Trophic niche structure of invertebrate-eating bats and birds in West African rice agroecosystems revealed by DNA metabarcoding

Tiago Morais Gonçalves , Patrícia Pereira Chaves, Paula Lopes, Christoph F.J. Meyer, Sérgio Timóteo, Miguel Lecoq, Ricardo F de Lima, Ricardo Rocha, Jorge M. Palmeirim, Vanessa Alves Mata, Ana Rainho

Knowledge of animal community diets is essential for understanding ecosystem functioning. Bats and birds are important groups of invertebrate predators, managing their populations. However, the diets of West African species and the mechanisms shaping them remain poorly understood. In this study, we investigated these mechanisms in agricultural landscapes of Guinea-Bissau using metabarcoding and next-generation sequencing. Specifically, we asked: 1) How do dietary breadth and composition vary among predator species and between bats and birds 2) How does dietary overlap vary within and between guilds? (3) To what extent is dietary dissimilarity associated with phylogeny?
We analysed the diet of 13 bat and eight bird species. Results revealed that Hemiptera (18.5%); Coleoptera (16.6%), Blattodea (15.8%), Lepidoptera (15.5%) and Orthoptera (11.4%) were the most consumed orders, with termites (Blattodea, Termitidae) standing out (8.2%). Based on OTU richness and sample-based rarefaction, all predators exhibited broad niches (99.7 ± 37.4 OTUs per predator species, on average), with bats generally exhibiting broader niches. Bats’ and birds’ diets differed significantly (ANOSIM R = 0.61, p = 0.001), possibly driven by differences in foraging periods. At the OTU level, birds displayed significant dietary segregation (Obirds = 0.05, p = 0.017), whereas some bats displayed significant dietary overlap (Obats = 0.23, p = 0.001), indicating low interspecific competition. However, we found no strong correlation between diet dissimilarity and phylogeny.
These findings provide insight into niche partitioning and may inform future assessments on the importance of the ecological role of bats and birds in West African agroecosystems.