A Case of Blue Coloration and Color Change in Pelophylax esculentus (Linnaeus, 1758) (Anura: Ranidae) in Denmark (original) (raw)
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Biology aspects in a population of Pelobates fuscus insubricus Cornalia, 1873 (Anura: Pelobatidae)
Herpetozoa
Pelobates fuscus insubricus CORNALIA, 1873 ist ein endemisches Taxon Norditaliens und der Südschweiz. Die Fortpflanzungsökologie ist recht gut untersucht, während die post-reproduktive Phase bisher kaum studiert wurde. Das Geschlechterverhältnis der untersuchten Population wich nicht signifikant von einem hypothetischen 1:1-Verhältnis ab. Die Art erwies sich als "explosive breeder", wobei die Fortpflanzungsperiode bei speziellen klimatischen Bedingungen (z.B. abwechselnd regnerische und trockene Phasen) verlängert sein konnte oder sogar bei besonders rauhem Klima ganz ausfiel. Frühlingsregen war wichtig zur Beendigung der Überwinterungsphase, bestimmte jedoch das anschließende Aktivitätsmuster nicht. Die Präsenz der Knoblauchkröten an der Oberfläche war nicht mit der Umgebungstemperatur korreliert. Weibchen waren in der Zeit nach der Fortpflanzung aktiver als Männchen, eventuell bedingt durch die Ernährungsbedürfnisse. Fünf Feuchtgebiete mit unterschiedlichen morphologischen Merkmalen sind im Untersuchungsgebiet vorhanden; sie alle wurden von P. fuscus insubricus als Laichgewässer genutzt. Diese Population zeigte also keine speziellen Habitatpräferenzen bezüglich Fortpflanzung. Im Gegensatz hierzu waren die Tiere während der Nachlaichzeit nur in Habitaten mit sandigen Böden aktiv.
Journal of Ornithology, 2017
of female quality, but further study is needed to determine if blue-green eggshell colour is a truly informative signal. Keywords Eggshell colour • Female traits • Quality signalling • Blue-green Zusammenfassung Unterschiedliche Farbmuster der Eier des Berghüttensängers (Sialia currucoides) bieten eine unklare Unterstützung der auf geschlechtlicher Selektion beruhenden "Eischalenfarben-Hypothese" Um die funktionelle Bedeutung schmückender, dekorativer Merkmale zu ermitteln und auch, ob sie ein Ergebnis sexueller Selektion sind, muss man verstehen, wie sie zwischen den einzelnen Individuen variieren und mit anderen qualitativen Merkmalen zusammenhängen. Eine auffällige Eierfärbung ist ein Merkmal, das sich durch sexuelle Selektion als ein Signal für die Qualität des Weibchens herausgebildet haben könnte. Diese Hypothese basiert auf der Annahme, dass das Pigment für blau-grüne Schalenfärbung möglicherweise eine begrenzte Ressource ist und es deshalb aufwendig wäre, diese für die Färbung von Eischalen zu verbrauchen. Für den Berghüttensänger (Sialia currucoides) untersuchten wir die mögliche Signalwirkung blau-grüner Schalenfärbungen durch die Quantifizierung der Farbmustervariationen innerhalb eines Geleges einerseits und andererseits zwischen einzelnen Gelegen, um herauszufinden, ob das Pigment begrenzt ist und ob bestimmte Farbmuster für individuelle Weibchen spezifisch sind. Über zwei Brutperioden hinweg untersuchten wir außerdem, ob es Zusammenhänge zwischen den Eierfärbungen und anderen Merkmalen der Weibchen und ihren "Investments" in die Eier gab. Innerhalb
Insect Coloration and Implications for Conservation
The Florida Entomologist, 1997
A BSTRACT Large, conspicuously colored insect taxa, due to associated logistical and anthropocentric biases in knowledge, public support and legislative consideration, are favored as targets of species protection, environmental monitors and education tools. They are also vulnerable to collection and perhaps, due to ecological specializations associated with apparency, to extinction. I discuss the implications for conservation.
Plastral Colour Fading of Pseudemys concinna Leconte 1830 (Testudines: Emydidae)
Journal of Veterinary Physiology and Pathology
Geometric techniques can be easily applied to many zoological problems, from recognizing subpopulations to studying sexual dimorphism. Pseudemys concinna (P. concinna) is a large terrapin species known as the Eastern River Cooter, native to North America. The hypothesis was to test if plastral pattern tends to fade with age. The present study applies geometric techniques to assess size in a sample of 20 fresh corpses of P. concinna (18 females and 2 males). Plastron color (red, blue, and green channels) was used to objectivize this fading pattern. A negative regression between size and color was registered, so the colour plastral intensity of P. concinna LeConte 1830 tends, effectively, to fade with age. Elucidating the cellular and chemical mediators and mechanisms of these slow color changes will likely require laboratory study.
Lizard blues: blue body colouration and ultraviolet polychromatism in lacertids
Understanding the evolution of conspicuous colour patterns has been a major challenge in evolutionary biology since Darwin's formulation of natural and sexual selection 150 years ago. A striking case of conspicuous colouration is the structural blue colour found in lizards belonging to several families, including lacertids (Lacertidae). Blue colouration can be restricted to discrete patches, as those found in the flanks or head of many lacertids, or can extend over large areas of the integument as in several insular populations of Lacertini. Recent research has shown that the blue flank and head patches of many lacertids have their peak of reflectance in the ultraviolet (UV) range. It has been suggested that these UV-blue patches may be part of a private (i.e. available only to receptors with UV vision) communication system. In contrast, nothing is known about the spectral characteristics of those species in which all or large portions of the body surface are blue. Using objecti...
Evolution, 2004
Pigmentation in the freshwater isopod Asellus aquaticus (Crustacea) differed between habitats in two Swedish lakes. In both lakes, isopods had lighter pigmentation in stands of submerged vegetation, consisting of stoneworts (Chara spp.), than in nearby stands of reed (Phragmites australis). Experimental crossings of light and dark isopods in a common environment showed that pigmentation had a genetic basis and that genetic variance was additive. Environmental effects of diet or chromatophore adjustment to the background had minor influence on pigmentation, as shown by laboratory rearing of isopods on stonewort or reed substrates, as well as analyses of stable isotope ratios for isopods collected in the field. In both study lakes, the average phenotype became lighter with time (across generations) in recently established stonewort stands. Taken together, these results indicate that altered phenotype pigmentation result from evolutionary responses to local differences in natural selection. Based on the assumption of two generations per year, the evolutionary rate of change in pigmentation was 0.08 standard deviations per generation (haldanes) over 20 generations in one lake and 0.22 haldanes over two generations in the other lake. This genetic change occurred during an episode of population growth in a novel habitat, a situation known to promote adaptive evolution. In addition, stonewort stands constitute large and persistent patches, characteristics that tend to preserve local adaptations produced by natural selection. Results from studies on selective forces behind the adaptive divergence suggest that selective predation from visually oriented predators is a possible selective agent. We found no indications of phenotype-specific movements between habitats. Mating within stonewort stands was random with respect to pigmentation, but on a whole-lake scale it is likely that mating is assortative, as a result of local differences in phenotype distribution.
Salamandra, 2018
Pelophylax esculentus is a vertebrate animal with hemiclonal heredity, attracting the interest of many reproductive and evolutionary biologists. It is a hybrid between P. ridibundus and P. lessonae. These three taxa form the so-called Pelophylax esculentus complex with a population structure usually comprising a hybrid taxa and one parental species. Data on population types at the southernmost distribution area of their sympatry are rare. Here we sampled five sites in inland Croatia in order to analyse the population structure, sex ratio and age structure. The individual genotypes of 93 randomly collected water frogs were verified with allozyme markers for three species-specific polymorphic loci. In order to estimate population age structure, the annual growth rate (skeletochronology) and growth index profiles were also investigated. The growth index profiles were analysed by an estimation of number of lines of arrested growth visible in the cross-section of femur bones. Our results...