Publications by authors named "Knud A Jonsson"

The parasite island syndrome denotes shifts in parasite life histories on islands, which affect parasite diversity, prevalence and specificity. However, current evidence of parasite island syndromes mainly stems from oceanic islands, while sky islands (i.e.

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Termites are important ecosystem engineers and play key roles in modulating microbial communities within and outside their mounds. Microbial diversity within termite mounds is generally lower than surrounding soils, due to termite-associated antimicrobial compounds and active sanitary behaviours. Microbial symbionts of termites can also influence the microbial landscape, by inhibiting or out-competing other microbes.

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Uropygial gland secretions of birds consist of host and bacteria derived compounds and play a major sanitary and feather-protective role. Here we report on our microbiome studies of the New Guinean toxic bird Pachycephala schlegelii and the isolation of a member of the Amycolatopsis genus from the uropygial gland secretions. Bioactivity studies in combination with co-cultures, MALDI imaging and HR-MS/MS-based network analyses unveil the basis of its activity against keratinolytic bacteria and fungal skin pathogens.

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Sexual selection can directly contribute to reproductive isolation and is an important mechanism that can lead to speciation. Lek-mating is one of the most extreme forms of sexual selection, but surprisingly does not seem to preclude occasional hybridization in nature. However, hybridization among lekking species may still be trivial if selection against offspring with intermediate phenotypes prohibits introgression.

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The family Melampittidae is endemic to New Guinea and consists of two monotypic genera: Melampitta lugubris (Lesser Melampitta) and Megalampitta gigantea (Greater Melampitta). Both Melampitta species have scattered and disconnected distributions across New Guinea in the central mountain range and in some of the outlying ranges. While M.

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The processes generating the earth's montane biodiversity remain a matter of debate. Two contrasting hypotheses have been advanced to explain how montane populations form: via direct colonization from other mountains, or, alternatively, via upslope range shifts from adjacent lowland areas. We seek to reconcile these apparently conflicting hypotheses by asking whether a species' ancestral geographic origin determines its mode of mountain colonization.

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  • β-Amino acid-containing macrolactams are bioactive compounds derived from polyketides, but there's limited understanding of their prevalence and biosynthetic diversity among bacteria.
  • This study used a specialized search method to find bacterial strains capable of producing these macrolactams, revealing that about 10% of certain actinobacterial genera have the necessary gene cluster for macrolactam production.
  • The research identified mutations in polyketide synthases as key factors influencing macrolactam diversity, validated known producers like ciromicin A, and discovered new variants of macrotermycins, enhancing methods for future macrolactam discovery.
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Gut microbial communities are complex and heterogeneous and play critical roles for animal hosts. Early-life disruptions to microbiome establishment can negatively impact host fitness and development. However, the consequences of such early-life disruptions remain unknown in wild birds.

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  • - Tropical islands serve as crucial sites for studying evolution, particularly in understanding how species colonize, diversify, and go extinct in unique ecosystems.
  • - The island thrush, a highly variable songbird, is one of the largest examples of an island radiation, showcasing significant plumage differences and a wide geographical distribution across the Indo-Pacific.
  • - Research utilizing genetic data indicates that the island thrush evolved from migratory ancestors and rapidly spread during the Pleistocene, raising questions about its movement patterns and adaptations to various environments in the region.
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  • - Toxicity has developed independently in various species for purposes like hunting, defense, and deterring parasites, with toxins sourced from the organism itself, symbionts, or diet.
  • - Researchers found that New Guinean toxic birds, which have evolved adaptations to tolerate the potent neurotoxin batrachotoxin (BTX), possess mutations in the SCN4A gene that enhance their resistance by reducing BTX's binding effect on crucial muscle channels.
  • - The study highlights a new diversity of toxic bird species and illustrates convergent evolution, showing how both birds and poison dart frogs have adapted at the molecular level to handle the same neurotoxin through changes in their Nav1.4 channels.
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Advances in tracking technology have helped elucidate the movements of the planet's largest and most mobile species, but these animals do not represent faunal diversity as a whole. Tracking a more diverse array of animal species will enable testing of broad ecological and evolutionary hypotheses and aid conservation efforts. Small and sedentary species of the tropics make up a huge part of earth's animal diversity and are therefore key to this endeavor.

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  • Subarctic caves are vulnerable to climate change, and this study aimed to understand the nutrient availability and biodiversity of their ecosystems by examining environmental factors and biological communities in six caves in Northern Norway.
  • Researchers found that cave ecosystems had low diversity of surface-dwelling invertebrates but higher diversity and complexity in bacterial communities compared to surface soil, with notable stability across caves due to harsher conditions.
  • The study indicates that changes in the environment, such as accelerated snowmelt due to global warming, could disrupt these unique cave ecosystems and their intricate microbial interactions, emphasizing the need for further research on their long-term biodiversity.
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Biological specimens in natural history collections constitute a massive repository of genetic information. Many specimens have been collected in areas in which they no longer exist or in areas where present-day collecting is not possible. There are also specimens in collections representing populations or species that have gone extinct.

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Tropical bird species are characterized by a comparatively slow pace of life, being predictably different from their temperate zone counterparts in their investments in growth, survival and reproduction. In birds, the development of functional plumage is often considered energetically demanding investment, with consequences on individual fitness and survival. However, current knowledge of interspecific variation in feather growth patterns is mostly based on species of the northern temperate zone.

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  • Haemosporidians are common bird parasites that affect host fitness, and their impact varies across different spatial scales (local to global).
  • The study investigates how both abiotic factors (like temperature and forest structure) and the ecological context (canopy vs. understory) influence haemosporidian prevalence in birds in Papua New Guinea's fragmented and continuous forests.
  • The findings indicate that infection levels are higher in specific bird habitats (canopy), and suggest that different bird species experience varying parasite pressures based on their environment and community interactions.
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  • Scientists need to classify species correctly to help protect endangered animals, and genomics (studying genes) is a great tool for this!*
  • The study looked at museum specimens of orioles to understand the relationship between the endangered silver oriole and others in its family, finding that the silver oriole is indeed a separate species.*
  • This research shows how using genetics and historical samples can help save endangered species and suggests that the classification of related birds, like the maroon oriole, needs to be updated.*
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The composition of gut bacterial communities is strongly influenced by the host diet in many animal taxa. For birds, the effect of diet on the microbiomes has been documented through diet manipulation studies. However, for wild birds, most studies have drawn on literature-based information to decipher the dietary effects, thereby, overlooking individual variation in dietary intake.

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Tropical mountains harbor exceptional concentrations of Earth's biodiversity. In topographically complex landscapes, montane species typically inhabit multiple mountainous regions, but are absent in intervening lowland environments. Here we report a comparative analysis of genome-wide DNA polymorphism data for population pairs from eighteen Indo-Pacific bird species from the Moluccan islands of Buru and Seram and from across the island of New Guinea.

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Birds harbor complex gut bacterial communities that may sustain their ecologies and facilitate their biological roles, distribution, and diversity. Research on gut microbiomes in wild birds is surging and it is clear that they are diverse and important - but strongly influenced by a series of environmental factors. To continue expanding our understanding of how the internal ecosystems of birds work in their natural settings, we believe the most pressing needs involve studies on the functional and evolutionary aspects of these symbioses.

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It is a broadly observed pattern that the non-recombining regions of sex-limited chromosomes (Y and W) accumulate more repeats than the rest of the genome, even in species like birds with a low genome-wide repeat content. Here, we show that in birds with highly heteromorphic sex chromosomes, the W chromosome has a transposable element (TE) density of greater than 55% compared to the genome-wide density of less than 10%, and contains over half of all full-length (thus potentially active) endogenous retroviruses (ERVs) of the entire genome. Using RNA-seq and protein mass spectrometry data, we were able to detect signatures of female-specific ERV expression.

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Animal hosts have evolved intricate associations with microbial symbionts, where both depend on each other for particular functions. In many cases, these associations lead to phylosymbiosis, where phylogenetically related species harbour compositionally more similar microbiomes than distantly related species. However, evidence for phylosymbiosis is either weak or lacking in gut microbiomes of flying vertebrates, particularly in birds.

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Hybridization, introgression, and reciprocal gene flow during speciation, specifically the generation of mitonuclear discordance, are increasingly observed as parts of the speciation process. Genomic approaches provide insight into where, when, and how adaptation operates during and after speciation and can measure historical and modern introgression. Whether adaptive or neutral in origin, hybridization can cause mitonuclear discordance by placing the mitochondrial genome of one species (or population) in the nuclear background of another species.

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Background: Gut microbial communities play important roles in nutrient management and can change in response to host diets. The extent of this flexibility and the concomitant resilience is largely unknown in wild animals. To untangle the dynamics of avian-gut microbiome symbiosis associated with diet changes, we exposed Parus major (Great tits) fed with a standard diet (seeds and mealworms) to either a mixed (seeds, mealworms and fruits), a seed, or a mealworm diet for 4 weeks, and examined the flexibility of gut microbiomes to these compositionally different diets.

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