341 research outputs found

    Longer wings for faster springs – wing length relates tospring phenology in a long-distanc e migrant across its range

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    In migratory birds, morphological adaptations for efficient migratory flight often oppose morphological adaptations for efficient behavior during resident periods. This includes adaptations in wing shape for either flying long distances or foraging in the vegetation and in climate-driven variation of body size. In addition, the timing of migratory flights and particularly the timely arrival at local breeding sites is crucial because fitness prospects depend on site-specific phenology. Thus, adaptations for efficient long-distance flights might be also related to conditions at destination areas. For an obligatory long-distance migrant, the common nightingale, we verified that wing length as the aerodynamically important trait, but not structural body size increased from the western to the eastern parts of the species range. In contrast with expectation from aerodynamic theory, however, wing length did not increase with increasing migration distances. Instead, wing length was associated with the phenology at breeding destinations, namely the speed of local spring green-up. We argue that longer wings are beneficial for adjusting migration speed to local conditions for birds breeding in habitats with fast spring green-up and thus short optimal arrival periods. We suggest that the speed of spring green-up at breeding sites is a fundamental variable determining the timing of migration that fine tune phenotypes in migrants across their range

    The effect of social structure on vocal flexibility in monk parakeets

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    The social complexity hypothesis argues that communicative complexity arises as a result of social complexity, with this occurring through mechanisms including plasticity and selection. Most research to date has focused on ultimate drivers of repertoire size, for example finding that cooperative breeding species exhibit larger repertoires. Until this date, to our knowledge, no study has focused on individual-level drivers of vocal diversity. Here, we examine social networks and vocalizations in wild colonial-nesting monk parakeets (Myiopsitta monachus). We recorded social networks for 337 individuals, relatedness for 100 individuals and matched these with 5599 vocalizations from 229 individuals over 2 years. Overall, we found that all individuals exhibited high contact-call diversity; however, individual-level diversity increased with age in 2020 and with number of nest mates in 2021. Call similarity was not predicted by relatedness, but individuals with stronger affiliative bonds had more dissimilar calls, suggesting an active process to sound unique among close associates. Finally, females had more diverse repertoires, producing relatively fewer contact calls across years and individuals living in larger groups had more diverse repertoires in 2021. Our results demonstrate a multi-faceted social influence on call content, diversity and repertoire diversity, exhibiting how fine-scale variation in social structure can influence expressed vocal complexity

    Evidence for vocal signatures and voice-prints in a wild parrot

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    In humans, identity is partly encoded in a voice-print that is carried across multiple vocalizations. Other species also signal vocal identity in calls, such as shown in the contact call of parrots. However, it remains unclear to what extent other call types in parrots are individually distinct, and whether there is an analogous voice-print across calls. Here we test if an individual signature is present in other call types, how stable this signature is, and if parrots exhibit voice-prints across call types. We recorded 5599 vocalizations from 229 individually marked monk parakeets (Myiopsitta monachus) over a 2-year period in Barcelona, Spain. We examined five distinct call types, finding evidence for an individual signature in three. We further show that in the contact call, while birds are individually distinct, the calls are more variable than previously assumed, changing over short time scales (seconds to minutes). Finally, we provide evidence for voice-prints across multiple call types, with a discriminant function being able to predict caller identity across call types. This suggests that monk parakeets may be able to use vocal cues to recognize conspecifics, even across vocalization types and without necessarily needing active vocal signatures of identity. © 2023 The Authors

    Dades de plantes al·lòctones per a l’est de la península Ibèrica

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    With the observations of the last years in the east of the Iberian Peninsula (specifically in Catalonia, Valencian Country and the Teruel province), records of 41 naturalized or casual alien plants are reported. It is worth noting Annona cherimola and Manihot grahamii that are reported for first time in the Iberian flora; Echinopsis pachanoi and Hydrocotyle verticillata for Catalonia; Solandra maxima for Valencian Country. Opuntia pestifer must be excluded from the Valencian flora, and it is confirmed that the previous data correspond to Opuntia aurantiaca. In addition, new localities of Acacia karroo, Cylindropuntia kleiniae, Euphorbia tirucalli, Leucaena leucocephala, Lophocereus marginatus, Nicandra physalodes, Pelargonium inquinans, Physalis peruviana, Podranea ricasoliana, Sedum pachyphyllum, Senna corymbosa, Tradescantia pallida and Tradescantia sillamontana, interesting and few known species in the eastern Iberian alien flora are provided.Con las observaciones de los últimos años en el este de la península ibérica (concretamente en Cataluña, País Valenciano y la provincia de Teruel), se aportan un conjunto de datos corológicos de 41 plantas alóctonas naturalizadas u ocasionales. Cabe destacar Annona cherimola y Manihot grahamii que se citan por primera vez en la flora ibérica; Echinopsis pachanoi y Hydrocotyle verticillata para Cataluña; Solandra maxima en el País Valenciano. Se tiene que excluir Opuntia pestifer de la flora valenciana, ya que se confirma que las citas anteriores corresponden a Opuntia aurantiaca. Además, se aportan nuevas localidades de Acacia karroo, Cylindropuntia kleiniae, Euphorbia tirucalli, Leucaena leucocephala, Lophocereus marginatus, Nicandra physalodes, Pelargonium inquinans, Physalis peruviana, Podranea ricasoliana, Sedum pachyphyllum, Senna corymbosa, Tradescantia pallida y Tradescantia sillamontana, táxones interesantes y poco conocidos en la flora alóctona del este ibérico. [ca] Amb les observacions dels darrers anys fetes a l’est de la península Ibèrica (concretament a Catalunya, País Valencià i la província de Terol), s’aporten un conjunt de dades corològiques de 41 plantes al·lòctones naturalitzades o ocasionals. Cal destacar Annona cherimola i Manihot grahamii que es citen per primera vegada a la flora ibèrica; Echinopsis pachanoi i Hydrocotyle verticillata per a Catalunya; Solandra maxima per al País Valencià. Cal excloure Opuntia pestifer de la flora valenciana, ja que es confirma que les cites anteriors corresponen a Opuntia aurantiaca. A més a més, s’aporten noves localitats de Acacia karroo, Cylindropuntia kleiniae, Euphorbia tirucalli, Leucaena leucocephala, Lophocereus marginatus, Nicandra physalodes, Pelargonium inquinans, Physalis peruviana, Podranea ricasoliana, Sedum pachyphyllum, Senna corymbosa, Tradescantia pallida i Tradescantia sillamontana, tàxons interessants i poc coneguts a la flora al·lòctona de l’est ibèric

    Comparing prey composition and prey size delivered to nestlings by great tits, Parus major, and blue tits, Cyanistes caeruleus, in a Mediterranean sclerophyllous mixed forest

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    Resource partitioning is a central issue in ecology because it can establish to which point similar species can coexist in the same habitat. Great tits and blue tits have been classical model species in studies of trophic competence. However, most studies on the topic have been conducted at localities where caterpillars are by far the most relevant prey brought to the nestlings. In Mediterranean mixed forests, nevertheless, the abundance of caterpillars is relatively low and it is spiders that play a key role in the diet of great tits, at least for nestlings. The aim of this paper was to study nest food provisioning to establish the degree of diet overlap of these two tit species in a Mediterranean forest. Our results showed that blue tit feeding rates were higher than those of great tits, probably to compensate for the smaller prey delivered to nestlings by blue tits. Blue tits brought more spiders than great tits, while grey tits brought larger prey and more caterpillars. This may be because larger great tits can prey upon larger prey items than blue tits. As a main result, this study supports the view of resource partitioning by great and blue tits in sclerophyllous Mediterranean forest ecosystem

    The reproductive capacity of Monk Parakeets Myiopsitta monachus is higher in their invasive range

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    Breeding parameters for Monk Parakeets Myiopsitta monachus nesting in Barcelona, Spain, were collected for 651 nests over five breeding seasons. This invasive population has a high reproductive capacity compared with the species in the native range: fledging success was double, the percentage of pairs attempting second broods three times higher and 55% of first-year birds bred compared with almost zero in South America

    Fine‐scale genetic structure reflects limited and coordinated dispersal in the colonial monk parakeet, Myiopsitta monachus

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    The genetic structure of animal populations has considerable behavioural, ecological and evolutionary implications and may arise from various demographic traits. Here, we use observational field data and molecular genetics to determine the genetic structure of an invasive population of monk parakeets, Myiopsitta monachus, at a range of spatial scales, and investigate the demographic processes that generate the observed structure. Monk parakeets construct large nests that can house several pairs occupying separate chambers; these nests are often aggregated within nesting trees. We determined patterns of relatedness within compound nests, within nesting trees and between trees. Spatial autocorrelation analyses of pairwise genetic relatedness revealed fine‐scale genetic structure with relatives of both sexes spatially clustered within, but not beyond, nesting trees. In addition, males were more related to males sharing their compound nests than to other males occupying the same nesting tree. By contrast, males and females within compound nests were not significantly more closely related than elsewhere in the same tree, and we found no evidence for inbreeding. Adults showed high breeding site fidelity between years despite considerable disturbance of nest sites. Natal dispersal was female‐biased, but dispersal distances were relatively short with some natal philopatry observed in both sexes. Sibling coalitions, typically of males, were observed amongst both philopatric and dispersing birds. Our results show significant clustering of kin within compound nests and nesting trees resulting from limited and coordinated natal dispersal, with subsequent breeding site fidelity. The resulting genetic structure has implications for social behaviour in this unusual parrot species

    The role of clonal communication and heterogeneity in breast cancer

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    Background: Cancer is a rapidly evolving, multifactorial disease that accumulates numerous genetic and epigenetic alterations. This results in molecular and phenotypic heterogeneity within the tumor, the complexity of which is further amplified through specific interactions between cancer cells. We aimed to dissect the molecular mechanisms underlying the cooperation between different clones. Methods: We produced clonal cell lines derived from the MDA-MB-231 breast cancer cell line, using the UbC-StarTrack system, which allowed tracking of multiple clones by color: GFP C3, mKO E10 and Sapphire D7. Characterization of these clones was performed by growth rate, cell metabolic activity, wound healing, invasion assays and genetic and epigenetic arrays. Tumorigenicity was tested by orthotopic and intravenous injections. Clonal cooperation was evaluated by medium complementation, co-culture and co-injection assays. Results: Characterization of these clones in vitro revealed clear genetic and epigenetic differences that affected growth rate, cell metabolic activity, morphology and cytokine expression among cell lines. In vivo, all clonal cell lines were able to form tumors; however, injection of an equal mix of the different clones led to tumors with very few mKO E10 cells. Additionally, the mKO E10 clonal cell line showed a significant inability to form lung metastases. These results confirm that even in stable cell lines heterogeneity is present. In vitro, the complementation of growth medium with medium or exosomes from parental or clonal cell lines increased the growth rate of the other clones. Complementation assays, co-growth and co-injection of mKO E10 and GFP C3 clonal cell lines increased the efficiency of invasion and migration. Conclusions: These findings support a model where interplay between clones confers aggressiveness, and which may allow identification of the factors involved in cellular communication that could play a role in clonal cooperation and thus represent new targets for preventing tumor progression
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