree obtained from the mtDNA of the parasites matched the phylogenetic tree of the bird hosts poorly. For example, the two tit species and the willow warbler (Phylloscopus trochilus) carried parasites differing by only 0.6% sequence divergence, suggesting that Haemoproteus shift both between species within the same genus and also between species in different families. Hence, host shifts seem to have occurred repeatedly in this parasite host system. We discuss this in terms of the possible evolutionary consequences for these bird species.
Asunto(s)
Grupo Citocromo c/genética , ADN Mitocondrial/sangre , ADN Protozoario/análisis , Haemosporida/genética , Malaria Aviar/parasitología , Plasmodium/genética , Pájaros Cantores/parasitología , Animales , Grupo Citocromo c/clasificación , ADN Mitocondrial/clasificación , Haemosporida/clasificación , Haemosporida/aislamiento & purificación , Interacciones Huésped-Parásitos , Malaria Aviar/sangre , Filogenia , Plasmodium/clasificación , Plasmodium/aislamiento & purificación , Reacción en Cadena de la Polimerasa/métodos , Especificidad de la EspecieRESUMEN
A total of 142 consecutive patients cared for by child and adolescent psychiatry were followed up to the age of 33-37 years; 49% were treated in adult psychiatry between the ages of 20-25 years, and 20% of these were hospitalized. The frequency of hospitalization was 4-5 times that of a control group. Between the ages of 20-34 years, 32% were admitted some time for inpatient psychiatric care. Psychiatric diagnoses of the patients: schizophrenia 4%, manic-depressive 5%, neurosis and reactive insufficiency 11%, personality disorders and/or abuse diagnosis 12%. Patients with a schizophrenia diagnosis in adulthood needed the most hospitalization. The symptom picture was stable from child and adolescent psychiatric care through to adulthood, but abuse increased with age. The frequency of sick leave was 2.5 times higher among the child and adolescent psychiatric care patients than among the control group. At the age of 34-36 years, 13% of the former patients received disability benefits as compared with 1% for the same age groups in the entire population of Sweden. Twenty-one percent received sentences for criminal offenses from the age of 20-34 years. The number of crimes decreased with increasing age. Nearly 50% were in contact with the social welfare services, 3 times as many as in the control group. A third of the men completed their national military service. A total of 6 men and 1 woman died, indicating an increased mortality rate for men. All deaths except one were related to the mental disorder.
Asunto(s)
Hospitalización , Trastornos Mentales/diagnóstico , Adolescente , Adulto , Factores de Edad , Causas de Muerte , Niño , Crimen , Empleo , Femenino , Estudios de Seguimiento , Humanos , Estudios Longitudinales , Masculino , Trastornos Mentales/psicología , Trastornos Mentales/terapia , Esquizofrenia/diagnóstico , Esquizofrenia/terapia , Psicología del Esquizofrénico , Factores Sexuales , Ajuste Social , Bienestar SocialRESUMEN
All 142 consecutive patients born between January 1, 1947 and February 28, 1949 who were cared for at the Department of Child and Adolescent Psychiatry at General Hospital in Uppsala are described. The patients' symptoms, family situation, early development, CNS dysfunction and social situation are presented. The negative factors were numerous: 78% of patients had some form of family affliction, 60% had minimal brain dysfunction (MBD) factors which, while not associated with a clinical diagnosis of MBD, included hyperactivity, motor handicap, reading and writing difficulties, poor fine muscle activity and pathological EEG, and 58% had negative factors in their home environment. The majority were judged as having been subjected to negative parental attitudes. When psychotic symptoms were present, there was a high prevalence of psychotic illness in the family. A negative social situation in the home environment was most common for maladjusted patients. The presence of MBD factors was associated with disturbances in the child's early development. Nevertheless, many background factors continually affected one another and contributed to the mental disorder.
Asunto(s)
Trastornos de la Conducta Infantil/psicología , Tratamiento Domiciliario , Adolescente , Niño , Estudios de Seguimiento , Humanos , Discapacidad Intelectual/psicología , Discapacidades para el Aprendizaje/psicología , Trastornos Neurocognitivos/psicología , Trastornos Psicofisiológicos/psicología , Trastornos Psicóticos/psicología , Factores de Riesgo , Ajuste Social , SueciaRESUMEN
In Sweden in-patient psychiatric care of children and adolescents is in decline. At the same time the out-patient care is increasing. These findings stem from a study of the annual patient statistics provided by the National Board of Health and Welfare. There are considerable differences among the counties in Sweden. In certain counties more than four times as many children and adolescents receive hospital care as in other counties. The distribution between child and adolescent psychiatry and adult psychiatry also varies considerably. However, it is usual that from the age of 18 years care is given in adult psychiatric clinics. Among patients with a diagnosis of psychosis and when compulsory care is necessary, adult psychiatric clinics are also responsible for patients 16 and 17 years old. Care of children at mental hospitals, still common in the 1960's, is nowadays no longer existent. The study is a starting-point for a discussion about how to attain better co-operation between child and adolescent psychiatry and adult psychiatry.