The ecosystem within: A meta-analysis on the role of the microbiome on the behaviour of animals

Schetini de Azevedo, C ORCID: 0000-0003-0256-9017, Schork, IG ORCID: 0000-0002-1300-7602, Figueiredo Passos, L ORCID: 0000-0003-4529-9950, Goodhead, I ORCID: 0000-0002-3110-9442 and Young, RJ ORCID: 0000-0002-8407-2348 (2026) The ecosystem within: A meta-analysis on the role of the microbiome on the behaviour of animals. Animal Behaviour, 238. ISSN 0003-3472

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Abstract

The relationship between animal behaviour and host-associated microbiota has become an increasingly prominent research topic, yet associations remain inconsistent across studies and taxa. We conducted a meta-analysis to synthesize empirical evidence on the behavioural effects of microbiota manipulations of animals. Fifty-seven peer-reviewed articles were included in the meta-analysis. Using a multivariate random-effects model that accounted for study-level dependencies, we found a pooled Hedges’ g of 0.45 (95% confidence interval: 0.05–0.85), indicating a moderate overall positive effect of microbiota manipulation on behaviour. However, heterogeneity was high (I2 = 85%; τ2 = 1.66), reflecting the wide variability in taxa, dosages, experimental designs and behavioural domains. No evidence of publication bias was detected, and influence diagnostics confirmed the robustness of the pooled effect. Exploratory metaregressions suggested possible influences of taxonomic group (Diptera) and behavioural context (feeding-related), but these effects did not remain significant in comprehensive models. Likewise, ecological and biological factors, including habitat, diet, social organization, encephalization quotient and microbiome type (gut versus skin), did not systematically predict behavioural responses. Overall, behavioural modulation by microbiota manipulations appears independent of these host and study-level factors. Collectively, these findings demonstrate that microbiota interventions can modulate animal behaviour but also expose substantial methodological and taxonomic heterogeneity that limits generalization. Standardized reporting, finer microbial resolution and integrative experimental designs combining behavioural, microbial and mechanistic data are crucial for advancing a unified understanding of microbiota–behaviour interactions.

Item Type:	Article
Uncontrolled Keywords:	3109 Zoology; 31 Biological Sciences; Microbiome; 06 Biological Sciences; 07 Agricultural and Veterinary Sciences; 17 Psychology and Cognitive Sciences; Behavioral Science & Comparative Psychology; 30 Agricultural, veterinary and food sciences; 31 Biological sciences; 52 Psychology
Subjects:	Q Science > QL Zoology Q Science > QR Microbiology
Divisions:	Biological and Environmental Sciences (from Sep 19)
Publisher:	Elsevier
Date of acceptance:	5 May 2026
Date of first compliant Open Access:	25 July 2026
Date Deposited:	24 Jul 2026 13:18
Last Modified:	25 Jul 2026 00:50
DOI or ID number:	10.1016/j.anbehav.2026.123649
URI:	https://researchonline.ljmu.ac.uk/id/eprint/29060

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