Biology subjects

Warudkar, A.

Publications and source records attributed to Warudkar, A..

4 recordsLinked to original sources

bioRxiv2025

Distinct, asynchronous processes underlie cultural and genetic variation in a bird species with a complex song repertoire

Dialects in birdsongs represent population clusters and cultural diversity. Cultural and genetic variation in animals, however, do not always evolve along the same trajectory. Few studies have tested this in a wild songbird with a continuous learning strategy. Songbirds (oscine Passeriformes) with a continual learning window exhibit great song diversity and may show cultural differentiation that outpaces genetic divergence. We investigate cultural and genetic variation in a tropical endemic songbird in a topographically and climatically complex sky-island landscape of the Western Ghats of India. We combine fine-scale acoustic, behavioural, and genetic data: from 90 individuals (10,816 songs), analysed using frequency-temporal parameters and a linguistic method for syntax; a playback experiment with 136 trials to compare behavioural responses to local and non-local songs; and blood samples from 242 individuals (10,638 SNPs) to infer genetic population structure. We find no difference in songs across locations and individuals in the time-frequency domain, but only in syntax. One-third of notes, the smallest vocal units, are widely shared across all individuals in their distribution. Longer note combinations result in greater individual differences within populations, but only form small differences between populations. Geographic distance strongly predicts genetic but not song syntactic differences, and playback experiments show equal responses to local and non-local songs. Thus, strong individual signatures but weak local-level dialects are generated by a shared note repertoire and associated combinatorial syntax. We highlight that cultural transmission may operate at fine social scales, decoupled from genetic structure, which is strongly driven by isolation-by-distance. Significance statementWhether learned behaviours exhibit patterns similar to those of inherited genes remains a long-standing question in evolutionary biology. Birdsong has a strong cultural component paralleling human language, yet most knowledge comes from birds with a narrow learning window. Open-ended learners, who acquire new songs throughout life like humans, are poorly documented in the wild. We studied such a songbird restricted to the tropical cloud montane forests of southern India. Songs appear acoustically similar across populations but differ in how basic units are ordered (syntax), while individuals are more distinct from each other in longer note combinations than populations are. Genetic similarity decreased with geographic distance. Culturally learned traits can thus evolve independently of genetic structure, showing how learning decouples behaviour from geography-driven genetic ancestry.

evolutionary biology↗

bioRxiv2025

Genome assemblies for seven families of birds from the Global South

Tropical regions are biodiversity-rich, yet remain underrepresented in the availability of genomic resources, as is evident in the Western Ghats of India, a biodiversity hotspot with high endemism. Here, we present high-quality, de novo genome assemblies for seven birds, representing seven families distributed in the Western Ghats: Black-naped Monarch (Monarchidae: Hypothymis azurea), Indian Yellow Tit (Paridae: Machlolophus aplonotus), Brown-cheeked Fulvetta (Leiothrichidae: Alcippe poioicephala), Malabar Trogon (Trogonidae: Harpactes fasciatus), Blue-bearded Bee-eater (Meropidae: Nyctyornis athertoni), Malabar Whistling-Thrush (Muscicapidae: Myophonus horsfieldii), Orange-headed Thrush (Turdidae: Geokichla citrina). Using a hybrid Oxford Nanopore long reads - Illumina short reads approach, we assembled genomes with sizes ranging from 1.03 to 1.13 Gbp. All assemblies demonstrated high contiguity and completeness (BUSCO scores >97%, UCEs >4799). Repeat masking identified [~]10% of the genomes as interspersed repeats, and functional annotations yielded an average of 9,619 protein-coding genes per species. Comparative analysis showed our assemblies had significantly higher contiguity than the median of existing avian genomes on NCBI (Wilcoxson test, p = 0.00226). Our genome assemblies fill a key geographic and taxonomic gap in the genomic data and provide a foundational resource for evolutionary and ecological research in the Old-World tropics.

genomics↗

bioRxiv2025

Host niche breadth differentially modulates the effects of anthropogenic disturbance across generalist and specialist parasites

Anthropogenic disturbances in natural habitats increase the risk of emerging infectious diseases in free-ranging host communities. Hence, understanding the processes driving such patterns is critical towards One Health. While anthropogenic disturbance is known to promote habitat-generalist host species through biotic homogenisation, generalist parasites (wider host breadth) also respond positively to the disturbed habitats. We hypothesise that generalist parasites are more likely to infect generalist hosts. We tested this hypothesis in a sky island system where generalist (Plasmodium) and specialist (Haemoproteus) haemosporidian parasites infect a range of bird hosts in disturbed and natural forest patches. We used a natural experiment framework to control for climatic differences (similar elevation) and habitat quality (same habitat type, but varying disturbance matrix). We collected 1106 samples from the field and examined the genus-level parasite prevalence and the host specificity of individual parasite lineages. Our results suggest that the generalist (Plasmodium) parasites are more prevalent in generalist birds, irrespective of disturbance. However, the specialist (Haemoproteus) parasites were more prevalent in specialist birds in natural forests than in disturbed forests. Among the individual parasite lineages, we found the host specificity to be associated with the degree of habitat specialisation of their host species. Our results provide evidence for the tendency of generalist parasites to infect generalist host species - a potential mechanism for a higher risk of emerging infectious diseases in human-dominated regions. We emphasise the role of host ecology in understanding the impact of anthropogenic disturbance on parasite prevalence in free-ranging host communities.

ecology↗

bioRxiv2024

State of India's Birds 2023: A framework to leverage semi-structured citizen science for bird conservation

Birds and their habitats are threatened with extinction around the world. Regional assessments of the State of Birds are a vital means to prioritize data-driven conservation action by informing national and global policy. Such evaluations have traditionally relied on data derived from extensive, long-term, systematic surveys that require significant resources, limiting their feasibility to a few regions in the world. In the absence of such structured long-term datasets, semi-structured datasets have recently emerged as a promising alternative in other regions around the world. Semi-structured data are generated and uploaded by birdwatchers to citizen science platforms like eBird. Such data contain inherent biases because birdwatchers are not required to adhere to a fixed protocol. An evaluation of the status of birds from semi-structured data is therefore a difficult task that requires careful curation of data and the use of robust statistical methods to reduce errors and biases. In this paper, we present a methodology that was developed for this purpose, and was applied to produce the comprehensive State of Indias Birds (SoIB) 2023 report. SoIB 2023 assessed the status of 942 bird species in India by evaluating each species based on three metrics: 1) long-term change: change in abundance between the year 2022 and the year-interval pre-2000; 2) current annual trend: mean annual change in abundance from 2015 to 2022; and 3) distribution range size. We found evidence that 204 species have declined in the long term, and 142 species are currently declining. We present and discuss important insights about Indias birds that can guide research and conservation action in the region. We hope that the detailed methodology described here can act as a blueprint to produce State of Birds assessments from semi-structured citizen science datasets and springboard conservation action in many other regions where structured data is lacking but strong communities of birders exist. Open Research StatementThe primary data are already publicly available on eBird (Sullivan et al. 2014), and other data are already published in a GitHub repository (stateofindiasbirds 2024).

ecology↗