摘要: Recent phylogenetic studies amended the taxonomy of three-toed jerboas (subfamily Dipodinae), including raising subspecies to full species. Here, we use geometric morphometrics to compare scaled-shape differences in dipodine crania while considering their revised taxonomy. We sampled Dipus deasyi, D. sagitta halli, D. s. sowerbyi, Jaculus blanfordi blanfordi, J. hirtipes, J. jaculus, J. loftusi, J. orientalis gerboa, J. o. mauritanicus, and Stylodipus andrewsi. Crania were not sexually dimorphic. Common allometry explained some of the shape variation, for example, reduced braincases in larger specimens. Most operational taxonomic unit pairs differed in both size and shape. Dipus and Stylodipus clustered together based on their cranial shape. Jaculus differed from the aforementioned genera by its larger tympanic bulla, broader braincase, larger infraorbital foramen, along with reduced molars and rostra. Jaculus orientalis differed from other Jaculus by its broader face versus reduced cranial vault. Jaculus blanfordi (subgenus Haltomys) resembles members of the subgenus Jaculus more than its consubgener (J. orientalis). Jaculus loftusi, previously considered a synonym of J. jaculus, clearly differed from the latter by its shorter rostrum, smaller infraorbital foramen, and more caudolaterally expanded tympanic bulla. Jaculus hirtipes, another recent synonym of J. jaculus, resembled J. blanfordi more in scaled cranial shape than it did J. jaculus. Dipus sagitta halli and D. s. sowerbyi were indistinguishable, but they clearly differed from D. deasyi (recently raised to full species) with the latter having a larger molar row, more inflated tympanic bulla, and shorter, slenderer rostrum. Ecological explanations for detected cranial shape differences are considered, including diet and habitat (particularly substrate).

摘要: Bird songs are considered a sexually selected trait that can reflect the individual health of males as well as the vitality of potential mates and their competitors. Vocalization features should, therefore, be related to parasite load and body condition. Here, we performed a thorough acoustic analysis of the display calls of 9-month-old sub-adults and 18-month-old adults of pasture-raised red junglefowls Gallus gallus. We investigated whether the calls of pasture-raised red junglefowls can indicate body size and body condition, in addition to the influence of parasitic infection intensity on the expression of sexual traits. We found that frequency-related syllable parameters were significantly positively correlated with wing length in adults, whereas body weight was independent of both the frequency and temporal parameters of calls. In addition, we correlated parasitic load with the expression of sexually selected traits and discovered a positive association between the intensity of parasite infection and wing length in sub-adults, independent of vocal parameters. Overall, the results suggest that the vocalization of red junglefowls may convey reliable body size information, which will facilitate further studies of different vocal parameters in the transmission of bird vocalizations.

摘要: Clonal organisms are particularly useful to investigate the contribution of epigenetics to phenotypic plasticity, because confounding effects of genetic variation are negligible. In the last decade, the apomictic parthenogenetic marbled crayfish, Procambarus virginalis, has been developed as a model to investigate the relationships between phenotypic plasticity and genetic and epigenetic diversity in detail. This crayfish originated about 30 years ago by autotriploidy from a single slough crayfish Procambarus fallax. As the result of human releases and active spreading, marbled crayfish has established numerous populations in very diverse habitats in 22 countries from the tropics to cold temperate regions. Studies in the laboratory and field revealed considerable plasticity in coloration, spination, morphometric parameters, growth, food preference, population structure, trophic position, and niche width. Illumina and PacBio whole-genome sequencing of marbled crayfish from representatives of 19 populations in Europe and Madagascar demonstrated extremely low genetic diversity within and among populations, indicating that the observed phenotypic diversity and ability to live in strikingly different environments are not due to adaptation by selection on genetic variation. In contrast, considerable differences were found between populations in the DNA methylation patterns of hundreds of genes, suggesting that the environmentally induced phenotypic plasticity is mediated by epigenetic mechanisms and corresponding changes in gene expression. Specific DNA methylation fingerprints persisted in local populations over successive years indicating the existence of epigenetic ecotypes, but there is presently no information as to whether these epigenetic signatures are transgenerationally inherited or established anew in each generation and whether the recorded phenotypic plasticity is adaptive or nonadaptive.

摘要: Altricial birds often display biased preferences in providing parental care for their dependent offspring, especially during food shortages. During this process, such inflexible rules may result in provisioning errors. To demonstrate how parents optimize their provisioning strategies, we proposed a diagnosis model of parental care to posit that parents will undergo a diagnosis procedure to test whether selecting against some particular offspring based on phenotype is an optimal strategy. We tested this model in an asynchronous hatching bird, the Azure-winged Magpie Cyanopica cyanus, based on 10 years of data about demography and parental provisioning behaviors. Given their higher daily survival rates, core offspring (those hatched on the first day) merits an investment priority compared with their marginal brood mates (those hatched on later days). However, a marginal offspring also merited a priority if it displayed greater weight gain than the expected value at the early post-hatching days. Parents could detect such a marginal offspring via a diagnosis strategy, in which they provisioned the brood at the diagnosis stage by delivering food to every nestling that begged, then biased food toward high-value nestlings at the subsequent decision stage by making a negative response to the begging of low-value nestlings. In this provisioning strategy, the growth performance of a nestling became a more reliable indicator of its investment value than its hatching order or competitive ability. Our findings provide evidence for this diagnosis model of parental care wherein parents use a diagnosis method to optimize their provisioning strategy in brood reduction.

摘要: Carotenoid-based ornaments are often considered reliable (honest) individual condition signals because their expression implies physiological costs unaffordable for low-quality animals (handicap signals). Recently, it has been suggested that efficient cell respiration is mandatory for producing red ketocarotenoids from dietary yellow carotenoids. This implies that red colorations should be entirely unfalsifiable and independent of expression costs (index signals). In a precedent study, male common crossbills, Loxia curvirostra, showing a red plumage reported higher apparent survival than those showing yellowish-orange colors. The plumage redness in this species is due to ketocarotenoid accumulation in feathers. Here, we correlated the male plumage redness (a 4-level visual score: yellow, patchy, orange, and red) and the body morphology in more than 1,000 adult crossbills captured in 3 Iberian localities to infer the mechanisms responsible for color evolution. A principal component analysis summarized morphometry of 10 variables (beak, wing, tarsus length, etc.). The overall body size (PC1) and the length of flight feathers regarding body size (PC3) showed significant positive relationships with plumage redness. Plumage redness was barely correlated with bill shape measures, suggesting no constraint in acquiring carotenoids from pine cones. However, large body sizes or proportionally long flying feathers could help carotenoid acquisition via social competition or increased foraging ranges. Proportionally longer flight feathers might also be associated with a specific cell respiration profile that would simultaneously favor flying capacities and enzymatic transformations needed for ketocarotenoid synthesis. Such a phenotypic profile would agree with the hypothesis of ketocarotenoid-based colors acting as individual quality index signals.