Staying on board: synchronized behavioral switching allows phoretic nematodes to persist through host molting

Habitat turnover can temporarily eliminate the environments that organisms depend on, posing a major challenge to their persistence. For epibionts living on animal body surfaces, periodic renewal of the host integument during molting causes a sudden and complete loss of habitat. How such epibionts persist on the same host individual through these drastic events has remained elusive. Here, we show that phoretic nematodes associated with the subterranean termite Reticulitermes speratus maintain attachment throughout host molting by adopting a synchronized behavioral strategy. We isolated two phylogenetically distant species of phoretic nematodes, Oigolaimella sp. and Diplogastrellus sp., from this termite. Both species were primarily attached to the mouthparts (labium and maxillae) of the worker caste, which undergoes periodic molting. Quantitative analyses of nematode abundance and attachment sites across defined worker molting stages revealed that nematodes temporarily migrated into the foregut during the period surrounding ecdysis to avoid being shed with the molted exoskeleton, which is subsequently consumed by nestmates. Our findings reveal a behavioral strategy that enables epibionts to persist despite complete host surface renewal. More broadly, this study highlights coordinated spatial reallocation as an adaptive mechanism facilitating persistence in environments characterized by cyclical disturbance.