Rhinella marina gut microbiota raw sequence reads

Invasive species cause negative environmental and economic impacts worldwide. Their management may be improved by clarifying the role of behaviours in advancing invasions. Gut microbial communities are known to affect behaviours in wild populations, but their impact on behaviours underlying invasiveness remain unexplored. Co-introduced to Australia with their native lungworm (Rhabdias pseudosphaerocephala), the cane toad (Rhinella marina) has expanded its range across northern Australia. Toads exhibit behavioural trait variation and variation in lungworm prevalence across their Australian range. We collected wild female toads from six locations in Queensland (n = 30) and Western Australia (n = 30) and conducted simple tests on behavioural traits previously associated with invasion ability. We investigated the relationships between toad gut microbiota, behavioural traits and lungworm presence in toad samples from both ends of their Australian range. Based on 16S rRNA sequencing data, we found that microbiota in cane toad colons were dominated by the phyla Bacteroidetes, Proteobacteria, Firmicutes, Verrucomicrobia, and Fusobacteria. We found significant differences in microbiota composition (p-value < 0.001) between regions and in predicted functional groups (p-value = 0.002). The occurrence of lungworms was strongly associated with variation in both microbial functional variation, but not microbial compositional variation. These results support the "holobiont concept", investigating the assemblage associated with a host, to fully understand drivers of invasion and highlight the need for experimental manipulations to detect causal relationships between microbiota, parasites and host behaviour.