The Lovebug Effect: Is the human biophilic drive influenced by interactions between the host, the environment, and the microbiome?

Psychological frameworks are often used to investigate the mechanisms involved with our affinity towards, and connection with nature--such as the Biophilia Hypothesis and Nature Connectedness. Recent revelations from microbiome science suggest that animal behaviour can be strongly influenced by the host's microbiome--for example, via the bidirectional communication properties of the gut-brain axis. Here, we build on this theory to hypothesise that a microbially-influenced mechanism could also contribute to the human biophilic drive - the tendency for humans to affiliate and connect with nature. Humans may be at an evolutionary advantage through health-regulating exchange of environmental microbiota, which in turn could influence our nature affinity. We present a conceptual model for microbially-influenced nature affinity, calling it the Lovebug Effect. We present an overview of the potential mechanistic pathways involved in the Lovebug Effect, and consider its dependence on the hologenome concept of evolution, direct behavioural manipulation, and host-microbiota associated phenotypes independent of these concepts. We also discuss its implications for human health and ecological resilience. Finally, we highlight several possible approaches to scrutinise the hypothesis. The Lovebug Effect could have important implications for our understanding of exposure to natural environments for health and wellbeing, and could contribute to an ecologically resilient future.