Diet composition and related metal exposure in insectivorous passerines inhabiting metal-polluted areas

Diet composition and related metal exposure in insectivorous passerines inhabiting metal-polluted areas | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL Journal of Avian Biology This is a preprint and has not been peer reviewed. Data may be preliminary. 13 May 2026 V1 Latest version Share on Diet composition and related metal exposure in insectivorous passerines inhabiting metal-polluted areas Authors : H.A.S.Sewwandi Alwis 0009-0000-9760-6030 [email protected] , Lyydia Leino [email protected] , Eero Vesterinen [email protected] , Miia Rainio [email protected] , and Tapio Eeva [email protected] Authors Info & Affiliations https://doi.org/10.22541/authorea.15003286/v1 21 views 18 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Anthropogenic pollution impacts insectivorous birds through both direct chemical exposure and indirect trophic effects. Environmental contamination alters plant and invertebrate communities, causing dietary shifts in birds inhabiting polluted environments. We used nestling feces to examine metal exposure, prey composition and fledging success of Parus major, Cyanistes caeruleus and Ficedula hypoleuca, across control and metal-polluted zones near a copper-nickel smelter in Finland. Taxonomic identification with DNA metabarcoding revealed four arthropod classes, 14 orders, 65 families, 157 genera, and 162 species of arthropods across all the birds’ diets. Orders Hymenoptera, Lepidoptera, Diptera, Coleoptera, Hemiptera and family Formicidae dominated both zones. P. major diet exhibited the lowest Shannon diversity due to Lepidoptera specialization, while F. hypoleuca showed the highest observed richness, reflecting opportunistic foraging. Species-specific dietary profiles revealed pronounced shifts from control to polluted zones: P. major reduced Lepidoptera while increasing Diptera and Coleoptera; F. hypoleuca shifted balance from Hymenoptera to Lepidoptera and Diptera; C. caeruleus maintained a diverse diet with no single order dominating either zone. Permutational multivariate analysis of variance confirmed distinct diets among species in the control zone, but pollution significantly reduced interspecific dietary differences. Pianka's Index revealed substantial dietary overlap increases under pollution, most notably a fivefold increase between C. caeruleus and F. hypoleuca, demonstrating dietary convergence among species. Fledging success of P. major was negatively associated with metal levels and caterpillar scarcity; C. caeruleus maintained dietary evenness across zones, and fledging success was positively associated with dietary evenness; F. hypoleuca was resilient to variation in metal levels but showed reduced fledging success in the polluted area despite increased dietary richness, suggesting reliance on less optimal prey. Together, these results demonstrate that heavy metal pollution restructures food webs, forcing higher dietary overlap and potentially escalating interspecific competition for remaining high-quality resources. Supplementary Material File (supporting_information.pdf) supporting_information Download 1.00 MB Information & Authors Information Version history V1 Version 1 13 May 2026 Collection Journal of Avian Biology Keywords Air pollution Heavy metals Metabarcoding Nestling diet Insects Diet shift eco-immunology maternal effects hormones life-history ageing Authors Affiliations H.A.S.Sewwandi Alwis 0009-0000-9760-6030 [email protected] University of Turku, Turku, Finland View all articles by this author Lyydia Leino [email protected] University of Turku, Turku, Finland View all articles by this author Eero Vesterinen [email protected] University of Turku, Turku, Finland View all articles by this author Miia Rainio [email protected] University of Turku, Turku, Finland View all articles by this author Tapio Eeva [email protected] University of Turku, Turku, Finland View all articles by this author Metrics & Citations Metrics Article Usage 21 views 18 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation H.A.S.Sewwandi Alwis, Lyydia Leino, Eero Vesterinen, et al. Diet composition and related metal exposure in insectivorous passerines inhabiting metal-polluted areas. Authorea . 13 May 2026. DOI: https://doi.org/10.22541/authorea.15003286/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . 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